193 results on '"Tempestite"'
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2. 鄂尔多斯盆地西缘徐庄组风暴沉积特征及沉积模式.
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师宇翔, 路向伟, 李国斌, 方泽鑫, 徐凯, 杨永祯, 张寰萌, and 郭岭
- Abstract
Copyright of Acta Sedimentologica Sinica is the property of Acta Sedimentologica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...
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- 2024
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3. Characteristics and sedimentary geological significance of tempestites in first member of Lower Cambrian Canglangpu Formation in north central Sichuan Basin
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Lizhou TIAN, Jinmin SONG, Yuehao YE, Shugen LIU, Zhiwu LI, Xin JIN, Di YANG, Lingli ZHAO, Yi DING, Jiaxin REN, Han WANG, Keran LI, and Haoshuang DENG
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storm sedimentation ,sedimentation model ,sedimentation sequence ,tempestite ,canglangpu formation ,lower cambrian ,north central sichuan basin ,Geophysics. Cosmic physics ,QC801-809 ,Geology ,QE1-996.5 - Abstract
Tempestite has been discovered in the Lower Cambrian Canglangpu Formation in the north central Sichuan Basin. However, there has been limited research on storm sedimentation and the Lower Cambrian sedimentary environments, ancient geography, and ancient sedimentary geomorphology in this region. By conducting detailed core observations and thin section identifications, the storm sedimentation sequence and sedimentation model of the Canglangpu Formation have been investigated, revealing its geological significance. Various storm sedimentation structures, such as gravel sections, graded sections, parallel laminated sections, and hummocky cross-stratifications (HCS), are present in the Canglangpu Formation. The tempestites within this formation can be categorized into five types of storm sedimentation sequences: Sequence Ⅰ includes gravel sections (A), parallel laminatedsections (C), and HCS (D) above the fair-weather wave base (FWB). Sequence Ⅱ comprises parallel laminated section (C), HCS (D), and horizontally laminated mudstone section (E) deposited near the storm wave base (SWB). Sequence Ⅲ includes scouring-fill structures and gravel section (A), as well as a graded section (B) deposited between the fair-weather wave base (FWB) and SWB. Sequence Ⅳ is characterized by a graded section (B) and parallel laminated section (C) located far from the storm center, above and near SWB. Sequence Ⅴ consists of scouring-fill structures and gravel section (A) located between the mean sea level (MSL) and FWB, close to FWB. The analysis of tempestites in north central Sichuan Basin suggests that the initial member of the Canglangpu Formation was deposited on the shelf-ramp-platform margin and shelf, indicating that the Upper Yangtze Plate was situated in a low latitude region during the sedimentation period of the Canglangpu Formation. This information provides valuable insights into lithofacies paleogeography reconstruction. Storm events have resulted in the formation of storm mudflats in the study area, which are favorable for reservoir development. The investigation of storms in the Canglangpu Formation aids in predicting the distribution of shoal facies in the study area. more...
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- 2024
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4. Discovery and significance of tempestites and storm deposits in the Qingshankou Formation of the Gulong Sag, northeastern China
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Wenyuan He, Jianhua Zhong, and Ningliang Sun
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tempestite ,storm deposit ,shale oil ,Qingshankou Formation ,Gulong Sag ,Science - Abstract
The Qingshankou Formation in the Gulong Sag has attracted significant attention due to its rich shale oil reserves. However, several fundamental geological problems associated with shale from the Qingshankou Formation remain unresolved. The Qingshankou Formation in the Gulong Sag is a set of deep-lake and semi-deep-lake fine-grained deposits primarily composed of mudstone and shale. Recent studies have shown that tempestites and storm deposits commonly occur in the Qingshankou Formation. Fine liquefaction veins often occur at the bottom of the tempestite, indicating that storm-shaking liquefaction is expected in the swale structure. Meanwhile, the mudstone and shales primarily have a sand structure with fine grain size, indicating that the environment is exposed to an undercurrent activity, with a water flow velocity of 20–55 cm s−1. Unlike previous studies, we posit that the ancient water depth was only 20–30 m or shallower. These phenomena have significance for understanding the formation environment and diagenetic process of shale in the first member of the Qingshankou Formation, which provides a reference for oil and gas exploration and development. more...
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- 2023
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5. Heterogeneous marine response during the Toarcian Oceanic Anoxic Event (TOAE): The potential role of storminess.
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Ge, Yuzhu, Han, Zhong, Algeo, Thomas J., Kemp, David B., and Wu, Luya
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VERTICAL mixing (Earth sciences) , *EUPHOTIC zone , *TROPICAL storms , *HYDROLOGIC cycle , *NITROGEN fixation - Abstract
The Toarcian Oceanic Anoxic Event (TOAE; ∼183 Ma) represents an important hyperthermal and deoxygenation event in the Early Jurassic. However, TOAE marine records are spatially heterogeneous with regard to nutrient levels, primary productivity, redox conditions and organic enrichment. This non-uniform response to global hyperwarming is not readily accounted for by local variations in paleogeography, climate, or water depth. Largely overlooked to date is the intensified storm activity that characterized the TOAE, and the role that this may have played in controlling marine responses to that event. A review of TOAE studies from multiple marine environments suggests that storm intensity covaried with paleoceanographic conditions, such as nutrient availability, primary productivity, redox conditions, and organic-rich sedimentation. At mid-paleolatitude sites, relatively weak storm activity during the TOAE induced short-term watermass oxygenation, and marine settings were mainly characterized by enhanced anoxia (even euxinia), water-column stratification, increased primary productivity (fueled by terrestrial runoff and P regeneration in euxinic settings), and organic-rich sedimentation. At low-paleolatitude sites, TOAE storm activity was relatively strong, and contributed to marine environments characterized by oxic to suboxic conditions, reduced water-column stratification, decreased primary productivity (possibly due to limited P regeneration and upwelling), low sedimentary organic content, and locally high oolite abundance. TOAE marine sites at all paleolatitudes exhibit: i) sea-level rise and enhanced continental weathering fluxes linked to an intensified hydrological cycle; ii) reduced dinoflagellate and increased cyanobacterial activity; and iii) low δ15N values (mainly −1‰ to +3‰) linked to enhanced diazotrophic nitrogen fixation. The spatial heterogeneity of the response of TOAE marine systems is difficult to reconcile with scenarios linking increased terrestrial flux to marine eutrophication, primary productivity increase and organic-rich sedimentation. Consequently, we hypothesize that the intensity of storm activity influenced TOAE marine systems, and that this factor can, at least partially, account for heterogeneous patterns of environmental changes at middle versus low paleolatitudes and open versus restricted marine settings. Importantly, increased storm activity can induce pycnocline deepening via vertical water-column mixing, thereby promoting: i) enhanced aerobic degradation of organic matter (low sediment organic matter content) due to a reduced oxygen-minimum zone; ii) less nutrient upwelling from deep waters into the photic zone (nutrient-depleted upper ocean), and iii) blooms of nitrogen-fixing cyanobacteria (low δ15N) and calcification (ooid formation). Thus, the interaction between storminess and pycnocline depth is a potentially important factor affecting marine environmental changes during TOAE. These findings have implications for modern oceans now experiencing climatic warming and intensified tropical storm activity. • Spatially heterogenous TOAE marine records with ambiguous origins. • Covariation of storm intensity and marine response along different latitudes. • Interaction between storminess and pycnocline possibly affects TOAE marine records. [ABSTRACT FROM AUTHOR] more...
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- 2024
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6. رخسارهها و محیط رسوبی سازند تیرگان در ناحیه بزنگان، شرق حوضه رسوبی کپهداغ.
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محمود شرفي, مریم محمدی, اسدالله محبوبي, and محم د خان هباد
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Introduction The Kopet-Dagh sedimentary Basin that crops out from NE Iran to Turkmenistan was formed as an intracontinental Basin due to the southeastern extension of the South Caspian Basin by Neotethyan back-arc rifting after the closure of the Palaeotethys and the early Cimmerian Orogeny (middle Triassic). A thick sedimentary package (10 kilometers) consisting of five transgressive- regressive super-sequences from Jurassic to Miocene time is deposited in the Eastern part of the sedimentary basin that is mainly controlled by NW-SW running major faults. The Cretaceous sequence in the Kopet-Dagh Basin is divided into nine formations, mainly composed of sandstones, conglomerates, mudstones, limestones, and dolomites with minor amounts of evaporates (Afshar-Harb, 1979). The regional trend of the Kopet-Dagh sedimentary basin was northwest-southeast during the Cretaceous. After the deposition of thick, red siliciclastic sediments of the fluvial system during the Early Cretaceous, a suitable condition for the deposition of carbonate sediments (named as Tirgan Formation) was provided as a result of major marine transgression during the Barremian- Aptian stages. The Tirgan Formation is one of the most widespread Upper Cretaceous formations in the eastern Kopet-Dagh that unconformably overlies the fluvial sediments of the Shurijeh Formation and is overlain by a sharp contact of the Sarcheshmeh Formation. Material and Methods This study is focused on two stratigraphic sections in the Eastern Kopet-Dagh in northern Iran. Ninety thin sections were examined to identify fine-scale physical characteristics (mineralogical composition and fossil contents). Lithology, grain size, and sedimentary structures were recorded. Discussion Based on sedimentological features, sixteen facies are recognized that grouped within five facies associations consist of deep and shallow open marine (FA), shoal (FB), lagoon (FC), and Tidal flat (FD). Deep open marine facies includes green-gray fissile (sandy-silty) shale and shallow open marine facies are mainly consist of bioclastic wackestone, ooid/peloid bioclastic floatstone, sandy intraclastic floatstone, sandy intraclastic bioclastic float-rudstone, and sandy peloid bioclastic grainstone. The main constituents in this association are brachiopods, bryozoans, echinoderms, oysters, orbitolinids, intraclasts, ooids, and peloids. Micrite envelopes and borings are the common features in this association. The skeletal elements display high fragmentation, preferentially horizontal orientation, and fining up-ward fabrics. Green-gray fissile shale is deposited in a low energy depositional setting below weather wave base (SWWB), periodically affected by storm waves, suggested by the presence of the siliciclastic grains. The skeletal elements of the shallow open marine facies offer a shallow full open marine setting between SWWB and fair-weather wave base (FWWB) (Bovar-Arnal et al., 2009). High fragmentation, preferentially horizontal orientation, and fining upward skeletal elements suggest the storm-generated shell concentrations. Low energy periods of the sedimentary environment (post- and pre-storm phase) are indicated by micrite envelopes and borings. Shoal association consists of ooid grainstone and sandy ooid grainstone facies with predominantly well-sorted fabric. The main sedimentary structures in this association are sigmoidal cross-beds, wave ripples, cross lamination, and planar cross-beds with the erosional surface. These sediments are deposited in medium-high energy shoal settings above FWWB in the inner ramp environment suggested by well sorting of the elements and predominantly grainstone facies (Bachmann & Hirsch, 2006; Brandano et al., 2012). The sedimentary structures clearly show that tidal currents controlled the association's deposition in a sandy shoal environment. Lagoon association includes sandy mudstone, bioclastic wack-packstone, sandy ooid wackestone, sandy peloid packstone, intraclast, ooid float-rudstone, ooid/peloid pack-grainstone, ooidal bioclastic float-rudstone with main ooids, peloids, benthic foraminifers, echinoderms, and minor content of green algae, bivalves, brachiopods as well as siliciclastic grains that are commonly floated in the micritic matrix. These sediments are mainly deposited in a semi-restricted to restricted (sandy mudstone) lagoon setting above FWWB. The periodical water circulation suggested by the mixture of the open marine (echinoderm, brachiopods) to more restricted and brackish water elements (ostracodes, benthic forams), floated within the micritic matrix (Colombie & Strasser, 2005; Bachmann & Hirsch, 2006; Bovar-Arnal et al., 2009). The tidal flat association mainly consists of peloids, benthic foraminifers, and ostracods surrounded by flat microbial laminations. The flat geometry of the microbial lamination and the presence of the peloids and benthic foraminifers as the main elements in this association demonstrate a flat substrate in a tidal flat setting of the most internal part of the carbonate platform. Conclusion In a general view, petrography and field observations, facies associations relationship, and vertical trend of the studied successions suggest Tirgan sediments in the Kopet-Dagh basin are deposited in shallow to the deep marine environment with tidal flat, lagoon, shoal, and shallow to deep marine facies zones. These sediments were deposited in a homoclinal ramp characterized by gradationally vertical changes in the facies associations and abundant storm deposits. This carbonate system was influenced by storm (shallow marine zone) and tidal (shoal zone) currents suggested by the storm-generated shell concentrations, wave ripples, cross laminations, and sigmoidal cross-beds. [ABSTRACT FROM AUTHOR] more...
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- 2022
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7. 四川盆地周缘灯影组风暴沉积特征及其地质意义.
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金 鑫, 宋金民, 刘树根, 李智武, 文 龙, 孙 玮, 罗 冰, 张玺华, 周 刚, 彭瀚霖, and 丁 一
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STORM surges ,TURBIDITES ,SEDIMENTARY structures ,EROSION ,LITHOFACIES ,NATURAL gas prospecting - Abstract
Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...
- Published
- 2021
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8. Modern coastal tempestite deposition by a non‐local storm: Swell‐generated transport of sand and boulders on Eleuthera, The Bahamas.
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Wilson, Kat, Mohrig, David, and McArthur, Adam
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BOULDERS , *SAND , *SAND waves , *TOPOGRAPHY , *CYCLONES , *BARRIER islands , *MAGNITUDE (Mathematics) , *COASTAL changes - Abstract
This paper presents an analysis of the transport conditions of a storm deposit (i.e. tempestite) produced by a non‐local cyclone. Observations and analysis of 'sand to boulder' transport and washover deposition in March 2018 at Gaulding Cay Quarry, Eleuthera, The Bahamas, confirm that swell waves can cause coastal change and affect the depositional record >1000 km from the storm centre. Drone video, news reporting, deposit stratigraphy, grain‐size measurements and wave data were all used to define three phases of washover fan construction: an aggradational phase associated with base‐level rise as the quarry filled with water; a progradational phase associated with quasi‐constant base‐level; and fan incision tied to base level fall as discharge through an outlet channel exceeded input discharge by overtopping waves. Washover fan location was controlled by antecedent topography and represented only a fraction of the swell‐impacted coastline. Sand and boulders were transported simultaneously, forming a complex poorly sorted deposit. Drone video, bedrock erosion and sediment‐transport estimates all indicated that overwash exceeded sediment availability. As a result, the measured washover fan was estimated to be an order of magnitude smaller than its potential volume if conditions had been transport‐limited. This study highlights the importance of pre‐event topography and independent measures of event duration on accurately reconstructing storm properties from the sedimentary record, as well as the challenges in reconstructing storm location, and therefore storm intensity and frequency, from sedimentary deposits alone. [ABSTRACT FROM AUTHOR] more...
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- 2021
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9. Comparativa de dataciones radiométricas en muestras de conchas marinas tardi-holocenas: El ejemplo de las tempestitas del estuario de Huelva.
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Gómez, P., Toscano, A., Rodríguez-Vidal, J., Cáceres, L. M., González-Regalado, M. L., Abad, M., Izquierdo, T., Ruiz, F., Monge, G., Campos, J. M., and Bermejo, J.
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RADIOACTIVE dating ,ESTUARINE sediments ,CARBON isotopes ,URANIUM ,HOLOCENE Epoch ,ESTUARIES - Abstract
Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...
- Published
- 2021
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10. Analysis of carbonate tempestite deposits of the Kangan Formation in the central Persian Gulf
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Vahid Tavakoli
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tempestite ,graded bedding ,kangan formation ,persian gulf ,Stratigraphy ,QE640-699 - Abstract
Abstract This study focuses on fining-upward sequences of carbonate-evaporite series of the Kangan Formation in the central Persian Gulf area. The studied sequences shows a typical succession of tempestite deposits. Comparison of these units with sedimentary deposits of other graded bedding forming mechanisms, showed that these strata have been formed during the occurrence of storms at the time of Kangan deposition in this region. Formation of these units in shallow depths of gently sloped ramp setting, well sorting especially at the middle of the unit, absence of slumping related structures in these sediments, centimeter to decimeter scale, lack of terrigenous sediments and their considerable repetition in middle to upper parts of the Kangan Formation confirms the role of storms in their formation during lower to middle Triassic in the Persian Gulf Basin. Study of these strata could be a great help for understanding the climate change at the Triassic time in Persian Gulf Basin. Introduction Event stratigraphy have been considered in many studies and many models have been proposed for their sediments deposition. The Bouma sequence is the most well-known model for these deposits which is the result of turbidity currents. There are not many studies about such deposits in carbonate formations. A total of four models have been proposed for deposition of fining-upward sequences in carbonates. They include 1) turbidity currents by rivers which could not be used for carbonates as they are not affected by runoffs. 2) Tempestites in carbonate formations. The term introduced by Aigner in 1982 and now has a wide application in carbonate storm deposits. 3) Slumping and their resulted local fining-upward sequences. 4) Internalites which are the result of wave breakdown in mid to outer ramp settings. The former have been introduced recently but their use in interpretation of fining-upward sequences is increasing in recent years. With respect to each model mechanism, the effective factors and so the depositional situations could be reconstructed. Tempestites have been frequently formed in the Triassic due to the warm and arid climate. The Persian Gulf basin was in 10 degree south in that time. So, the Kangan Formation was selected for more considerations to find possible tempestite deposits. This study focuses on the event deposits in this formation using cores and thin sections’ data. With respect to the reservoir quality of this formation in our country, determination of its sedimentary environment and processes are so important. Material & Methods Macroscopic studies was carried out on 540 m cores of the Kangan Formation in three wells. A total of four plugs prepared from each meter of core. Thin sections were prepared from trims of plugs. One third of each thin section stained with Alizarin Red-S to distinguish calcite from dolomite (Dickson 1965). Facies named according to Dunham classification (Dunham 1962). Discussion of Results & Conclusions Fenestral mudstone, stromatolite boundstone and anhydrite have been deposited in peritidal environment. These deposits have unique structures such as bird’s eye or anhydrite nodules. Massive to layered anhydrites shows deposition in warm and dry climate sabkha environment. Mudstones associated with anhydrites have no allochems. The facies have been dolomitized in most cases. Dolomites are fine and xenotopic. Stromatolite boundstone exhibit fine lamination and fenestral voids. Thrombolite has been formed in the base of the formation after the Permian–Triassic mass extinction. The lagoon environment has low energy and limited water circulation. Low diversity of fauna, lack of exposure related structures, frequency of micrite and peloids denote to lagoon environment. Both small and large allochems are visible. Bioturbation and micritization are obvious. Ooid and peloid grainstones build the main part of the shoal depositional setting. These facies have been deposited in high energy environment which is obvious from sand size ooids, lack of lime mud (micrite) and well sorting. Cross-bedding could be seen on core samples. Intraclast/bioclast grainstone is related to sea-ward shoal sub-environment. Gradual change in facies and lack of a complete build-up reveal that these facies have been deposited in a ramp setting. There are also no slumping related structures. Core and thin sections’ studies show that the studied sequences begin with an erosional surface. Erosional related evidence including rip-up clasts and flame structures are evident. The basal facies show clear fining-upward sequence. Toward the top, cross-laminations are visible which have been developed within the well sorted grainstones. There are no silt or fine sand size particles in this sequences and so the parallel lamination never developed at the topmost intervals. The uppermost facies are consist of massive micrites with anhydrite cement or nodules. Tempestite deposits are developed in shallow to deep carbonate and siliciclastic environments. They are thicker with larger size particles in shallow settings. They are also more mature with basal erosional surface in such environments. The fining-upward sequence and erosional surface show that the environmental energy decreases after a sudden increase. Presence of anhydrite shows that the environment was arid and warm during deposition of these units. Results of this study show that there have been many storms in present Persian Gulf location at Early and Middle Triassic time. The resulted sequence starts with an erosional surface and continues with parallel lamination in high current regime. The uppermost units could not be distinguished and have a massive structure due to high micrite content. The main difference of these sequences with turbidites lies in their mechanism. Their high frequency and shallow environment, lack of slumping related structures and terrigenous sediments as well as low clay content and high frequency of intraclasts and pleoids demonstrate a storm mechanism for their deposition. The result is tempestite deposits in the Kangan Formation. more...
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- 2018
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11. A New Ichnospecies of Gyrolithes from the Austin Chalk, Upper Cretaceous, Texas, USA.
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Morgan, Ryan F.
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TRACE fossils , *MORPHOLOGY - Abstract
Gyrolithes, a helical marine trace fossil, occurs in beds of the Austin Chalk near Waco, McLennan County, Texas. The new ichnospecies Gyrolithes texanus is characterized by unique morphology and wall construction. This discovery expands the current geographic and environmental range of Gyrolithes, extending this ichnogenus into the chalk-dominated beds of the Cretaceous of Texas. Irregular bedding features from the Gyrolithes locality indicate this section of the Austin Chalk was deposited within a storm-dominated depositional regime, interspersed with periods of quiescence which allow for firm ground formation and colonization by the trace maker. Occurrences of Gyrolithes have been associated by previous publications with marginal marine settings but not associated with storm deposits; therefore, this discovery constitutes an expansion of associated environment for this ichnogenus. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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12. Coquina depositional model, Buzios Field, Brazil.
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de Carvalho Antunes, Rafaella, Guerrero, Júlia Campos, and Jahnert, Ricardo Jorge
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BIVALVE shells , *ROCK texture , *TAPHONOMY , *PETROLEUM reservoirs , *SILICICLASTIC rocks , *MUDSTONE , *FACIES - Abstract
Increasingly relevant as petroleum reservoirs, the coquina deposits of the pre-salt section of the Santos and Campos Basin display a wide variety of sedimentary systems that reflect a complex storm-dominated depositional environment. This complexity resulted in the deposition of numerous sedimentary facies distributed among structural lows and highs, and their understanding is an essential aspect in order to reduce exploration risks. Therefore, the aims of this contribution are twofold: (a) to understand the depositional processes during the generation of the Itapema Formation coquina deposits in the offshore pre-salt Buzios Field, Santos Basin, and (b) to establish a depositional model and identify stacking patterns in the coquina section. The facies analysis was based on rock texture, structure, allochemical composition, taxonomic composition, and taphonomic characteristics of bivalve shells, such as fragmentation, abrasion, sorting, thickness, orientation, and articulation. We described 695 thin-sections and sidewall samples distributed among ten wells in the field area. The analysis resulted in sixteen facies grouped into eight facies associations: (1) bioclastic bars, (2) washover deposits, (3) backshore, (4) bioclastic beaches, (5) tempestites, (6) tempestites with articulated shells, (7) offshore and offshore transition deposits, and (8) offshore siliciclastic mudstones. These carbonate facies associations were deposited mainly under the influence of waves and currents in isolated ramp-shaped margined platforms with low continental input associated with active faults, characteristic of the rift phase of the basin evolution. The stacking of the facies associations indicates that the Itapema Formation coquinas were deposited in an environment that became progressively shallower towards the top contact with the overlying Barra Velha Formation. Siliciclastic mudstones mark the top of the Itapema Formation immediately below the Pre-Alagoas unconformity, indicating a significant lake deepening that drowned the coquina section. The depositional model is the first one about the Buzios Field and the first about the pre-salt fields coquinas based on field-scale information. [Display omitted] • Depositional model for the pre-salt Buzios Field coquinas. • Coquina sedimentary facies and their respective depositional processes. • Paleoenvironmental implications of bivalve shell taphonomy. • Porosity distribution based on facies succession and stacking model. [ABSTRACT FROM AUTHOR] more...
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- 2024
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13. Sedimentary facies analysis of the Upper Bahariya sandstone reservoir in East Bahariya C area, North Western Desert, Egypt.
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Almoqaddam, Radwa.O., Darwish, M., EL-Barkooky, A.N., and Clerk, C.
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SANDSTONE ,ARENITES ,SILICICLASTIC rocks ,SEDIMENTARY rocks ,CONGLOMERATE - Abstract
Abstract The present work aims to deduce the depositional processes of the Lower Cenomanian Bahariya Formation, that is one of the main hydrocarbon siliciclastic reservoirs in the Northern Western Desert of Egypt. This has been achieved through the analyses of the core photographs, micro-resistivity image logs, mud logs and conventional wireline logs. The Bahariya Formation comprises a complex of depositional lithofacies such as interbedded siltstone, shale, sandstones and pebbly sandstones. The current work highlights the effectiveness of the integrative approach. A variety of datasets including core photographs, micro-resistivity image logs, mud logs and conventional wireline logs are integrated to define the conceptual depositional model in the study area. Different recorded sedimentary features point to various depositional processes. Hummocky cross stratification (HCS) is the common sedimentary structure indicating the storm action. Wave ripples are recorded providing evidence for fair-weather action on shoreface. Rhythmic heterolithics, tidalites indicate the tidal processes. The upper part of the Bahariya Formation has been influenced by wave and storm processes more than the lower parts. The core and image facies are designated, being dominated by Sandstone (S), Siltstone (Z), Mudstone (M), Heterolithic (H) and Limestone (L.s). The studied core and image facies with wireline logs facies are grouped into five major facies associations (FA). They are Tidal Channel and Tidal Creeks, Tidal Flat, Storm, Shoreface, Offshore Transition to Offshore Facies Associations. The integrative approach indicates that the Upper Bahariya Member has been deposited in a storm influenced tidal coastal realm. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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14. Sedimentology of the Belfast Member of the Brassfield Formation (Silurian, western Ohio and northern Kentucky, U.S.A): Implications for regional sea-level changes and tectonics.
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Zaleha, Michael J.
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ORDOVICIAN Period , *WATER depth , *SEDIMENTOLOGY - Abstract
The lowermost Silurian Brassfield Formation of the Cincinnati Arch area records mid-continent deposition on a carbonate ramp that sloped gently into the Taconic foreland basin. The Brassfield is significant because it represents earliest Silurian deposition in the area resulting from sea-level rise following the late Ordovician glacial maximum, it records the faunal transition from the terminal Ordovician extinction, and its upper part contains tabulate coral-stromatoporoid reefs that are among the oldest Silurian reefs in North America. The lowermost unit of the Brassfield Formation, the Belfast Member, is the focus of this study. The Belfast previously has been interpreted as representing relatively shallow water deposition associated with the initial early Silurian transgression. Newly recognized sedimentological features, however, together with previous information, indicate that the Belfast was deposited in water deeper than previously recognized. The purpose of this paper is to evaluate previous studies of the Belfast that have lead to interpretations of shallow water deposition, present new sedimentological information indicative of deeper water deposition, and discuss the implications of those results. Previous interpretations of the Belfast as having been deposited in relatively shallow water, intertidal to shallow subtidal, including lagoonal, are equivocal. The Belfast exhibits 3D ripple marks and associated cross laminae, hummocks, hummocky and swaley cross stratification, and planar stratification, with thin interbeds of planar laminated mudstone, all consistent with deposition in an inner shelf-type setting, below fair-weather wave base, but above storm wave base (possibly on the order of 10-60 m deep). Trace fossils, including Chondrites, Rosselia, Teichichnus, Thalassinoides, and Palaeophycus, indicate that during rapid sedimentation associated with storms, organisms adjusted vertically. Under fair-weather conditions following storms, settling of suspended sediment formed planar laminae and organisms recolonized upper portions of some beds, while totally bioturbating others. Hence, the Belfast represents relatively deep-water deposition on the Ordovician-Silurian unconformity (which developed primarily under subaerial conditions) associated with a relatively rapid sea-level rise. The transition from the Belfast Member to the overlying part of the Brassfield Formation appears to record a sea-level fall. As such, the Belfast is a low-order sequence. The sea-level changes recorded by the Belfast and overlying part of the Brassfield are consistent with glacio-eustatic variations evident on published sea-level curves. An increase in subsidence also may have contributed to the rapid deepening recorded by the Belfast. Increased subsidence may have been associated with hydrostatic and/or sediment loading, Taconic orogenesis, dynamic subsidence (vis-à-vis dynamic topography) associated with northward directed subduction along the southern margin of Laurentia, or movement on regional structures, reflecting the influences of events at the southern plate margin or induced by hydrostatic loading. [ABSTRACT FROM AUTHOR] more...
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- 2018
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15. Cretaceous echinoids in Paleocene reworked tsunamite from Coahuila, NE Mexico.
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Cadena-González, David, Flores-Ventura, José, Vega-Sandoval, Francisco A., and Vega, Francisco J.
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- *
PALEOCENE Epoch , *COASTAL plains , *SPECIES diversity , *PALEOGENE , *AMMONOIDEA - Abstract
The Maastrictian echinoid species Hardouninia mortonis (Michelin, 1850) typical from Upper Cretaceous deposits along the Gulf and Atlantic Coastal plains of USA and Canada, is here reported for the first time for Mexico into a peculiar matrix, which consists of a K/Pg reworked tsunamite deposited during an early Paleocene storm event in the NW portion of the Parras Basin, Difunta Group, NE Mexico. Our specimens have a peculiar small size compared with those reported for Maastrichtian localities in Mississippi amd North Carolina. Small-sized specimens are abundant in late Maastrichtian Las Encinas Formation of the Parras Basin, and are identical to the more than 50 specimens found included in reworked K/Pg tsunamite at Arroyo Amargos, Coahuila. Our interpretation is that the tsunamite was reworked during an early Paleocene storm, forming a channel-like structure of microconglomeratic sandstone, which includes ammonites (Sphenodiscus pleurisepta), the small Hardouinia mortonis , and delicate early Paleocene ostreoids. Other localities with reworked K/Pg tsunamite deposits are found in the adjacent La Popa Basin, interpreted also as deposited by early Paleocene storms in this area of NE Mexico, in Coahuila and Nuevo León states, but mix of Maastrichtian and Paleocene invertebrates has only been observed in Amargos. • Cretaceous echinoids embedded into reworked K/Pg tsunamite. • First record of mixed Cretaceous and Paleocene invertebrates in tsunamite. • High diversity of echinoid species in the Digunta Group, NE Mexico. • Extension of paleogeographic range of an echinoid species from the USA Gulf and Atlantic. [ABSTRACT FROM AUTHOR] more...
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- 2023
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16. Taphonomy of Condensed Shell Storm beds of the Teresina Formation in Rio Preto (State of Paraná, Middle Permian, Paraná Basin): Paleoenvironmental Implications
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Jacqueline Peixoto Neves, Rosemarie Rohn Davies, and Marcello Guimarães Simões
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Parana Basin ,Permian ,Passa Dois Group ,Carbonate ,Bivalve mollusk ,Tempestite ,Geology ,QE1-996.5 - Abstract
The deposits of the Permian Teresina Formation are mainly characterized by fi ne-grained siliciclastic rocks and centimetricintercalations of tempestites (bioclastic sandstones and coquinas). Despite the relevance of the bivalve-rich carbonate bedsof the Teresina Formation to paleoenvironmental studies, their taphonomy is still poorly studied. The fossil concentrationstudied in this work was found in a quarry in the city of Irati, Rio Preto district, Paraná State. The fossil concentration is locatedin the middle/upper portion of the unit, far from the top. The studied bed is a bioclastic, intraclastic, peloidal, grainstone/packstone, with abundant bivalve shell fragments, pelitic and micritic intraclasts, peloids, rare ooids and oncoids, as well aspermineralized of Lycophyta microphylles and fi sh scales. The grains of this carbonate concentration show: high degree oftime-averaging, variable degree of packing (dense to disperse), no sorting and chaotic orientation. Notably, the concentrationincludes a mixture of elements which are indicative of: a) restrictive, low energy, carbonate environment (peloids, ooidsand oncoids); b) subaerial environment surrounding the main body of water (Lycophyta microphylles) and c) quiet-waterenvironment punctuated by storm events, where the suspension-feeding bivalves thrived. At least four depositional eventscaused by storm fl ows were recorded. The amalgamated nature of the bed is a result of storm events in an intracratonic basinwith very low seafl oor slope and low rates of sedimentation and subsidence. more...
- Published
- 2011
17. Ichnocoenoses and taphocoenoses of posidoniid-bearing marl-limestone rhythmites and event beds, Toarcian-Aalenian, Northern Apennines, Italy.
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Monaco, Paolo
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THANATOCOENOSES , *LIMESTONE , *JURASSIC Period , *COUPLETS , *CALCIUM carbonate - Abstract
The Posidoniid-bearing rhythmic deposits, Toarcian to Aalenian (Early/Middle Jurassic) in age, of the Umbria-Marche basins (Fiuminata Colle Corno and Valdorbia type section) consist of hundred couplets, each composed by two semicouplets, a calcium carbonate-poor bed and a calcium carbonate-rich bed, respectively (CacO 3 between 10% to 85%), where event tempestite beds randomly occurs. The aim of this work is to show ichnocoenoses and taphocoenoses as well as the faunistic variations of each semicouplet and event beds. Each couplet is ∼30 cm thick in the Toarcian Rosso Ammonitico and up to 40 cm in the Aalenian Calcari e Marne a Posidonia Formation, where the sedimentation rate increased. Here, couplets were deposited in the dysaerobic/aerobic transition zone. The clay-rich portion contains abundant thin-shelled poikilaerobic bivalves and benthic foraminifers (whithout radiolarians) and shows oxygen-poor ichnocoenosis with Chondrites , while the taphocoenosis exhibits convex-upward disposition and disarticulated bivalve shells. Conversely, the limestone semicouplet is rich in radiolarians and thin-shelled bivalves, usually more burrowed (ichnocoenosis including Chondrites and few Planolites and Thalassinoides ) than the former, with grouping, dispersion, biogenic fragmentation and orientation-reorientation. In all marl-limestone semicouplets, foraminifers and radiolarians exhibit a periodic inverse correlation in abundance, while thin-shelled bivalves are always abundant. Rhythmically disposed within the rhythmites are also event beds indicating an occasional oxygen-rich substrate, fine-grained calcarenitic tempestites with hummocky cross-stratification, and winnowed bed (thin shelled bivalve concentrations). These deposits are intensely bioturbated (ichnocoenosis including Skolithos , Planolites , Trypanites , Chondrites , and Thalassinoides ). Taphocoenoses include fragmentation, grouping, surficial burrowing, biogenic reorientation, and deep burrowing. Ichnological and taphonomical features indicate high physical and biogenical reworking affecting sediments. The Jurassic depocenters of Valdorbia and Fiuminata that received rhythmical dilution (clay) or productivity (carbonate) cycles during Toarcian and Aalenian time can therefore strongly contribute to the study of ichnological and taphonomical variations in rhythmic conditions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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18. Discussion of Yang et al. (2017, Acta Geologica Sinica 91:749–750) A new discovery of the Early Cretaceous supercritical hyperpycnal flow deposits on Lingshan Island, East China
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Zexuan Liu, Bing Zhao, Zhufu Shao, Gail Maxwell, John A. Howell, Weimin Ran, Wen Xin Zhang, and Xiwu Luan
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Tempestite ,Hummocky cross-stratification ,Flow (mathematics) ,Facies ,Geochemistry ,Geology ,Structural basin ,Supercritical flow ,Cretaceous ,Supercritical fluid - Published
- 2020
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19. Storms in the deep: Tempestite- and beach-like deposits in pelagic sequences (Jurassic, Subbetic, South of Spain)
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P. A. Ruiz-Ortiz, Luis Pomar, J. A. Vera, and José Miguel Molina
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010504 meteorology & atmospheric sciences ,Hummocky cross-stratification ,Stratigraphy ,Geochemistry ,Geology ,Pelagic zone ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Sedimentary structures ,Geophysics ,Tempestite ,Radiolarite ,Grainstone ,Facies ,Marl ,Economic Geology ,0105 earth and related environmental sciences - Abstract
Fine-peloidal- to coarse oolitic-bioclastic grainstones with hummocky cross stratification (HCS) occur interbedded in Jurassic pelagic lime-mudstone successions (Subbetic, Betic ranges, Southern Spain). These strata were deposited in pelagic troughs and swells, away from continental areas, in the Southern Iberian Paleomargin of the Western Tethys. Selected examples presented in this study include: a) coarse oolitic grainstones, encased in pelagic marls, holding characteristics similar to the ridge-berm-swash zone of modern beaches; b) peloid grainstones with HCS interbedded with radiolarite marls deposited on the flanks of volcanic guyots. The interbedded lime muds and marls contain “filaments”, sponge spicules and radiolarians; c) peloid-bioclastic (radiolarians, “filaments”, etc.) grainstone beds with HCS, interbedded with pelagic lime muds; d) crossbedded peloidal-skeletal (Saccocoma) grainstones with HCS and wave ripples on top, interbedded with pelagic mudstones and wackestones with abundant bioturbation and ammonites (Ammonitico Rosso facies). All the examples here presented share: 1) grainstone beds are interbedded with pelagic mudstones and marls; 2) grainstone components were reworked by oscillatory flows superimposed to unidirectional tractive flows (unidirectional ripple lamination and HCS); 3) components, either derived from shallow-water environments (e.g., ooids) or produced in pelagic conditions (e.g., radiolarians, Saccocoma, “filaments”, peloids, etc) were reworked by high-energy processes unrelated to surface storm waves; 4) Internal waves (IWs) propagating along a pycnocline and breaking against a sloping surface are the best candidates to induce the sedimentary structures and sediment organization that characterize these grainstone beds. Coarser sediments “trapped” at the breaker zone form sediment accumulations similar to the sediments caught by the “littoral fence” in the surface beach. This scenario evidences the HCS not to be necessarily linked to the surface storms but to the pycnocline bathymetry, solving the problem of having HCS in pelagic zones where the storm and hurricanes wave action can be considered “out-of-context”. more...
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- 2019
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20. Evidence of high-energy storm and shallow water facies in Pabdeh sedimentary phosphate deposit, Kuhe-Lar-anticline, SW Iran
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Ayyub Memarkouchehbagh, Farid Bolourchifard, Behzad Mehrabi, and Farajollah Fayazi
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Ripple marks ,010506 paleontology ,Hummocky cross-stratification ,Geochemistry ,010502 geochemistry & geophysics ,01 natural sciences ,Sedimentary depositional environment ,Tempestite ,Geochemistry and Petrology ,Facies ,Marl ,Sedimentary rock ,Graded bedding ,Geology ,0105 earth and related environmental sciences - Abstract
Kuhe-Lar sedimentary phosphate deposit is a major phosphate prospect located in Zagros folded basin in the flank of the Kuhe-Lar-anticline in the southeast of Iran. Phosphate deposits in the Middle East extend in Neo-Tethys basin rim through several countries from North Africa, Syria, Iraq, Turkey, Iran, and Oman. The sedimentary phosphate mineralization occurred in the Pabdeh Formation, which is comprised of a marl, limestone, and shale sequence. Based on comprehensive field and laboratory studies, facies zones, standards microfacies, and standard ramp microfacies were recognized in the Pabdeh Formation. Sedimentary features such as tempestite, hummocky cross stratification, ripple marks, couplets of fine and coarse laminae, erosional surface, graded bedding, and shell lag features strongly supported a high-energy storm and shallow water depositional conditions. The main evidence of storm origin for the Pabdeh Formation is the occurrence of sandstones interbedded with bioturbated mudstones commonly as upward fine grade forms. Negative carbon isotopic composition (δ13C, − 1.85 to − 4.89) of bulk phosphatic rock shows that it may be formed within the suboxic-to-anoxic zone, almost 100-cm depths (under seafloor). These values are within the range of recent and ancient phosphorites, suggesting their good preservation. more...
- Published
- 2019
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21. Ichnology in storm and fair-weather beds of an epeiric sea (Pimenteira Formation, Devonian, Brazil).
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Neto, Emmanuel Franco, Agostinho, Sonia, Sedorko, Daniel, de Jesus Andrade, Edilma, Vieira Batista, Zenilda, Alves Moreira Junior, Carlos, and Lima Filho, Mario
- Subjects
- *
STORMS , *OCEAN bottom , *ICHNOLOGY , *TRACE fossils , *WINTER storms , *COLONIZATION (Ecology) - Abstract
Trace fossils in storm-generated beds of shelf siliciclastic settings have been investigated mostly to understand the effect of waves in the infauna distribution. It is possible to identify a post-storm ichnofauna (with features attributable to Skolithos ichnofacies) and a resident ichnofauna (attributable to Cruziana ichnofacies) and this ichnologic signature can bring data about the frequency of storms (weak, moderate, or strong) in the lower shoreface zone. Thus, the ichnologic signature can be a key feature to understand the depositional setting in storm-dominated environments. An excellent unit to apply these concepts is the Pimenteira Formation (Eifelian-Frasnian, Parnaíba Basin), interpreted as result of deposition in a storm-dominated platform. In ichnological terms, this unit has a great ichnodiversity and abundance of ichnofossils, but few studies have integrated the trace fossil suites with a facies analysis to understand the storm influence during deposition. Thus, this study aims to (i) characterize storm-related ichnofaunas from the Pimenteira Formation, ParnaíbaParnaíba Basin, Brazil; and (ii) understand the paleocological controls in the colonization of shoreface beds in an epeiric sea. The ichnotaxons were grouped in four suites: Skolithos, Palaeophycus, Bifungiites, and Lophoctenium suites. The Skolithos suite characterizes the post-storm ichnofauna, while Palaeophycus, Bifungiites, and Lophoctenium suites characterizes the resident ichnofauna. The predominance of proximal Cruziana ichnofacies, associated with layers generated by storm events, attests colonization in shallow marine environment. However, the general absence of deposit-feeders indicates short term in the colonization window for the resident ichnofauna, implying in a shoreface setting moderately impacted by storms. • The post-storm ichnofauna in Pimenteira Formation is composed of a low diverse Skolithos suite. • The resident ichnofauna of the storm-influenced beds is composed of shallow-tier trace fossils from Cruziana ichnofacies. • Winter storms are interpreted as the main controlling factor for the ichnofauna distribution. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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22. Comparativa de dataciones radiométricas en muestras de conchas marinas tardi-holocenas: el ejemplo de las tempestitas del estuario de Huelva
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Gómez Gutiérrez, Paula, Toscano Grande, Antonio, Rodríguez Vidal, Joaquín, Cáceres Puro, Luis Miguel, González-Regalado Montero, María Luz, Abad de los Santos, Manuel, Izquierdo, Tatiana, Ruiz Muñoz, Francisco, Monge Gómez, Guadalupe, Campos Carrasco, Juan Manuel, and Bermejo Meléndez, Javier more...
- Subjects
Datación ,Series de Uranio ,Holocene ,Tempestite ,Estuario de Huelva ,25 Ciencias de la Tierra y del Espacio ,Radiocarbon ,Holoceno ,Radiocarbono ,Huelva Estuary ,Dating ,Uranium series ,Tempestita - Abstract
El estudio del registro sedimentario holoceno del estuario de los ríos Tinto y Odiel (Huelva) se ha realizado históricamente por medio de sondeos y de afloramientos superficiales. Nuevos perfiles naturales en la Isla de Saltés (La Cascajera) están ofreciendo una nueva perspectiva sobre la génesis y cronología de los depósitos. Para la determinación temporal de estos procesos se llevaron a cabo dataciones radiométricas mediante el análisis de series de Uranio y de radiocarbono. El contraste de los resultados de ambas técnicas ha permitido observar grandes desfases temporales en las series de Uranio, siendo las edades de 14C unos 200 años más antiguas que las de U/Th, para las mismas muestras. La contaminación postsedimentaria en estos sistemas abiertos, ha favorecido el rejuvenecimiento de la edad de la muestra, por el continuo aporte al sistema de 234U y 238U. Esto pone de manifiesto lo inapropiado del método U/Th en sedimentos estuarinos recientes y, sobre todo, altamente contaminados; no debiendo utilizarse este método de forma exclusiva. El método de radiocarbono parece ser más preciso y adecuado, aplicándose a los resultados las pertinentes calibraciones marinas regionales (ΔR), siendo aconsejable su modelización Bayesiana (OxCal)., The study of the Holocene sedimentary record of the Estuary of the Tinto and Odiel rivers (Huelva) has been carried out historically by boreholes and surficial outcrops. New natural profiles on Saltés Island (La Cascajera) are offering a new perspective on the genesis and chronology of the deposits. For the temporal determination of these processes, radiometric dating was carried out by radiocarbon and uranium series analysis, being the ages of 14C are about 200 years older than those of U / Th, for the same samples. The contrast of the results of both techniques has allowed us to observe large time lags in the uranium series. Post-sedimentary contam ination in these open systems has favored the rejuvenation of the age of the samples, due to the continuous contribution of 234U and 238U to the system. This highlights the inappropriateness of the U/Th method in recent estuarine sediments and, above all, highly polluted; therefore, this method shouldn’t be used exclusively. The radiocarbon method seems to be more precise and adequate, always applying the pertinent regional marine calibrations (ΔR) to the conventional results, being advisable a Bayesian modeling (OxCal). more...
- Published
- 2021
23. Late Triassic (Norian-Rhaetian) brackish to freshwater habitats at a fluvial-dominated delta plain (Seinstedt, Lower Saxony, Germany).
- Author
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Barth, Gregor, Franz, Matthias, Heunisch, Carmen, Kustatscher, Evelyn, Thies, Detlev, Vespermann, Jürgen, and Wolfgramm, Markus
- Abstract
The historic Late Triassic outcrops at Fuchsberg and Langenberg near Seinstedt (Lower Saxony, Germany) are constrained to the Norian/Rhaetian boundary interval by means of conchostracan and palynomorph biostratigraphy. A comprehensive revision revealed a fluvial-dominated delta plain that formed in response to the successive transgression of the 'Rhaetian Sea' and received siliciclastics from southern source areas. At Fuchsberg and Langenberg, the distal lower delta plain is exposed and brackish subaqueous delta plain wetlands, mouthbar/distributary channel complexes and interdistributary bay subenvironments are reconstructed. Delta formation was controlled by bifurcation of distributary channels and avulsion of delta lobes. A diverse ecosystem is documented: a rich invertebrate fauna of limulids (1 taxon), insects (at least 20 taxa of 9 orders), malacostracans and conchostracans (several taxa) and a vertebrate fauna of amphibians (at least 1 taxon), sharks (9 taxa) and osteichthyan fishes (at least 6 taxa). In particular, fossiliferous interdistributary bay lithologies detail trophic systems of autochthonous subaqueous and parautochthonous riparian habitats. Abundant remnants of cycadophytes, ferns, horsetails and large vertebrates from Fuchsberg and adjacent outcrops of the Seinstedt area enable the reconstruction of vegetated upstream environments at the upper delta plain and floodplain. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
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24. Feature and duration of metre-scale sequences in a storm-dominated carbonate ramp setting (Kimmeridgian, northeastern Spain).
- Author
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Colombié, C., Bádenas, B., Aurell, M., Götz, A.E., Bertholon, S., and Boussaha, M.
- Subjects
- *
CARBONATES , *STORMS , *CYCLOSTRATIGRAPHY , *KIMMERIDGIAN Stage , *OXYGEN isotopes - Abstract
Metre-scale sequences may result from the combined effects of allocyclic and autocyclic processes which are closely inter-related. The carbonate ramp that developed northwest of the Iberian Basin during the late Kimmeridgian was affected by northwestward migrating cyclones. Marl–limestone alternations that settled in mid-ramp environments contain abundant mm to cm thick coarse-grained accumulations that have been related to these events. The aim of this paper is to determine the impact of storm-induced processes on the metre-scale sequence features. Four sections (R3, R4, R6, and R7), which are 5 to 7 m in thickness, were studied bed-by-bed along a 4 km-long outcrop, which shows the transition between the shallow and the relatively deep realms of the middle ramp. Metre-scale sequences were defined and correlated along this outcrop according to the detailed microfacies analysis of host, fine-grained deposits, palynofacies and sequence-stratigraphic analyses, and carbon- and oxygen-isotope measurements. The evolution through time of sedimentary features such as the size of quartz grains and the relative abundance of grains other than quartz (i.e., muscovite, bivalve, ooid, and intraclast) does not correlate from one section to the other, suggesting that the finest as well as the coarsest sediment was reworked in these storm-dominated environments. Small- and medium-scale sequences are defined according to changes in alternation, marly interbed, and limestone bed thickness, and correlated from one section to the other. Because of the effects of storms on sediment distribution and preservation, sequence boundaries coincide with thin alternations and marly interbeds in the most proximal sections (i.e., R3, R4), while they correspond to thin alternations and limestone beds in the most distal sections (i.e., R6, R7). Field observations and palynofacies analyses confirm this sequence-stratigraphic analysis. The excursions in carbon- and oxygen-isotope values are consistent with the lithological correlations, but in themselves are not conclusive. Marl–limestone alternations, and small-, and medium-scale sequences are hierarchically stacked, suggesting an orbital control on sedimentation with alternations lasting 20 kyr, small-scale sequences, 100 kyr, and medium-scale sequences, 400 kyr. As biostratigraphic analyses and spectral analysis are not the most appropriate tools to validate this time calibration in such a short interval and highly dynamic system, an alternative approach is developed, which is based on the quantification of the rates of sediment accumulation, preservation, and sea-level rise. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
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25. Ground Penetrating Radar digital imaging and modeling of microbialites from the Salitre Formation, Northeast Brazil
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Washington Luiz Evangelista Teixeira, Francisco Pinheiro Lima-Filho, Filipe Ramos de Albuquerque, and Rebeca Seabra de Lima
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geography ,geography.geographical_feature_category ,Geophysical imaging ,Microbialites ,lcsh:QE1-996.5 ,Digital imaging ,Geophysical attributes ,Mineralogy ,Geology ,Ground Penetrating Radar ,Arid ,lcsh:Geology ,Lamination (geology) ,Tempestite ,Cave ,Ground-penetrating radar ,Scale (map) - Abstract
Thanks to the discovery of new giant oil fields in the South Hemisphere in the last decades, named Pre-salt, there has been a considerable interest in the geometrical and sedimentological characterization of microbial deposits, coquinas, and collapsed caves, which represent a considerable part of these reservoirs. It is known that exposures analogous to oil reservoirs are an important source of information at the sub-seismic scale, as this information is helpful in parametrizing and modeling reservoirs, especially microbial reservoirs. This scenario is more favorable when the Ground Penetrating Radar (GPR) method is used in analogous exposures located in arid regions with scarce or no soil, such as the Fazenda Arrecife, in the Chapada Diamantina (Salitre Formation), Northeastern Brazil. Although rarely mentioned in the literature on microbialite geophysical imaging, GPR has been used in microbial deposits associated with the Neoproterozoic storm deposits of the Salitre Formation. The results of 3D imaging of a microbial colony, using the 200 MHz antenna, with both conventional processing and processing using geophysical attributes, are presented in this study. The conventional processing produced a 3D digital model that allowed the geometrical characterization and parametrization of the imaged microbial colony. The use of four geophysical attributes yielded good results, establishing the contact between the microbial colony and tempestite deposits, and determining the internal geometry of microbial deposits. The processing with “instantaneous amplitude” and “Hilbert trace with energy” highlighted the contact between the microbialite colony (low amplitude) and tempestite deposits (high amplitude), whereas the processing with the “energy” attribute provided a better visualization of the internal lamination of columnar microbialites, result similar to that obtained in the processing with “Hilbert trace with similarity”. GPR obtained images of up to 10 m in depth, with excellent resolution for microbial deposits and tempestites associated with them. The processing using geophysical attributes achieved considerably better results when compared to conventional processing, allowing a better visualization of the internal and external geometry of the imaged colony. more...
- Published
- 2018
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26. Depositional processes on oceanic island shelves - Evidence from storm-generated Neogene deposits from the mid-North Atlantic.
- Author
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Meireles, Ricardo P., Quartau, Rui, Ramalho, Ricardo S., Rebelo, Ana C., Madeira, José, Zanon, Vittorio, Ávila, Sérgio P., and Trofimovs, Jess
- Subjects
- *
SEDIMENTATION & deposition , *STORMS , *MARINE sediments , *SEDIMENT transport , *NEOGENE Period - Abstract
Oceanic islands - such as the Azores in the mid-North Atlantic - are periodically exposed to large storms that often remobilize and transport marine sediments along coastlines, and into deeper environments. Such disruptive events create deposits - denominated tempestites - whose characteristics reflect the highly dynamic environment in which they were formed. Tempestites from oceanic islands, however, are seldom described in the literature and little is known about storm-related sediment dynamics affecting oceanic island shelves. Therefore, the geological record of tempestite deposits at oceanic islands can provide invaluable information on the processes of sediment remobilization, transport and deposition taking place on insular shelves during and after major storms. In Santa Maria Island (Azores), a sequence of Neogene tempestite deposits was incorporated in the island edifice by the ongoing volcanic activity (thus preserved) and later exposed through uplift and erosion. Because it was overlain by a contemporary coastal lava delta, the water depth at the time of deposition could be inferred, constituting an excellent case-study to gain insight on the still enigmatic processes of insular shelf deposition. Sedimentological, palaeontological, petrographic and palaeo-water depth information allowed the reconstruction of the depositional environment of these sediments. The sequence typifies the characteristics of a tempestite (or successive tempestites) formed at ca 50 m depth, in a steep, energetic open insular shelf, and with evidence for massive sediment remobilization from the nearshore to the middle or outer shelf. The authors claim that cross-shelf transport induced by storm events is the main process of sediment deposition acting on steep and narrow shelves subjected to high-energetic environments, such as the insular shelves of open-sea volcanic islands. [ABSTRACT FROM AUTHOR] more...
- Published
- 2013
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27. Tempestites in a teapot? Condensation-generated shell beds in the Upper Ordovician, Cincinnati Arch, USA
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Dattilo, Benjamin F., Brett, Carlton E., and Schramm, Thomas J.
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- *
ORDOVICIAN Period , *FACIES , *SEDIMENTOLOGY , *TAPHONOMY , *PETROLOGY , *BEDS (Stratigraphy) , *TSUNAMIS , *MUDSTONE , *OCEAN bottom , *TURBULENCE - Abstract
Abstract: Skeletal concentrations in mudstones may represent local facies produced by storm winnowing in shallow water, or time-specific deposits related to intervals of diminished sediment supply. Upper Ordovician (Katian) of the Cincinnati region is a mixed siliciclastic-carbonate succession including meter-scale cycles containing a shelly limestone-dominated phase and a mudstone-dominated phase. The “tempestite proximality model” asserts that shell-rich intervals originated by winnowing of mud from undifferentiated fair-weather deposits. Thus shell beds are construed as tempestites, while interbedded mudstones represent either fair-weather or bypassed mud. Meter-scale cycles are attributed to sea-level fluctuation or varying storm intensity. Alternatively, the “episodic starvation model” argues, on the basis of petrographic, taphonomic, and stratigraphic evidence, that, despite widespread evidence for storms or other turbulence events (e.g. tsunamis), winnowing alone could not generate shell beds where none had previously existed. Instead, variations in sediment supply are construed as the principal cause of shelly-mudstone cycles. Shell-rich deposits accrue during periods of siliciclastic sediment starvation and relatively shell-free mud accumulates during periods of sediment influx. Tempestite proximality and episodic starvation models lead to contrasting predictions about proximal-to-distal facies patterns. These are: (i) large versus small volumes of distally-deposited, bypassed mud; (ii) proximal grainstones and distal packstones versus distal grainstones and proximal packstones; and (iii) proximal versus distal amalgamation and condensation of shell beds. In this paper, these predictions are tested by (i) comparing meter-scale cycles from different horizons and depositional environments through the lower Cincinnatian succession (Kope through McMillan Formations representing deep subtidal through intertidal environments), and (ii) correlating intervals and individual meter-scale cycles from the Fairview Formation of the Cincinnati Arch (shallow subtidal) north and west into the Maquoketa Shale (deep subtidal) in subsurface of Ohio and Indiana. Both approaches show patterns consistent with episodic starvation, not winnowing, including: (i) small differences in stratigraphic thickness indicate small volumes of bypassed mud; (ii) discrete distal deep-water grainstones that splay proximally into bundles of thinner shallow-water packstones alternating with shelly muds show that grainstones formed from a lack of, rather than removal of mud; and (iii) distal shell‐bed amalgamation and condensation (and corresponding proximal splaying) of shell beds shows a proximal source of mud. Thus, winnowing by storms or other turbulence events did not generate shell beds or cycles from undifferentiated sediments despite abundant evidence for storm deposition. High-resolution correlations imply that the shell-bed and mud-bed hemicycles reflect simultaneous basin-wide changes in sedimentary style rather than contemporaneous facies belts that track sea level. In this sense, shell-rich and mud-rich hemicycles are “non-Waltherian” facies. [Copyright &y& Elsevier] more...
- Published
- 2012
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28. Late Cretaceous tempestite in northern Songliao Basin, China
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Liu, Xuan, Zhong, Jianhua, Grapes, Rodney, Bian, Shuhua, and Liang, Chen
- Subjects
- *
CRETACEOUS paleogeography , *GEOLOGICAL basins , *FACIES , *CLASTIC rocks , *EROSION - Abstract
Abstract: A Late Cretaceous tempestite in the northern Songliao Basin, China, was studied based on thin-section and granularity analyses of borehole samples. The results indicated that the local tempestite can be categorized into several clastic constituent types, which include bottom erosion structures, graded beds, hummocky cross stratification (HCS), parallel beds, wave marks, and bioturbation structures. Based on these sedimentary characteristics and vertical sequence combinations, four tempestite sedimentary models were developed: (I) an autochthonous tempestite facies, (II) an allochthonous tempestite facies (the proximal subfacies), (III) a second allochthonous tempestite facies (the distal subfacies), and (IV) a turbidite facies. [Copyright &y& Elsevier] more...
- Published
- 2012
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29. The geologic record of Hurricane Irma in a Southwest Florida back-barrier lagoon
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Joanne Muller and Tynisha Martin
- Subjects
Oceanography ,Tempestite ,Barrier island ,Horizon (archaeology) ,Geochemistry and Petrology ,Storm surge ,Sediment ,Geology ,Storm ,Geologic record ,Deposition (geology) - Abstract
On 10 September 2017, Category 3 Hurricane Irma made landfall along the Southwest Florida coastline between Cape Sable and Cape Romano. Geologic evidence of this storm is preserved in a back-barrier lagoon behind the Big Hickory Barrier Island, which is located ~64 km north of the landfall point and is positioned 43–65 m east of the Gulf of Mexico. Modern dune height is ~0.83–0.88 m, which was exceeded by the storm surge (recorded height 0.9–1.5 m) allowing for sediment deposition in the Big Hickory Island Lagoon. Geologic evidence is likely found at this location due to proximity to the Gulf of Mexico and the shallow barrier itself. Three cores were analyzed for moisture, inorganic content, grain size, and foraminiferal assemblages. The presence of a hurricane signature (tempestite) is evident in the uppermost horizon of all the cores and includes a fining upward trend of medium sand to clay against a background of organics and fine-grained sediments. Tempestite layers were thicker behind narrower sections of the beach, indicating preferential back-barrier deposition behind narrow barrier sections. Several different foraminiferal species within the tempestite sediments corroborate a marine sediment origin. In addition, historic satellite imagery shows that the Big Hickory Barrier Island is very susceptible to geomorphological change through time, especially due to storm impacts. This research demonstrates the utility of back-barrier sediment cores in understanding hurricane history and barrier island vulnerability. more...
- Published
- 2021
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30. Multi-proxy characterization of storm deposits on Sanibel Island, Florida: A modern analog for paleotempestology.
- Author
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Muller, Joanne, Ercolani, Christian, Collins, Jennifer, and Ellis, Shelby
- Subjects
- *
STORM surges , *BARRIER islands , *HURRICANES , *RADIOACTIVE dating , *SEA level , *ISLANDS , *CALCIUM carbonate , *GRAIN size - Abstract
Hurricanes have serious impacts on human lives and infrastructure, especially as a result of flooding caused by storm surge and precipitation. To better prepare coastal populations for future hurricanes due to an increasingly warming world, a better understanding of hurricane storm surge is key. Southwest Florida is particularly vulnerable to hurricane storm surge where most of the coastline is within 2.5 m of sea level and population is on the rise (2.5% between 2019 and 2020 in Lee County). This study presents a geologic record of intense hurricane strikes from Sanibel Island dating back to approximately ca. 1920. Based on sedimentary proxies such as grain size, organics, moisture content, and calcium carbonate, three tempestites were identified in cores from the Sanibel Island Marsh. Radiometric dating constrained Tempestite 1 as Hurricane Donna (1960) and Tempestites 2 and 3 as the 1926 Great Miami Hurricane and the Tampa Bay hurricane of 1921. Of the eight intense hurricanes (category 3–5) taking place between ~1920–2016, only three hurricanes were recorded in the geologic record. Tempestites 1, 2, and 3 were deposited by intense, large radius storms with significant storm surge, which would indicate that at least three storms made significant impact on the Southwest Florida region between ~1920–1960. Since 1960 no storms have breached the Sanibel Island barrier. It is important for the public to recognize that even though this region has not experienced significant storm surge in the last ~60 years, several hurricanes occurring between 1920 and 1960 produced storms surges greater than ~10 ft. that were able to breach a major barrier island (Sanibel Island). Human-induced climate change is predicted to increase storminess and sea level rise in Southwest Florida with concomitant risk for future storm surge. • This manuscript presents a geologic record of intense hurricane strikes for Sanibel Island, FL, dating back to approximately ca. 1920. • Hurricanes Donna (1960), Great Miami (1926), and Tampa Bay (1921) made significant impact on the Southwest Florida region between ~1920–1960. • This research confirms the hypothesis that tempestites are often deposited by intense, large radius storms with significant storm surge. • Several hurricanes occurring between 1920 and 1960 produced storms surges greater than ~10 ft. that were able to breach the Sanibel Island barrier. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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31. Shell concentrations of Early Silurian virgianid brachiopods in northern Guizhou: Temporal and spatial distribution and tempestite formation.
- Author
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Li Yue and Rong Jiayu
- Subjects
- *
BRACHIOPODA , *INVERTEBRATES , *ANIMALS - Abstract
Shell beds in the uppermost Xiangshuyuan Formation and its coeval Upper Shihniulan Formation (Lower Silurian), northern Guizhou, SW China, are interpreted as tempestites occurring on the Upper Yangtze Platform. The shells are dominated by two endemic and transient virgianid (brachiopod) taxa, Paraconchidium shiqianensis and Virgianella glabera, which vary in relative abundance and deposited as fragments of valves with cemented micrite that differs from the surrounding sediment, demonstrating that the shells were not originally preserved in growth positions. The thicknesses of individual shell layers vary from ten centimeters to more than four meters. Shells had been strongly stirred up by high-energy currents, mainly caused by ocean storm events and probably related to the profile of the geographic shape of the coastline. Fragmentation of shells, in particular, their thinning anterior parts of ventral and dorsal valves are more intensive. The benthic assemblages are from lower BA2 to upper BA3 in depth, assigned to near shoal belt in geographic background. Breakage and stacking density are of the indexes of proximal and distal transportations. Northern Guizhou was located within the lower latitudes of the Southern Hemisphere during the Silurian time, and obviously affected the depth of the virgianid inhabitation. Most of these shells were disturbed repeatedly by surges. It is inferred that on average, several ten thousand years of growth of shells were required for development of shell layers, followed by storm disruption. [ABSTRACT FROM AUTHOR] more...
- Published
- 2007
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32. Characteristics of the Middle-Late Triassic sedimentary facies assemblages in the Songpan-Ruoergai area.
- Author
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Yan Zhen, Yu Liangjun, Li Jiliang, Bian Qiantao, Wang Zongqi, and Yang Yongcheng
- Subjects
- *
TRIASSIC stratigraphic geology , *FACIES , *SEDIMENTARY rocks , *SILTSTONE , *FELDSPATHOID - Abstract
The Middle-Late Triassic sedimentary rocks in the Songpan-Ruoergai area mainly consist of calcareous siltstone, muddy limestone, lithic arkose, feldspathic litharenite, mudstone, wormkalk, oolithic limestone, and conglomerate. Except for limestone bed in- creasing eastward longitudinally and vertically, the calcareous component of the sandstones increases obviously. Abundant benthic and plant fossils and their clasts occur within these rocks. The sedimentary structures predominately contain flaser, parallel, tabular, wavy, and herringbone cross beddings. These data coevally imply that the Middle-Late Triassic sediments deposited in the fluvial, lake and tide environments. Additionally, the rocks display graded, parallel, hummocky beddings, and sandy lamination, a feature characteristic of storm deposits. [ABSTRACT FROM AUTHOR] more...
- Published
- 2007
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33. An improved method of laser particle size analysis and its applications in identification of lacustrine tempestite and beach bar: An example from the Dongying depression
- Author
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Min Wang, Chenlin Hu, Zaixing Jiang, Yuanfu Zhang, Junjie Li, and Xingmou Wang
- Subjects
010504 meteorology & atmospheric sciences ,Mineralogy ,Silt ,010502 geochemistry & geophysics ,01 natural sciences ,Grain size ,Tempestite ,Decantation ,Saltation (geology) ,Particle-size distribution ,General Earth and Planetary Sciences ,Particle size ,Siltstone ,Geology ,0105 earth and related environmental sciences - Abstract
Grain size analysis is a common method in the study of sedimentology. For the consolidated sedimentary rocks, the traditional methods are rock slice observation and image analysis. In recent years, laser particle size analyzer is used widely in particle size analysis of sedimentary rock. Unlike the pretreatment of loose samples, the rock samples must be crushed, added acid to wipe out cement, and washed. However, in the step of washing, most of the fines component (less than 63 μm) in the suspended state should be inevitably lost. It will significantly affect the accuracy of particle size analysis, especially for siltstone. This paper presents a siltstone sample pretreatment method which core step is washing acid by centrifuge. Compared with traditional decantation method, the results show that the median particle size reduced 33.2 μm on average. Compared with the precipitation method which is commonly used for handling loose samples, the change of solid-liquid separation time is from 12 h to 10 min, while the average reduction of median particle size is about 15 μm. The grain size value corresponded to the cumulative volume of 10%/90% reduced 2.5 μm/20.3 μm on average. The percentage of the clay component less than 2 μm increased 2.88% on average. The fine particle (2–4 μm) and silt component (4–63 μm) increased 1.71% and 5.56% on average. Based on this method, two kinds of similar lacustrine siltstone were analyzed. They are tempestite and beach bar which are difficult to identify in the Lijin sub-depression, Dongying depression, Shengli oilfield, China. The final grain-size probability plot of tempestite is the type of “one saltation component and three suspension components”. The content of suspension components can reach to 80%–90%. The beach bar is the type of “one saltation component and two suspension components”. The content of suspension components can reach to 40%–45%. They both have the characteristics of high slope which means well sorting. But they can be distinguished based on the suspension sedimentary characteristics which were preserved by maximum degree in this kind of sample pretreatment method. more...
- Published
- 2017
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34. Tsunami killed and backwashed accumulated crinoids in Middle Triassic (Anisian) intracratonic Germanic Basin carbonates of central Europe
- Author
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Cajus G. Diedrich
- Subjects
010506 paleontology ,biology ,Sorting (sediment) ,Biozone ,010502 geochemistry & geophysics ,biology.organism_classification ,Crinoid ,01 natural sciences ,Antidune ,Paleontology ,Tempestite ,Geochemistry and Petrology ,Grainstone ,Facies ,Encrinus ,Geology ,0105 earth and related environmental sciences - Abstract
In Germany tens to hundreds of kilometres-laterally distributed sedimentological heterogene crinoid accumulation bed with partly articulated Encrinus liliiformis specimens is dated within a complete trans-regression cycle of higher order into the upper Illyrian, Anisian (Middle Triassic, pulcher biozone). The crinoid bearing layer differs much from under- and overlaying tempestite parasequence sets of the Meisner Formation. The tsunamite layer consists of different laterally grain size sorted facies types ranging from unsorted bioclastic floatstones of large-scaled antidune megaripples, which continue in oscillation-ripple-marked oolithic grainstone surfaces that end into crinoid filled scour troughs in wacke/mudstones (=horizontal grain sorting in backwash direction). The tsunamite bed of Lamerden that consists of mixed reworked oolithic bar to crinoid ramp facies areas (sediments/biota to the outer ramp facies) can be correlated to a crinoid bed of Bissendorf within northwestern Germany at minimum (about 50 km) and appears within the tectonical deepening period of the Central European intracratonic Germanic Basin. The heterotope crinoid taphocoenosis was built in the outer ramp Tonplatten facies, in the deepest part of the Germanic Basin (Hesse-Depression) due to backwash. The mixed macro fauna originate from the crinoid bioherms and terebratulid hardgrounds of the inner/middle ramp facies (such as the sediments). From 350 analysed crinoid individuals (of 1500), only 1 % are complete with 120–160 cm short-stemmed ecotypes of the inner ramp crinoid meadows which settled along the sand bars basinwards. The Lamerden crinoids are scattered or are concentrated differently condensed in scour trough-like structures on wackestones/mustone areas and more rare or scattered on osciallation-ripple marked grainstones and allow only local bottom current estimations. In interfingering floatstones, more rare crowns are found unsorted within dominat chaotic oriented terebratulids. Most crinoid specimens (83 %) were found with relic stems and the others (16 %), only as crowns. The echinoderms survived a tsunami event, for at least a few hours/days under 10–30 cm of mud coverage. Only 1 % of the crowns have opened arms (=postmortal embedding); all others (99 % are closed crowns) are “buried alive” specimens. The crinoids closed the nutrition canal immediately and started regeneration of the distal stem for new attachment purposes; therefore, those have all rounded distal stems. The northern German Lamerden crinoid layer is most similar to the southern German Neckarwestheim site, but is different in its origin to other German sites, where crinoids have been found around bioherms or with long-stemmed specimens not far from their patch-reef like habitats in channels of the upper middle ramp facies. The tsunamite demonstrate the problem of the “Triassic time scale” which is tempestite and Milankovitch cycle based on an intracratonic basin, because there seem to be several further tsunamite bioclastic layers, which were misidentified as “tempestites”. more...
- Published
- 2017
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35. Oxygen-related facies in Lake Pannon deposits (Upper Miocene) at Budapest-Köbánya.
- Author
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Magyar, Imre, Müller, Pál, Sztanó, Orsolya, Babinszki, Edit, and Lantos, Miklós
- Abstract
Oxygen availability is considered to have been a major factor in shaping the sedimentary facies and biofacies of a Late Miocene (8–8.5 Ma old) Lake Pannon sequence studied in the Kozma-street outcrop in Budapest-Köbánya. The sequence contains blue clays deposited in low-oxygen conditions between the storm and the fair-weather wave bases and thin intercalations of laminated fine sand interpreted as tempestites. The storms caused temporary oxygenation of the bottom and thus promoted bioturbation, as indicated by the presence of trace fossils belonging to the Arenicolites ichnofacies or a lacustrine equivalent of the marine Skolithos ichnofacies. Fully bioturbated sand layers with the infaunal Dreissenomya and other littoral molluscs indicate longer periods of bottom ventilation. The blue clays immediately above these sand layers also contain abundant and diverse mollusc fauna. Oxygen deficiency on the “shelf” of Lake Pannon was a local phenomenon probably caused by a high organic loading and/or a salinity-induced stratification. [ABSTRACT FROM AUTHOR] more...
- Published
- 2006
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36. Diversity of vertebrate remains from the Lower Gogolin Beds (Anisian) of southern Poland
- Author
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Maciej R. Ruciński, Mateusz Antczak, Jan J. Król, Michał Stachacz, and Michał Matysik
- Subjects
Reptilia ,fossil vertebrate ,biology ,Actinopterygii ,Stratigraphy ,Vertebrate ,Geology ,Structural basin ,Middle Triassic ,Paleontology ,Taxonomic composition ,tempestite ,Geography ,biology.animal ,%22">Fish ,Assemblage (archaeology) ,coprolite ,Economic Geology ,Chondrichthyes ,Stratigraphic column - Abstract
Middle Triassic (Muschelkalk) limestones and dolostones of southern Poland contain vertebrate remains, which can be used for palaeoecological and palaeogeographical analyses. The results presented concern vertebrate remains uncovered at four localities in Upper Silesia and one on Opole Silesia, a region representing the south-eastern margin of the Germanic Basin in Middle Triassic times. The most abundant remains in this assemblage are fish remains, comprising mostly actinopterygian teeth and scales. Chondrichthyan and sauropsid remains are less common. Reptilian finds include vertebrae, teeth and fragments of long bones, belonging to aquatic or semi-aquatic reptiles, such as nothosaurids, pachypleusorosaurids, and ichthyosaurids. Also, coprolites of possibly durophagous and predacious reptiles occur. In the stratigraphic column of Mikołów, actinopterygian remains are the most numerous and no distinct changes of the taxonomic composition occur. Although this assemblage differs from those described at other localities (Ząbkowice with numerous chondrichthyans, Żyglin, and Płaza with com-mon sauropsid fossils), sampling bias has to be considered. more...
- Published
- 2020
37. Sedimentationsprozesse in den jüngeren Tonmergelschichten und Bausteinschichten der Unteren Meeresmolasse am Grünten im Allgäu (nordalpines Molassebecken, Bayern).
- Author
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Reineck, Hans-Erich, Schwerd, Klaus, and Gerdes, Gisela
- Abstract
Copyright of Senckenbergiana Maritima is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...
- Published
- 2001
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38. Tempestite facies variability and storm‐depositional processes across a wide ramp: Towards a polygenetic model for hummocky cross‐stratification
- Author
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Lars Stemmerik, Sten-Andreas Grundvåg, Snorre Olaussen, Mads E. Jelby, and William Helland-Hansen
- Subjects
010506 paleontology ,Hummocky cross-stratification ,Stratigraphy ,Geology ,Storm ,010502 geochemistry & geophysics ,01 natural sciences ,Sedimentary depositional environment ,Paleontology ,Tempestite ,VDP::Mathematics and natural science: 400::Geosciences: 450::Sedimentology: 456 ,Facies ,Sedimentology ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Sedimentologi: 456 ,0105 earth and related environmental sciences - Abstract
This is the peer reviewed version of the following article: Jelby, M.E., Grundvåg, S.‐A., Helland‐Hansen, W., Olaussen, S. & Stemmerik, L. (2020). Tempestite facies variability and storm‐depositional processes across a wide ramp: Towards a polygenetic model for hummocky cross‐stratification. Sedimentology, 67, 742-781, which has been published in final form at https://doi.org/10.1111/sed.12671. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. The hydrodynamic mechanisms responsible for the genesis and facies variability of shallow‐marine sandstone storm deposits (tempestites) have been intensely debated, with particular focus on hummocky cross‐stratification. Despite being ubiquitously utilized as diagnostic elements of high‐energy storm events, the full formative process spectrum of tempestites and hummocky cross‐stratification is still to be determined. In this study, detailed sedimentological investigations of more than 950 discrete tempestites within the Lower Cretaceous Rurikfjellet Formation on Spitsbergen, Svalbard, shed new light on the formation and environmental significance of hummocky cross‐stratification, and provide a reference for evaluation of tempestite facies models. Three generic types of tempestites are recognized, representing deposition from: (i) relatively steady and (ii) highly unsteady storm‐wave‐generated oscillatory flows or oscillatory‐dominated combined‐flows; and (iii) various storm‐wave‐modified hyperpycnal flows (including waxing–waning flows) generated directly from plunging rivers. A low‐gradient ramp physiography enhanced both distally progressive deceleration of the hyperpycnal flows and the spatial extent and relative magnitude of wave‐added turbulence. Sandstone beds display a wide range of simple and complex configurations of hummocky cross‐stratification. Features include ripple cross‐lamination and ‘compound’ stratification, soft‐sediment deformation structures, local shifts to quasi‐planar lamination, double draping, metre‐scale channelized bed architectures, gravel‐rich intervals, ‘inverse to normal’ grading, and vertical alternation of sedimentary structures. A polygenetic model is presented to account for the various configurations of hummocky cross‐stratification that may commonly be produced during storms by wave oscillations, hyperpycnal flows and downwelling flows. Inherent storm‐wave unsteadiness probably facilitates the generation of a wide range of hummocky cross‐stratification configurations due to: (i) changes in near‐bed oscillatory shear stresses related to passing wave groups or tidal water‐level variations; (ii) multidirectional combined‐flows related to polymodal and time‐varying orientations of wave oscillations; and (iii) syndepositional liquefaction related to cyclic wave stress. Previous proximal–distal tempestite facies models may only be applicable to relatively high‐gradient shelves, and new models are necessary for low‐gradient settings. more...
- Published
- 2019
39. Volcaniclastic tide-modulated tempestite in a coastal tuff ring, Jeju Island, Korea
- Author
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Chanwoo Sohn and Young Kwan Sohn
- Subjects
0301 basic medicine ,education.field_of_study ,Multidisciplinary ,lcsh:R ,Population ,lcsh:Medicine ,Storm ,Surf zone ,Article ,Sedimentary depositional environment ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Oceanography ,Tempestite ,lcsh:Q ,Sedimentary rock ,lcsh:Science ,education ,030217 neurology & neurosurgery ,Geology ,Sea level ,Swash - Abstract
The need for more accurate and extensive records of storm activity is increasing because of growing population and infrastructure in coastal areas. Records of past storm activity have consequently been sought from diverse sedimentary proxies in marginal marine environments, as well as historical documents. In this paper, we introduce a unique record of a 3.7 ka BP storm event preserved in a coastal tuff ring on Jeju Island, Korea. The tuff ring formed mostly above high tide level by primary volcanic processes, but contains three interbeds of horizontally laminated to hummocky/swaly cross-stratified deposits with intervening mud drapes up to an altitude of ~4.6 m above high tide level. These interbeds were formed by wave activity in a swash to surf zone when the sea level rose several meters above normal high-tide level during a storm event, and the triple intercalation of the wave-worked deposits reflects three tidal cycles during a storm event that lasted 1.5 day. Jeju Island contains the most complete record of an ancient storm event ever reported in the tuff ring, and highlights the significance of coastal volcanoes in the study of extreme depositional events in coastal areas, such as storms and tsunamis. more...
- Published
- 2019
40. Paleoenvironmental analysis of the ichnogenus Zoophycos in the Lower Devonian tempestite sediments of the Longmenshan area, Sichuan, China
- Author
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Fengjie Li, Hao Zhang, Xigui Jing, and Xiaoyu Cheng
- Subjects
010506 paleontology ,Paleontology ,Storm ,Trace fossil ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Wackestone ,Devonian ,Tempestite ,Zoophycos ,Sedimentary rock ,Ecology, Evolution, Behavior and Systematics ,Wave base ,Geology ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
The trace fossil Zoophycos is characteristic of the Lower Devonian in the Longmenshan area of southeastern China. Three distinct storm-generated or induced types of sedimentary sequences bearing Zoophycos have been identified in shallow marine deposits of the Bailiuping Formation and the Yangmaba Formation. The type A deposit is composed of siltstones with shell concentrations and wave ripples and small Zoophycos at the top. The type B deposit is characterized by fine-graded sandstone with long wavelength hummocky cross-stratification and black gray mudstone as well as the largest and densest Zoophycos at the top. The type C deposit has graded bioclastic limestone with short wavelength hummocky cross-stratification, muddy wackestone and large Zoophycos at the top. Based on the features of the types of Zoophycos, the distribution zone of the Zoophycos ichnogenus that preserved in tempestite sequence was built between the fair weather wave base and storm wave base in the Lower Devonian. This research suggests that the distribution patterns of Zoophycos formed in storm-induced deposits may not provide significant clues for the estimation of relative water depths. The hydrodynamic conditions and sedimentation rate are two important environmental factors of the development of the Zoophycos in the Lower Devonian shallow marine deposits where it was mainly affected by storms between the fair weather and storm wave bases. The abundance of Zoophycos at the top of locally frequent storm deposits could indicate a fairly opportunistic behavior and they were formed in the early HST deposit, which had a relatively stable environment with low energy and higher sedimentation rate. more...
- Published
- 2017
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41. Assessment of Holocene Sedimentary Environment Using Particle Size Characteristics of Coastal Sediments in the Gochang Area
- Author
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Yang Dong Yoon, Kim Ju Yong, and Han Min
- Subjects
Sedimentary depositional environment ,Oceanography ,Tempestite ,Sorting (sediment) ,Geochemistry ,Environmental science ,Particle size ,Holocene - Published
- 2016
- Full Text
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42. Sedimentology and ichnology of an Early-Middle Cambrian storm-influenced barred shoreface succession, Colville Hills, Northwest Territories
- Author
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D.S. Herbers, R.B. MacNaughton, E.R. Timmer, M.K. Gingras, and Steven Hubbard
- Subjects
010506 paleontology ,Upper shoreface ,Lithology ,Energy Engineering and Power Technology ,Geology ,Ecological succession ,010502 geochemistry & geophysics ,01 natural sciences ,Paleontology ,Tempestite ,Ichnology ,Geochemistry and Petrology ,Facies ,Earth and Planetary Sciences (miscellaneous) ,Sedimentary rock ,Sedimentology ,0105 earth and related environmental sciences - Abstract
This study presents the first detailed sedimentological and ichnological study of the Cambrian Mount Clark Formation from the Colville Hills region of the Northwest Territories, Canada. Based on analyses of four industry drill cores, eight lithofacies are identified that occur in a recurring facies association. This facies association records a progradational storm-influenced shoreface succession preserving offshore to upper shoreface sedimentary environments. Storm influence is indicated by the presence of hummocky cross-stratification (HCS) and of tempestite/fair-weather couplets consisting of low-angle cross-bedded sandstone with thin bioturbated interbeds. Marine flooding surfaces are expressed as pebbly transgressive lags that separate near-shore and overlying offshore sedimentary environments. Piperock is common, represents the most oil stained lithology, and is preserved within a wave-dominated shoreface succession. The sedimentological and ichnological character of this succession suggests that predictable shoreface stacking patterns and sandstone distributions characterize the Mount Clark Formation in the subsurface of the study region. more...
- Published
- 2016
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43. Sedimentary mode and reservoir genesis of dual grain banks at the Lower Cambrian Longwangmiao Fm carbonate ramp in the Sichuan Basin
- Author
-
Jingjiang Liu, Chunchun Xu, Hua Jiang, Xiuqin Shan, Long Wen, Hui Zhou, Jinhu Du, Jing Zhang, Caineng Zou, Baomin Zhang, Jian Zhang, Ping Shen, and Zecheng Wang
- Subjects
020209 energy ,Sichuan basin ,Geochemistry ,Karst reservoir ,Energy Engineering and Power Technology ,02 engineering and technology ,Structural basin ,010502 geochemistry & geophysics ,01 natural sciences ,chemistry.chemical_compound ,Carbonate ramp ,0202 electrical engineering, electronic engineering, information engineering ,Geomorphology ,0105 earth and related environmental sciences ,lcsh:Gas industry ,lcsh:TP751-762 ,Process Chemistry and Technology ,Dual grain banks ,Geology ,Geotechnical Engineering and Engineering Geology ,Sedimentary model ,Waves and shallow water ,Longwangmiao Fm ,chemistry ,Tempestite ,Denudation ,Pore-cellular vug ,Modeling and Simulation ,Facies ,Dolomitization ,Carbonate ,Sedimentary rock - Abstract
The gas reservoir of the Lower Cambrian Longwangmiao Fm in the Sichuan Basin is a supergiant integral marine carbonate gas reservoir whose single scale is currently the largest in China. In order to figure out its sedimentary model and reservoir genesis, its geological structures and sedimentary settings and facies were analyzed comprehensively and the lithofacies paleographic map was plotted. It is revealed that the following sedimentary facies are successively developed in the Longwangmiao Fm from West Sichuan to Southeast Chongqing: diamictic tidal flat at the back ramp, grain bank (the upper bank) at the inner/shallow ramp – interbank sea (depression), deeper open bay at the platform depression of inner ramp → evaporative lagoon → evaporative tidal flat, tempestite at the middle ramp – barrier beach – mud mound beach (the lower bank), and outer ramp – basin. Accordingly, the specific sedimentary model of dual grain banks in the Longwangmiao Fm carbonate ramp was established as follows. Firstly, in this model, dual grain banks are symmetrically developed with Wanzhou–Yibin platform depression as the axis, on whose dual sides the paleohighs have shallow water bodies with strong energy. Compared with the classical model, the new one has a new upper bank which is developed around the paleohighs covering an area of about 8 × 10 4 km 2 . Secondly, the upper bank is large for its paleogeomorphology being located at the highest position with the strongest water energy during deposition. Therefore, it is prone to dolomitization and meteoric dissolution respectively during contemporaneous–penecontemporaneous hot-dry and hot-humid periods, and especially the Caledonian–Early Hercynian denudation wedge out tends to undergo post-supergene multiphase karstification. Therefore, quality reservoirs are more developed on scale. Thirdly, the intergranular pores and vermes moldic pores were dissolved and enlarged due to the multiphase atmospheric fresh water leaching, and together with tectonism, grain bank facies controlled multicyclic laminated–quasi-laminated, fracture-pore and cellular vuggy karst reservoirs were formed. more...
- Published
- 2016
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44. The Monotis–Dactylioceras Bed in the Posidonienschiefer Formation (Toarcian, southern Germany): condensed section, tempestite, or tsunami-generated deposit?
- Author
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Arp, Gernot and Gropengießer, Sebastian
- Published
- 2016
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45. Ichnological analysis of the Lower Morne L'Enfer Formation, Cedros Bay, Trinidad, West Indies: evidence of delta asymmetry
- Author
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Shaliza Ali, Murray K. Gingras, and Brent G. Wilson
- Subjects
Delta ,010506 paleontology ,Fluvial ,Geology ,Trace fossil ,010502 geochemistry & geophysics ,01 natural sciences ,Skolithos ,Paleontology ,Tempestite ,Ichnology ,Ichnofacies ,Cruziana ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
The Pliocene Silt and Sandstone Members of the Lower Morne L'Enfer Formation at Cedros Bay, SW Trinidad, reflect mixed wave, fluvial and tidal influence. Integrated ichnological analyses of these deposits reveal that the prodelta and delta front successions vary notably along-strike. These along-strike variations fit well into an asymmetric delta model. Trace fossil assemblages on the downdrift side of the delta lobe are characterised by diminutive, morphologically simple and facies-crossing forms due to heightened riverine influence. Ichnofossil assemblages on the updrift side of the lobe are robust and diverse, as a result of persistent wave reworking, generally unstressed. Mud- and silt-dominated prodelta and delta front deposits in the downdrift region are characterised by a low abundance and low diversity trace fossil assemblage reflecting a stressed expression of the Cruziana ichnofacies. Slumping and scouring structures are common within the distal prodelta deposits. Prodelta to distal delta front intervals on the updrift side are densely bioturbated. These trace fossil assemblages are abundant and diverse, representing a proximal to archetypal expression of the Cruziana ichnofacies. These deposits coarsen upward into fine and -grained sandstone beds of the proximal delta front. Strong storm influence in the proximal delta front produced amalgamated tempestite beds void of bioturbation. Lower to middle shoreface deposits comprise fine grained sandstone dominated by robust burrows of suspension feeders attributable to a proximal expression of the Skolithos ichnofacies. more...
- Published
- 2020
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46. Facies and depositional environments of the Upper Muschelkalk (Schinznach Formation, Middle Triassic) in northern Switzerland
- Author
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Larryn W. Diamond and Arthur Adams
- Subjects
010506 paleontology ,Tempestites ,010502 geochemistry & geophysics ,Homocline ,01 natural sciences ,7. Clean energy ,Middle Triassic ,Article ,Sedimentary depositional environment ,Paleontology ,Facies associations ,550 Earth sciences & geology ,0105 earth and related environmental sciences ,Sabkha ,Upper Muschelkalk ,geography ,geography.geographical_feature_category ,Homoclinal ramp ,Shoal ,Geology ,Tempestite ,13. Climate action ,Facies ,Sedimentary rock ,Marine transgression - Abstract
Subsurface sedimentary strata in northern Switzerland, such as the Middle Triassic Upper Muschelkalk, are attracting interest as potential reservoirs for CO2 sequestration and for geothermal energy production. Characterizing facies in such strata aids prediction of reservoir properties in unexplored areas. Although well studied elsewhere, the Swiss Upper Muschelkalk has received little attention despite containing the southern-most deposits of the Central European Basin. The Upper Muschelkalk represents the deposits of a storm-dominated, homoclinal carbonate ramp, developed during a basin- wide 3rd-order transgressive–regressive cycle. Our facies analyses of nine boreholes across northern Switzerland reveal 12 lithofacies, eight lithofacies associations and four types of metre-scale 5th-order cycles corresponding to at least 23 short orbital eccentricity cycles. During the 3rd-order transgression, crinoidal bioherms developed across Switzerland followed by deep-ramp environments. Subsequently, tempestites were deposited up to and after the basin-wide maximum flooding surface. Lateral tempestite correlations indicate that Switzerland lay within an open-marine, mid-ramp environment during almost half of the depositional history. Mid-ramp deposits pass upwards to prograding shelly shoals, which sheltered a back-shoal lagoon containing patchy oolitic shoals. At the top of the Upper Muschelkalk, back-shoal sediments give way to coastal sabkha facies, which were overlain by oolitic shoals during a marine transgression. Shortly thereafter the top of the Upper Muschelkalk was dolomitized by brines from an overlying hypersaline environment that was later removed by a basin-wide erosive event. Overall, the paucity of porous shoal facies, unlike in southern Germany, has resulted in poor primary reservoir properties in the Upper Muschelkalk of Switzerland. more...
- Published
- 2018
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47. Indication of calcareous tempestite inside the Qulqula Group in the Zagros Suture Zone, KRI
- Author
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Mushir M. Baziany
- Subjects
Paleontology ,Tempestite ,Suture (geology) ,Anatomy ,Calcareous ,Geology - Published
- 2016
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48. Genetic processes and environmental significance of Lower Devonian brachiopod shell concentrations in Longmenshan area, Sichuan, China
- Author
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Chengjin Yang, Fengjie Li, Junwu Li, Lingchun Du, Tingyong Dai, Yuchuan Yang, and Xuelin Qu
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Shore ,010506 paleontology ,geography ,geography.geographical_feature_category ,Taphonomy ,biology ,Intertidal zone ,Geology ,Storm ,010502 geochemistry & geophysics ,biology.organism_classification ,01 natural sciences ,Devonian ,Paleontology ,Protochonetes ,Tempestite ,Genetic model ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
The distinctive features of the Lower Devonian rocks of the Longmenshan area in southwestern China are brachiopod shell concentrations, especially in the Bailiuping, Ganxi and Xiejiawan Formations, where brachiopod shell concentrations occur widely throughout. Depending on the dominant skeletal elements, six types of shell concentrations can be distinguished: Protochonete, Acrospirifer, Howellella, Orientospirifer, polyspecific shell and polyspecific fragments concentrations. According to the shell features, taphonomic signature, host sediments and their relationships, four genetic models of the various shell concentrations are described in this paper. The genetic processes and distributions along an onshore–offshore area were clarified on the base of taphonomic analysis. Pavements of opportunistic species of Protochonetes are autochthonous assemblages living in quieter, deeper, more offshore waters near the maximum storm wave base. The pavements are the result of reduced sedimentation; the substrate was silty and water-saturated with variable turbidity soupy-mud. Transport by high-energy processes is interpreted as the final formation process of polyspecific fragments concentrations with most extensive scope from intertidal zone to the maximum storm wave base. The Acrospirifer, Howellella, and Orientospirifer concentrations have been stirred by storm wave action and quickly buried after short transport tempestite model. They are most easily preserved around the average storm wave-base. The polyspecific shell concentrations, which include large bivalves are autochthonous assemblages living in shallow and relatively quieter water near shore environments. Autochthonous assemblages of the opportunist Protochonetes bailiupingensis occurring in the Bailiuping Formation of the Longmenshan area not only record of storm events, but are also important features to identify and correlate the Bailiuping Formation in the field. more...
- Published
- 2016
- Full Text
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49. Analysis of marrow cavity fillings as a tool to recognise diverse taphonomic histories of fossil reptile bones: Implications for the genesis of the Lower Muschelkalk marine bone-bearing bed (Middle Triassic, Żyglin, S Poland)
- Author
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Monika Kowal-Linka
- Subjects
Taphonomy ,Micrite ,Paleontology ,Oceanography ,Calcirudite ,Diagenesis ,Petrography ,Tempestite ,Grainstone ,Lithification ,Ecology, Evolution, Behavior and Systematics ,Geology ,Earth-Surface Processes - Abstract
The bone-bearing bed from Żyglin (S Poland), which likely represents the oldest Lower Muschelkalk accumulation of reptile remains in the SE part of the Germanic Basin, has been investigated in order to determine its genesis. The basic methods were supported by petrographic analysis of the marrow cavity and large inter-trabecular pore space fillings of fossil bones, which was used to check its usefulness to identify the environments where the bones were initially deposited and to decipher taphonomic histories of the remains. The bone-bearing bed is a composite deposit, which consists of three distinct layers (from bottom to top): micritic limestone (mudstone, bioturbated autochthonous mud), crinoidal limestone (grainstone to packstone, calcirudite), and shell-rich limestone (packstone to wackstone, calcirudite). The crinoidal limestone layer, the main bone-bearing bed, is recognised as the proximal tempestite deposited in the mid-ramp zone. The petrographic analysis of the fillings reveals the prevalence of minute ostracod carapaces, accompanied by other grains, embedded together with micrite to microspar. Such compositions suggest that these sediments may have been inserted into the bone pore spaces in lagoons and tidal-flat ponds. Features of some bones record their early diagenetic burial and lithification before the final redeposition. The isopachous spar, blocky spar and weathered pyrite document changes in the chemical composition of fluids that flowed into the bone interiors. The burrow found in the marrow cavity of specimen IGUAM-ZOV-7 provides evidence that some remains were inhabited by minute or juvenile invertebrates. All recognised features indicate that both invertebrate and vertebrate bioclasts, included in the tempestite, were initially deposited in various settings of the carbonate ramp and in the end redeposited as a result of a heavy storm or a hurricane. The examined bone-bearing bed represents time-averaged assemblage, which originated due to hydraulic concentration of the vertebrate bioclasts. The petrographic analysis of the fillings is a valuable tool to identify complex taphonomic pathways of vertebrate bioclasts. more...
- Published
- 2015
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50. Storm Swash Deposition On An Embayed Rock Coastline: Facies, Formative Mechanisms, and Preservation
- Author
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Andrew Green, Shannon Dixon, and Andrew Cooper
- Subjects
Sedimentary depositional environment ,Headland ,geography ,geography.geographical_feature_category ,Tempestite ,Terrace (geology) ,Facies ,Geology ,Storm ,Sedimentary rock ,Geomorphology ,Swash - Abstract
Storm swash terraces mark the most distal, landward deposition of storm wave events on high-energy rock coasts. They form a potential, but as yet unexploited, sedimentary archive of past storminess. This paper describes storm swash terraces at Morgan Bay, Eastern Cape, South Africa. They form as steeply seaward dipping (30–60°), partially vegetated terraces comprising alternating beds of organic-rich sand, mud, and gravel. The terraces are up to 5 m thick, and the basal elevations range from 0.5 m amsl in the embayment, to 6.5 m amsl on the headland margins. Regardless of location, they are always fronted by a rocky shore platform on which most storm wave energy is attenuated. Six sedimentary facies are delineated on the basis of their lithological and paleontological characteristics and the nature of each bounding surface. Deposits in the most exposed headland locations are thicker and coarser-grained than those formed in the embayment. Composition of the depositional terrace reflects the fronting shore platform, indicating a short source-to-sink transport distance. The thickest storm deposits form where the backing topography is high and accommodation is limited. Storm swash terraces have a high preservation potential with successive storms depositing material in an aggradational manner: reworked material is incorporated into subsequent depositional units. The spatial controls on facies partitioning in each terrace appear to be a function of position in the embayment, the availability of material to seaward, and the presence of accommodation space. Areas of particularly limited accommodation space produce aggradational storm sequences that form especially good archives of marine storminess. more...
- Published
- 2015
- Full Text
- View/download PDF
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