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The East China Sea Shelf Basin (ECSSB) lies at the south‐eastern margin of the Eurasian Plate and was affected by the subduction of the Pacific Plate and the Philippine Plate. It experienced and recorded multistage tectonic inversions in the Cenozoic, especially in the Xihu Sag. In an attempt to investigate the evolution and mechanism of tectonic inversion, this paper presents numerical simulation results by the finite element method to the Xihu Sag. Combined with comprehensive structural analyses of seismic profiles, this paper determines the structural geometry of the sag for establishing a viscoelastic geologic model including six‐layer strata and nine major faults. Simulation results show that the boundary conditions of transtension and transpression control the inversion process that propagates from east to west, and the distribution of low compressive stress displays certain correlations with the distribution of oil deposits. Based on quantitative analysis of the vertical displacement field of the Xihu Sag, this paper identifies a tectonic inversion process, which indicates that the western part of the sag uplifts and the eastern part subsides during the first‐stage inversion; whereas the western part subsides and central‐eastern parts uplift during the second and third stages. The formation of the tectonic inversion is controlled by the adjustment of the stress field from dextral transtension to sinistral transpression caused by the change of subduction rates and direction of the Pacific Plate and the Philippine Sea Plate. [ABSTRACT FROM AUTHOR]

Using analyses of the lithology, sequences, paleoenvironment, and tectonic setting, the depositional system of the Carboniferous Huanglong Formation in the eastern Sichuan Basin was identified. The lithological characteristics of the Lower Member, Middle Member, and Upper Member were analyzed and classified. Before the use of carbon, oxygen, and strontium isotopes in the analysis, all of the geochemical data were tested for validity. On the basis of the Z values obtained from carbon and oxygen isotopes, the paleoenvironments of the three members were elucidated. Lower Member was dominantly an enclosed marine environment with intense evaporation and little freshwater input into the sea. Middle Member developed in a semi-enclosed to normal marine environment with many rivers. Upper Member was formed in a normal marine environment. The east Sichuan Basin was enclosed by paleouplifts before the deposition of the Huanglong Formation, forming a relatively enclosed depositional setting. Paleogullies developed in the Silurian strata that underlie the Carboniferous rocks; these paleogullies can be identified. On the basis of a comprehensive analysis, we propose that the Huanglong Formation developed in a platform system. Four microfacies were identified: supratidal flat, dolostone flat, grain shoal, and shelf microfacies. The high-permeability and high-porosity characteristics of the grain shoal microfacies are favorable for hydrocarbon accumulation, while the supratidal flat and shelf microfacies developed very few high-quality reservoirs. The paleogullies, in which increased amounts of grain shoal microfacies developed, controlled the distribution of high-quality reservoirs. [ABSTRACT FROM AUTHOR]

The late Ediacaran Billy Springs Formation is a little-studied, mudstone-dominated unit deposited in the Adelaide Rift Complex of South Australia. Sediments are exposed in an approximately 11 km × 15 km synclinal structure interpreted as a salt-withdrawal minibasin. The stratigraphic succession is characterized by convolute-laminated slump deposits, rhythmically laminated silty mudstones, rare diamictites and fining-upward turbidite lithofacies. Lithofacies are the product of deposition in a deepwater slope or shelf setting, representing one of the few such examples preserved within the larger basin. Although exact correlations with other formations are unclear, the Billy Springs Formation probably represents the distal portion of a highstand systems tract, and is overlain by coarser sediments of the upper Pound Subgroup. Diamictite intervals are interpreted to be the product of mass flow processes originating from nearby emergent diapirs, in contrast to previous studies that suggest a glacial origin for extrabasinal clasts. Within the spectrum of outcropping minibasins around the world, the sediments described here are unique in their dominantly fine-grained nature and overall lithological homogeneity. Exposures such as these provide an opportunity to better understand the sedimentological processes that operate in these environments, and provide an analogue for similar settings in the subsurface that act as hydrocarbon reservoir-trap systems. [ABSTRACT FROM AUTHOR]

The Tombador Formation exhibits depositional sequence boundaries placed at the base of extensive amalgamated fluvial sand sheets or at the base of alluvial fan conglomeratic successions that indicate basinward shifts of facies. The hierarchy system that applies to the Tombador Formation includes sequences of different orders, which are defined as follows: sequences associated with a particular tectonic setting are designated as 'first order' and are separated by first-order sequence boundaries where changes in the tectonic setting are recorded; second-order sequences represent the major subdivisions of a first-order sequence and reflect cycles of change in stratal stacking pattern observed at 102 m scales (i.e., 200-300 m); changes in stratal stacking pattern at 101 m scales indicate third-order sequences (i.e., 40-70 m); and changes in stratal stacking pattern at 100 m scales are assigned to the fourth order (i.e., 8-12 m). Changes in palaeogeography due to relative sea level changes are recorded at all hierarchical levels, with a magnitude that increases with the hierarchical rank. Thus, the Tombador Formation corresponds to one-first-order sequence, representing a distinct intracratonic sag basin fill in the polycyclic history of the Espinhaço Supergroup in Chapada Diamantina Basin. An angular unconformity separates fluvial-estuarine to alluvial fan deposits and marks the second-order boundary. Below the angular unconformity the third-order sequences record fluvial to estuarine deposition. In contrast, above the angular unconformity these sequences exhibit continental alluvial successions composed conglomerates overlain by fluvial and eolian strata. Fourth-order sequences are recognized within third-order transgressive systems tract, and they exhibit distinct facies associations depending on their occurrence at estuarine or fluvial domains. At the estuarine domain, they are composed of tidal channel, tidal bar and overlying shoreface heterolithic strata. At the fluvial domain the sequences are formed of fluvial deposits bounded by fine-grained or tidal influenced intervals. Fine grained intervals are the most reliable to map in fourth-order sequences because of their broad laterally extensive sheet-like external geometry. Therefore, they constitute fourth-order sequence boundaries that, at the reservoir approach, constitute the most important horizontal heterogeneity and, hence, the preferable boundaries of production zones. The criteria applied to assign sequence hierarchies in the Tombador Formation are based on rock attributes, are easy to apply, and can be used as a baseline for the study of sequence stratigraphy in Precambrian and Phanerozoic basins placed in similar tectonic settings. [ABSTRACT FROM AUTHOR]

Soft-sediment deformation structures are abundant in the Cambrian Zhushadong and Mantou formations of the Dengfeng area, Henan Province, China. Soft-sediment deformation structures of the Zhushadong Formation consist of fluidized deformation, synsedimentary faults, seismo-folds and plastic deformation; the Mantou Formation is dominated by small-scale horst faults, intruded dikes, fluidized veins, and seismo-cracks. These structures are demonstrated to be earthquake-related by analysis of trigger mechanisms, and may indicate the activity of the Qinling tectonic belt during the early Cambrian. Furthermore, the assemblages of soft-sediment deformation structures altered with time: large-scale, intense deformation in the Zhushadong Formation alters to small-scale, weak deformation in the Mantou Formation. This striking feature may have been caused by changes in hypocentral depth from deep-focus to shallow-focus earthquakes, indicating that the Qinling tectonic belt developed from the subduction of the Shangdan Ocean to the extension of the Erlangping back-arc basin. This study suggests that soft-sediment deformation structures can be used to reveal the activity of a tectonic belt, and, more importantly, changes in deformation assemblages can track the evolution of a tectonic belt. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous Fortress Mountain Formation occupies a spatial and temporal niche between syntectonic deposits at the Brooks Range orogenic front and post-tectonic strata in the Colville foreland basin. The formation includes basin-floor fan, marine-slope and fan-delta facies that define a clinoform depositional profile. Texture and composition of clasts in the formation suggest progressive burial of a tectonic wedge-front that included older turbidites and mélange. These new interpretations, based entirely on outcrop study, suggest that the Fortress Mountain Formation spans the boundary between orogenic wedge and foredeep, with proximal strata onlapping the tectonic wedge-front and distal strata downlapping the floor of the foreland basin. Our reconstruction suggests that clinoform amplitude reflects the structural relief generated by tectonic wedge development and load-induced flexural subsidence of the foreland basin. [ABSTRACT FROM AUTHOR]

The tectonics of the Virgin Islands Basin are controlled by the plate boundary between the Puerto Rico-Virgin Islands Microplate and the stable part of the Caribbean Plate. Several contradicting theories about the formation and development of this basin have previously been proposed. As part of the Danish Galathea 3 expedition, extensive marine geological investigations of the basin were carried out in March 2007 including sediment coring and acquisition of multi-beam and two-dimensional seismic data. This paper represents a summary of the key observations from the multi-beam and the seismic data set. The interpretation of these observations leads to the proposition of a tectonic model for the Virgin Islands Basin. The model consists of N-S to NW- SE directed extension combined with E-W trending sinistral strike-slip and the new structural evidence from the Virgin Islands Basin is entirely consistent with the most recently published GPS data. [ABSTRACT FROM AUTHOR]

Geochemical analysis of sandstones from the Sardar Formation (from two stratigraphic successions) in east-central Iran were used for identification of geochemical characterization of sandstones, provenance and tectonic setting. Sandstones in the two lithostratigraphic successions have similar chemical compositions suggesting a common provenance. Bulk-rock geochemistry analysis of Carboniferous sandstones from Sardar Formation indicates that they are mainly quartz dominated and are classified as quartzarenites, sublitharenites and subarkoses, derived from acid igneous to intermediate igneous rocks. Discrimination function analysis indicates that the sandstones of Sardar Formation were derived from quartzose sedimentary provenance in a recycled orogenic setting. Also, major and trace elements in sandstones of Sardar Formation (e.g., K2O/Na2O vs. SiO2) indicate deposition in a stable passive continental margin (PM). Chemical index of alteration (CIA) for these rocks (> 65%) suggests a moderate to relatively high degree of weathering in the source area. [ABSTRACT FROM AUTHOR]

This article deals with the stratigraphic record of a climatic or tectonic perturbation of an experimental coupled catchment-fan system. Following Bonnet & Crave's results (2003), which suggest that it is possible to differentiate between climatic or tectonic causes of surface uplift of an erosional topography from the record of sediment flux output, we design a new experimental device to test this proposition in the sedimentary signal. This device allows the study of a coupled erosion-sedimentation system at the laboratory scale for given and changing uplift and rainfall rates. On the basis of experimental results, we propose a methodology to study alluvial fan architecture from large-scale geometries to stacking pattern and sequence analysis. In these experiments, the erosional perturbation resulting from climate or tectonic forcing induces a typical dynamic in terms of both sediment supply and the ratio between the sediment and water supply, which controls the transport capacity. The four possible forcings (rainfall rate and uplift rate increase or decrease, respectively) then result in unique dynamics of the combined parameters such as the fan slope, apex aggradation, mean sedimentation rate, grain size distribution, bed thickness and frequency and facies stacking. We first analyse large-scale geometries (onlap, toplap, downlap or truncation) and then fine-scale sedimentological features (fining, thinning, coarsening, thickening) in order to discriminate the nature of the forcing. This conceptual model could be adapted to real world alluvial fans in order to recognize and separate the driving mechanisms from each other. [ABSTRACT FROM AUTHOR]

Six sequences, each with a distinct shape, stratal anatomy, bounding surfaces, lithofacies composition and stacking patterns, were identified in the Djebel Bou Dahar isolated carbonate platform which developed in a half-graben in the High Atlas marine rift basin during the Early Jurassic. Sequences are believed to have a complex, multi-process origin as the result of tectonic processes (regional subsidence and fault-block rotation) overprinting the eustatic signal. In addition, changing carbonate producers with shifting centres of deposition and relative accumulation potential influenced the filling and anatomy of the accommodation space that had been created by the hybrid tectonic and eustatic processes. Sequences I and II are tabular in shape and interpreted to primarily reflect the combined processes of uniform tectonic subsidence and eustacy which resulted in a ramp to shelf carbonate system with lagoon and tidal flat lithofacies. Onset of a rifting episode around the base of the Lotharingian and fault block rotation were responsible for the development of the angular unconformity with the underlying Sequence II, and the progressive development of a shallow-water isolated platform and the wedge-shaped depositional Sequences III to VI during the Lotharingian and Pliensbachian. Concurrent variations in palaeoceanographic conditions and in the carbonate factory caused a shift towards a flat-topped platform geometry with high-energy coated grains and sub-photic sponge-microbial deposition around the margin. The aggradational to retrogradational character of Sequences III, IV and VI is inferred to be a result of the combined effect of in situ carbonate production coupled with high rates of creation of accommodation space in the hanging wall. Environmental effects on carbonate production were the most probable cause for drowning of the Djebel Bou Dahar platform during the Toarcian but also influenced the filling and geometry of Sequences IV to VI. This study suggests that the commonly accepted model of pulse-driven sequence-development in half-grabens may not be fully applicable for the Djebel Bou Dahar, where a more continuous rotation at sequence scale, associated with subsidence pulses of the Djebel Bou Dahar block, seems to have interacted with eustacy and carbonate production to generate sequences. Continuous rotation is suggested by the presence of regular patterns of diverging strata and numerous minor exposure surfaces in lagoonal deposits of Sequences V and VI. In addition, this study demonstrates that eustacy and variations in the carbonate factory might be as significant as tectonics in sequence development and platform drowning in carbonate platforms within rift basins. This observation could imply that the effects of eustacy and the carbonate factory might not have been correctly recognized in other similar carbonate platforms due to a tectonic-biased interpretation. [ABSTRACT FROM AUTHOR]

Incised valleys are canyon-like features that initially form near the highstand shoreline and evolve over geological time as rivers erode into coastal plains and continental shelves to maintain equilibrium-gradient profiles in response to sea-level fall. Most of these valleys flood during sea-level rise to form estuaries. Incised-valley morphology strongly controls the rate of creation of sediment accommodation, valley-fill facies architecture and the preservation potential of coastal lithosomes on continental shelves, and affects coastal physical processes. Nonetheless, little is known about what dictates incised-valley size and shape and whether these metrics can be used to explain principal formation processes. The main control on alluvial channel morphology over human time scales is discharge; this is based on numerous empirical studies and is well-constrained because all variables are easily measured at this short time scale. Knowledge of long-term river evolution over a complete glacio-eustatic cycle, on the contrary, remains largely conceptual, experimental and based on individual systems because variables that are thought to drive morphological change are not easily quantified. In spite of this difficulty, existing models of incised-valley formation at the coast suggest that valley evolution is driven largely by downstream forcing mechanisms, highlighting sea-level and shelf gradient/morphology as the dominant controls on valley incision. Although valleys are cut by rivers, whose channels are a direct reflection of discharge, little empirical data exist in coastal areas to address the degree to which valley evolution is governed by upstream controls. The late Quaternary is the best time period to examine because it provides the most complete sedimentary record and many variables, including sea-level, tectonics, substrate lithology and drainage network characteristics, are accurately constrained. Here, 38 late Quaternary valleys along the coast of two different passive continental margins are compared, which suggests that valley shape and size are governed primarily by upstream, intrinsic controls such as discharge. Valley width, depth and cross-sectional area are found to be predictable at the highstand shoreline and are scaled with the size of their drainage basin, which has important implications for estimating sediment discharge to continental shelves and deep water environments during periods of low sea-level. [ABSTRACT FROM AUTHOR]

Brittle fault zones are among the geological formations, which demand particular attention during the design phase and also during the construction of underground structures. The characterisation of fault zones is one of the essential interdisciplinary tasks in the fields of engineering geology and geotechnics. The forecast of the rock mass model and detailed knowledge about the mechanical properties of the various fault rocks are of particular significance. The complexity of fault zones and their relevance for construction make it necessary to implement a projectspecific characterisation of the rock mass, which describes the relevant geological, hydro-geological and geotechnical rock mass conditions. In addition, the construction and economic background of each project has to be taken into consideration in order to get practical information for the tunnel design team. Considering this, a clear path from investigation, through the development of the engineering geological ground model, to geotechnical design and construction planning and construction is essential. The article summarizes the significant characteristics of fault zones and presents their practical implementation in a project- specific classification and description of types of fault rocks and fault zones. The intention is to illustrate the engineering geological characterisation of fault rocks and fault zones in order to provide the data needed for geotechnical and construction design. Sprödtektonische Störungszonen zählen zu jenen geologischen Formationen, denen im Rahmen der Planungstätigkeit und im Zuge der Bauausführung von Untertagebauten besonderes Augenmerk geschenkt werden muss. Die Charakterisierung von Störungszonen stellt eine der wesentlichen interdisziplinären Aufgaben der Fachgebiete Ingenieurgeologie und Geotechnik dar. Dabei stehen die Prognose des Gebirgsmodells und die Detailkenntnis über die mechanischen Eigenschaften der unterschiedlichen Störungsgesteine im Vordergrund. Die Komplexität von Störungszonen sowie deren bautechnische Relevanz machen eine projektspezifische Gebirgscharakterisierung erforderlich, welche die jeweiligen geologischen, hydrogeologischen und geotechnischen Gebirgsverhältnisse widerspiegelt. Darüber hinaus sind die bautechnischen und wirtschaftlichen Rahmenbedingungen des jeweiligen Projekts zu berücksichtigen, um verwertbare Informationen für die Tunnelplanung liefern zu können. In diesem Zusammenhang ist ein nachvollziehbarer Weg, von der Erkundung über die ingenieurgeologische Prognose und Modellbildung bis hin zur geotechnischen/bautechnischen Planung und Bauausführung, wesentlich. Der Beitrag fasst die wesentlichen Charakteristika von Störungszonen zusammen und präsentiert deren mögliche Umsetzung in projektspezifische Klassifikationen und Typisierungen von Störungsgesteinen und Störungszonen. Die Intention liegt darin, die ingenieurgeologische Charakterisierung von Störungsgesteinen und Störungszonen zu veranschaulichen, um darauf die geotechnische und bautechnische Planung von Untertagebauten aufbauen zu können. [ABSTRACT FROM AUTHOR]

New dates from Meso- and Neoproterozoic strata contribute to the recently defined Precambrian stratigraphical timescale of China agreed by the Subcommission on the Precambrian System, and the National Commission on Stratigraphy of China on Nov. 24, 2009. First, the age range of the Changcheng System, including the Changzhougou, Chuanlinggou, Tuanshanzi and Dahongyu formations has been constrained to 1.8-1.6 Ga. Second, the Jixian System including the Gaoyuzhuang, Yangzhuang, Wumishan, Hongshuizhuang and Tieling formations has been constrained to 1.6-1.4 Ga. Third, an as-yet unnamed (undefined) system (1.4-1.0 Ga) is only developed in the Xiamaling Formation at the Jixian section, Tianjing. Fourth, the Qingbaikou System, including the Luotuoling and Jing'eryu formations has been constrained to 1.0-0.78 Ga. Fifth, the Nanhuan System ranges between 780-635 Ma, and the Sinian System is within 635-542 Ma. However, according to a series of SHRIMP U-Pb dates from the late Precambrian in the Jiangnan Orogen Belt in South China Platform, the constrained strata will be redefined as in the upper part of the Qingbaikou System. To aid global geodynamics, it is useful to denote a late Precambrian section with unified, precise and high-precision chronological dating; this is here defined in North China Block and Jiaoliao-Korean Block. However, the Neoproterozoic Qingbaikou study in North China will be influence in whole Meso- and Neoproterozoic in the Jiangnan Orogenic Belt in between the Yangtze Block and the Cathaysia Block in South China. [ABSTRACT FROM AUTHOR]

This study highlights three-dimensional variability of stratigraphic geometries in the ramp crest to basin of mixed carbonate–siliciclastic clinoforms in the Permian San Andres Formation. Standard field techniques and mapping using ground-based lidar reveal a high degree of architectural complexity in channellized, scoured and mounded outer ramp stratigraphy. Development of these features was a function of location along the ramp profile and fluctuations in relative sea-level. Deposition of coarse-grained and fine-grained turbidites in the distal outer ramp occurred through dilute and high-density turbidity flows and was the result of highstand carbonate shedding within individual cycles. In this setting, high-frequency cycles of relative sea-level are interpreted on the basis of turbidite frequency, lateral extent and composition. Submarine siliciclastic sediment bypass during lowstand cycles resulted in variable degrees of siliciclastic preservation. Abundant siliciclastic material is preserved in the basin and distal outer ramp as point-sourced lowstand wedges and line-sourced early transgressive blankets. In mounded topography of the outer ramp, siliciclastic preservation is minimal to absent, and rare incised channels offer the best opportunity for recognition of a sequence boundary. Growth of mounded topography in the outer ramp began with scouring, followed by a combination of bioherm construction, fusulinid mound construction and isopachous draping. Intermound areas were then filled with sediment and continued mound growth was prevented by an accommodation limit. Mound growth was independent of high-frequency cycles in relative sea-level but was dependent on available accommodation dictated by low-frequency cyclicity. Low-angle ramp clinoforms with mounded topography in the outer ramp developed during the transgressive part of a composite sequence. Mound growth terminated as the ramp transformed into a shelf with oblique clinoform geometries during the highstand of the composite sequence. This example represents a ramp-to-shelf transition that is the result of forcing by relative sea-level fluctuations rather than ecologic or tectonic controls. [ABSTRACT FROM AUTHOR]

Dating of zircon cores and rims from granulites developed in a shear zone provides insights into the complex relationship between magmatism and metamorphism in the deep roots of arc environments. The granulites belong to the uppermost allochthonous terrane of the NW Iberian Massif, which forms part of a Cambro-Ordovician magmatic arc developed in the peri-Gondwanan realm. The obtained zircon ages confirm that voluminous calc-alkaline magmatism peaked around 500 Ma and was shortly followed by granulite facies metamorphism accompanied by deformation at c. 480 Ma, giving a time framework for crustal heating, regional metamorphism, deformation and partial melting, the main processes that control the tectonothermal evolution of arc systems. Traces of this arc can be discontinuously followed in different massifs throughout the European Variscan Belt, and we propose that the uppermost allochthonous units of the NW Iberian Massif, together with the related terranes in Europe, constitute an independent and coherent terrane that drifted away from northern Gondwana prior to the Variscan collisional orogenesis. [ABSTRACT FROM AUTHOR]

The late Hercynian tectonic evolution of the Calabria crust is characterized by peak metamorphic conditions up to 800 °C and 1000 MPa, and coeval mid-crustal granitoid emplacement at 304–300 Ma. To check if a post-collisional extensional framework, similar to that of other Hercynian massifs, can explain petrologic data, we model the pressure–temperature evolution of the crust during extension following granitoid emplacement. Model parameters are constrained by petrologic, geochemical and structural data. Computed P– T paths are characterized by nearly isothermal decompression followed by isobaric cooling, which show a good fit to petrologic P– T paths for duration of extension between 5 and 10 Ma. The model results, therefore, support an interpretation of the magmatic and metamorphic evolution of the Calabria crust in terms of the late Hercynian extension. In this framework, slab break-off is a reasonable explanation for the common evolution of the southern European Hercynian massifs. [ABSTRACT FROM AUTHOR]

Studies of Quaternary extensional faults indicate that they have instantaneous amounts of throw (0·4 to 4 m), average slip rates (0·05 to 2·8 m kyr−1) and frequency of recurrence (<40 000 years) accounting for the accommodation space required for the accumulation of peritidal carbonate parasequences (PCPs). Hangingwall sites and graben are characterized by fault down-dropping together with regional subsidence, and footwall sites and horsts by fault-related uplift alternating with periods of regional subsidence. The relative sea-level curves generated by these processes operating in a maritime rift setting are used as inputs to a forward stratigraphic modelling program SedTec2000 to simulate how fault-related changes in accommodation space can account for high-frequency PCP formation. Each instantaneous fault slip generates a flooding surface or aggradation in hangingwall and graben settings. High-frequency cycles in hangingwall sites are either symmetric (deepening then shallowing upward) or asymmetric (shallowing-upward). The major factor controlling cycle types is the balance between rates of carbonate accumulation and generation of accomodation space. High-frequency cycles in footwall sites and horsts comprise shallow subtidal facies, with no distinctive bathymetric trends, capped by erosional boundaries generated by footwall uplift. The modelled cycles are of the same thickness, with bathymetric trends and frequency to cycles commonly interpreted to be due to orbitally driven eustatic sea-level changes or autocyclic processes. These numerical experiments demonstrate that high-frequency PCPs can be generated by tectonic, fault-related processes, a hypothesis that is frequently discounted. [ABSTRACT FROM AUTHOR]

Geodynamic modelling indicates that the emergence of initially submarine convergent orogens above sea level can have a significant influence on their subsequent tectonic development. This is because of two effects. First, surface uplift under submarine conditions, and the resulting decrease in gravitational loads, tends to reactivate deformation in the uplifting part of the submerged orogen. Second, an increase in the rate of erosion associated with the emergence of land can cause increased exhumation rates, reduced thrust-front advance rates, narrowing of the orogen width, and a shift from slow deposition in piggyback basins to rapid deposition in the foredeep. These effects result from the ability of erosion to perturb mass balance at the orogen-scale. Based on these results, I hypothesize that the emergence of initially submerged orogens such as the Alps and Taiwan played a direct role in explaining major changes in orogen dynamics and basin evolution that are known to occur in these examples. [ABSTRACT FROM AUTHOR]

The structure, paleomagnetism and biostratigraphy of the Nishizaki and Kagamigaura formations on the southern Boso Peninsula, central Japan, were investigated to determine the chronographic constraints on the accretion, post-Late Miocene rotation and regional tectonics in the Izu–Bonin island arc collision zone. The geological structures on the southern Boso Peninsula are characterized by an east–west trending and south-verging fold and thrust belt that curves toward the northwest–southeast in the northwest extent of the Nishizaki Formation. Two stages of tectonic rotation were revealed by paleomagnetic and structural studies. The first is believed to have occurred after the accretion of the Nishizaki Formation and before the deposition of the Kagamigaura Formation, while the second is confidently correlated with the 1 Ma Izu block collision. The northwest extent of the Nishizaki Formation was rotated clockwise by approximately 65–80°, whereas the rotation was only 25–30° in the east, and 11–13° in the overlying Kagamigaura Formation. Radiolarian biostratigraphy suggests a depositional age of 9.9–6.8 Ma (Upper Miocene period) for the Nishizaki Formation and 4.19-3.75 Ma (Pliocene period) for the lower Kagamigaura Formation. These results indicate that the age of accretion and first-stage rotation of the Nishizaki Formation can be constrained to the interval of 6.80–3.75 Ma. This structure most likely represents the northward bending caused by collisions of the Tanzawa and Izu blocks with the Honshu island arc, and suggests rapid processes of accretion, collision, uplift and the formation of new sedimentary basins within a relatively short period of time (2.61–3.05 my). [ABSTRACT FROM AUTHOR]

The Dakota Formation in southern Utah (Kaiparowits Plateau region) is a succession of fluvial through shallow-marine facies formed during the initial phase of filling of the Cretaceous foreland basin of the Sevier orogen. It records a number of relative sea-level fluctuations of different frequency and magnitude, controlled by both tectonic and eustatic processes during the Early to Late Cenomanian. The Dakota Formation is divided into eight units separated by regionally correlatable surfaces that formed in response to relative sea-level fluctuations. Units 1–6B represent, from bottom to top, valley-filling deposits of braided streams (unit 1), alluvial plain with anastomosed to meandering streams (2), tide-influenced fluvial and tide-dominated estuarine systems (3A and 3B), offshore to wave-dominated shoreface (4, 5 and 6A) and an estuarine incised valley fill (6A and 6B). The onset of flexural subsidence and deposition in the foredeep was preceded by eastward tilting of the basement strata, probably caused by forebulge migration during the Early Cretaceous, which resulted in the incision of a westward-deepening predepositional relief. The basal fluvial deposits of the Dakota Formation, filling the relief, reflect the onset of flexural subsidence and, possibly, a eustatic sea-level rise. Throughout the deposition of the Dakota Formation, flexure controlled the long-term, regional subsidence rate. Locally, reactivation of basement faults caused additional subsidence or minor uplift. Owing to a generally low subsidence rate, differential compaction locally influenced the degree of preservation of the Dakota units. Eustasy is believed to have been the main control on the high-frequency relative sea-level changes recorded in the Dakota. All surfaces that separate individual Dakota units are flooding surfaces, most of which are superimposed on sequence boundaries. Therefore, with the exception of unit 6B and, possibly, 3B, most of the Dakota units are... [ABSTRACT FROM AUTHOR]

The article focuses on findings of a study on shallow water sandy braided river reservoir architecture. Topics include significance of the reservoir analytic hierarchy process (AHP); major reservoir located at the part of Minghuazhen formation and the Guantao Formation in Neogene; and results like formation of braided sand bar, and architecture of braided river.

The article talks about geological formation such as extensional tectonics, rifting, formation of sedimentary basins, cretaceous volcanism, emplacement of dyke swarms and development of hydrocarbon pools in and around Peninsular India. It talks of seismic profiles generated by Pre-Stacking and Depth Migration (PSDM) and Pre-Stacking and Time Migration (PSTM) processing techniques having great potential in mapping the basement faults. It also mentions mapping of dyke swarms and integration.