Search

Objective The sedimentary palaeogeomorphology of the Permian Qixia Formation in Sichuan Basin has key influence over the distribution and evolution of carbonate reservoirs. Restoring and characterizing the sedimentary palaeogeomorphology of Gaoshiti area can gain further understanding of the distribution of favorable sedimentary facies and predict the distribution of high-quality reservoirs. Methods Based on the division of the third-order sequence, the high-resolution sequence stratigraphic framework was established by using geochemical proxies, petrological markers and logging markers. Two kinds of sedimentary microfacies, i.e. beach core and beach wing, were also identified. In addition, this study has calculated the difference of layer thicknesses in the sequence, and has identified different types of sedimentary sequences. A number of values including the beach core/beach wing value, Fe/Mn and MgO/Al2O3 ratios and other geochemical parameters were also calculated. The characteristics of the above parameters on the plane are analyzed and re-evaluated, which are all used to restore the palaeogeomorphic characteristics of the sedimentary period of the Qixia Formation in the study area. Results The result of research shows that the palaeogeomorphic characteristics of the 1st Member of Qixia are higher in the northwest and south, lower in the middle, and the palaeogeomorphic drop is obvious. Our new results show that the palaeogeomorphic highlands of the 2nd Member of Qixia are distributed in the middle of the study area, that the western palaeogeomorphology is low, and that the overall difference of palaeogeomorphology is small. Conclusion According to the results of ancient landform restoration, Gaoshiti-Moxi area forms a shallow water ring zone in the northeast-southwest direction where granular shoals are developed. Local micro-positive structures and granular shoals are developed in the south. However, the distribution of micro-positive structures is so limit that the extension range of granular shoals is limit. This study highlights that future exploration and development should focus on the development area of granular shoals in the northeast-southwest direction.

Radiocarbon dates on multiple individual charcoal fragments floating together down the Macdonald River, New South Wales, Australia, have calibrated ages spanning >1700 years. Partial explanations of this range of inherited ages can be attributed to the inbuilt age of living biomass, charcoalisation conditions, hillslope transport and storage and/or valley floor (fluvial) transport and storage, but the contribution of each of these components can be constrained only rarely. These results caution against using radiocarbon dating of charcoal as the sole dating technique to interpret Late-Holocene sedimentary histories. These findings also show that it is unlikely that deposit age has a dependable relationship to charcoal age. [ABSTRACT FROM AUTHOR]

Two impressed leaflet remains described here as a new species Pterocarpus emarginaticus Patel, Rana and Khan sp. nov., showing close resemblance with the extant leaflets of Pterocarpus marsupium Roxb. (Fabaceae), commonly known as the Indian kino tree, have been recorded from the Early Cenozoic sedimentary sequences of the Gurha opencast lignite mine (Early Eocene, Palana Formation), Rajasthan, northwestern India. The diagnostic macromorphological characteristics of the fossil leaflets are elliptical to obovate shape, microphyll size, acute base, characteristic emarginate apex, pulvinate petiolule, entire margin, brochidodromous secondary veins, presence of thin intersecondary veins and reticulate tertiary veins. This is reliable fossil evidence of leaflets similar to modern P. marsupium from India and abroad. The occurrence of this species and the earlier reported angiosperm, including Fabaceae taxa from the same formation, suggest the existence of a tropical, warm and humid climate during deposition. [ABSTRACT FROM AUTHOR]

Data on litho- and biostratigraphy of major sedimentary sequences and their geochronological records were compiled and summarized to describe the Late Pleistocene–Holocene marine and glacial events in the Kola-Northern Karelia region. In the coastal Kola Peninsula and its inner part, three marine units and two glacial events were identified in the Upper Pleistocene sequences. The first marine unit (Ponoi Beds in the regional stratigraphy) can be definitely referred to the significant Late Pleistocene transgression known as the Boreal in northern Eurasia. Data on the Kola Peninsula show that the warm-water Boreal transgression was longer than the Eemian one in western Europe, comprising at least MIS 5e-d (from 130–120 to 105–100 ka BP) in the White Sea depression and MIS 5e-c (earlier at least 90 ka BP) in the Barents Sea. Forested environments dominated on the Kola Peninsula at that time. The second Interglacial marine unit (Strelna Beds) attributed to the subsequent Belomorian transgression was deposited in relatively cold settings at the final phase of the Mikulinian Interglacial (MIS 5), about 100 to 70–80 ka BP. Adjacent areas were covered with open forest and tundra. The third marine unit referred to the Interstadial Leningrad Group was formed 60–40 ka BP in rather a cold marine reservoir, when the environmental conditions were more severe than now. The Late Pleistocene glacial events are correlated to the Podporozhie and Ostashkov Groups (MIS 4 and 2). The Podporozhian glacial unit seems to be associated with the Barents-Kara Ice Sheet and its melting caused the glacioeustatic transgression in the White Sea during the Leningradian Substage (MIS 3). During the Late Glacial and Holocene, a periglacial freshwater lake, brackish-water basin and marine reservoir successively appeared in the White Sea depression successively. Two marine events are suggested here based on the key sedimentary sequences from the coastal isolated lake, i.e. the Late Glacial transgression and the early-middle Holocene (Tapes) transgression. [ABSTRACT FROM AUTHOR]

Neoproterozoic tectonic evolution, magmatic activities, and sedimentary sequences are fundamental in understanding the transition from the dispersing of Rodinian continents to the assemblage of Gondwana and simultaneously supply crucial evidence for the global climate–environment change, i.e., from the Snowball Earth to a habitable Earth. In this contribution, we comprehensively synthesize the well-preserved Cryogenian–Cambrian sequences, multiple-phased magmatic activities, paleoclimate and environment in the Tarim Block of northwestern China to sketch a tectonic-sedimentary process from the breakup of Rodinia to the assemblage of Gondwana. We address the coupling between tectonic evolution process, glacial–interglacial cycles, paleoclimate and environment changes, and the formation of petroleum resources. In this study, we establish the stratigraphic frameworks in Kuruktag, Aksu, Tieklik areas in the northeast, northwest, and southwest of the Tarim Block, respectively. We review the differential geodynamic mechanisms and development processes of rifts in two discrete terranes, namely the North Tarim Terrane and South Tarim Terrane, of the Tarim Block to reconstruct the tectonic evolution process of Tarim during the Cryogenian–Cambrian interval and further decipher its control on the paleogeographic framework. The transition from extensional to compressional conditions during the early Cryogenian to Cambrian, combined with multiple phases of magmatic and glaciations, led to the three-stage evolution of sedimentary filling styles. We also document the evolution of glacial–interglacial cycles and how it impacts the paleoclimate and environment, sedimentary sequences, and the evolution and preservation of early life. The formation of organic-rich black mudstone/shale is attributed to the increasing nutrients in marine water and blooming of life in a warm-humid climate during interglacial periods; and thus, we propose the formation models of three favorable ancient petroleum source rocks in response to different tectono-sedimentary evolution stages and further estimate their quality, distribution, and resource potential. This review provides an improved understanding of the Cryogenian–Cambrian tectono-sedimentary evolution in the Tarim Block and its effects on the formation of ancient petroleum source rocks. It sheds insights into hydrocarbon accumulation theories and exploration strategies in ultra-deep ancient strata. • Stratigraphic frameworks in the northeast, northwest and southeast Tarim Block were established. • Tectonic evolution of the Tarim Block and its relationship with supercontinents were reviewed. • Multiple phases of magmatic events and glaciations affected paleogeographic framework. • Glacial-interglacial cycles controlled the formation of organic rich mudstone/shale. • Formation environment, model, and distribution of three sets of ancient petroleum source rocks. [ABSTRACT FROM AUTHOR]

Lago Chepelmut is a relatively small lake in size, of ellipsoidal shape, located in the outer fold-and-thrust belt of the Fuegian Andes (southernmost South America). High-resolution single-channel seismic profiles, integrated with geological information in the surrounding area, have allowed to reconstruct for the first time a bathymetric map of the lake and the architecture, distribution and thickness of the sedimentary cover. Two main seismic units were identified in the seismic records: (i) a Lower Unit of glacial nature, likely associated to the Last Glacial Maximum (LGM), and irregularly distributed through the basin, and (ii) an Upper Unit of lacustrine origin which drapes the entire basin. Submerged moraine deposits within the lake were also found from seismic data, and correlated with moraine arcs widespread distributed in the surroundings of the basin. These morphologies represent the recessional deposits left by the Ewan glacier lobe, one of the easternmost fronts of the Tierra del Fuego glaciers during the LGM. The lacustrine sedimentary record shows that the lake level was not constant through the recent history of the lake. Moreover, data analysis has shown that there is also an important structural component that has conditioned the evolution of the basin, in addition to that linked to glacial activity. [ABSTRACT FROM AUTHOR]

The Pennsylvanian to lower Permian succession at Madiyi, South China, represents a nearshore mixed siliciclastic‐carbonate system characterized by cyclic sedimentation patterns along a depth gradient from continental siliciclastics to marine open platform carbonates. Various palaeokarst features related to subaerial exposure are widely distributed. Additionally, pedogenesis was pervasive. The identification of twenty‐eight sedimentary cycles grouped into five sequences allows the reconstruction of a relative sea‐level curve. The cycles represent higher frequency changes superimposed on the long‐term evolution. After the initial transgression, the sea level remained relatively low in the late Bashkirian to early Moscovian. Then, it rose stepwise until a major drop occurred in the late Moscovian. Afterwards, the sea level rose again, but marine sedimentation ceased during at least the early Kasimovian. The area was flooded in the late Kasimovian, and the sea level rose until a late Gzhelian sea‐level drop. The subsequent marine sequence contains uppermost Gzhelian to upper Asselian deposits, which are capped by lower Permian continental facies associated with a major regional regression. Shallow to deeper marine sedimentary settings recorded high‐frequency sea‐level changes throughout South China during the late Bashkirian to Asselian. The main transgression–regression cycles are clearly associated with different depositional settings during several time intervals. Furthermore, the good correlations among South China, Ukraine, and the U.S. Mid‐continent are rooted in the impact of Gondwanan glaciations on the global sedimentation patterns. However, not all changes at Madiyi are the result of glacio‐eustatic sea‐level fluctuations; some are related to the local subsidence history and the rise of the Xuefeng Uplift. [ABSTRACT FROM AUTHOR]

Four lithofacies and 12 microfacies types recognized in an upper Aptian section in the Sierra de Bedmar-Jódar (Prebetic of Jaén) represent shallow lagoonal environments (marl and marly limestone) and sand bars that delimited the lagoon. The lagoonal facies reflect subtidal restricted water circulation with low energy. The sand bar facies (intertidal environment) have upper surfaces that show the effects of supratidal and subaerial conditions. The presence of early fractures in particular lithofacies shows the importance of local synsedimentary tectonics during sedimentation. Thalassinoides, ? Arenicolites, Diplocraterion, Circolites, Gastrochaenolites and Trypanites are recorded in different beds of this section, reflecting various states of substrate consistency, in the form of firmground, hardground, and rockground. Whereas firmground conditions were dominant in the lower part of the section, hardgrounds and rockgrounds are mainly present in the upper part of the section. Four types of shallowing-upward elementary sequence are recognized. All the sequences show at the base mudstone or wackestone microfacies representing a lagoonal environment, overlain by sand-bar grain-pack-stone facies corresponding to a bar bounding the lagoon. The factors that controlled their development were carbonate production and tectonic movements. [ABSTRACT FROM AUTHOR]

It remains unclear whether a crystalline basement exists in SE China (including Taiwan), whether the formation of the Tananao metamorphic belt in Taiwan was linked to subduction of the Palaeo-Pacific Plate, and whether the source rocks of the sedimentary sequences in the metamorphic belts are late Mesozoic or Palaeozoic in age. Field investigations and zircon age data in the present study indicate that there is no pre-Palaeozoic gneiss (crystalline basement) in Taiwan (although orthogneisses were produced during deformation and metamorphism of Mesozoic granites), and investigations of the metasediments show that the sedimentary sequences in the Tailuko and Yuli belts are similar. Moreover, LA-ICP-MS dating of detrital zircons from the Pingtan–Dongshan belt in Fujian Province yields a cluster of 206Pb–238U ages at ~ 210–190 Ma, and the Tailuko and Yuli belts in Taiwan have similar clusters of detrital zircon ages at 200 Ma, 160 Ma, 120 Ma and 110 Ma, as well as a later overprinting caused by arc–continent collision. The cathodoluminescence images and trace-element characteristics of the zircons show that they were originally magmatic in origin. This finding, combined with the Hf isotope data, indicates that the sources of sediments in the Tananao belt (Tailuko and Yuli belts) were relatively close to an active continental margin, and that both the Tailuko and Yuli belts have similar sedimentary sources. From the margin of the Chinese mainland to Taiwan, the metasediments seem to represent a continuous sequence of deposits ranging in age from Jurassic to Cretaceous, but with the sediments becoming progressively younger towards the east. It can be inferred that the sediments in the Tailuko and Yuli belts were continental-shelf sequences with sources in SE China. [ABSTRACT FROM AUTHOR]

The climatic changes in the Late Quaternary have led to a series of environmental changes in the coastal area of the southern North Sea. The Pleistocene landscape around the Jade Bay was gradually inundated and covered with Holocene coastal deposits during sea-level rise after the Last Glacial Maximum (LGM). In this context, a data base of 827 core logs and 8 piston cores was interpreted with regard to lithological indicators of environmental changes south of the modern Jade Bay. By the sedimentological and stratigraphical analysis of ancient extended salt marsh belts, silting-up zones and tidal flat / tidal channel complexes, the position, internal structure and extension of the land-sea interface was reconstructed in detail giving insight into principle processes and interactions taking place in this highly sensitive zone during sea-level changes. The Holocene coastal sediment sequence in the Jade area consists of four distinct lithological units representing semiterrestrial, brackish-lagoonal and shallow marine sub-environments. With regard to small scale sea-level fluctuations in the latest phase of the Holocene transgression, distinct periods of stagnation or even regression occurred. In contrast to the typical internal composition of the Holocene deposits of the backbarrier coast with a multiple alternation of landward and seaward facies shifts, indicating repeated shoreline displacements, the Holocene sequence of the Jade Bay is characterised by only one landward-seaward facies shift. However, the sedimentary record is displayed in complex sequences of clastic deposits of tidal flat and brackish environments and intercalated beds of autochthonous fen and raised bog peat. From 11th century, onward increasing human activity has significantly influenced the development of the coastal landscape by dike construction, dewatering and land reclamation along the entire coastline. Consequently, the former swamptype characteristic of the extended lower supratidal zone has significantly changed into a narrow belt of salt marshes restricted by an artificially fixed coastline and the decoupling of marine-terrestrial processes. In the light of recent regional sea-level curve discussions, the presence of sea-level index points is critically discussed, due to the widespread existence of thick peat beds. [ABSTRACT FROM AUTHOR]

Major Mediterranean deltas began to develop during a period between 8000 and 6000 yr BP when the rate of fluvial sediment input overtook the declining rate of sea-level rise. However, different authors have argued that the Ebro Delta primarily formed during the late Middle Ages as a consequence of increased anthropogenic pressure on its river basin and these arguments are supported by the scarcity of previous geological studies and available radiocarbon dates. To reconstruct the environmental evolution of the Ebro Delta during the Holocene, we used micropalaeontological analysis of continuous boreholes drilled in two different locations (Carlet and Sant Jaume) on the central delta plain. Different lithofacies distributions and associated environments of deposition were defined based on diagnostic foraminiferal assemblages and the application of a palaeowater-depth transfer function. The more landward Carlet sequence shows an older and more proximal progradational delta with a sedimentary record composed of inner bay, lagoonal and beach materials deposited between 7600 and >2000 yr BP under rising sea-level and highstand conditions. This phase was followed by a series of delta plain environments reflected in part by the Carlet deposits that formed before 2000 yr BP. The Sant Jaume borehole is located closer to the present coastline and contains a much younger sequence that accumulated in the last 2.0 ka during the development of three different deltaic lobes under highstand sea-level conditions. The results of this study reinforce the idea that the Ebro Delta dates to the early Holocene, similar to other large Mediterranean deltas. [ABSTRACT FROM AUTHOR]

Abstract: Geochemical and isotopic (Sm–Nd and Sr) studies of deposits of the Baikal and Oselok Groups in the southern Siberian Craton and LA-ICP-MS U–Pb dating of detrital zircons show that they accumulated in passive continental-margin settings in the Vendian. The time limits of sedimentation were assessed on the basis of Sr chemostratigraphy of carbonate deposits of the Baikal Group and LA-ICP-MS U–Pb dating of detrital zircons in first-cycle terrigenous deposits of the Oselok Group. The main provenances for rocks of these groups were constant. These were rocks of the cover and basement of the Siberian Craton. Tuffite horizons in upper portions of the groups are the only sign of Late Vendian activation of this block, which is reflected in changes of geochemical indices of terrigenous rocks and their younger Sm–Nd model ages. [Copyright &y& Elsevier]

The different hydrodynamic behaviour of detrital clay minerals in the marine depositional environment allows assessment of relative sea-level variations in the sedimentary record. Comparison of smectite and kaolinite:illite (S+K:I) changes with the global sea-level curves and with the third-order cycles of the eustatic curve for European basins allows assessment of the influence of global eustasy and local tectonics on sequence stratigraphy. In the South Iberian Margin, sedimentation took place both on open-marine platforms and in deeper water areas. On this margin during the Late Oligocene to Early Aquitanian, the variations in sedimentation were caused not only by global eustasy but also by compressive tectonics. Correlations were made between the S+K:I cycles and the third-order cycles for European basins, enabling the definition of four third-order sedimentary sequences (here called C1, C2, C3, and A1) and two lower-order sequences within C3 and A1 (here called C3a, C3b, A1a, and A1b) related to tectonic movements. High S+K:I values were observed during episodes of maximum flooding in each sequence and lower-order sequence and in each succession, enabling changes in palaeocoastal morphology to be considered. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Llancanelo Lake region (Southern Mendoza Province, Western Argentina) is a key area for investigating the regional evolution of a tectonic basin affected by intense arc- and back-arc volcanism. However, the lack of enough outcrops makes it difficult to perform such reconstructions. In order to solve this problem, and with the aim of depicting the subsurface stratigraphy, 22 geoelectric surveys reaching more than 100 m depth were performed. The applied methodology, that combined geoelectrical measurements and field observations, is a continuation of previous works carried out in the region, and allowed for the first time to establish a near-surface stratigraphy that records the last evolutive stages of the lake. The studied region is mainly composed of Quaternary volcanic and sedimentary sequences. Four units were recognized on the basis of the geoelectrical differences (resistivity signal) supported by field observations where they crop out. Two of them have very high resistivity and are composed of basaltic lava flows, hence indicating the volcanic influence in the region. The other two have very low resistivity and correspond to sedimentary deposits, being the uppermost one composed of lacustrine sediments. The units were named according to the well-known stratigraphic scheme valid for the region. The studied stratigraphic sequence encompasses the time-span from the Pliocene to the present, and its interpretation allowed to establish the main evolutive stages, characterized by a complex interaction among tectonic, volcanic and climatic factors. The damming of the lake by basaltic flows and the consequent reduction of the lake''s extension at times of intensive volcanic activity is one of the most significant events in its evolution. [Copyright &y& Elsevier]

The third terrace of the Yellow River was well developed in Xunhua basin in the north-east margin of the Tibetan Plateau. The terrace was formed at ca 75 ka as dated by the optically stimulated luminescence (OSL) method. On the basis of grain size, magnetic susceptibility and palynological data, six episodes of the climatic change were identified in Xunhua basin; they include very warm and humid period during 120-114 ka, cool and dry period during 114-105 ka, warm and humid period during 105-98 ka, gradually cooling period during 98-85 ka, warm and humid period during 85-75 ka, very cold and dry period during 75-63 ka. The six stages of climatic change recorded in Xunhua basin correspond to the marine oxygen isotope stages (MIS) of 5e, 5d, 5c, 5b, 5a and 4, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Late Burdigalian to Langhian series (nannoplankton zones NN3 to NN5) are overlying unconformably, or are imbricated with Mesozoic strata of different ages. A description of the marine Cala d’Hort formation is given, which is overlain by the brackish to continental Cape Jueu formation. Based on micropaleontological studies, the presence of Aquitanian is doubtful. The interpretation of a “Langhian fore-deep” with “sedimentary klippen” is discussed. A comparison of the sedimentary sequences and biostratigraphy between Eivissa (Ibiza), the eastern Pre-Betics and Majorca is given. [Copyright &y& Elsevier]

Ubiquitous post-Variscan dolomites occur in Zn–Pb–Cu veins at the Nízký Jeseník Mountains and the Upper Silesian Basin (Lower and Upper Carboniferous siliciclastics at the eastern part of the Bohemian Massif). Crush–leach, stable isotope (oxygen and carbon) and microthermometry analysis of the fluid inclusions in dolomites enable understanding the geochemistry, origin and possible migration pathways of the fluids. Homogenisation temperatures of fluid inclusions range between 66 and 148°C, with generally higher temperatures in the Nízký Jeseník Mountains area than in the Upper Silesian Basin. The highest homogenisation temperatures (up to 148°C) have been found near major regional faults and the lowest in a distant position or at higher stratigraphic levels. Highly saline (16.6–28.4 eq. wt% NaCl) H2O–NaCl–CaCl2 ± MgCl2 fluids occur in inclusions. Na–Cl–Br systematics of trapped fluids and a calculated oxygen isotopic fluid composition between −0.9 and +3.0‰ V-SMOW indicate that the fluid was derived from evaporated seawater. Stable isotopic modelling has been used to explain stable isotopic trends. Isotopic values (δ13C = −6.0/+2.0‰ V-PDB, δ18O = +15.5/+22.5‰ V-SMOW of dolomites) resulted from fractionation and crystallisation within an open system at temperatures between 80 and 160°C. Rock-buffering explains the isotopic composition at low w/r ratios. Organic matter maturation caused the presence of isotopically light carbon in the fluids and fluid–rock interactions largely controlled the fluid chemistry (K, Li, Br and Na contents, K/Cl, I/Cl and Li/Cl molar ratios). The fluid chemistry reflects well the interaction between the fluid and underlying limestones as well as with clay- and organic-rich siliciclastics. No regional trends in temperature or fluid geochemistry favour a fluid migration model characterised by an important vertical upward migration along major faults. A permeable basement and fractured sedimentary sequence enhanced the general nature of the fluid system. Fluid characteristics are comparable with the main post-Variscan fluid flow systems in the Polish (Cracow-Silesian ore district) and German sedimentary basins. [ABSTRACT FROM AUTHOR]

Abstract: As part of the Gran Chaco, the Andean piedmont in Eastern Bolivia is characterized by a highly seasonal climate and large rainfall variability. It receives sediments from small drainage basins in the Subandean ranges. Therefore it should constitute a suitable sedimentary and geomorphic archive for the detection of past environmental changes. This study reconstructs Holocene landscape evolution along the Andean piedmont in the Bolivian Chaco by combining large-scale geomorphological analysis and the investigation of sedimentary sequences. Fluvial aggradation and channel avulsions are the dominant processes of piedmont construction, and were particularly pronounced during the mid-Holocene. This is interpreted to reflect a generally active landscape characterized by reduced forest cover as result of increased aridity. Widespread soil formation and landscape stability in all investigated catchments start after 4 cal ka BP indicating the onset of wetter conditions and successively denser forest cover in the Bolivian Chaco. Renewed sedimentation during the last millennium could imply a shift to more arid environmental conditions, probably in relation to larger-scale climatic phenomena such as the Little Ice Age (LIA). Particularly during the last centuries the fluvial system of the study area has undergone the most profound changes of the entire Holocene with sedimentation of very coarse sediments and subsequent incision. This reflects important changes both in discharge and sediment supply, and might be the result of either shorter-term climate changes or increasing human impact. [Copyright &y& Elsevier]

Chabahar Bay is located along the coast of Sistan province in SE Iran. This area is part of the coastal Makran zone (one of the geological zones of Iran), which had undergone sea-level changes along the Late Quaternary. Due to these processes, multiple sedimentary sequences and several paleoshorelines were created. In this investigation, by using the Geological Information System method, 21 paleoshorelines were recognized. In the borehole at the north of Chabahar Bay, we found 14 layers, which were related to Late Quaternary sedimentary sequences and correlated to glacial and interglacial periods. All layers of borehole were analyzed for grain size, sedimentary structures, and fossil content. Four radiocarbon measurements were done on the lowest and uppermost marine layers of borehole and on C7 and C21 of paleoshorelines. The lowest layer of borehole has 17,600 14C YBP date, related to Cataglacial or Flanderian Transgression, which outcropped at 15 m height and 5,300 m distance to the present shoreline. Sedimentary sequences showed four transgressions and retrogressions occurred from cataglacial to the present. On the other hand, from 4690 ± 40 YBP, 20 paleoshorelines have been created, for which the duration of each may have been about 230 years. [ABSTRACT FROM AUTHOR]

We studied upper Albian to Turonian shallow-marine shelf deposits (Ajlun Group) of west central Jordan along a NNE-SSW running transect. The carbonate-dominated succession includes few siliciclastic intercalations, claystones and shales, and can be subdivided into five formations. The Naur, Fuheis and Hummar Formations of upper Albian to upper Cenomanian age represent shallow subtidal to supratidal platform environments. The uppermost Cenomanian to middle Turonian Shueib Formation includes deeper water deposits of the inner/mid-shelf and locally TOC-rich black shales. Shallow-marine platform environments once again dominate the Wadi As Sir Formation (middle-upper Turonian). A new multibiostratigraphic framework is based on ammonites (mainly of the middle Cenomanian rhotomagense Zone to the middle Turonian woollgari Zone) and calcareous nannofossils (biozones CC 9–CC 11), supplemented by benthic and planktonic foraminifers and ostracods. It forms the base of a sequence stratigraphic subdivision, containing eight sedimentary sequences (S1–S8), which are separated by four Cenomanian sequence boundaries (CeJo1–CeJo4) and three Turonian sequence boundaries (TuJo1–TuJo3). This scheme allows the correlation of the platform succession from distal to proximal shelf areas in contrast to previous correlations using lithologic units. Furthermore, comparisons between the platform successions and sequence patterns of west central Jordan and those from neighbouring areas allow to differentiate local, regional, and global controlling factors of platform development within the study area. [ABSTRACT FROM AUTHOR]