Sedimentological Research Research Articles

Eolian-fluvial succession in the Early Cretaceous from the Ordos Basin

Cretaceous eolian deposits are widely developed in North China, among which the Lower Cretaceous eolian (erg) sedimentary strata in the Ordos Basin are the most representative. Many studies have been conducted on eolian deposits in the Ordos Basin, especially the Luohe Formation; however, there is a lack of systematic sedimentology research and the corresponding research on the evolution of sedimentary facies. Therefore, to explore the Mesozoic drought events and the systematic evolution of the sub-tropical erg zone, this study reports the fluvial–eolian sedimentary sequences of the Early Cretaceous Luohe and Yijinhuoluo Formations in the Ordos Basin. Spatially, through detailed sedimentary lithofacies and structural analysis of different outcrops, the combination law of sedimentary facies can be determined. Based on this, a three-dimensional sedimentary model of erg is reconstructed. The erg environment is divided into three sub-environments: erg margin, erg margin–centre transition and erg centre. According to the evolution of the sedimentary facies, the sedimentary evolution from the Latef Jurassic to the Early Cretaceous in the Ordos Basin is divided into five stages. The Ordos Basin has experienced the delta, erg formation, erg deposition, erg shrinkage and evaporating salt-lake stages. The vertical sedimentary evolution indicates climatic oscillation in North China from the Late Jurassic to the Early Cretaceous. Under the control of the sub-tropical high belt, the Ordos Basin experienced a hot and arid climate during the Cretaceous, forming a widely distributed erg belt in the region. During this period, a small-scale climate shock occurred under the hot and arid background, changing the sedimentary environment.

Gravel-inlaid mud clasts as indicators of transport processes of subaqueous sediment gravity-flows

Much sedimentological research aims to understand the depositional processes by establishing the relationship between the transport processes of subaqueous sediment gravity flows (SSGFs) and the characteristics of their deposits. A distinctive type of gravel-inlaid mud clasts, which has been largely overlooked, is embedded with occasional granules or pebbles, and exhibits various angular shapes that are present in cores of SSGF deposits worldwide. SSGF deposits from four cored wells in the Liushagang Formation of the Weixi'nan depression, China, have been analyzed to explore the characteristics, distribution, and potential formation mechanisms of gravel-inlaid mud clasts, thereby revealing the transport processes of SSGFs. In the research area, SSGF deposits are dominated by gravelly high-density turbidites, sandy high-density turbidites, low-density turbidites, and hybrid event beds. Gravel-inlaid mud clasts are common in massive sandstones and bipartite or tripartite beds, exhibiting various distribution patterns. The erosional contact at the base of these beds, where coarse grains are partially embedded within the muddy substrate, indicates that gravel-inlaid mud clasts originate through processes of erosion and delamination. Their distribution from the lower to the upper part of massive sandstones and bipartite or tripartite beds suggests a floating process from base to top. The formation and distribution of gravel-inlaid mud clasts demonstrate the downflow transformation from high-density turbidity currents to low-strength debris flows, driven by the erosion of the underlying muddy substrate, ultimately resulting in the formation of hybrid event beds. The lofting of gravel-inlaid mud clasts increases the cohesion of the upper part of the high-density turbidity current, facilitating its transformation into a low-strength debris flow. Furthermore, the occurrence of gravel-inlaid mud clasts within massive sandstones clearly demonstrates that they are products of high-density turbidity currents rather than sandy debris flows. The identification of gravel-inlaid mud clasts and their distribution within deep-water deposits can be regarded as a reliable indicator for reconstructing SSGF transport processes from high-density turbidity currents to low-strength debris flows, ultimately transitioning into low-density turbidity currents.

Glacial history of the King Haakon trough system, sub-Antarctic South Georgia

The glaciated island of South Georgia in the sub-Antarctic is a key area for climate reconstructions, because it is positioned in the Southern Ocean amidst the core belt of the Southern Westerlies and the main fronts of the Antarctic Circumpolar Current. This makes it particularly susceptible to changes in local, regional, but also Southern Hemisphere-wide climate conditions. Marine-geological records recovered from its continental shelf therefore offer unique potential to constrain how ice masses in this part of the Southern Ocean responded to Quaternary climate change, but despite this, little glacial-geomorphological and sedimentological research has been done offshore South Georgia. Here, we present a new suite of glacial landforms, identified from high-resolution bathymetry data, supplemented with acoustic facies from sub-bottom profiles, in order to reconstruct the pre-Holocene glacial history of the King Haakon Trough System on the southwestern South Georgia continental shelf. Our data show numerous landforms common for phases of ice advance and retreat, which are interpreted to document the confluence of two major trunk glaciers during peak glaciation. Progressively elongated linear bedforms imply accelerated ice flow and/or softer sediment substrate towards the shelf edge and suggest that the South Georgia Ice Cap experienced streaming ice and behaved similarly to other palaeo-ice sheets. A grounding-zone wedge close to the shelf edge marks the position of maximum ice extent during a peak glaciation, while clusters of recessional moraines and three large morainal banks indicate repeated phases of staggered retreat. Multiple extensive ice advances are indicated by stacked till sequences within the sub-bottom profiles of the mid- and outer shelf. The second-to-last till generation appears to be slightly more extensive than the most recent glacial till, and could suggest that South Georgia may have had a similar glacial evolution to other sub-Antarctic islands. This paper complements two studies focusing on the Holocene depositional environments and their associated sedimentary processes in the same trough system, in an effort to elucidate an important part of the Quaternary evolution of South Georgia's marine environment.

A Novel Method for Analyzing Sandbar Distribution in Shelf-Type Tidal Deltas Using Sediment Dynamic Simulation

Shallow marine shelf sedimentation is a hot and difficult topic in today’s reservoir sedimentology research, and it is widely present in the world. The shallow marine shelf sedimentation is not only affected by complex hydrodynamic effects such as tides and waves, but also controlled by bottom tectonic features, forming a complex and varied sedimentation pattern. During the Middle Jurassic period, the northern part of West Siberian Basin was characterized by a shallow marine shelf sedimentary environment. In the central reion of this basin, a typical tectonic uplift zone developed, forming a tectonic background of “one uplift zone between two depressions”. Simultaneously, the dominant influence of tides in the shallow marine shelf environment facilitated the formation of a typical shelf-type tidal delta sedimentation system in the Jurassic strata of the northern part of West Siberian Basin. This sedimentation constitutes a significant natural gas reservoir, and it is important to investigate the sedimentary evolution of shelf-type tidal deltas and to clarify the internal structure and distribution of sedimentary sand bodies and interlayers in shelf-type tidal deltas, which is the basis for the fine development of this type of reservoir. This paper takes the Jurassic strata in the Y region of northern part of West Siberian Basin as the research object, and conducts numerical simulation based on sedimentary dynamics for the shelf-type tidal delta sedimentation formed under the tectonic background of “one uplift zone between two depressions”. In addition, tidal amplitude and initial water level were selected for different hydrodynamic factors to study the main controlling factors of shelf-type tidal delta sedimentation. The simulation results show that tidal amplitude is positively correlated with three-dimensional configuration characteristic parameters of the sedimentary sand bodies, and the development of tidal bars becomes more and more limited as the initial water level increases. This paper systematically investigates the sedimentary evolution of shelf-type tidal delta under the tectonic background of “one uplift zone between two depressions” by the sedimentary dynamics method, which deepens the understanding of the shelf-type tidal delta sedimentation process and provides a new thinking for the development of this sedimentary reservoir type (School of Geosciences China University of Petroleum (East China)).

The discrimination of tidal- and fluvial-dominated sedimentary systems based on quantifying the degree of serration in gamma-ray logging curves: East China Sea Shelf Basin

Using quantitative methods to distinguish tidal- and fluvial-dominated sedimentary systems is currently a challenge in sedimentological research. This paper establishes and verifies a new quantitative method through the degree of serration of gamma-ray logging curves. This method depends on the fundamentals of core-based and gamma-ray logging pattern interpretation of the depositional environment, using one-dimensional continuous wavelet transform to denoise the initial curve to enhance the effects of tides and rivers processes, and then expands to an analysis of the degree of serration in noise-reduced gamma-ray curves. The results may then be used to constrain a single best-boundary value to distinguish a tidal- or fluvial-dominated area, avoiding subjectivity and uncertainty. A case study of the Pinghu Formation showed that the degree of serration (defined here as DeltaGr) of the fluvial-dominated sediments was less than 10 in the depth dimension and that the average degree of serration (defined here as the average square of DeltaGr) was less than 7 in the layer dimension. Values that deviate from these imply a close relation to tide-dominated sedimentary systems, which provides a quantitative basis for the interpretation of sedimentary environments in both the depth and layer dimensions in the Pingbei Slope. Seismic attribute-based sedimentary analysis, relative sea-level changes, and the basin architecture of the Pingbei Slope clarify the reason for these changes and verify that this method is reliable. However, owing to the limitations of logging and core samples, the criteria remain an approximation of the actual situation. This study may, however, enable the discrimination of other similar sedimentary systems dominated by tidal and fluvial processes and therefore provide a further constraint on the reconstruction of the filling of basins.

Optimization Method for Water-Flooded Beach-Bar Sand Bodies: A Case Study of the Fourth Member Red Beds of the Paleogene Shahejie Formation in the Dongying Depression

As water flooding continues to advance in mature oil fields, conventional well logging curve responses exhibit anomalies, particularly in deep-seated beach-bar thin-layer sand bodies. These sand bodies exhibit strong vertical and planar heterogeneity, which hinders a clear understanding of their distribution and connectivity. This paper conducts a sensitivity analysis of the lower part of the 4th member of the Shahejie Formation in fault block C26, based on core data analysis and the integration of drilling, logging, recording, and production dynamic data. Natural potential and resistivity curves are selected as the sensitive curves for identifying sand bodies. Preliminary processing of well logging curves is carried out using the “standard layer constraint and multi-standardization method comparison” principle. Employing sedimentological research methods and the principles of wavelet transformation, the well logging curves within the study area undergo extraction of both high and low frequencies. This procedure accentuates details related to thin sand bodies and responses indicative of sedimentary cyclicity. Through a thoughtful amalgamation of multiple curves, the investigation achieves a systematic fusion of natural potential curves via multi-curve frequency division fusion, employing reconstruction optimization. This method adeptly mitigates interference stemming from water-flooded layers, effectively addressing challenges such as excessive calibration and ambiguous identification of sand bodies. As a result, a comprehensive analytical approach is established for assessing the distribution and connectivity of deep-seated, beach-bar thin sand bodies influenced by water-flooded layers, providing clarity on the connectivity relationships among the sand bodies. Additionally, in combination with the results of mercury injection experiments in the water-flooded layer segments, favorable reservoir criteria for the study area are determined, providing a scientific basis for adjusting future development plans.

Environmental and Human Impact on Gully Erosion Recorded in Fan Sediments: A Case Study of the Vilnius area, Lithuania

Abstract Geomorphological and sedimentological research carried out in the vicinity of Vilnius (SW Lithuania) aimed to determine the age and stages of development of gullies in relation to climatic conditions and human activity. Two gullies located on the northern slope of the Vilnia river valley were examined in detail. The sedimentological features of the sediments which form fans at the mouths of the gullies were analysed. Three main lithological units were distinguished. On the basis of radiocarbon datings, the beginning of gully erosion was determined to be in the Middle Ages. This process began with intensive settlement in this area. Further stages of a cutting which were distinguished include early modern times and the period from the seventeenth century to the present day.

John Robert Lawrence Allen. 25 October 1932—18 October 2020

John Allen was one of the leading British geologists of the late twentieth century, who changed his primary research focus in mid career from clastic sedimentology to geoarchaeology. He read for a BSc degree in geology at the University of Sheffield, graduating with first class honours in 1955. He continued at Sheffield as a postgraduate student researching the geology of the Old Red Sandstone of the Clee Hills in Shropshire, but never submitted a PhD thesis. However, in 1958 the University of Reading offered him a research fellowship to investigate the geology of the hydrocarbon-rich River Niger delta region. In 1961 he became a lecturer in geology and a member of the new purpose-built Sedimentology Research Laboratory at Reading. The international renown of the laboratory was largely based on his prodigious sedimentological research output relating to sedimentary structures, river and coastal environments and Devonian continental deposits. He was appointed reader in 1967 and professor in 1972. In 1974 he led the founding of a taught MSc course in ‘Sedimentology and its applications’, which soon became a world leader. In 1988, in the context of the rationalization of university geology departments, Reading's department was selected for closure. However, John Allen's research esteem was such that a special case was made and a postgraduate-only institute specializing in sedimentology was established with him as director. He resigned the directorship after five years in favour of a research professorship. His objectives changed from orthodox old-rock studies to research on recent muddy estuarine sediments. By selecting the estuary of the River Severn as his new field area, he soon realized that this opened up a rich area of collaboration with colleagues in archaeology. His geological skills were subsequently applied to a range of archaeological problems. He became a key contributor to a new MSc degree course in geoarchaeology.

A database of detrital zircon U–Pb ages and Hf isotopic compositions from the Tarim, West Kunlun, Pamir, Tajik and Tianshuihai terranes

AbstractWith the development of detrital zircon U–Pb ages and Hf isotope analysis as conventional sedimentological research methods, a large number of studies have been conducted in the Tarim, West Kunlun, Tajik, Pamir and Tianshuihai regions and abundant data have been accumulated. Summarizing these data to characterize sedimentary units and source regions is more important than local studies of specific geological epochs; therefore, we compiled a database of detrital zircon U–Pb ages and Hf isotope analyses from the Tarim, West Kunlun, Pamir, Tajik and Tianshuihai terranes. The database contains data from 90 papers, including 35,281 individual U–Pb ages and 4,181 Hf isotope analyses. The database records the literature source, petrologic sample information, regional geological information, geographic coordinates and analytical parameters for each data point in as much detail as possible to allow readers to review, process, analyse and use the data. The database relies on the Deep‐time Digital Earth (DDE) platform and uses an open database update system to enable sharing and collaborative building. We encourage other researchers to contribute relevant published data to facilitate wider use.

Sedimentary Filling Evolution under Paleoclimate Transition—A Case Study from the Middle Jurassic Zhiluo Formation, Ordos Basin

Under a specific tectonic background, the change in paleoclimate can show different facies associations and depositional architecture. The Jurassic China continent was an important region for transforming the Paleotethys tectonic domain to the circum-Pacific tectonic domain, and its paleoclimate information was entirely preserved in the continental sedimentary successions. The Middle Jurassic Zhiluo Formation, in the Ordos Basin, was at just the critical period of paleostructure and paleoclimate transition, preserving considerable sedimentological evidence; however, little sedimentological research has been conducted under the transition. This study reconstructed the sedimentary filling characteristics of the Zhiluo Formation under paleoclimate transition based on field outcrop survey, thin section observation, geochemical indices, stratigraphic correlation, and depositional environment analysis. The results showed that with the paleoclimate change from warm and humid to hot and arid, the sedimentary facies of the Zhiluo Formation were characterised by the change from the braided river/braided river delta in the J2z1-1 sedimentary period to the meandering river/meandering river delta in the J2z1-2 sedimentary period, and finally the change to the meandering river, meandering river delta, and lacustrine in the J2z2 sedimentary period. The combined action of the southern super monsoon effect, the increasing global CO2 concentrations, the moving southward of the East Asian block, and the terrain elevation difference, changed the basin’s climate from warm and humid to hot and semi-arid/arid. This study provides a crucial basis for reconstructing the interplay between paleoclimate and paleotectonics, and guiding sedimentology and paleoenvironment research on East Asia during the Middle Jurassic period.

A classification scheme for sedimentary architectures arising from aeolian-fluvial system interactions: Permian examples from southeast Utah, USA

• Novel classification scheme for types of aeolian-fluvial interaction in ancient erg deposits. • Scheme applied to outcrops of Permian Cutler Group to enable 3D architecture analysis. • Classification scheme is generally applicable. • Classification scheme assists palaeoenvironmental interpretation. The preservation of the sedimentary deposits of arid environments is determined by both geomorphic and geologic processes. Sedimentary evidence of aeolian-fluvial system interactions in arid-climate settings are preserved in both recent and ancient sedimentary successions. However, despite considerable prior sedimentological research, there is no unifying scheme to provide generalized definitions of commonly occurring types of preserved aeolian-fluvial interactions. This study addresses this shortcoming by introducing a novel classification scheme for sedimentary architectures arising from such system interactions. The scheme is demonstrated through reference to examples from the Permian Cutler Group, Paradox Basin, Southeast Utah, USA – a sedimentary record of competing aeolian dune-field and fluvial-fan systems along a palaeo-coastline. Well-preserved, laterally continuous outcrops arranged in different orientations enable three-dimensional architectural characterization. The sedimentary record of eight distinct types of aeolian-fluvial interaction are identified: (i) water-table-controlled interdune sedimentation; (ii) deposits of low-energy fluvial floods; (iii) isolated fluvial channel-fills originating from episodic and confined flooding of interdunes in orientations parallel to the trend of dune crestlines; (iv) channel fills oriented perpendicular to the trend of dune crestlines; (v) amalgamated fluvial channel elements resulting from persistent, long-lived but confined dune-field flooding; (vi) deposits of unconfined sheet-like flood deposits; (vii) fluvial breaching of dunes and their reworking by catastrophic flooding; (viii) aeolian reworking of fluvial deposits. Each interaction type is characterized in terms of preserved sedimentary facies, architectural element geometries and associated proprieties, to demonstrate sedimentary variability in three dimensions. Results provide a guide with which to make sedimentological comparisons and interpretations between active systems and their preserved depositional record.

Source-to-sink system and sedimentary characteristics of the lower Miocene submarine fans in the eastern deepwater area of the Qiongdongnan Basin, northern South China Sea

As the main target of deepwater oil and gas exploration, submarine fans are also the frontier and focus of sedimentology research. Based on the latest three-dimensional (3D) seismic data covering the study area, as well as heavy mineral, rare earth elements, and other data and guided by the theory of seismic sedimentology, this study analyzes the lower Miocene provenance system and sediment dispersion system in the eastern deepwater area of the Qiongdongnan Basin, northern South China Sea, from the perspective of source-to-sink system research. Our research defines the sediment supply function of provenance, paleogeomorphology and valley transport system, sedimentation results and distribution, and the coupling relationship between the source–channel–sink system and comprehensively constructs a set of application guidelines of source-to-sink system research to guide the exploration and prediction of favorable play in the study area and other similar basins. This study shows that in the early Miocene, as controlled by tectonics and paleogeomorphology, uplift areas developed on both the northern and southern sides of the Songnan, Baodao, and Changchang Sags in the Qiongdongnan Basin and small provenances of near-sag uplifts were found in the southern part of the sag. The provenance area in the northern part of the sag was large but not unified, and it formed different provenance systems consisting of the Hainan Uplift in the northern Songnan Sag, Hainan Uplift in the northern Baodao Sag, and Shenhu Uplift in the northern Changchang Sag. A series of canyon systems that developed in the early Miocene were the main channels for sediment transport from the shelf to the slope in the northern Songnan, Baodao, and Changchang Sags. In the early stage of the early Miocene, due to regional sea level decline, the scale of the canyons was generally large, and the scale of the canyons on the northern edge of the Songnan Sag was significantly larger than that of the Baodao Sag. As the relative sea level rose, the canyons became small, narrow, and shallow in the late stage of the early Miocene. Under the dual control of the “source–channel” system, multiple “delta–canyon–submarine fan” depositional systems developed in the Songnan, Baodao, and Changchang Sags in the early Miocene, and large deltas in the depositional systems were mainly located along the northern part of the sag and prograded to the shelf edge of the northern Songnan, Baodao, and Changchang Sags from north to south, providing a good material basis for the development of deepwater sediments.

Nearshore Pelagic Influence at the SW Margin of the Paratethys Sea—Examples from the Miocene of Croatia

(1) The ancient Paratethys Sea was a spacious inland salt-water basin, extending from the Alps, over Central Europe, to Central Asia. The southwestern part of its central area, the Croatian part of the Pannonian Basin System (CPBS), is generally known for shallow-water deposition and biota. The main purpose of this paper is to emphasize the significance of its less widespread deeper-water deposits in environmental and applied geology. (2) The authors consulted the previously published data, combined with their own results, obtained from the paleontological and sedimentological research, seismic stratigraphy and well-log analyses. (3) During our research in the CPBS, we noticed the connection between the tectonic structures and deep marine canyons and depressions within the Paratethyan shallows. Such structures can be recognized on well-logs and seismic or surface outcrops. They are situated along the faults, and deposits are characterized by the domination of pelagic over the benthic biota, sometimes with visible selective dissolution of aragonite/calcite tests. (4) Studied sedimentary sequences from these structures proved to be a precious source of data on the transgressive-regressive cycles, ancient migrations, modes of deposition and hydrocarbon formation during the Miocene Epoch in the CPBS.

Trends of Geosciences after the Pacific War in Japan, 1945 to 1965 Part 7

Developments in geology, historical geology, sedimentology, and paleontology in Japan after the Second World War, from 1945 to 1965 are described. The Geological Society of Japan was reconstructed soon after the war and established the foundations for geological studies. The Tokyo Geographical Society compiled documents on geological research in East Asia before and during the war. The Coal Exploration Advisory Committee (CEAC) and the Petroleum Exploration Advancement Committee (PEAC) made progress on research related to oil and coal. New geological maps were compiled; the nomenclature of strata was formulated; and, regional geologies were summarized. Studies of Precambrian and Paleozoic strata continued to advance, while investigations on the geology of the Mesozoic challenged to establish theories posited before the war. Areas of studies such as “Green tuff,” radiocarbon measurement, tephrochronology, and neotectonics in the Cenozoic strata were opened up. Around 1950, sedimentological themes emerged; the Sedimentology Institute was founded at the University of Tokyo in 1951; and a sedimentology research group was formed in 1957. Research, for example, on recent sediments in Tokyo Bay were started. Soon after the war, the Palaeontological Society of Japan collated data on type species and their descriptions collected since 1868 for the development of palaeontological studies in Japan. Studies on Desmostylus, Naumann elephant, and Metasequoia fossils were launched. Micropaleontology including foraminifera studies made remarkable contributions.

Diachronous closure of the Mesotethys along the Shiquanhe-Namco mélange belt: Evidence from age and nature of the Aptian turbidites in Central Tibet

As a part of the Bangong-Nujiang suture, the Shiquanhe-Namco ophiolite mélange belt (SNM), together with the Bangong-Nujiang ophiolite mélange belt (BNM), records the evolutionary history of the Mesotethys. In terms of the closure of the Mesotethys, previous sedimentological research has focused on the BNM, while the SNM remains insufficient. On the basis of detrital zircon dating and sedimentologic data, in this study, we determined the existence of Aptian deep-marine turbidites in the Zhongcang and Lhakorco areas of the SNM. Sandstone petrographic and detrital zircon analysis combine to show that the Zhongcang turbidites provide records of the recycled from the accretionary complex and Triassic-Jurassic strata in the southern Qiangtang margin, with the minor addition of Qiangtang magmatic arc rocks, while sediments in the Lhakorco turbidites were derived mainly from recycled orogen source and Late Jurassic-Early Cretaceous magmatic arc in the Lhasa Terrane . Further analysis suggests that the Aptian turbidites were deposited in a deep-marine oceanic basin of Mesotethys and this oceanic basin prevented Qiangtang-derived sediments transported onto the Lhasa terrane. The Mesotethys experienced diachronic closure from east to west during the Early Cretaceous , and the final closure was most likely completed along the SNM after Aptian. • Discovery of the Aptian deep-marine fan turbidities in SNM • Featuring the Aptian Qiangtang and Lhasa source separation along SNM • Implications for diachronous closure of the Mesotethys

GlaciDat – a GIS database of submarine glacial landforms and sediments in the Arctic

A digital database for submarine glacial landforms and sediments formed in the Arctic during and since the Last Glacial Maximum was created in order to facilitate and underpin new research on palaeo‐ice sheets and tidewater glacier dynamics. The glacimarine database (GlaciDat) documents and standardises evidence of previous glacial activity as visible on the contemporary seafloor of fjords and continental shelves around Svalbard, Greenland, Alaska, northern Russia and north of 66°30′N in Canada and Norway. An extensive literature search was conducted to create GlaciDat, which compiles nearly 60 000 individual submarine landforms, more than 1000 sediment cores and 232 radiocarbon dates. Glacial landforms included are cross‐shelf troughs, trough‐mouth fans, grounding‐zone wedges, lateral moraines, overridden moraines, (mega‐scale) glacial lineations, drumlins, crag‐and‐tails, medial moraines, terminal moraines, debris‐flow lobes (including glacier‐contact fans), recessional moraines, De Geer moraines, crevasse‐fill ridges, eskers, hill‐hole pairs, crescentic scours, and submarine channels. They were digitised as point, line and polygon features alongside a list of their individual characteristics. Sediment core locations are attributed with a description of the sampled lithofacies and sedimentation rates where available. Landforms and sediments have been standardised according to predefined nomenclatures to make the glacial evidence as consistent as possible. Marine radiocarbon dates were included when thought to be relevant for constraining the timing of large‐scale palaeo‐ice dynamics. Outlines of bathymetric data sets, which have previously been used for glacial geomorphological mapping, were also included to give an overview of already investigated research areas. GlaciDat is available for download (https://doi.pangaea.de/10.1594/PANGAEA.937782) and will aid researchers in the reconstruction of past ice dynamics and the interpretation of Arctic glacial landform–sediment assemblages. Moreover, as well as providing a comprehensive bibliography on Arctic glacial geomorphological and sedimentological research, it is intended to serve as a basis for future modelling of Arctic glacier and ice‐sheet dynamics.

First fossil record in Tambería formation (Neogene) in Bolsón de Fiambalá, Catamarca province, Argentina: Palaeoenvironmental inferences through Leguminosae woods

The aim of this study is to report the first fossil wood record of Leguminosae in miocene sediments from Tambería Formation outcropping in the center-west of Catamarca province, Argentina. This Leguminosae specimen was found on levels of multi-colored sandstones that alternated with dark brown pelites and gray conglomerates. It is characterized by the presence of: semi-ring porous wood with vestured ornamented pits, helicoidal thickenings on the vessel walls, paratracheal parenchyma, homogeneous and multiseriate rays, all of which justify its assignment to Gleditsioxylon Müller-Stoll and Mädel. Six species are known and distributed in: Argentina, the United States, China and Japan in Miocene sediments coetaneous with sediments from Tambería Formation. The fossil wood specimen documented in this study is assigned to Gleditsioxylon fiambalense nov. sp. taking into account the combination of its anatomical features. Vulnerability and mesomorphy indices reveal its subtropical environmental condition which is not only typical of Gleditsia amorphoides, the current species, but also coincides with the palaeoenvironmental inferences derived from sedimentological research. This first paleontological record promises interesting analyses to understand the paleobiological and paleoecological aspects of the Tambería Formation and adds another new evidence to show the diversity of the neogene Leguminosae lignofloras of northern Argentina.

Tidal deposits in the Early Miocene Central Paratethys: the Vučji Jarek and Čemernica members of the Macelj formation (NW Croatia)

The Macelj formation is an informal Eggenburgian-early Ottnangian lithostratigraphic unit that is established in the area of the Hrvatsko Zagorje Basin, which represented a marginal zone of the Early Miocene Central Paratethys Sea. Modern studies, as a part of the Geologic Map of the Republic of Croatia 1:50 000 project, yielded new data that improves the knowledge of the depositional and stratigraphic characteristics of the formation. The sedimentological research within this study was focused on the two older lithostratigraphic units of the Macelj formation: the Vučji Jarek member and the Čemernica member. The Vučji Jarek mb. is represented by three facies. The Facies of horizontally bedded sandstones is characterized by mostly medium-grained, moderately sorted sandstones that reflect deposition on the foreshore to the upper shoreface. The facies of horizontally and cross-bedded glauconitic sandstones is composed of fine- to coarsegrained, well-sorted sandstones that indicate foreshore to shoreface deposition under tidal influence. The Facies of horizontally and cross-bedded pyroclastics consists of tuff, pumice, lapilli and large blocks, showing a chaotic structure in places. Deposition occurred at the shoreface under tidal influence. The Čemernica mb. is represented by the Facies of structureless clayey-silty sands that are poorly sorted and bioturbated, and indicates deposition below the fairweather wavebase, in the offshore-transition zone. Deposits of the members include marine macro- and microfossil associations. K-Ar dating of separated glauconite mineral fractions yielded an early Eggenburgian age for the Vučji Jarek mb. glauconitic sandstones (19.2±0.64 Ma) which is in accordance with biostratigraphical analyses. Sedimentological characteristics of the Eggenburgian Macelj fm., especially those that reflect the tidal influence, fit the general characteristics of the Central Paratethys Sea in the Early Miocene.

Major challenges and development in Chinese sedimentological research on petroliferous basins

Major challenges and development in Chinese sedimentological research on petroliferous basins

Sedimentology of the Godula Formation in the Moravskoslezské Beskydy Mts. (Outer Western Carpathians, Czech Republic)

The present account summarizes the results of lithological and facies analysis of representative sections of the Godula Formation, in order to contribute to the understanding of the lithofacies structure of this formation, the processes involved in its development and the character of the depositional environment. The sedimentology of different parts of the Godula Formation was investigated in six representative sections in the western and central parts of the Moravskoslezske Beskydy Mts. The Godula Formation is made up mainly of Upper Cretaceous siliciclastic turbidites and was formed during the most significant depositional phase of the filling of the deep-sea Silesian Basin. On the basis of sedimentological research, five facies classes (including four subclasses) were defined: 1) conglomeratic sandstones, 2) sandstones, 3) sandstones with mudstones, 4) mudstones with sandstones and siltstones, and 5) mudstones with siltstones. The methodology of facies analysis allowed the identification of several facies association, corresponding to the medial and distal parts of a turbidite fan and associated siliciclastic apron. The facies of depositional lobes, lobe transitions and the apron are described. The sandstone and mudstone facies (F3) occurs mostly in the depositional lobes. The sandstone facies (F2) and mudstone with sandstone and siltstone facies (F4) are present only to a lesser degree. The facies of the lobe transitions include lithologic associations of the lobe fringe and channel levee environments. They comprise mainly the mudstones with sandstones and siltstones (F4) and the mudstone with siltstone facies (F5). In the apron deposits, the sandstone facies (F2) and the conglomeratic sandstone facies (F1) predominate. Palaeocurrent analysis from measurements made in selected profiles showed that in the Moravskoslezske Beskydy Mts., the dominant direction of sediment transport was from SW to NE. After applying correction of the known counterclockwise rotation of the nappes of the Outer Carpathians, this corresponds to a longitudinal direction along the original axis of the basin.