The upper Oligocene Huagang Formation is crucial for oil and gas exploration in the central and southern Xihu sag of the East China Sea Shelf Basin. However,there has been ongoing debate on the sedimentary system,and limited research has been conducted on the characteristics of sand body architecture and the controlling factors. This paper studied the sedimentary environment,microfacies types,sand body architecture,and controlling factors of the upper Oligocene Huagang Formation through a comprehensive analysis of core,logging,and seismic data. The upper Huagang Formation in the central-south part of Xihu sag shows shallow-water delta plain sedimentation,with distributary channels being the predominant type of sand body. These distributary channels are categorized into three types based on their curvature: braided(curvature=1~1.05),meandering(curvature>1.15),and braided-meander transition(curvature=1.05~1.15). The sand bodies found in braided distributary channels are wide and thick,with intertwined wide bands. Channel bars in these channels are arranged in a speckled pattern. The sand body’s vertical stacking style is mainly characterized as incised stacking. In contrast,the sand bodies in meandering channels are narrow and thin,appearing as either single strip type or bifurcation-merging type in the planar direction. Thick sand layers are distributed as point bars in the channel margin,and the vertical stacking style is mostly isolated. The braided-meandering type of diversion channel is a transitional type between braided and meandering channels. It is characterized by moderate-sized channel sand bodies containing inner channel bars and point bars. The thickness and width of these distributary channels are positively correlated in a logarithmic manner. The ratio of width to thickness follows the pattern of braided type>transitional type>meandering type. The architecture characteristics of distributary channels are primarily influenced by paleogeomorphology and changes in base levels. Paleogeomorphology controls changes in channel types within shallow water delta plain,and low curvature braided distributary channels are more likely to develop in steep terrain. As the long-term base level increases,the size of distributary channels decreases,while a rise in mid-term base level has resulted in the transition of distributary channel sand bodies from incised to superimposed and isolated stacking types. This research enhances our understanding of the sedimentary structure of shallow water deltas and provides valuable guidance for predicting and developing distributary channel reservoirs in underground shallow water deltas within oil and gas fields.

The in-depth analysis of the development process of the delta front is of great significance for the judgment of the sedimentary environment,and it is necessary to deeply explore the formation characteristics and mechanism of the delta front from the perspective of hydrodynamics. In this study,the vertical distribution of the flow velocity in river water bodies and the development characteristics of delta front sedimentary bodies are investigated,from multiple perspectives of hydrodynamics,flume experiments,and underwater geomorphological observations. The results show that the phenomenon of river flow velocity,exhibiting a monotonic decrease with depth,has not been given sufficient attention. The terrain undulation of the middle and lower reaches of the riverbed increases with the flow direction,resulting in the underwater sand waves perpendicular to the flow direction,while the terrain undulation of the river section perpendicular to the flow direction becomes more and more gentle. During the process of rivers entering the sea,there will be a mainstream channel without branching channels underwater. Additionally,the originally undulating riverbed will gradually be filled up,changing from a sharp V-shaped or W-shaped to a U-shaped. It can be concluded that most of the front edge of the delta are sheet-like or fan-shaped,rather than a strip of erosion surface along the flow direction. Microfacies such as underwater distributary channels and bays do not develop in the delta front subfacies,which cannot be found in the modern delta front subfacies and are not supported by flume experiments. Furthermore,a water depth velocity interaction model for river channel and delta sedimentation is proposed.

This paper briefly describes the new achievements of oil and gas exploration in carbonates,deeply buried carbonate rocks,especially the genetic theory of dolomites at the 17th National Congress of Palaeogeography and Sedimentology. The relevant theme includes 55 oral presentations and 15 panels,which are related to(1)the genesis and reservoir of dolomite in Tarim,Sichuan,Ordos,Qaidam,Tuha and Bohai Bay basins,(2)formation,characteristics and preservation mechanism of deep and ultra-deep dolomite reservoirs,and(3)quantitative evaluation of bioliths and carbonate formation processes. It is worth recommending the study on the characteristics and genetic mechanism of high-quality,ultra-deep(10 km)dolomite reservoir,Exploration of the ultra-deep dolomite has become a representative result of the genetic theory of dolomite,guiding production practice. It is a supplement to the weak link in the application of basic research of dolomite genesis in the 21st International Sedimentology Congress(2022,Beijing)and in recent years. The summary of the characteristics and genetic mechanism of deep dolomite reservoirs in various parts of the Sichuan Basin comes from graduate students’ summary of the results of different university projects,which is very valuable. The theory of formation of deep dolomite reservoir,evaluation and exploration of high-quality ultra-deep dolomite reservoir is put forward. In particular,the laser ablation plasma mass spectrometry U-Pb dating technique has been widely used,which has realized the qualitative and quantitative analysis of the characteristics and genetic mechanism of dolomitization in geological time. The discussion of biolith is characteristic. They represent the close integration of sedimentology,lithofacies and paleogeography,mineralogy and petrology,new technology and dolomite genetic theory and practical application. The overall innovation depth,research means,system theory and application characteristics in oil and gas exploration deployment are significant,which is the highlight of this conference. Shortcomings are represented by the only one poster on marine reef dolomite. It is expected that the 18th Karamay Conference will further deepen the research in the above fields,and the topic of marine island dolomite research will be paid more attention.

Silicate rocks are factors that influence the global carbon cycle as well as climate change by chemically reacting with carbon dioxide,removing atmospheric carbon dioxide and sequestering it in weathering products or ocean carbonate rocks. Quantifying the total amount of carbon dioxide consumed by weathering of global silicate rocks is key to understanding the Earth’s current and past climate change. This paper systematically investigates the data sources,research methods,calculation formulas,and main influencing factors of five quantitative models of chemical weathering-CO₂ consumption of silicate rocks. The CO₂ consumption calculated by the latest Celine model serves as a reference standard for comparing the advantages,disadvantages and scope of application of each model. The existing models estimate the global carbon dioxide consumption of chemical weathering of rock silicate rocks to be 69-169 Tg/yr,in which the main parameters of each model include climate(temperature,runoff)and lithology,and the secondary parameters include tectonic uplift,volcanism and plant interaction. Future exploration of the quantitative calculation of carbon dioxide consumed by the chemical weathering of silicate rocks should consider more control effects and the interconnections between factors. In addition,the use of big data analysis methods to generalize these quantitative models to the reconstruction of the palaeoclimate of the deep earth may be a future research trend.

In recent years,oil and gas exploration in the Junggar Basin has gradually shifted from conventional traps outside the source to lithological traps within the source. The Upper Urho Formation is currently the main exploration target for boosting reserves and production in the basin. The distribution of sedimentary system has a controlling effect on the distribution of lithological reservoirs in the Upper Urho Formation. Using drilling cores,thin sections,combined with seismic data and drill cuttings and wireline logs,this study identified and characterized the sedimentary facies and depositional systems of the Upper Urho Formation in the Junggar Basin,and summarized the large-scale transgression. The sedimentary model of fan(braided river)delta-beach bar composite sandy conglomerate body was analyzed,and its controlling factors were analyzed. The results show that: (1)The study area is characterized by various sedimentary facies,including fan delta,braided river delta,and shallow lake beach bar. Among them,fan-delta plain and fan-delta front are mainly developed in the west of the basin,while braided river-delta plain and braided river delta front mainly developed in the east and north of the basin,and beach-bar is mainly superimposed on fan-delta and braided river-delta fronts or occurs independently at their front ends. (2)The depositional system of each member of the Upper Urho Formation developed under the background of overall lacustrine transgression. During the first member of Urho Formation,the basin was relatively small,and the deposited sand bodies were thick and of limited lateral extent,located in proximity to the depression center;during the second member of Upper Urho Formation,with continuous sediment supply and increased water depth the area of the lacustrine basin increased,with thinner but more extensive sand bodies deposited;during the third member of Upper Urho Formation,lacustrine transgression was enhanced,basin area was thus further expanded,and lacustrine mudstone was widely developed in the basinal area. (3)The fan(braided river)delta front-beach-bar composite gravel body was formed under continuous change of lake level and transformation of lake waves in the fan delta state and braided river delta front. (4)During the depositional period of the Upper Urho Formation in the Junggar Basin,the main controlling factors of the depositional system were climate,source supply,lake-level changes,and palaeotopographic slope and palaeogeomorphology at the time of deposition. This study provides a geological basis for oil and gas exploration in the Upper Urho Formation.

The Ghadames Basin has become one of the significant basins for overseas exploration and project investment in China. Accurate understanding of the early Paleozoic sedimentary system and lithofacies palaeogeographic characteristics is the basis for further exploration and the key to establish the early tectonic-sedimentary evolution history of the basin. Based on the comprehensive analysis of core,seismic and logging data in Ghadames Basin,combined with the restoration of palaeogeomorphology,the sedimentary system and lithofacies palaeogeographic characteristics are discussed. The results show four types of depositional systems in the early Paleozoic of Ghadames Basin: alluvial fan,braided river,braided river delta and shallow marine. In the early and middle Cambrian,the Avalon terrane drifted toward the Baltic plate,the Proto-Tethys Ocean initially expanded,and the active continental margin was formed. During this period,the whole basin was dominated by continental deposits. During the Cambrian-Ordovician,the platform uplift and depression pattern was initially formed owing to the Caledonian movement. Large-scale denudation occurred in the western and northern parts of the Ghadames Basin,and large-scale glacier deposits were developed to form glacial moraine reservoirs. In the Early and Middle Silurian,the Palaeo-Tethys Ocean continued to expand,the sea level rose,and a extensive transgression occurred in the northern part. Shallow marine sedimentary environment predominated in the area during this time,and hot shale and mudstone were widely developed which are important source rocks and cap rocks in the region. In the Devonian period,the Hercynian movement uplifted the region as a whole,and the sea area in the basin was reduced and replaced mainly by continental sediments. On this basis,the establishment of the marine-continental transition sedimentary model under the early Paleozoic Tethys Ocean evolution background in the Ghadames Basin is established,which can provide a reference for the next exploration work in the study area.

This study assesses the historical lakes in the lower reaches of the Yellow River using ancient documents,estimating the general shape and approximate area of over 130 ancient lakes during historical times. We have meticulously analyzed the extinction process of these ancient lakes and discussed the factors contributing to their demise. Our findings reveal that during the historical period,there were at least 135 lakes in the lower reaches of the Yellow River,covering a total area of 16195.64 km². These lakes were primarily situated along the ancient channel of the Yellow River,with small and medium-sized lakes(areas under 100 km²)constituting the majority. These smaller lakes accounted for 74.81% of the total number of lakes and 30.23% of the total area. Since the Song Dynasty,there has been a noticeable shrinkage in these ancient lakes. Among the smaller and medium-sized paleolakes,60.34% of 135 lakes have disappeared. Only 28 ancient lakes remain today,marking a decline of 79.26% in their number,and their total area has reduced to 4910.66 km²,a decrease of 69.68%. The study suggests climate change is the background for the extinction of ancient lakes. The sediment accumulation caused by the Yellow River avulsion and flooding is the direct reason for the disappearance of these ancient lakes. Meanwhile,human activities such as land reclamation around the lakes have accelerated this process.

It is of great significance for understanding the initiation and evolution of sandstone-type uranium deposits from the perspective of tectono-sedimentary evolution. In this study,based on a literature review,fieldwork,logging and seismic data,the tectono-sedimentary evolution of the Shizigou and Qigequan Formations in Qigequan Anticline in the Qaidam Basin and its links to the mineralization of sandstone-type uranium deposits are revealed. Our findings indicate that: (1)The Shizigou Formation is characterized by argillaceous-sandstone-rich stratum associated with retrogradation,while the Qigequan Formation is characterized by conglomerate-rich stratum associated with progradation. The Neogene-Quaternary angular unconformity developed between the Shizigou and Qigequan Formations and the Intra-Quaternary angular unconformity developed inside the Qigequan Formation. Large-scale alluvial fans,composed of debris flow,incised-valley-fill,and sheet flow deposits,were developed in the Shizigou and Qigequan Formations,and the sandy earthquake-induced soft-sediment deformation layers were frequently developed in the Shizigou and Qigequan Formations. (2)The most intensive uplift and denudation events occurred between the Neogene and the Quaternary,resulting in the initiation of the Neogene-Quaternary angular unconformity and the tectonic setting of the Qigequan Anticline. (3)It can be inferred that these potential uranium mineralization columns of the Shizigou Formation in the Qigequan Anticline developed in the uplift and denudation events between the Neogene and the Quaternary. The uplift and denudation events led to the initiation and evolution of the uranium-bearing structure,and increased the uranium flux from the source area and dominated the spatial distribution of the potential uranium mineralization columns ultimately. The Neogene-Quaternary angular unconformity can be used for the spatial distribution predicting of the potential uranium mineralization columns as a key tectonic identification mark. In addition,the thin interbeds of sandstone(including the conglomerate)and mudstone in the middle and distal parts of alluvial fans,with sand(including the conglomerate)percentage ranging from 20% to 50%,can be used for the spatial distribution predicting of the potential uranium mineralization columns as a key sedimentary identification mark. This research provides sedimentary and stratigraphic evidence for the basin analysis of the northeastern Tibetan Plateau and is of great reference value for the exploration of sandstone-type uranium deposits in other anticlines in the Qaidam Basin.

As a key interface connecting the deep-time Earth's internal and external systems,paleo-landscape reconstruction provides an important way for studying deep Earth sciences. The development of computer simulation tools makes it possible to reconstruct deep-time dynamic paleo-landscape. Badlands(Basin and Landscape Dynamics)and goSPL(Global Scalable Paleo Landscape Evolution)software are designed to understand the evolution of surface Earth system and its interaction with the solid Earth system,by combining factors of different spheres such as deep tectonic process,precipitation and sea level change. Based on these new technical basis,some achievements have been made,e.g. regional models that reproduce the topographic inversion and drainage reorganization processes in East Asia and global models that couple the landscape dynamics with the Phanerozoic diversification of the biosphere. However,some differences among different paleo-landscape reconstruction models arise due to uncertainty in elevation proxy indicators. In addition,it is difficult to make the simulated results to be completely consistent with the high-precision geological observation records. It is urgent to carry out global paleo-landscape models of ultra-high resolution in time and space.

Since the Mesozoic,North China experienced an abrupt landscape transition from the collapse of the paleo-plateau to the formation of the Bohai Bay Basin. The distribution of the Mesozoic North China Paleo-plateau and the Paleogene rifting in the Bohai Bay Basin have been well known. However,factors driving the Late Cenozoic landscape evolution of the region remain a subject of debate,due to major geological events,such as the uplift of the Taihang Mountain,the sediment transport and the evolution of the Yellow River and marine transgression. In this study,we used Badlands software to quantitatively analyze the contributions of mantle convection,tectonic events,paleoclimate change,erosion and deposition to landscape,respectively. We then reconstructed the paleo-landscape evolution of eastern North China since the Late Cenozoic(25 Ma). The credibility of the modeled results was validated by comparing with existing geological data on tectonic frameworks and sedimentary facies patterns. We suggested that the landscape configuration in eastern North China was primarily established during the Miocene,controlled by the subsidence of continental shelf sea. Notably,our model identified an ancient river,termed'the East China River' near the Shandong Peninsula,which formed no later than the Early Neogene and disappeared by the Holocene. Our results are of great scientific significance to the systematic study on the multiple-sphere coupling in the eastern North China Ocean-Continent Connection Zone.

A shallow water delta was developed in the Lower Jurassic period in the Dongdaohaizi sag,Junggar Basin,but its sedimentary evolution and main controlling factors were not fully understood. Through the analysis of well logging,core and geochemical data from the Dongdaohaizi sag and its surrounding areas,the sedimentary facies,paleogeomorphology and paleoclimate of this region were analyzed. The study identified three subfacies within the shallow water delta: delta plain,inner front,and outer front. The delta plain subfacies consisted mainly of distributary channels,forming glutenite layers over a hundred meters thick. The inner front featured medium-fine sandstone with argillaceous interlayers,while the outer front was mainly composed of sheet sandstone microfacies interbedded with mudstone and argillaceous siltstone. The paleogeomorphology of the area was higher in the east and lower in the west,categorized into paleo-highland,paleo-slope and paleo-depression based on relative positions and slopes. Analysis of geochemical indicators and sedimentary characteristics suggested fluctuations between humid and arid conditions during the Early Jurassic,with the lake level experiencing three progression-regression cycles. The progradation and regradation of the delta extended over tens of kilometers with the sedimentary distribution and evolution influenced by both paleogeomorphology and paleoclimate. The gentle overall paleogeomorphology provided a foundation for shallow water delta development,while regional paleogeomorphology height and evolution affected sedimentary system distribution and transition. Alternating dry and wet paleoclimate conditions affected lake level fluctuations,thereby controlling delta progradation and regradation. Through a comprehensive analysis,the progradational and regradational depositional models were established for shallow water delta sedimentary patterns,offering valuable insights into the impact of paleogeomorphology and paleoclimate on shallow water delta,and serving as a reference for future exploration in the area.

Given China's oil and gas demand and the endowment of domestic and foreign oil and gas resources,it is the era's responsibility and duty for various oil companies to use foreign oil and gas resources effectively to alleviate domestic energy demand pressure,in line with the trend of energy transformation and green energy development. Geological research serves as a fundamental aspect of oil and gas exploration and development. Accordingly,a special issue dedicated to foreign oil and gas geological research has been issued. To help readers better understand the five overseas regional research papers published in this issue,editors have written this article to introduce the overall research background,individual achievements,features,and the innovative understanding of these five overseas papers.

The Huaiyuan Movement is an important tectonic event in the early Paleozoic of the North China Platform,resulting in a regional unconformity. Based on outcrop data,geological maps,drilling data and new seismic data,the identification marks,types and distributions of unconformities formed during the Huaiyuan movement in the Ordos Basin were analyzed. The results show that(1)sandy conglomerate and weathered crust developed near the unconformity surface;additionally,high acoustic time,high gamma values,high content of trace elements(U,Th and K),high thorium-uranium ratios,low resistivity,and low density of logging curves occurred near the unconformity surface. The seismic response of the unconformity is characterized by a strong phase,and there are obvious differences in amplitude intensity,frequency and continuity in the wave groups on both sides of the unconformity. In addition,the truncation point reflections can be observed in local domain. (2)The Huaiyuan movement caused both parallel-unconformity and low-angle cutting unconformity in the basin. The former was widely distributed in the basin and its periphery areas,and the latter was distributed near the paleo-uplift in the basin. (3)The Ordos Basin and its periphery areas were affected by three stages of the Huaiyuan tectonic movement: during the depositional period of the Zhangxia Formation in the Middle Cambrian,uplift first occurred in the southeast region of the basin and then moved to the northwest direction;at the end of the Sanshanzi Formation deposition period in the late Cambrian,paleo-uplifts developed in the basin,and they were subjected to erosion; at the end of the late Cambrian, before the Ordovician Majiagou Formation was deposited,the negative drift of carbon isotopes first occurred in the bottom layer of Majiagou Formation due to the influence of global sea level decline. These results provides a reference for the research of new fields of oil and gas exploration in Lower Paleozoic in the Ordos Basin.

North Africa,located on the northern margin of the Gondwana continent in Paleozoic era,is one of the important oil and gas enrichment areas worldwide,experiencing two rift-sag-foreland basin evolution cycles,namely the Paleozoic Gondwana and the Mesozoic Cenozoic Tethys. Based on a comprehensive analysis of publicly available geological data and oil and gas exploration data,this article identified three types of petroliferous basins in the North African region: cratonic superimposed sags,rifts,and passive margin related basins;summarized two basin evolution cycles: Gondwana and Tethyan basin-forming cycle;clarified the controlling role of tectonic evolution on basin types,basin structures,and the development of source,reservoir,and cap rocks. Under the influence of the global plate tectonic evolution,different regions in North Africa have gone through five stages of tectonic evolution: (1)late Proterozoic-early Cambrian basement assembly and rift stage;(2)Cambrian-Early Carboniferous intra-cratonic sag stage;(3)Late Carboniferous-Early Permian Hercynian orogenic stage;(4)Late Permian-Early Cretaceous rift stage; and (5)Late Cretaceous-Present Alpine orogenic stage. Marked by the Hercynian orogeny,the basin features cycles that consist of the Paleozoic Gondwana Cycle and the Mesozoic-Cenozoic Tethyan Cycle. The evolution of the basins in western North Africa are dominated both by the Gondwana and Tethyan cycles,forming superimposed sag basins, while the evolution of the eastern basins are dominated by the Mesozoic and Cenozoic Tethyan cycle,forming the Mesozoic and Cenozoic rift basins and passive continental margin basins. Controlled by the development differences of basins,the source rocks of the western superimposed sag basins are developed mainly in Silurian and Devonian,with including the Paleozoic and Triassic reservoirs. The regional cap rocks are Silurian shale and Upper Triassic-Lower Jurassic evaporate. In comparison the source rocks of the eastern rift basins developed in Cretaceous,Paleogene,and Neogene,with pre-rift Paleozoic and syn-rift Mesozoic and Cenozoic reservoirs. The regional caprocks include the Late Mesozoic and Cenozoic evaporites rocks deposited in the rifting stages. Overall,the differential tectonic evolution in the North African controls the formation mechanism of petroliferous basins and the distribution of source,reservoir,and cap rocks.

Historically,two kinds of storm surge disasters occurred frequently along the coast of Jiangsu Province,which brought huge losses to this region. Establishing a long-term sequence of these disasters is crucial for understanding historical patterns and forecasting future events. Based on the records of storm surges in historical documents,local chronicles,marine disaster bulletins,etc.,a storm surge disaster identification system has been established,and the storm surge disaster sequence along the coast of Jiangsu Province from 1300 to 2019 has been reconstructed. Then,the temporal and spatial variation characteristics of the storm surge disaster along Jiangsu coast have been analyzed. Finally,the relationship between the storm surge disaster and climate anomalies,the evolution of the estuaries of the Yellow River and the Changjiang River have been explored. Our analysis of the temporal and spatial variations reveals that Jiangsu's coast experienced 246 storm surge disasters from 1300 to 2019,averaging one every 2.9 years,with a notable increase in frequency over the past century. There are 17,61 and 115 year time scale cycles in the interannual variation by wavelet analysis,of which the 115 year cycle is most pronounced. We observed that typhoon storm surges tend to decrease during active El Niño years,possibly due to air-sea interactions. Additionally,our study indicates a positive correlation between temperature rise and the frequency of typhoon storm surges,although the underlying mechanisms remain unclear. Geographically,Yancheng,Nantong,and Suzhou are the regions with high incidence of storm surge disasters,while Changzhou and Wuxi are less affected. Since 1855,climate warming and coastal erosion and siltation changes in Jiangsu Province,result in an increase in storm surge disasters in Yancheng and Nantong,and a significant rise in the Lianyungang region. Following the migration of coastline and the evolution of the Changjiang River estuary,the impact of storm surge disasters in Zhenjiang,Yangzhou,Taizhou,and Suzhou,Wuxi,and Changzhou regions has decreased.

Despite significant breakthroughs in oil and gas exploration in the glutenite section of the Qingshuihe Formation in the southern Junggar Basin,the sedimentary characteristics,genetic mechanism and controlling factors of the glutenite remain unclear,which has become a key restricting factor for hydrocarbon exploration. As such,we investigated the lower Qingshuihe Formation glutenite body in the western section of the southern Junggar Basin based on wireline logs,cores,outcrops and experimental data,with a focus on the lithofacies,lithofacies assemblage and distribution of the glutenite body,as well as their main controlling factors and genetic mechanism. Six types of lithofacies and lithofacies assemblages and genetically different glutenites are identified in the lowstand and transgression systems tracts of the Qingshuihe Formation in the western section of the southern Junggar Basin. The lowstand and transgression systems tracts of the Qingshuihe Formation in the southern Gaoquan area of the western section are dominated by alluvial fan and fan delta depositional systems,and braided river delta depositional system predominates the northern Caindic area. During the depositional period of the Qingshuihe Formation,glutenite sedimentation in the south western section of the Junggar Basin was affected by the nature of the parent rock in the provenance area,sediment supply and paleoclimate. Among them,nature of the parent rock in the provenance area and sediment supply control the sedimentary type and scale of the glutenite body. While paleoclimate affects the weathering and denudation degrees of the parent rock area and the sedimentary transport environment. Based on the controlling factors and sedimentary characteristics,a sedimentary model for the southern alluvial fan-fan delta and the northern braided river delta front of the Qingshuihe Formation lowstand and transgression systems tract in the western section of the southern Junggar Basin has been established,which can provide a geological basis to aid discrimination between different glutenite bodies and hydrocarbon exploration in similar settings.

The Jurassic Qigu Formation in the Yongjin area is a set of important oil-bearing strata in the central Junggar Basin. It is a typical deep-buried sandstone reservoir with a burial depth of 5400~6100 m,and its reservoir quality controls oil and gas reserves and production. In this paper,the diagenetic evolution process of deep-buried sandstone reservoirs in the Qigu Formation is studied by using the data of cast thin section,cathodoluminescence,scanning electron microscopy,XRD whole rock and clay mineral analysis. A diagenetic sequence is established,and the impacts of various diagenetic processes on reservoir quality are quantitatively assessed,integrating regional burial and hydrocarbon charge histories to delineate the reservoir’s diagenetic evolution. The lithology of the Qigu Formation reservoir in the Yongjin area is mainly composed of feldspathic lithic sandstone and lithic sandstone. The cement includes mainly carbonate minerals,siliceous minerals and clay minerals with low composition maturity and high texture maturity. The reservoir space types are mainly the remaining primary intergranular pores and secondary intergranular dissolved pores. Overall,the reservoir porosity changes are mainly controlled by compaction,cementation and dissolution,which are the main diagenetic factors reducing reservoir porosity,resulting in primary pore loss rates of 65.98% and 21.80% respectively. Dissolution increases the porosity by 5.13%,which effectively improves the physical properties of the reservoir. The comprehensive study shows that the diagenetic evolution of the Qigu Formation reservoir in the Yongjin area is mainly controlled by four factors: sedimentary environment,diagenesis,burial history and oil and gas charging. Diagenesis plays a role in the transformation of reservoir physical properties and is the critical determinant of the observed reservoir heterogeneity.

Carboniferous-Permian period was the key tectonic transition period in the ocean-continental transition in the eastern Xinjiang region,during which multiple oceanic crust closure and continental collision occurred. Due to the complexities of ocean basin properties,trench-arc-basin subduction events and land-land collisions in the eastern Xinjiang region,there is insufficient understanding of the late Paleozoic stratigraphic framework comparison and sedimentary filling characteristics in the basin. The theory of active tectonic palaeogeography was used to restore the tectonic-sedimentary features of basin-mountain tectonic belt in the eastern Xinjiang region,and the tectonic-sedimentary environment of each tectonic stratigraphic unit was determined. The prototype basin restoration was carried out comprehensively and dynamically from the perspectives of sedimentary filling,tectonic evolution restoration and the peripheral tectonic environment. The results show that the eastern Xinjiang region experienced five stages of extension and convergence cycles: Early Carboniferous extension,late Early Carboniferous-early Late Carboniferous weak extension,late Late Carboniferous compression,early Early Permian extension,and late Early Permian compression. Subsequently,5 tectonic transformation processes occurred: Late Permian,Late Triassic,Late Jurassic,Late Cretaceous-Paleogene and Late Cenozoic. The reconstruction of the basin-mountain tectonic pattern reveals that the southern boundary of the Tuha Basin in the Carboniferous period is approximately 46-70 km south of the present basin-mountain boundary. The Kelameili Mountains in the northern part of the eastern Junggar Basin during the Carboniferous period were approximately 30 km north of the current boundary. The northern orogenic belt of the Santanghu Basin in the Carboniferous period has a boundary of about 55 km south of the current boundary. The sedimentary environment experienced a transition from the Carboniferous marine to the Early Permian marine-continental transitional phase,and then to Middle-Late Permian continental facies. During the Carboniferous period,the marine arc-related rift basins,rift marginal basins and rift basins were developed. During the early Permian,marine and continental rift basins were mainly developed. During the middle Permian period,continental depression basins were mainly developed. During the late Permian period,compressional depression basins developed. The analysis of basin-mountain tectonic patterns and tectonic palaeogeographic evolution of the Carboniferous-Permian strata in the eastern Xinjiang region lays a good foundation for exploring the reservoir formation conditions and source-reservoir combination distribution of the Carboniferous-Permian period in the main sedimentary basins of the eastern Xinjiang region.

The‘Taishan earthquake’ named after Mount Taishan,occurred in 1831 BC,which was the earliest historical earthquake recorded by writing-materials in China. Bamboo Annals recorded that the strong earthquake occurred,when the emperor named “Fa” was climbing the Mount Taishan in the seventh year of Xia Di Fa(i.e.1831 BC). The earthquake shocked the emperor at that time,so for the first time,it was written and named after Mount Taishan. Apparently,the geographical position that the emperor “Fa” was threatened by the earthquake was at the hillside of the Mount Taishan. However,seismic geologists have been unable to find any seismic-geological records or traces of the historical earthquake in the Taishan area and its surroundings. Therefore,the epicenter and magnitude of the “Taishan earthquake” have been a mystery. By reobserving the discovered seismo-geological remains,combined with a series of tests,experiments and analysis,the paper provides evidences that the “Taishan earthquake” was a strong and historical earthquake with its epicenter located in the Anqiu area within the Tanlu fault zone. First of all,in the Holocene soft soil layers of limnetic facies in the Anqiu-Xiazhuang Basin of the Tanlu fault zone about 200 km away from Mount Taishan,there are macroscopical seismic traces such as seismic-subsidence synclines and co-seismic micro-faults,which recorded epicenter-intensity for degree of IX ,seismic magnitude for M7.0. Second,by means of the results of dating¹⁴C isotope,combining with calculating the sedimention time of the related soil layer,the earthquake time(i.e.1827 BC)obtained is very close to 1831 BC. Third,based on seismic intensity attenuation model in North China,the attenuation intensity induced by the earthquake is calculated to the degree of VI near Taishan. The Chinese earthquake intensity table shows that the VI intensity completely makes people stand unstable or escape outdoors,which accords with the historical records that the mountaineering emperor was frightened by the earthquake.

The boundary belt of the eastern margin of Ordos Basin is believed to be composed of the Jinxi flexural fold belt and Lishi fault,but this boundary is a residual boundary and not the original sedimentary boundary. Taking the northern region of Shillou as an example,a regional geological profile was constructed at the basin-mountain scale in the eastern part of the Ordos Basin. The 2D-Move software was used for inversion and forward simulation of tectonic evolution,and quantitative analysis of structural deformation was conducted. Based on theseresults,the eastern boundary of the Ordos Basin was redefined. (1)In the late Caledonian period,the northern part of the Shiliouarea was affected by deep basement fault activity,and salt detachment folds were formed in the Ordovician gypsum salt rock layers,followed by the deposition of the Carboniferous,Permian,Triassic,Jurassic and Cretaceous systems. During the Yanshanian,the strata were subjected to E-W compressive stress,causing the overall strata to tilt. In the Cenozoic Lvliang uplift,they accelerated and underwent differential weathering and erosion,forming the present tectonic pattern. (2)The present length of the regional geological profile is 263.76 km,with an altitude of up to 2000 m. The shortening of strata from the late Caledonian to the Cretaceous sedimentary period is 3.14 km,with a shortening rate of 1.18%. The elevation of the formation uplift is 3.82 km. (3)Based on the characteristics of stratigraphy,structure,and evolution,the eastern boundary of the Ordos Basin during the Yanshan Movement is redefined,and it is believed that the eastern boundary should extend easternward to the east side of Lvliang Uplift. This paper can provide a reference and new ideas for studying the eastern margin of the Ordos Basin,structural deformation,and coalbed methane exploration and development in the western Shanxi flexural fold belt.

During the Caledonian tectonic movement period,the Ordos Basin was uplifted as a whole in the Middle and Late Ordovician,and underwent deposition again in the Late Carboniferous. It has experienced nearly 150 million years of weathering and erosion,resulting in the development of an Ordovician carbonate weathering crust,which is highly important for natural gas accumulation. In this paper,a typical well was selected from the southern margin of the Ordos Basin. Based on the mineral composition,major and trace elements,and logging response characteristics,the vertical structure,degree of weathering and alteration,and paleoclimate environment of the weathering crust were analyzed,and the formation process and preservation mechanism were reconstructed. The results indicate that: (1)The weathered crust can be divided into a weathered residual layer,a strongly weathered layer,a weakly weathered layer,and a bedrock layer from top to bottom. The overall weathering degree is strong,and the logging response characteristics in each layer segment are very significant. (2)In this weathering crust profile,the main elements TiO₂,Al₂O₃,and Fe₂O₃ are enriched,with slight depletion of SiO₂ and strong depletion of Ca,Mg,and Na. (3)Based on paleolatitude data and relevant geochemical indicators,it is believed that the southern part of the Ordos Basin developed transitional sedimentary facies between sea and land during the late Paleozoic. The average annual temperature during the formation of weathered crust was 28.15 ℃,and it was in a humid-semi-arid environment,belonging to a tropical-subtropical climate. (4)The widespread development of cracks in each layer of the weathered crust indicates the existence of a karst fracture-cave system in the southern region of the Ordos Basin. Although the thickness of each structural layer of the weathered crust varies due to the influence of terrain elevation differences in the later stage,the probability of preserving the weathered crust structural layer is greater in areas with relatively flat terrain,suggesting that this location is favorable for later exploration of weathered crust gas reservoirs. These results can provide a reference for the exploration of oil and gas reservoirs in karst weathering crusts in the Majiagou Formation and aluminum-bearing rock series in the Benxi Formation in the Ordos Basin in the future.

Uplift processes of the southern margin of the North China Block are of great significance for understanding interactions between the Qinling Orogenic Belt and the North China Basin. Based on sedimentary facies analysis,this paper studies the detrital zircon U-Pb geochronology and fission track chronology of the Permian Shihezi Formation in Luonan area,and discusses the source characteristics and uplift processes of the southern margin of the North China Block. It is expected to provide a sedimentary constraint for the subduction time of the Mianlue Ocean Basin and provide a possible source area for the Triassic recycled sediments in the southern North China Basin. The results show that the Permian Shihezi Formation in Luonan area experienced an upward change in sedimentary facies from alluvial fan to braided river,and then to delta. The sample from the lower part of the strata contains three groups of U-Pb ages,i.e.,353-280 Ma,1139-400 Ma,and 2620-1306 Ma. The fission track ages are decomposed into three peaks of 199 Ma,255 Ma,and 408 Ma. The sample from the upper part of the strata contains two U-Pb age groups,i.e.,339-259 Ma and 2655-1700 Ma,and the fission track ages were decomposed into three peaks of 205 Ma,268 Ma and 656 Ma. The results show that the southern margin of the North China Block received sediment from the Qinling Orogenic Belt during the early sedimentary period of the Shihezi Formation,but the sediments mainly came from the northern margin of the North China Block in the late depositional stage. The tectonic pattern had been transformed from high in the south to high in the north in this time. The initial uplift of the southern margin of the North China Block occurred during the Middle-Late Permian,which was related to the initial subduction of the Mianlue Ocean Basin,and became a potential provenance area to the Triassic strata in the south of the North China Basin.

随着气候模式在古气候研究中的应用越发广泛，更加准确的古地理边界条件重建成为研究深时气候变化机制的关键，而古地理边界条件重建过程中的不确定性却少有人关注。本研究基于古海陆分布、古海深、古地形重建方法及资料选择，研究古地理边界条件重建过程中的不确定性以及其对气候模式模拟结果的影响。结果显示，重建过程中板块运动模型的选择、海陆分布的修正、海洋洋壳年龄数据的更新、大洋深度—洋壳年龄关系模型选择、沉积物模型选择以及古地形高度代用指标的选择都会导致不同的古地理边界条件重建结果。更重要的是，这种古地理边界条件的差异会进一步影响模式模拟结果中的温度、盐度以及洋流等重要的气候环境变量。这表明重建气候模式中古地理边界条件时需根据具体需求合理选择重建资料，同时也需基于密集和可靠的代用指标进一步优化重建资料，从而减少古地理边界条件对古气候模式结果可靠性的影响。

The trace fossils are well developed in the Neogene strata with the huge thickness in northern Qiongdongnan Basin. Based on detailed observation of the cores from seven drilling wells,combining with the thin section analysis,imaging logging and related experiments,the ichnofabric characteristics and sedimentary environment of the Neogene Sanya Formation were studied in detail. The results show that a total of 14 genera of trace fossils have been identified in the Neogene Sanya Formation in northern part of the Qiongdongnan Basin. Based on the types,occurrence,abundance and diversity of trace fossils,biodisturbance degree,and symbiotic relationship between biological burrows,five ichnofabrics can be classified. Among them,the Ophiomorpha-Thalassinoides ichnofabric was mainly developed in the upper shoreface,the Palaeophycus ichnofabric was mainly developed in the middle shoreface,the Planolites-Talassionides ichnofabric was mainly developed in the lower shoreface,the Phycosiphon-Planolites ichnofabric is mainly developed in the upper shallow sea,and the Phycosiphon-Chondrites ichnofabric was mainly developed in the lower shallow sea. Based on analysis of the ichnofabrics and logging facies,it is believed that the coastal and offshore sedimentary environment was mainly dominated in the Neogene Sanya Formation in the study area. The first section of Sanya Formation transited from coast to shallow marine,while the second section of Sanya Formation was mainly dominated by shallow sea deposition. Based on the analysis of lithofacies,fossils,ichnofabric characteristics,logging facies and sedimentary microfacies of Sanya Formation,the sedimentary model of Neogene Sanya Formation in the northern part of the Qiongdongnan Basin has been established. It has an important guidance for the hydrocarbon exploration of the Neogene in the northern South China Sea.

Based on 3D seismic and borehold data,seven seismic sequence boundaries and seven drilling sequence boundaries are identified in the Carboniferous carbonate platform of North Troyes Oilfield. The KT-I reservoir group is divided into three and a half third-order sequences,and the KT-Ⅱ reservoir group is divided into three third-order sequences. The sedimentary environment evolved stratigraphically from open platform,through restricted platform,to evaporative platform. According to the palaeo-geomorphic restoration and sedimentary evolution within the sequence framework of the study area,the palaeogeomorphic and sedimentary evolution of the study area can be divided into three stages: the initial phase of differential platform uplift and depression(SQ2-SQ3 sequence),the finalizing phase of differential uplift and sedimentary differentiation fixing period(SQ4 sequence),and the inherited development phase(SQ5-SQ7 sequence). Further analysis shows that the uplift and depression pattern under the control of sequence framework controls the plan-view distribution of dolomite subclasses. The lower part of the sequences are dominated by micritic dolomite-gypsum and micritic dolomite-micritic limestone assemblages,which are characteristic of mainly lagoonal lacustrine deposits,while the higher part of the sequences are dominated by micritic dolomites,fine micritic dolomites and residual micritic dolomites.The results show that deposition of the KT-I oil formation in the study area results from inherited differential subsidence,rather than erosion and subsidence of the “western highland and eastern lowland”as previously thought. The overall palaeogeographical pattern is characterized by “Platform in the east,trough in the west,high in the north and low in the south”,which consistently controls the development and distribution of favorable facies and high-quality reservoirs. This finding is vitally important in screening for hydrocarbon exploration and production prospects in Pre-Caspian Basin.

塔里木盆地顺北地区中下奥陶统鹰山组白云岩是极具勘探潜力的岩相类型，但目前对该地区成层分布的白云岩成因及其物性差异尚无系统阐释。本研究基于详细的岩石学观察、碳氧同位素和微区微量稀土元素分析、碳酸盐岩U-Pb定年、覆压孔渗测试等资料，对鹰山组内幕成层发育的白云岩类型、成因机制进行探讨，并初步评价了不同成因白云岩的物性差异。研究发现：（1）顺北地区鹰山组下段白云岩相对发育，主要包括2类成层分布白云岩，分别是埋藏压溶白云岩（Ⅰ类）和准同生渗透—回流白云岩（Ⅱ类）;（2）I类白云岩为埋藏白云石化成因，分布于低能沉积相内，为埋藏过程中缝合线建造驱动黏土矿物转化成因机制，在顺北中部地区较为发育；（3）Ⅱ类白云岩为准同生渗透—回流白云石化成因，主要分布于地貌较高、相对高能的沉积相区，在顺北西区、顺南地区相对发育；（4）Ⅰ类白云岩实测物性数据(φ:0.3%～1.0%;K:0.003×10^-3～0.074×10^-3μm²)低于Ⅱ类白云岩(φ:0.4%～2.0%;K:0.009×10^-3～0.055×10^-3μm²),但Ⅰ类白云岩的发育可提升地层中白云岩和灰岩互层的比例，具裂缝改造成储潜力。研究成果对于塔里木盆地顺北地区超深层白云岩油气勘探选区具有借鉴意义。

The sand bodies of the Member 2 of the Upper Triassic Xujiahe Formation in the Xinchang structural belt of western Sichuan Basin are widely distributed,with various types of sand bodies and large thickness differences. This results in uneven distribution of interlayer barrier bed and intraformational bed in gas reservoirs,and strong reservoir heterogeneity. Therefore,it is crucial to investigate the sedimentary microfacies,distribution characteristics and architecture of reservoir sand bodies,so as to lay a foundation for the following reservoir prediction and efficient gas reservoir development. Using core,well logs,3D seismic and laboratory data,and guided by the theory of high-resolution sequence stratigraphy proposed by T.A. Cross,the authors systematically examined the structural characteristics and controlling factors of sand bodies in the second member of Xujiahe Formation in the Xinchang structural belt,western Sichuan Basin. The results show that: The study area was largely located in a shallow water delta front environment,which consists mainly of subaqueous distributary channel sand bodies with subordinate mouth bar sand bodies. These channel sand bodies are characterized by frequent lateral migration,multiple vertical amalgamation and extensive areal coverage. It is concluded that in the study area there are two main categories and nine subcategories of sand body vertical stacking patterns and three lateral contact patterns. The structural characteristics and development patterns of sand bodies are controlled mainly by base-level fluctuation and river energy. Finally,the sedimentary facies and sand body development model of the Xinchang structural belt in western Sichuan Basin are established,which has important applications for guiding exploration and development of gas reservoirs in similar settings.

The newly discovered hyoliths yielded from the Lower Devonian of East Junggar of Xinjiang,China,are documented herein for the first time,including three genera and three species: Fuyunotheca wangi gen. et sp. nov.,Costulatotheca schleigeri Earp,2019,and Ottomarites sp. As a new genus and species,F.wangi gen. et sp. nov. is mainly distinguished by typically oblate oval to subtriangular cross-section,swollen dorsal side with a pronounced median ridge,ventral side weakly convex. Surface sculpture prominent transverse striations and weakly longitudinal streaks on both dorsum and venter,and several sets of remarkable ribs parallel to the aperture in the anterior third of the conch. Palaeoecological analysis shows that F.wangi gen. et sp. nov. is a kind of orthothecids,which could live in a normal,oxygenated shallow-marine environment with certain degree of hydrodynamics. Furthermore,based on the Devonian hyoliths reported so far from all over the world,it has been recognized 14 genera and 66 species as valid from 12 areas in 11 countries(excluding indeterminate genera and species). Palaeogeographic distribution analysis shows that the Devonian hyoliths were mainly distributed in the southern hemisphere,that were positioned near the Laurussia and Gondwana,with a few species sporadically distributed in other plates or blocks. Newly discovered specimens of these early Devonian hyoliths not only expands the palaeogeographic distribution range of hyoliths during the Devonian period,but also provides new evidence for inter-continental biostratigraphic correlation.

Phylum uncertain

Class Hyolitha Marek, 1963

Order Orthothecida Marek, 1966

Family INDET.

Fuyunotheca gen. nov.

Type species Fuyunotheca wangi gen. et sp. nov.

Etymology Fuyun(Gr.)is derived from the Chinese Pinyin of the word “Fuyun” of Fuyun County,Altay Prefecture,Xinjiang. The theca(Gr.)means the capsule,membrane,sheath,and shell of organisms.

Diagnosis Orthothecids having straight and middle-sized conch with oblate oval to subtriangular cross-section;swollen dorsal side with a pronounced median ridge;ventral side flat to weakly convex. Aperture straight or almost straight. Apical part of shell blunt. No apical septa were found. Surface sculpture prominent transverse striations and weakly longitudinal streaks on both dorsum and venter,and several sets of remarkable ribs parallel to the aperture in anterior third of the conch near the apertural side. The separation distances between each set of transverse ribs gradually widen from the aperture to the apical end of the shell. Operculum is unknown.

Remarks The main difference between Hyolithida and Orthothecida is that the former has protrusions(lips)on the ventral side of aperture(Malinky and Racheboeuf,2010). The aperture of the new genus Fuyunotheca gen. nov. is straight and without protrusions,so it can be attributed to the order Orthothecida Marek,1966. According to the taxonomy of Orthothecidae Sysoev,1958 revised by Malinky(2009b),its venter is concave to flat,and sculpture of conch consists of longitudinal ridges or lines,without transverse ornamentation. The new genus has the similar conch with that of the family Orthothecidae,but differs from them in having a flat to slightly convex venter and sets of unique transverse ribs on the conch. The new genus is similar to Bolitheca Marek and Isaacson,1992 and Neobactrotheca Marek and Isaacson,1992 from the Middle Devonian Icla Formation of Bolivia. However,specimens of Bolitheca exhibit pronounced longitudinal ridges on the dorsum,the semi-elliptical cross-section,and rounded lateral ridges(Malinky and Racheboeuf,2011). Specimens of Neobactrotheca have many longitudinal ridges and no median ridges on the dorsum. Besides,the conch of Neobactrotheca differs from that of this new species by having elliptical cross-section and smooth transitions to the lateral ridges(Marek and Isaacson,1992). It is for this reason that we establish a new genus,belonging to the indeterminate family.

Fuyunotheca wangi gen. et sp. nov.

Fig.2

Etymology The species is named in honor of Wang Hongzhen,the famous paleontologist who described hyoliths from China for the first time.

Holotypoe One well-preserved dorsum of conch,specimen number: XJLD-001(Fig.2-A).

Paratype One well-preserved venter of conch,specimen number: XJLD-003(Fig.2-C).

Other materials Specimen registration number: XJLD-002,004—046. Venter or dorsum of 44 conchs with incomplete aperture or initial part.

Diagnosis As for the genus.

Description The conch is straight and conical,expanding gradually and evenly from the apex to the aperture, and the aperture is thickened(Fig.2-E,ta). The growth angle of the conch is about 9.90°. The length of the shell is about 41 mm,and the diameter of the aperture is about 9 mm. The dorsum passes through the oblate lateral ridge to the venter,and its cross-section has oblate oval to subtriangular shape(Fig.2-B2). There is a median ridge running through the conch(Fig.2-A,B1,dmr)in the middle of dorsum. There are slightly inclined surfaces on both sides of the ridge,and a longitudinal groove on the right slope(Fig.2-A,gr). Sets of remarkable ribs(Fig.2-A,2-C,2-D,tr)parallel to the aperture are distributed in the anterior third of the conch. There are five groups of ridges(Fig.2-A,tr₁-tr₅)which are made up of 2-5 transverse ridges in each group. The separation distances between each set of transverse ribs gradually widen from the aperture to the apical end of the shell. Surface of shell from the middle to the initial part covered with slight growth lines(Fig.2-F,tl). In addition,the conch is also decorated with weakly longitudinal lines(Fig.2-G,ll),that are most prominent next to aperture but become fainter in direction of apex. But longitudinal lines become thicker near the lateral ridge(Fig.2-G,tll),which may be caused by pressure applied to the shell during diagenes. Ventral side almost flat to very slightly convex,and bears the same ornamentation as the dorsum without a median ridge(Fig.2-C,2-D,tr). The apex is damaged to some extent,but it still can be seen that it is bluntly rounded in form,and no septa are visible.

Locality and horizon The first member of the Tuoranggekuduke Formation,Emsian Age,Lower Devonian,Chawukar area,Fuyun County,Altay Prefecture,Xinjiang.

塔里木盆地塔河油田西北部中下奥陶统发育深切的地表水系结构，对水系两侧岩溶缝洞的发育影响显著，因此，对水系结构的定量描述及其演化模式的研究至关重要。基于三维地震资料，通过地震属性提取技术，对古岩溶台面和古岩溶地表水系进行了识别。同时，对水系的平面和垂向形态学结构参数进行了量化表征，据此探讨了古岩溶地表水系的形成与演化模式，剖析了水系演化与古岩溶缝洞发育的关系。研究结果表明：(1)塔河油田西北部自东向西发育3个岩溶台面和一个深切曲峡型地表流域结构。该流域的主干水系南北向汇流、分支水系东西向汇流，呈不对称分布。(2)水系单河曲弯曲率均大于1.5,超过了定义蛇曲的弯曲率临界值，具有典型的蛇曲特征。东西向河曲带弯曲率为2.42,南北向河曲带弯曲率为1.78。(3)东西向水系形态以单一“V”字形为主，南北向水系具有复合“V”字形，水系下切深度可达100～200 m。自东向西3个岩溶台面中水系的下切深度逐渐加大，水系宽深比平均值分别为4.06、3.52、3.03。(4)研究区古岩溶地表水系经历了自由曲流和深切曲流2个阶段，分别反映了水系的侧向侵蚀和垂向侵蚀作用过程。其中，水系的垂向侵蚀是逐步发生的，与3个岩溶台面的逐级抬升相适应。(5)深切曲流是区域性的最低排泄基准面，控制了河流两侧大型岩溶暗河的发育。每个岩溶台面具备独立的水循环结构，岩溶台面的逐级抬升促进了水系的差异演化，进而控制了岩溶暗河的规模和类型的差异性。对研究区古水系结构及其演化的认识对于古岩溶缝洞储集空间发育特征与分布规律的研究提供了重要的参考依据。

It is suggested that the spatio-temporal evolution of the Jehol Biota in northeastern North China is driven by the North China Craton destruction during the Early Cretaceous,due to the abrupt changes in paleogeographic environment. However,little quantitative work on the dynamic paleo-landscape evolution in North China has been done. In this study,we employed paleosoil weathering indices(PWI and CFX_Na)and carbonate isotopes to reconstruct the paleo-elevation of North China around 145 ma. We then integrated factors such as tectonic movements,sedimentology,paleoclimate,and sea level changes using the Badlands software to model the Early Cretaceous paleo-landscape evolution of North China. Our findings reveal that the eastern North China experienced an abrupt geomorphological transition from the collapse of a paleo-plateau to the formation of the Bohai Bay Basin due to the subduction retreat of the paleo-Pacific Plate. The geomorphological transitions led to the formation of a series of eastward-migrating rifted basins,including several newly-formed isolated intermountain basins in the Yanshan area where the Jehol Biota first emerged. Frequent volcanic activity provides rich nutrients for the lakes,and the paleoclimate turns to warm and humid gradually,which provide favorable conditions for the prosperity of the Jehol Biota. The eastward migrating subsidence basin,eruption of volcanoes and suitable paleoclimate jointly controlled the eastward migration of the Jehol Biota.

The mineral composition and particle size of heavy minerals in sediment are important indicator for revealing sediment sources and hydrodynamic sorting processes. However,due to the limitations of research methods,there is still no research on the relationship between the heavy mineral composition, provenance and hydrodynamic sorting of fine-grained sediments in the Yangtze River. In this study,the TESCAN Integrated Mineral Analyzer(TIMA)was used to study the composition and particle size of heavy minerals in different water layers of the Yangtze River Estuary and East China Sea inner continental shelf. In parallel, the automatic identification results of fine-grained heavy minerals were verified by electronic probe analysis. The study shows that the characteristic heavy mineral assemblages in the suspended solids in the Yangtze River Estuary is hornblende,epidote and ferruginous metal minerals,which is consistent with the characteristic heavy mineral assemblages in the sediments of the lower reaches of the Yangtze River. There is an excellent correlation between the heavy mineral composition of suspended matter in the Yangtze River estuary and sediment in the lower reaches of the Yangtze River,indicating that its source is related to the Yangtze River. However,hematite/magnetite is relatively enriched in the suspended matter outside the Yangtze River estuary,which may be the result of the reworking and diffusion of medium density heavy minerals caused by strong tide. It is worth noting that abnormal enrichment of chromite appears in suspended matter samples at stations near Zhoushan Islands,which may be related to human production activities in the sea area. The vast majority of suspended heavy mineral particles in the Yangtze River Estuary are coarse silt to extremely fine sand,enriched in the coarser fractions(Ф<D_0.5)of suspended solids,which are mainly carried and transported by runoff. There is no significant difference in the particle size between different types of heavy minerals in suspended solids in different water layers, indicating that they are less affected by sedimentation differences.

A series of tectonic movements during the Late Mesozoic greatly changed the topography and landform in eastern China,forming a geomorphic pattern of “high in the east and low in the west”. There is still a controversial issue on the existence of plateaus or mountains in eastern China during the Cretaceous,and thus the evolutionary processes,paleoaltitude and the extensional range of plateaus or mountains need further studies. In this paper,we collected the palynological data of xerophyte and disaccate pollen from vorious localities of China during the Cretaceous,and further discussed the paleovegetation succession and palaeoclimate evolution,which provides paleontological evidence for the interpretation of the geomorphology in eastern China at that time. The result shows that there were three climate zones in China during the Cretaceous: (i)the northeastern region was a warm and humid subtropical-warm climate zone;(ii)the northern region was a semi-arid tropical-subtropical transitional climate zone;(iii)the Tibet,Xinjiang and southern China were a hot and tropical-subtropical climate zone. The interpretation of the geomorphology shows that there was a high-altitude landform in northeast China during the early Early Cretaceous. Additionally,it is likely that coastal mountains existed in the Fujian and Zhejiang regions during the Early Cretaceous. In early Late Cretaceous,the range of coastal mountains in eastern China reached its maximum. From the late Late Cretaceous to Early Paleocene,the mountains in eastern China gradually collapsed,and by the Early Paleocene,the mountains were probably disappeared.

The deep-water area of the northern South China Sea experienced a transition from lacustrine to marine environments in the Paleogene,and has rich oil and gas resources and broad exploration prospects. Due to the limitation of water depth,the provenance of sediments and the palaeogeographic evolution of the basin are not clear. In this paper,the Paleogene of the Zhu-2 depression in the Pearl River Mouth Basin is systematically studied by means of detrital zircon U-Pb ages and source-sink correlation. The results show that in the Early and Middle Eocene,the sediments of the Zhu-2 depression were mainly from local uplift area around the depression. In the Late Eocene,the Kunyingqiong River originated from the western side of the depression provided a large amount of sediments for the basin,whereas the Paleo-Pearl River sediments had little influence on the deposition in the depression. In the Oligocene,the Paleo-Pearl River crossed the Panyu low uplift and entered the Baiyun sag,carrying sediments mixed with the Kunyingqiong River sediments in the form of delta deposition in the north and mid-west of the sag,forming a dual provenance river-delta system. The Paleogene provenance evolution of the deep-water area of the northern South China Sea was obviously controlled by regional tectonic palaeogeography of the Mesozoic. Identifying the provenance evolution during this period is of great significance for restoring the regional palaeogeography pattern.

The carbonate-evaporite symbiotic system is a rock symbiotic association formed by chemical depositional differentiation. Microfacies analysis and sedimentary model construction of such a system are conducive to revealing the sedimentary information that have guiding significance for oil and gas exploration in evaporatic environments. Based on a large number of borehole data of the Majiagou Formation in Ordos Basin,macro-and microscopic observation of the rocks was carried out to identify sedimentary microfacies,analyze sedimentary sequence,and construct sedimentary model.The results show that there are ten types of sedimentary microfacies(MFT1-MFT10)in the carbonate-evaporite symbiotic system of the Majiagou Formation: halite,gypsum,gypsum-bearing dolomite,laminated dolomite,crystalline dolomitic grainstone,microcrystalline dolomite,microbial dolomite,bioturbated dolomite,laminated limestone,crystalline grainstone. four types of sedimentary sequence are developed in the symbiotic system: (1)upper intertidalto supratidal dolomite-gypsodolomite-argillaceous dolostone;(2)lower intertidal evaporite-algal dolomite-dolomite;(3)subtidal laminated limestone-churned limestone-bioturbation limestone;(4)lagoonal laminated evaporite-lumpy evaporite-salt rock. Evaporites of the Majiagou Formation were formed during the shallow basins period and low sea level period,while carbonates were formed during the high sea level period.The giant carbonate-evaporite symbiotic system formed through repeated fluctuations in sea level.

As a large continental depression oil-and gas-bearing basin formed during the Cretaceous period,Songliao Basin contains a huge thickness of lacustrine fine-grained sediments,characterized by great exploration potential for unconventional oil and gas in recent years. The Qingshankou Formation is the key breakthrough layer of shale oil in Songliao Basin,and the mechanism of organic matter enrichment in fine-grained sediments is crucial for unconventional oil and gas exploration. Three wells located in different sedimentary areas in Changling sag of southern Songliao Basin were selected for detailed studies in this study. Based on core observation,organic geochemistry and biomarkers analysis of the fine-grained sedimentary rocks of the Member 1 of Qingshankou Formation(K₂qn¹),the transgressive systems tract,and the source and preservation conditions of organic matter in different sedimentary environments and processes were analyzed. Then the key control factors of organic matter enrichment were discussed,and the relevant enrichment models were established. Our results show that the organic matter abundance of fine-grained sedimentary rocks of K₂qn¹ was relatively high,and the kerogen is dominated by type Ⅱ. The overall organic matter abundance was low values in the south but high values in the north,low values in the lower part and high values in the upper part. Normal alkanes in saturated hydrocarbons predominantly exhibit single-peak and pre-peak patterns,with a slight odd-carbon preference. The terpenoids are primarily composed of tricyclic terpenoids and pentacyclic triterpenes. C_27-29 regular steroids are dominated by C₂₇ regular steroids. The major compound of the trifluorene series in aromatic hydrocarbons is dibenzothiophene. The organic matter in fine-grained sedimentary rocks of K₂qn¹ is mostly derived from the endogenous bacteria and algae in lakes,containing a certain amount of terrestrial higher plants. The water body is a weakly reduced,brackish environment. The source of organic matter and salinity are key factors controlling the enrichment of organic matter. Horizontally,the semi-deep lake to deep lake is less affected by riverine influences compared to the delta’s outer front,exhibiting weaker terrestrial input,higher water salinity,superior organic matter types,and greater organic matter richness. Vertically,as the water depth increases,riverine influence diminishes,the water salinity trends upward,the quality of organic matter improves,and organic matter becomes more enriched.

Beibu Gulf Basin is one of the five major oil-bearing basins in the north of the South China Sea, with great potential for oil and gas resources and good exploration prospects. However, little research has been done on the thick Weizhou Formation in the Haizhong Depression, the third-level structural unit of the Beibu Gulf Basin. This significantlyhinders the hydrocarbon exploration in the Haizhong Depression. High resolution sequence stratigraphy is an effective method for stratigraphic division in geographic exploration frontiers. Using 3D seismic, well logs and core data, and on the basis of identification of second-order and third-order sequence boundaries on seismic profiles and wells, this paper uses maximum entropy spectral analysis, wavelet transform analysis and core analysis methods to identify and subdivide the high-resolution sequences of the Weizhou Formation. The results show that the maximum entropy spectral analysis has high resolution for third-order and fourth-order sequence boundaries; wavelet transform can analyze fourth to sixth order cycles and higher order cycles; Core data can be used for short-term and ultra-short-term cycle analysis. Based on 3D seismic, well logging, maximum entropy spectral analysis, wavelet transform technology and core data, the Weizhou Formation can be divided into 1 second-order sequence that includes 6 third-order sequences, which are in turn composed of 13 fourth-order sequences. According to the comparison of 13 fourth-order sequences, the highest sand ratio occurs in SQ6 LST , which is followed by SQ6 HST, suggesting great exploration potential. This study indicates that high resolution sequence stratigraphy of multi-scale and multi-method has certain guiding significance for screening key intervals in depression with low degree of exploration.

Carboniferous-Permian period was the key tectonic transition period in the ocean-continental transition in the eastern Xinjiang region,

中国大陆地壳在奥陶纪时由华北、扬子、塔里木三大陆块及围绕它们的诸多微陆块和造山带组成。基于陆块、微陆块和造山带等不同属性地体的识别特征，按陆块、洋板块中的微陆块、造山带和疑问块体4种类型，分别阐述它们在中国奥陶纪的发育特征。在此基础上，综合古地理信息，提出中国奥陶纪共划分出4个大区16个地理区的新认识。该时期中国各陆块主要在环西伯利亚、古亚洲洋、原特提斯洋和冈瓦纳北缘分布，由此归纳为4个大区，其中华北和塔里木分割了古亚洲洋和原特提斯洋，但归入原特提斯洋大区中。环西伯利亚大区可分为北疆区和兴安区，前者由阿尔泰、准噶尔—吐哈微陆块和东西准噶尔造山带组成，后者囊括额尔古纳、兴安、锡林浩特、松辽和佳木斯等东北微陆块群。古亚洲洋大区仅分出中天山—北山区，伊宁微陆块为该区成员。原特提斯洋大区除了华北区和塔里木区外，还包括柴达木—祁连、昆仑—秦岭、扬子、华夏、印支和松潘—甘孜区，其中中阿尔金和全吉微陆块属于柴达木—祁连区，义敦微陆块属松潘—甘孜区。冈瓦纳大区分为羌塘、拉萨、喜马拉雅、滇缅泰马和海南区，其中保山微陆块和临沧微陆块为滇缅泰马区的组成部分。此外，阿拉善和敦煌块体分别归入华北和塔里木区中。上述中国奥陶纪地理分区的认识与前人存在较大差异，作者旨在抛砖引玉，希望能引起更多学者关注并探求更合理的划分方案。

为阐明塔里木盆地阿瓦提凹陷三叠系的沉积特征、层序格架及沉积古地理，根据陆相层序地层学和湖盆沉积学研究思路，利用钻井、岩心、地震等基础资料，提出了井震结合层序划分、物源与沉积特征、沉积古地理分布与演化等研究新认识。将阿瓦提凹陷三叠系俄霍布拉克组和克拉玛依组划分了7个三级层序，俄霍布拉克组分为5个层序(SQ1—SQ5),克拉玛依组分为2个层序(SQ6—SQ7)。各层序自下而上由低位体系域(LST)、湖侵体系域(TST)和高位体系域(HST)组成。研究认为阿瓦提凹陷三叠系发育多物源控制下的扇三角洲相、辫状河三角洲相和滨浅湖亚相等沉积。凹陷周边存在4大物源，主要来自西南部巴楚隆起和西部柯坪断隆，其次是北部塔北隆起和东南部塔中隆起。辫状河三角洲平原亚相主要分布在凹陷的南部—西南部边缘，以辫状分流河道微相的粗粒砂岩和砂砾岩体为主。湖盆主体位于凹陷东部地区，向凹陷内为辫状河三角洲前缘亚相和湖泊相，以水下分流河道、滩坝砂体为主。三叠纪湖盆经历了从初始形成、发育鼎盛、到充填消亡的过程。早三叠世早期(SQ1—SQ2),即俄霍布拉克组下段时期，是三叠纪阿瓦提湖盆的初始形成期。物源主要来自南部的巴楚隆起和西部的柯坪断隆地区，沉积相带从南向北呈不对称带状分布，发育辫状河三角洲平原—辫状河三角洲前缘—滨浅湖亚相等，湖盆呈南浅北深、西浅东深。早三叠世中—晚期(SQ3—SQ5),即俄霍布拉克组上段时期，是湖盆扩张发育鼎盛期。伴随着西南部和西部物源不断向盆地进积，形成扇三角洲相沉积。同时，湖盆向北部和北东部扩展，形成自南向北不断进积的辫状河三角洲平原和前缘亚相，北东部为滨浅湖—半深湖亚相。中三叠世早—中期(SQ6—SQ7),即克拉玛依组沉积时期，是湖盆充填消亡期。沉降中心向北东方向迁移，物源不断进积造成湖盆迅速萎缩，直至消亡。

塔里木盆地北部库车坳陷库姆格列木群（54-46 Ma）厚层含盐层系为油气成藏的优质区域盖层，但该套含盐层系的原始时空展布、古地理环境和沉积控制因素尚不明确，给盐下油气藏钻井施工造成了较大困难。通过盆缘野外露头剖面实测与盆内录井元素分析相结合，开展盐湖中心与边缘沉积旋回对比研究，探讨库姆格列木群含盐层系发育的主控因素。库姆格列木群发育3个Ⅲ级旋回：第1个Ⅲ级旋回Ⅰ₁以盆缘砂砾岩—泥岩—石膏岩组合、湖盆中心泥岩—石膏岩—盐岩—碳酸盐岩组合为特征，指示陆内盆地向陆缘盆地的古地理环境转变。第2个Ⅲ级旋回Ⅰ₂以盆缘砂砾岩—泥岩—石膏岩组合、湖盆中心厚层盐岩加泥岩组合为特征，为陆缘盆地盐湖沉积模式。第3个Ⅲ级旋回Ⅰ₃盆缘—盆内沉积具有相似的膏质泥岩和泥岩组合特征，为陆内干盐湖沉积模式。结合早始新世全球气候和海平面升降变化历史，认为Ⅰ₁旋回（约54-51 Ma）由陆内向陆缘环境的转变及厚层石膏岩的沉积受早始新世气候适宜期（53-51 Ma）和全球海平面升高的影响，Ⅰ₂旋回（约51-48 Ma）厚层盐岩的沉积受全球持续干旱气候和海平面再次升高的影响，而Ⅰ₃旋回（约48-46 Ma）厚层含盐层系沉积的缺失与全球气候持续干旱和海平面下降有关。