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.

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.

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.

Quartz is an important part of shale,making it crucial to clarify its genetic mechanism for the reconstruction of shale diagenetic process and the formation of shale oil and gas reservoir. The genesis of quartz in shale is complex,with the main types, including terrigenous detrital quartz,biogenic quartz and diagenetic authigenic quartz, identifiable through ordinary thin section observation,scanning electron microscopy,energy spectrum analysis and cathodoluminescence. The main sources of diagenetic authigenic quartz silica are clay mineral transformation,felsic dissolution and biosilicon dissolution,and volcano-hydrothermal activity. Terrigenous detrital quartz is mostly silt-grade and strongly emits light under cathodoluminescence,typically displaying a two-peak spectrum. Micron-sized biogenic quartz does not emit light,and clay mineral-derived quartz is predoninantly found around or embedded within clay minerals, such as illite. In addition to the morphology and occurrence characteristics of different types of quartz,there are also differences in geochemical elements. Quartz affected by hydrothermal activities is rich in Fe and Mn,while terrigenous detrital quartz is rich in Ti and Al elements. Detrital SiO₂ and Zr are positive correlation,as does biogenic quartz with TOC content. The biogenic quartz Fe/Ti ranges between 0.4 and 20. Diagenetic authigenic quartz is formed in multiple stages,which is closely related to the burial diagenesis process of shale and affects the properties of shale reservoirs. Diagenetic authigenic quartz is mainly formed in early and middle diagenetic stages. Terrigenous detrital quartz and biogenic quartz are conducive to inhibiting compaction and protecting primary pores. Processes involving diagenetic authigenic quartz, like clay mineral transformation and felsic dissolution create dissolution pores and organic pores,with quartz filling some pores,thereby reducing porosity. Identifying the origin of quartz in shale is of great significance to the analysis of shale sedimentary environment and the prediction of favorable reservoir distribution.

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.

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.

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.

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.

河控浅水三角洲前缘砂体可分为分流沙坝型和指状沙坝型2类河-坝组合类型，前人多关注扇状的分流沙坝型与鸟足状的指状沙坝型的前缘砂体，而对多个指状沙坝组成的树枝状沙坝关注不足，其沉积构型与形成机理尚不清楚。以鄱阳湖日帽洲三角洲为例，综合卫星地图、探地雷达、浅钻孔、沉积数值模拟数据，揭示了河控浅水三角洲前缘树枝状沙坝的沉积构型与形成机理。研究认为，树枝状沙坝是由多个相互分叉、交汇的指状沙坝拼接而成，呈现“河在坝上走”的河-坝组合关系，其间发育分流间湾。根据规模差异，树枝状沙坝内的分流河道可分为主支分流河道与侧支分流河道，主支分流河道的宽度大、数量少，多发育于近源端并延伸至沙坝末端，分布于沙坝中部；侧支分流河道的宽度小、数量多，多分布于前缘两侧与末端。树枝状沙坝的形成与细粒、黏性、高排量河流供给相关，细粒与黏性沉积物促进了稳定天然堤的加积与指状沙坝的形成，高排量导致了分流河道的分流与决口，从而形成树枝状的指状沙坝。河控浅水三角洲前缘树枝状沙坝储集层的侧向连通性较差，优势储集层位于指状沙坝中部，为分流河道砂体与近岸河口坝砂体。

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 Yangtze River,Asia's largest river,represents a significant geomorphological event within the integrated tectonics-climate-landscape system of the Cenozoic era in China. A key point of debate in understanding its formation is the timing of the incision of the Three Gorges,situated between the Sichuan and Jianghan basins,which marked the emergence of the modern Yangtze River. Despite abundant geological data,there remains controversy over when exactly the Three Gorges were formed or incised. Previous studies usually focused on isolated factor affecting the river development,e.g., tectonic movements,sedimentology,paleo-climate and sea level changes,to resolve this key issue. In contrast,our study utilizes Badlands,a software for simulating paleo-landscape,to integrate these key factors quantitatively. Focusing on the area east of the “first bend”(Shigu Town in Yunnan Province)of the Yangtze River,we used Badlands to reconstruct the paleo-landscape and river system evolution process since the Late Cretaceous(80 Ma). We further validated our model results using seismic data from the Sichuan and Jianghan basins. The results revealed that the river flow direction in the Sichuan Basin was reversed to drain northwards due to the Late Eocene-Oligocene uplift in the eastern Tibet and the southwestern Upper Yangtze Plate. The Jianghan Basin maintained a consistently low base level during the early Paleogene,influenced by the continental rifting environment in eastern China. The reversal of the drainage direction in the Sichuan Basin and the long-lasting low base level in the Jianghan Basin eventually made the Three Gorges to be incised at the latest Oligocene. We propose that the reversal and subsequent capture of the Upper Yangtze River's flow by the middle Yangtze River played a crucial role in the incision mechanism of the Three Gorges.

洪水类型与流量变化是影响扇三角洲地貌形态与沉积特征的主要因素，但不同类型洪水作用下扇三角洲沉积单元发育规律研究薄弱。论文以滦平盆地桑园剖面下白垩统西瓜园组为例，通过剖面测量和岩相划分，恢复了沉积流体类型、沉积过程及其沉积响应单元，建立了不同洪水作用下扇三角洲沉积模式。根据岩相组合将该剖面的主控沉积过程解释为碎屑流、洪流与片流3种洪水，分别对应于碎屑流建造期、洪流建造期与片流建造期。结合沉积过程与砂砾岩沉积形态特征，将目的层解释为8种沉积单元，具体包括扇三角洲平原环境的陆上碎屑流舌状体、洪流主控辫状河道和扇三角洲前缘的水下碎屑流舌状体、高密度浊流水道、牵引流水下分流河道、高密度浊流朵体、水下片流朵体及滑塌体。在扇三角洲碎屑流建造期，发育多期垂向上叠置的、向湖盆进积的碎屑流舌状体；在洪流建造期，平原中形成洪流主控辫状河道，而进入湖盆后洪流转化为高密度浊流，发育高密度浊流水道与朵体；在片流建造期，则以水下快速沉积形成的水下片流朵体为特征。洪水期扇三角洲前缘沉积物快速沉积和沉积物坡失稳易于形成滑塌体，而间洪期则以平原上辫状河道和前缘中低流态水下分流河道的发育为特征。基于洪水类型及其沉积过程的扇三角洲沉积规律的研究，深化了对其砂体形态与结构规律的认识。

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.

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.

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.

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.

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.

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.

渤海湾盆地济阳坳陷沾化凹陷埕岛—桩海地区侏罗系三台组近年来成为油气勘探重点层系，但受构造演化复杂、沉积类型多样、岩性多变的影响，储集层非均质性极强，储集层质量预测难度大，而成岩相类型的精确识别与划分对储集层的评价起至关重要的作用。传统利用有监督学习识别全井成岩相的方法在学习样本数目较少的情况下实用性有限，本研究开展基于单因素约束的无监督全井成岩相测井识别方法研究。结合视压实率、胶结物含量、面孔率和裂缝率将研究区成岩相划分为致密压实相、碳酸盐胶结相、溶蚀与裂缝相和不稳定成分弱溶蚀相。确定了GR(自然伽马)、AC(声波时差)、DEN(密度)、RD(深侧向电阻率)4条对成岩作用敏感的测井曲线作为成岩相测井识别的依据。分别对4条曲线聚类范围进行约束，确保了无监督学习方法与成岩相良好的映射关系。基于无监督学习划分的测井相种类，利用铸体薄片等资料实现测井相与成岩相的标定，完成地区成岩相的识别与划分。划分结果表明，溶蚀与裂缝相、不稳定成分弱溶蚀相为研究区储集层有利成岩相，2类成岩相对应较高的孔渗度，溶蚀与裂缝主要分布在含砾砂岩等粗粒岩中，不稳定成分弱溶蚀相主要分布在粉砂岩等细粒岩中。通过盲井成岩相对比，验证学习方法的准确性，进而为缺乏取心井段的储集层成岩相识别提出新的预测方法，对有利储集层的评价及预测具有一定意义。

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.

Mahu sag,Shawan sag,and Pen-1 well west sag are the three major hydrocarbon rich sags in the west of Junggar Basin. Through the analysis of deep drilling wells,well logging,and deep reflection seismic profile data,these three sags were revealed to belong to the same depression in the early Permian,and the scope of the Western Depression of the Junggar Basin was determined accordingly. Three sets of regional unconformity surfaces were identified and three sets of structural layers were divided in the Permian to the upper Triassic within the Western Depression, i.e. ,the lower Permian structural layer,the middle Permian structural layer,and the upper Permian-Triassic structural layer. The fault related fold theory and balanced profile technique are used in the fine tectonic interpretation and tectonic evolution analysis. In combination with the previous analysis on thermal history and geochemical characteristics of volcanic rocks in the Junggar Basin,the tectonic evolution of the Western Depression in the Permian-Triassic period was mainly divided into three stages: the extensional rifting of the early Permian and the compression in the late Permian,the weak extensional depression of the Middle Permian,the compression uplift of the late Permian to Triassic period. The tectonic evolution of the western depression belt is spatiotemporally coupled with the anti-clockwise rotation of the western Junggar and Junggar Block. These results are of great significance for revealing the characteristics of the Junggar Basin during the Permian period and the evolution of intracontinental processes since the Permian period.

大陆风化是地球表层系统中的关键过程，涉及多种能量形式(太阳能、风能、化学能和重力势能)和物理化学过程，是地球化学元素在地球不同层面(如岩石圈、水圈、生物圈和大气圈)之间迁移和重新分配的基础。在此过程中，异常的元素富集可形成工业级的风化淋滤矿床。风化淋滤矿床可进一步区分出风化矿床和沉积—淋滤型矿床2种类型。传统的矿床学和沉积学研究方法在理解风化淋滤矿床形成过程中存在局限性，特别是在解析成矿阶段和动态成矿过程方面仍不甚明晰，导致该类型矿床在基础研究和勘查方面长期存在亟待解决的一批问题。本研究在厘清大陆风化作用、风化壳(古风化壳)、土壤(古土壤)等概念的基础之上，对现代风化淋滤剖面(如广西贵港三水铝石矿床)和古老风化淋滤型矿床(如中国华南地区早石炭世—晚二叠世铝土矿床及沉积淋滤型稀土矿床)开展了系统的沉积学分析与对比工作。研究发现，风化淋滤矿床的结构组分主要包括碎屑、团粒与包粒、块状黏土等结构类型，分别对应碎屑状、包粒状、致密状矿石的形成。成岩过程主要依赖于氧化物矿物及黏土质的胶结与填隙作用。基于上述认识，提出了风化淋滤矿床的淋滤序列和剖面结构划分方案。该方案以风化剖面中渗流带与潜流带作为基本的划分依据，进一步区分出风化矿床序列与沉积—淋滤型矿床序列，两者主要以是否出现沉积单位作为主要识别标志。以古气候为主线分析了风化淋滤矿床的成因机理，并结合近年来质量平衡计算相关成果，总结了淋滤过程中元素迁移规律，将风化淋滤型矿床的成矿过程概括为成矿母质形成、成矿物质风化和后期改造3个阶段。

The study of incidence and attributes of regional extreme climatic events under the background of global change is a frontier of climate change research. This paper reconstructs the extreme flooding events with a probability of 10% in the Northeast China in 1750-2020 using historical documentary records and precipitation data,and then analyzes its incidence characteristics and driving mechanism. The main conclusions include: (1)In 1750-2020,29 extreme flooding events were identified in the Northeast China,exhibiting fluctuating patterns,with 1871 to 1930 marking the period of highest frequency over the past 270 years;(2)The global and regional warming significantly enhanced the frequency of extreme flooding events in the Northeast China;(3)The anomaly of the monsoon rain belt caused by the change of the East Asian summer monsoon is the direct cause of the occurrence of extreme flooding events in the Northeast China. Particularly,periods with a stronger monsoon and a northward shift in the rain belt significantly raise the likelihood of such events;(4)The Indo-Pacific warm pool and the sea surface temperature anomalies in the tropical central and eastern Pacific caused the incidence of extreme floods events in northeast China by affecting the location of the East Asian summer monsoon and the water vapor transport. The positive anomaly of water vapor transport at the time of La Niña years is crucial for the occurrence of extreme flooding,and is a reliable predictor of extreme flooding events in the Northeast China.

探究遗址沉积过程与古环境背景对于全面了解古人类生存行为信息具有重要意义。江西上湖遗址是中国南方地区新近发掘的一处旧石器时代旷野遗址，遗址均质红土B层中出土了丰富的石制品，表现出小型化特点，年代始于距今约2.6万年前。本研究对上湖旧石器遗址沉积地层开展了野外考察和室内土壤微形态、磁化率、粒度和地球化学元素分析，同时对出土的石制品进行了考古埋藏学分析。地学和考古学方法二者相互印证，明确揭示出该遗址区均质红土B层仅受到了低能坡面流水作用，保存了较为完整的古人类技术行为信息。推测古人类在MIS2阶段频繁占据和使用上湖遗址等区域，可能与拥有小型石片石器技术的华北地区人群难以忍受该时段北方极端寒冷干燥的气候条件被迫向南迁徙、从而到达了气候相对干凉的长江中下游地区进行生产活动有关。并且上湖遗址古人类采取了偏后勤式流动策略，以应对异常极端气候带来的资源分布不均和可预测性降低等风险。

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.

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.

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.

陆相优质烃源岩发育大多与湖泊咸化相关，但湖泊咸化对页岩发育的影响仍不清晰。以东营凹陷古近系页岩重点取心井樊42井为例，通过岩石薄片观察、XRD、岩石热解测试、XRF二维元素扫描、微量元素测试等分析，结合有机地球化学测试数据、微量元素含量的垂向变化等，分析不同盐度演化阶段页岩成分、纹层结构、有机质丰度的变化。结果表明，研究区目的层段页岩可划分为5种岩相类型。目的层段环境演化可以划分为5个阶段，受控于气候、陆源输入等因素。古气候在沙三下亚段沉积时期呈现暖湿—相对湿冷—暖湿—相对干冷—相对暖湿的变化特征。陆源输入量呈多期旋回变化。不同类型岩石的沉积环境特征各异，高盐度的湖泊水体营养盐浓度高，具有较高的初级生产力，水体分层强烈，水体循环较弱。氧/盐度跃层位置相对较高，富氧带水深较浅，使得有机质更快脱离氧化环境沉降进入还原性水体，有利于有机质的保存。碳酸盐矿物含量高，且呈纹层状发育于滞水层中。

四川盆地志留系龙马溪组烃源岩的厚度中心位于川南地区，其上覆石牛栏组石灰岩具备近源成藏的巨大优势，然而当前尚未取得石牛栏组规模储集层勘探突破。研究基于大量的钻测井、岩心、露头及三维地震资料，通过地层学、沉积学及地球物理学等方法手段，开展川南地区石牛栏组古地貌格局及沉积演化特征研究。结果表明：(1)川南地区石牛栏组自南向北发育南部高带、中部洼地及北部高带3个古地貌单元，明确了3个古地貌单元的平面分布范围；(2)3个古地貌单元控制了川南地区石牛栏组沉积相带的展布，南、北2个构造高部位发育礁滩体及碳酸盐岩台地等高能沉积相带，以生物碎屑灰岩、生物礁(珊瑚)灰岩、鲕粒灰岩、砂屑灰岩等岩性发育为主要特征，中部洼地主要发育泥质浅水陆棚泥岩夹薄层灰质泥岩、泥灰岩沉积，石牛栏组碳酸盐礁滩体是该区油气储集层预测的重要目标；(3)早志留世川中隆起、黔中隆起的抬升隆起塑造了石牛栏组古地貌及沉积格局，随着川中隆起、雪峰古陆的持续活动以及陆源供给增强，伴随着海平面持续下降则导致石牛栏组碳酸盐岩台地的逐渐消亡，至韩家店组则发育1套海相碎屑岩沉积。希望通过本次研究，能够为该区石牛栏组油气勘探开发提供一定的理论参考。

江苏徐州地区寒武系馒头组发育极具特色的陆源碎屑组分与碳酸盐组分混合沉积现象。本研究以寒武系馒头组一套典型的混合沉积序列为例，依据剖面实测与镜下特征，对该序列中的混合沉积组合类型开展了系统的岩石学研究；通过分析不同沉积环境中的混合沉积特征，建立了陆表海近岸背景下陆源碎屑组分与碳酸盐组分混合沉积模式，探讨了各种混合沉积组合类型的混积成因类型、混积过程及主控因素等。结果表明：徐州地区寒武系馒头组混合沉积序列中主要发育含砂鲕粒灰岩、含内碎屑砂质灰岩、灰质细砂岩、含灰粉砂岩等11种混合沉积组合类型；混合沉积序列整体为陆表海海侵背景下次级海平面频繁波动且伴随多期次风暴作用的产物，主要表现为海侵作用下由近岸的混积潮坪逐渐演化为混积局限台地；混合沉积主要为相混合与间断混合，局部发育原地混合与母源混合。气候、陆源输入程度、海平面变化、碳酸盐产率是形成相混合的主控因素，同时也受到生物活动、水动力条件的调控；多期次风暴作用在主导间断混合形成的同时，一定程度上会促进相混合与母源混合的发育；在各因素叠加影响下，研究区具有多种混积成因类型组合发育的特征。厘清各种混积成因类型的分布与混积过程可为华北板块寒武纪古环境恢复与沉积演化提供参考，并为“深时”陆表海台地混合沉积相关研究提供典型范例。

中亚内陆地区晚侏罗世气候干旱化，准噶尔盆地发育风成沉积，该风成沉积的分布范围和共存的沉积体系还有待研究。为探究该问题，作者对准噶尔盆地南缘上侏罗统进行了详细的沉积学考察，发现喀拉扎组风成沉积位于侏罗系—白垩系不整合面之下，沉积记录范围东西向可达100 km,最厚处约250 m,其中建功煤矿剖面的风成沉积砂体厚度十余米，受到多期砾质辫状河的冲刷。风成沙具有较好的成分成熟度和结构成熟度，以跳跃组分为主。风成沙丘具有大型高角度交错层理和反粒序层理，风成沙席发育平行层理和低角度交错层理，侧向延续性好。河流沙和同期的风成沙具有相似的粒度组成和沉积物源，古风向与河流古流向正交，这说明了风成物源来自于附近河流沙，河流沙来自于风成沙地。晚侏罗世风成—冲积沉积体系受到气候干旱化和天山构造活动的控制，气候干旱导致沉积物供给减少，基准面上升，辫状河转换为季节性曲流河；天山的构造活化导致基准面下降，在准噶尔盆地南缘风成沉积扩大，且形成广泛分布的冲积扇砾岩。准噶尔盆地南缘侏罗纪至早白垩世沉积环境发生了从沼泽遍布的河流—三角洲体系演化到风成—冲积沉积体系、再到湖泊—三角洲沉积体系的2次重要变化，记录了中亚地区晚侏罗世气候变干和早白垩世气候转为半湿润的气候变化，可能与侏罗纪真极移事件和古天山水汽阻隔有关。

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.

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.

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 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.

南海西部Y盆地L地区中新统地层呈高温、超高压特征，钻井难度大、取心资料少，岩屑录井反映岩性的精度较低，难以满足岩性精细识别的要求。以Y盆地L地区黄流组二段深层复杂碎屑岩为例，首先，利用有限的壁心粒度分析、录井、测井等资料，优选出表征岩性的粒度参数：粒度中值Md和对粒度变化敏感的自然伽马、密度、中子、声波时差、电阻率5条测井曲线，构建粒度中值Md-测井5变量数据集；其次，采用K-MEANS聚类方法，将数据集根据“误差平方和与聚类数”最优关系划分成了4类(简称“粒度分类”),分类后优化了粒度中值Md与测井响应的相关性，且获得不同类别的测井响应特征和相应岩性类型；然后，在实际井资料处理过程中，应用Fisher判别方程来判别未知深度点所属的粒度分类类型；最后，建立粒度分类下基于XGBoost算法的粒度中值测井智能计算模型，依据不同岩性对应粒度中值的数值范围，实现了井筒剖面上根据测井反演粒度中值Md曲线进而达到岩性精细识别的目的。研究结果表明：L地区黄流组二段考虑粒径的差异将砂岩岩性划分为：粉砂岩、细砂岩、中砂岩、粗砂岩，其中细砂岩和中砂岩是最主体发育的岩性，粒度中值Md与不同粒径岩性的关系最密切，是最能反映不同粒径岩性的粒度参数；粒度分类后基于XGBoost算法的粒度中值测井智能计算模型预测效果优于多元回归预测模型，计算粒度中值与实测值的相关系数达0.9397,平均绝对误差MAE为0.0195 mm,平均相对误差MRE为17.52%。该模型是一种有效实现深层复杂碎屑岩岩性精细识别的方法，也为纵向剖面上沉积粒序分析和储层构型精细解释、有效性评价奠定了基础。

目前对于被动大陆边缘沉积古环境演化的研究相对较少，特别是对上升洋流活动变化规律认识不足，导致对有机质富集主控因素认识不清。据此，以渝北地区下志留统龙马溪组为例，基于岩心/露头、矿物岩石学、有机地球化学和元素分析等资料，探讨被动大陆边缘页岩沉积古环境及其对有机质富集的控制。研究表明，区内有机质富集受保存条件、陆源输入和古生产力水平等因素控制，但不同时期主控因素存在差异：鲁丹期(LM1-LM5沉积期),保存条件、陆源输入和古生产力水平共同控制有机质富集，TOC含量最高；埃隆早期(LM6沉积期),盆地进入挠曲—迁移期，构造活动增强，渝北地区障壁开口打开，上升洋流活动增强，保存条件变差是造成TOC含量降低的主因；埃隆中期(LM7沉积期),迁移作用增强，障壁开口进一步打开，上升洋流活动达到最强，保存条件变差和古生产力水平急剧升高是导致TOC含量与LM6沉积期差异不大的主因；埃隆晚期(LM8沉积期),障壁开口向西北方向迁移，TOC含量降低，有机质富集主控因素与LM1-LM5一致；特列奇早期(LM9沉积期),海平面降至最低，以富氧环境为主，TOC含量降至最低，保存条件是控制有机质富集的主要因素。总体而言，研究区不同时期有机质富集主控因素变化与构造活动和海平面变化引起的沉积古环境变化密切相关。

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 of great significance to study the mechanism of hydrothermal activity,related to the Yanshanian thermal events in Majiagou Formation,Fuxian area of the Ordos Basin,to reveal the origin of reservoirs. The two stages of hydrothermal activity related to the Yanshanian thermal events in Majiagou Formation,Fuxian area are identified,based on a comprehensive analysis of petrology and geochemistry,including core and thin section observation and cathode luminescence,homogenization temperature of fluid inclusions,carbon and oxygen stable isotopes,strontium isotope,electron probe microanalysis and rare earth element analyses. The results show that the stage-Ⅰhydrothermal activity is characterized by the development of saddle dolomite in the fissure-cavern systems,with low and negative δ¹³C and δ¹⁸O values,higher strontium isotope value than normal marine limestone,negative abnormal Eu and La in rare earth elements,rich content of MnO,FeO,SrO and poor content of K₂O and Na₂O in trace elements,and high homogenization temperature of fluid inclusions. The geochemical characteristics reveal that the saddle dolomite was formed by the combined action of internal fluids in the Ordovician strata,shallow fluids in the Carboniferous-Permian strata,and deep hydrothermal fluid under Early Cretaceous extensional fault activity,in which the deep hydrothermal fluid is post-magmatic hydrothermal fluid related to basalt eruption. The stage-Ⅱhydrothermal activity is characterized by quartz precipitation in fracture-vug systems,and the development of fractures calcite that cut saddle dolomite,with δ¹³C values close to the background value of Ordovician carbonate rocks,low δ¹⁸O value,higher strontium isotope value than saddle dolomite,negative abnormal La and positive abnormal Eu in rare earth elements,rich content of MnO,FeO,K₂O,Na₂O in trace elements,and high homogenization temperature of fluid inclusions in quartz. The geochemical characteristics reveal that the calcite and quartz were formed by the combined action of internal fluids in the Ordovician strata and deep hydrothermal fluid under Early Cretaceous extensional fault activity,in which the deep hydrothermal fluid is the post-magmatic hydrothermal fluid related to the activities of the Early Cretaceous monzonite and monzonitic diorite magmatic intrusion. Hydrothermal activity related to Yanshanian thermal events has both constructive and destructive effects on the formation and preservation of reservoir space in the Majiagou Formation,but the overall sphere of influence is limited.

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.