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The control of astronomical cycles on lacustrine fine-grained event Sedimentation——A case study of the Chunshang sub-member of the upper Es_(4) in the Dongying Sag
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作者 Tian-Yu Xu Jun Peng +4 位作者 Le-Dan Yu Hao-Dong Han Yi-Ming Yang Yao Zeng Yu-Bin Wang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1395-1410,共16页
Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fi... Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fine-grained sedimentation,but how they affect the lacustrine fine-grained event sedimen-tation has been rarely studied.Therefore,this work researched the characteristics of event sedimentation by systematically observing the cores from 30 cored wells in the Shahejie Formation of the Dongying Sag at a depth of over 1800 m,with more than 4000 thin sections being authenticated and over 1000 whole rocks being analyzed by X-ray diffraction(XRD).The research object was the Chunshang Sub-member of Upper Es_(4) in the Fanye 1 well,as it had the most comprehensive analysis data and underwent the most continuous coring.We divided astronomical cycles into different orders and made corresponding curves using the gamma-ray(GR)curve,spectral analysis,power spectrum estimation,and module extreme values,there were 6 long eccentricity periods,22 short eccentricity periods,65.5 obliquity cycles,and 110.5 precession cycles in this sub-member.On this basis,this study analyzed the control of astronomical cycles on the lacustrine fine-grained event sedimentation,and the research shows deposits were developed by slide-slump,turbidities,hyperpycnites,and tempestites in the Chunshang Sub-member of the Upper Es_(4),with higher long eccentricity,the monsoon climate contributes to the formation of storm currents,while with lower long eccentricity,the surface deposits are severely eroded by rivers and rainfalls,thus developing the slide-slump,turbidities,and hyperpycnites.The relationship between the lacustrine fine-grained event sedimentation and astronomical cycles was studied in this case study,which can promote research on fine-grained sedimentary rocks in genetic dynamics and boost the theoretical and disciplinary development in fine-grained sedimentology. 展开更多
关键词 Astronomical cycle fine-grained event sedimentation Long eccentricity Chunshang sub-member of the upper Es_(4) Dongying Sag
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Lacustrine sedimentary responses to earthquakes—soft-sediment deformation structures since late Pleistocene:A review of current understanding 被引量:2
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作者 Long Guo Zhongtai He Linlin Li 《Earthquake Research Advances》 CSCD 2023年第2期46-53,共8页
The traces left by earthquakes in lacustrine sediments are studied to determine the occurrence of ancient earthquakes by identifying seismically induced soft-sediment deformation structures(SSDS).Dating can help recon... The traces left by earthquakes in lacustrine sediments are studied to determine the occurrence of ancient earthquakes by identifying seismically induced soft-sediment deformation structures(SSDS).Dating can help reconstruct the relative frequency of earthquakes.Identifying seismically induced seismites,which carry abundant seismic information from numerous SSDS,is both critical and challenging.Studying the deformation mechanism of SSDS and learning about the common criteria of seismically induced SSDS improve the identification of earthquake triggers.With better research into SSDS,seismic events can be effectively captured,and temporal constraints can be carried out by 14C dating and optically stimulated luminescence(OSL)dating to identify and date the occurrence of ancient earthquakes.The present contribution primarily addresses the meaning and mechanism of SSDS and their relationship with earthquake magnitude as well as the common criteria of the SSDS induced by earthquakes. 展开更多
关键词 Soft-sediment deformation structures lacustrine sediments EARTHQUAKES LIQUEFACTION
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Sedimentology and Paleoenvironmental Characteristics of Fine-grained Sediments in Coal-bearing Strata in the Eastern Ordos Basin:A Case Study of the Exploratory Well in the Zizhou Area
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作者 LI Guanlin GUO Yinghai +3 位作者 WANG Huaichang LI Mi HAN Jiang YANG Xiaokai 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第4期1181-1195,共15页
The continuously collected cores from the Permo-Carboniferous coal-bearing strata of the eastern Ordos Basin are essential for studying the hydrocarbon potential in this region.This study adopted sedimentological and ... The continuously collected cores from the Permo-Carboniferous coal-bearing strata of the eastern Ordos Basin are essential for studying the hydrocarbon potential in this region.This study adopted sedimentological and geochemical methods to analyze the sedimentary environment,material composition,and geochemical characteristics of the coal-bearing strata.The differences in depositional and paleoclimatic conditions were compared;and the factors influencing the organic matter content of fine-grained sediments were explored.The depositional environment of the Benxi and Jinci formations was lagoon to tidal flat with weakly reduced waters with low salinity and dry-hot paleoclimatic conditions;while that of the Taiyuan Formation was a carbonate platform and shallow water delta front,where the water was highly reductive.The xerothermic climate alternated with the warm and humid climate.The period of maximum transgression in the Permo-Carboniferous has the highest water salinity.The Shanxi Formation was deposited in a shallow water delta front with a brackish and fresh water environment and alternative weak reductiveness.And the paleoclimate condition is dry-hot.The TOC content in fine-grained samples was averaging 1.52%.The main controlling mechanism of organic matter in this area was the input conditions according to the analysis on input and preservation of organic matter. 展开更多
关键词 fine-grained sediments paleo-sedimentary environment coal-bearing strata PERMO-CARBONIFEROUS
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Cycles of fine-grained sedimentation and their influences on organic matter distribution in the second member of Paleogene Kongdian Formation in Cangdong Sag,Bohai Bay Basin,East China
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作者 ZHAO Xianzheng PU Xiugang +10 位作者 YAN Jihua JIN Fengming SHI Zhannan CHAI Gongquan HAN Wenzhong LIU Yan JIANG Wenya CHEN Changwei ZHANG Wei FANG Zheng XIE Delu 《Petroleum Exploration and Development》 SCIE 2023年第3期534-546,共13页
According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G... According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G108-8 in the Cangdong Sag,Bohai Bay Basin,was tested and analyzed to clarify the high-frequency cycles of deep-water fine-grained sedimentary rocks in lacustrine basins.A logging vectorgraph in red pattern was plotted,and then a sequence stratigraphic framework with five-order high-frequency cycles was formed for the fine-grained sedimentary rocks in the Kong 2 Member.The high-frequency cycles of fine-grained sedimentary rocks were characterized by using different methods and at different scales.It is found that the fifth-order T cycles record a high content of terrigenous clastic minerals,a low paleosalinity,a relatively humid paleoclimate and a high density of laminae,while the fifth-order R cycles display a high content of carbonate minerals,a high paleosalinity,a dry paleoclimate and a low density of laminae.The changes in high-frequency cycles controlled the abundance and type of organic matter.The T cycles exhibit relatively high TOC and abundant endogenous organic matters in water in addition to terrigenous organic matters,implying a high primary productivity of lake for the generation and enrichment of shale oil. 展开更多
关键词 fine-grained sediment high-frequency cycle lamina density organic matter Paleogene Kong 2 Member Cangdong Sag Bohai Bay Basin
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A Preliminary Study on the Soft–Sediment Deformation Structures in the Late Quaternary Lacustrine Sediments at Tashkorgan, Northeastern Pamir, China 被引量:11
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作者 LIANG Lianji DAI Fuchu +1 位作者 JIANG Hanchao ZHONG Ning 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2018年第4期1574-1591,共18页
This study identified soft-sediment deformation structures (SSDS) of seismic origin from lacustrine sediments in the late Quaternary paleo-dammed lake at Tashkorgan, northeastern Pamir. The observed deformation stru... This study identified soft-sediment deformation structures (SSDS) of seismic origin from lacustrine sediments in the late Quaternary paleo-dammed lake at Tashkorgan, northeastern Pamir. The observed deformation structures include sand dykes, liquefied diapir and convolute structures, gravity induced SSDS, and thixotropic pillar and tabular structures. We conducted a preliminary study on the morphology, formation and trigger mechanisms of pillar and tabular structures formed by liquefaction of underlying coarse sand and thixotropy of the upper silty clay. The regional tectonic setting and distribution of lacustrine strata indicate that the most probable trigger for the SSDS in lacustrine sediments was seismic activity, with an approximate earthquake magnitude of M〉6.0; the potential seismogenic fault is the southern part of the Kongur normal fault extensional system. AMS ^4C dating results indicate that the SSDS were formed by seismic events occurring between 26050±100 yrBP and 22710±80 yrBP, implying intense fault activity in this region during the late Pleistocene. This study provides new evidence for understanding tectonic activity and regional geodynamics in western China. 展开更多
关键词 soft-sediment deformation structures lacustrine sediment PAMIR LIQUEFACTION THIXOTROPY paleo-seismicity
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Vertical Migration of Fine-Grained Sediments from Interior to Surface of Seabed Driven by Seepage Flows–‘Sub-Bottom Sediment Pump Action' 被引量:9
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作者 ZHANG Shaotong JIA Yonggang +5 位作者 WEN Mingzheng WANG Zhenhao Zhang Yaqi ZHU Chaoqi Li Bowen LIU Xiaolei 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第1期15-24,共10页
A scientific hypothesis is proposed and preliminarily verified in this paper: under the driving of seepage flows, there might be a vertical migration of fine-grained soil particles from interior to surface of seabed, ... A scientific hypothesis is proposed and preliminarily verified in this paper: under the driving of seepage flows, there might be a vertical migration of fine-grained soil particles from interior to surface of seabed, which is defined as ‘sub-bottom sediment pump action' in this paper. Field experiments were performed twice on the intertidal flat of the Yellow River delta to study this process via both trapping the pumped materials and recording the pore pressures in the substrate. Experimental results are quite interesting as we did observe yellow slurry which is mainly composed of fine-grained soil particles appearing on the seabed surface; seepage gradients were also detected in the intertidal flat, under the action of tides and small wind waves. Preliminary conclusions are that ‘sediment pump' occurs when seepage force exceeds a certain threshold: firstly, it is big enough to disconnect the soil particles from the soil skeleton; secondly, the degree of seabed fluidization or bioturbation is big enough to provide preferred paths for the detached materials to migrate upwards. Then they would be firstly pumped from interior to the surface of seabed and then easily re-suspended into overlying water column. Influential factors of ‘sediment pump' are determined as hydrodynamics(wave energy), degree of consolidation, index of bioturbation(permeability) and content of fine-grained materials(sedimentary age). This new perspective of ‘sediment pump' may provide some implications for the mechanism interpretation of several unclear geological phenomena in the Yellow River delta area. 展开更多
关键词 sediment PUMP action vertical migration fine-grained PORE pressure SEEPAGE flows
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Flocculation process of fine-grained sediments by the combined effect of salinity and humus in the Changjiang Estuary 被引量:5
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作者 LIU Qizhen LI Jiufa DAI Zhijun LI Daoji 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2007年第1期140-149,共10页
For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the hi... For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum (TM) . For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum (TM) . The effects of salinity and humus on the fine-grained sediments have been analyzed through the synthetic study of the aspects of flocculation/coagulation power ( F), diameter (D) and zeta potential (Z). And the microcosmic configuration of the flocs has been analyzed by using a scan electron microscope and Fourier Transform Infrared Spectrometry. The results show that: ( 1 ) with the increase of salinity, F and D become greater and Z becomes smaller, and with the increase of the concentration of humus, F becomes smaller, but D and Z become greater; (2) the microcosmic configuration of the flocculation shows that humus packs on the fine sediments in the form of salt, and the flocculation model of C - P - OM (C stands for clay; P cations; OM organic materials) can successfully demonstrate the mechanism of the formation of the finegrained sediments in the high-turbid area of the Changjiang Estuary. 展开更多
关键词 Changjiang Estuary fine-grained sediment floceulation SALINITY
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The Effect of Grain Size on the Viscosity and Yield Stress of Fine-Grained Sediments 被引量:2
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作者 Sueng Won JEONG 《Journal of Mountain Science》 SCIE CSCD 2014年第1期31-40,共10页
In debris flow modelling,the viscosity and yield stress of fine-grained sediments should be determined in order to better characterize sediment flow.In particular,it is important to understand the effect of grain size... In debris flow modelling,the viscosity and yield stress of fine-grained sediments should be determined in order to better characterize sediment flow.In particular,it is important to understand the effect of grain size on the rheology of fine-grained sediments associated with yielding.When looking at the relationship between shear stress and shear rate before yielding,a high-viscosity zone(called pseudoNewtonian viscosity) towards the apparent yield stress exists.After yielding,plastic viscosity(called Bingham viscosity) governs the flow.To examine the effect of grain size on the rheological characteristics of fine-grained sediments,clay-rich materials(from the Adriatic Sea,Italy; Cambridge Fjord,Canada; and the Mediterranean Sea,Spain),silt-rich debris flow materials(from La Valette,France) and silt-rich materials(iron tailings from Canada) were compared.Rheological characteristics were examined using a modified Bingham model.The materials examined,including the Canadian inorganic and sensitive clays,exhibit typical shear thinning behavior and strong thixotropy.In the relationships between the liquidity index and rheological values(viscosity and apparent yield stress),the effect of grain size on viscosity and yield stress is significant at a given liquidity index.The viscosity and yield stress of debris flow materials are higher than those of low-activity clays at the same liquid state.However the viscosity and yield stress of the tailings,which are mainly composed of silt-sized particles,are slightly lower than those of low-activity clays. 展开更多
关键词 DEBRIS Flow VISCOSITY YIELD Stress GRAIN Size fine-grained sedimentS
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Sedimentation History of Neogene Lacustrine Sediments of Sueoka Bela Stena Based on Geochemical Parameters(Valjevo-Mionica Basin,Serbia) 被引量:1
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作者 Aleksandra AJNOVI Vladimir SIMI +3 位作者 Branimir JOVANIEVI Olga CVETKOVI Radovan DIMITRIJEVI Nenad GRUBIN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第6期1201-1212,共12页
Sediments of the western part of the Valjevo-Mionica basin (Serbia) were examined both geochemically and mineralogically to explain, on the basis of their sedimentologicai characteristics, the causes of changes in t... Sediments of the western part of the Valjevo-Mionica basin (Serbia) were examined both geochemically and mineralogically to explain, on the basis of their sedimentologicai characteristics, the causes of changes in their qualitative and quantitative composition. A total of 62 samples obtained from the drillhole at depths up to 400 m was investigated. Using correlation of the obtained data, six geochemical zones were defined, two of which being specially distinguished by their mineralogical, geochemical and sedimentological characteristics. The first one, upper zone A, consists of banded marlstones interbedded with clay and oil shales and is characterized by presence of analcite and searlesite. These minerals and very high contents of Na20 indicate sedimentation in alkaline conditions with increased salinity in arid climate. That provided pronounced water stratification, as well as higher bioproductivity in the basin and sedimentary organic matter preservation. Therefore, the zone A sediments are characterized by high organic matter contents of the type which provides good potential for production of liquid hydrocarbons. Another specific zone, zone F, contains sediments with very high MgO, K2O and Li concentrations. Their geochemical correlation, as well as almost complete absence of illite in this zone, indicates the presence of interstratified clay mineral type illite-saponite (lithium-bearing Mg-smectite). 展开更多
关键词 lacustrine sediments GEOCHEMISTRY searlesite statistical analysis
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CHARACTERIZATION OF FINE-GRAINED TURBIDITE DEPOSITS FROM THE SOUTH CHINA SEA SEDIMENT CORES 被引量:1
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作者 陈峰 蔡峰 +2 位作者 杨宝华 宋文隆 陈承惠 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1992年第2期184-192,共9页
Two depositional processes controlled the muddy sediments in the South China Sea Basin. Bathyal sediments depositional rate was 7.66 cm/la in the northern continental slope of the Basin where turbidity current was alm... Two depositional processes controlled the muddy sediments in the South China Sea Basin. Bathyal sediments depositional rate was 7.66 cm/la in the northern continental slope of the Basin where turbidity current was almost nonexistent. In the northern margin of the Basin, abyssal sediment depositional rate was 5.05cm/ka and turbidity current occurrence averaged 0.22 per 1000 years. Turbidite was found in the middle of the Basin. Over half of the muddy sediments in the deep sea basin were deposited by turbidity currents, and had typically graded bedding, and contents of organic matter, calcareous material and micropaleontologic species inconsistent with the environment. 展开更多
关键词 fine-grained TURBIDITE DEPOSITS sediment CORES
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Reservoir Characteristics of Fine-grained Sedimentary Rocks in Saline Lakes in the Cenozoic Upper Ganchaigou Formation,Southwestern Qaidam Basin,NW China 被引量:1
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作者 SHENG Jun LIU Jincheng +7 位作者 LI Yunlong ZOU Haiyan LONG Anlin WANG Lin LI Jiyong QI Qingshan YANG Xiaojing LI Yanan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第3期1070-1081,共12页
Cenozoic fine-grained sedimentary rocks in the southwestern Qaidam Basin,as typical salinized lacustrine sediments,are significantly different from those in other freshwater lakes under the impact of the high salinity... Cenozoic fine-grained sedimentary rocks in the southwestern Qaidam Basin,as typical salinized lacustrine sediments,are significantly different from those in other freshwater lakes under the impact of the high salinity in the lake.Many fine-grained sedimentary rock samples were selected from the lower member of Neogene(N_(1))in the Gaskule Oilfield,Qaidam Basin,northwest China,with the aim to analyze and test their petrology,pore structure,and organic geochemical characteristics and determine its genesis and geological significance.Based on previous results,a new genesis of mixed sedimentary rocks is proposed.The Cenozoic lacustrine fine-grained sedimentary rocks in SW Qaidam Basin belong to mixed sedimentary rocks,which can be divided into three types,including carbonate and terrigenous clastic-bearing mudstone,carbonate-bearing to terrigenous clastic mixed sedimentary rocks,and carbonate-terrigenous clastic mixed sedimentary rocks.The geneses of mixing are quite different from that of mixed marine rocks.According to the sedimentary characteristics of the salinized lakes,three new geneses of mixed deposits are proposed:syn-sedimentary mixing,varve interbedded mixing,and biogenic mixing.The reservoir spaces of the Cenozoic lacustrine fine-grained sedimentary rocks in SW Qaidam Basin include residual intergranular pores,intercrystalline pores,microfractures,and minor dissolved pores.The reservoirs have super-low porosity and ultra-low permeability,with a porosity of 1.82%-21.04%,averaging 7.71%,and permeability of(0.0028-254.86)×10^(−3)μm^(2),averaging 2.82×10^(−3)μm^(2).The test results of total organic carbon(TOC)content show that the highest content of organic carbon reached 1.41%,and those of vitrinite reflectance show that Ro ranges from 0.525%-0.824%,with an average of 0.806%.The organic geochemical characteristics show that the fine-grained mixed sedimentary rocks of SW Qaidam Basin have the potential for self-generation and self-storage.As an unconventional reservoir,it has potential industrial value.This is the first study of fine-grained sedimentary rocks in the Qaidam Basin,which offers certain theoretical and practical values. 展开更多
关键词 energy resources unconventional reservoir sedimentary petrology organic geochemistry SALINIZATION lacustrine sediments NEOGENE
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Laminae characteristics of gas-bearing shale fine-grained sediment of the Silurian Longmaxi Formation of Well Wuxi 2 in Sichuan Basin,SW China 被引量:1
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作者 SHI Zhensheng QIU Zhen +3 位作者 DONG Dazhong LU Bin LIANG Pingping ZHANG Mengqi 《Petroleum Exploration and Development》 2018年第2期358-368,共11页
Based on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina,... Based on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina, namely organic-rich lamina, organic-bearing lamina, clay lamina and silty lamina, are developed in the Longmaxi Formation of Well Wuxi 2, and they form 2 kinds of lamina set and 5 kinds of beds. Because of increasing supply of terrigenous clasts and enhancing hydrodynamics and associated oxygen levels, the contents of TOC and brittle mineral reduce and content of clay mineral increases gradually as the depth becomes shallow. Organic-rich lamina, organic-rich + organic-bearing lamina set and organic-rich bed dominate the small layers 1-3 of Member 1 of the Longmaxi Formation, suggesting anoxic and weak hydraulic depositional setting. Organic-rich lamina, along with organic-bearing lamina and silty lamina, appear in small layer 4, suggesting increased oxygenated and hydraulic level. Small layers 1-3 are the best interval and drilling target of shale gas exploration and development. 展开更多
关键词 Sichuan Basin Longmaxi Formation fine-grained sediment SHALE GAS lamina WELL WUXI 2
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Structural and Sedimentary Characteristics of Hydrocarbon-Rich Sags in Lacustrine Sub-Basin of Half Graben Type, Pearl River Mouth Basin, South China Sea 被引量:1
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作者 Lei He Xiaolong Wang +3 位作者 Ningbo Cai Jie Qu Xiong Zhu Daomao Lin 《Open Journal of Yangtze Oil and Gas》 2019年第3期194-211,共18页
Pearl River Mouth Basin undergoes complex tectonic evolution processes and forms lacustrine,transitional and marine sediments.Drilling shows that there exist large petroleum reserves in the hydrocarbon-rich sags of Pe... Pearl River Mouth Basin undergoes complex tectonic evolution processes and forms lacustrine,transitional and marine sediments.Drilling shows that there exist large petroleum reserves in the hydrocarbon-rich sags of Pearl River Mouth Basin,South China Sea.To reduce the risk,the exploration,structural and sedimentary characteristics of the hydrocarbon-rich sags should be identified and described.Drilling,seismic,and microfossil data are integrated to interpret the structural and sedimentary evolution of the hydrocarbon-rich sags in Pearl River Mouth Basin.By analyzing the tectonic and sedimentary evolutionary characteristics,three conclusions may be drawn:1、The present regional tectonic characteristics of the PRMB are formed by mutual interactions of the Eurasian Plate,Pacific Plate,Philippine Plate and Indian Plate.During the Paleocene to early Eocene and late Eocene and early Oligocene,the PRMB is at the rifting stage.During the late Oligocene,the PRMB was at the rifting-depression transitional stage.After the Oligocene,the PRMB is at the depression stage.2、Tectonic conditions control the sedimentation process in the hydrocarbon-rich sags.During the lacustrine sedimentation stage,synsedimentary faults and intense faulting control the sedimentation.During the transitional sedimentation stage,weak fault activity influences the deposition process in the hydrocarbon-rich sags.During the marine sedimentation stage,weak fault activity and depression activity control the deposition process in the hydrocarbon-rich sags.3、Tectonic evolution affects the deposition process.The lacustrine,transitional and marine sedimentation corresponds to different tectonic conditions.The lacustrine sedimentation is formed under fault activity during the rifting stage.The transitional sedimentation is formed under weak fault activity during the late rifting stage.The marine sedimentation is formed under weak fault activity and depression activity during the rifting-depression and depression stages.4、The half graben is beneficial for the formation of lacustrine source rocks,which is responsible for the hydrocarbon-rich sag.Therefore the half graben mode contributes to the hydrocarbon-rich sags. 展开更多
关键词 HALF GRABEN lacustrine sedimentATION Transitional sedimentATION Marine sedimentATION Hydrocarbon-Rich Sag Pearl River Mouth Basin
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Wave-Enhanced Sediment-Gravity Flows in Bohai Bay Lacustrine Basin, Eastern China
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作者 BAI Chenyang YU Bingsong +3 位作者 DONG Tianyang HAN Shujun GE Jia ZHU Donglin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2018年第6期2416-2431,共16页
Sequences of wave-enhanced sediment-gravity flows(WESGFs) have been widely recognized in the marine shelf environment. In this study, we show observations of WESGF deposits in lacustrine settings using well core and t... Sequences of wave-enhanced sediment-gravity flows(WESGFs) have been widely recognized in the marine shelf environment. In this study, we show observations of WESGF deposits in lacustrine settings using well core and thin section data from the Paleogene in the Jiyang sub-basin, Bohai Bay basin, eastern China. The findings of this study include the following: 1) the sequence of WESGFs in the lacustrine basin is similar to that of marine; it consists of three units, MF1 unit: siltstone with basal erosion surface, MF2 unit: silt-streaked claystone, and MF3 unit: silty-mudstone; and 2) prodelta sand sheets are found in the lacustrine WESGF sequence and are classified as the MFd unit: clay-streaked siltstone. However, because the system size and variability in hydrodynamic conditions are different between the lacustrine and marine basins, lacustrine WESGFs do appear to have three distinguishable features: 1) the sediment grain size and sand content are slightly higher than those of the marine WESGFs; 2) lacustrine WESGFs may contain prodelta sediments or sedimentary sequences of other types of gravity flows, such as hyperpycnal flows; and 3) the scale of the sedimentary structures for lacustrine WESGFs is smaller. The WESGFs found in the continental lacustrine basin provide a new model for sediment dispersal processes in lake environments and may be helpful to explain and predict the distribution of sandy reservoirs for oil and gas exploration. 展开更多
关键词 wave-enhanced sediment-gravity flows sediment transport lacustrine basin Shahejie Formation Bohai Bay basin
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Aeolian component records in lacustrine sediments and its atmospheric circulation significance for evolution of Qarhan salt lake,NE Qinghai-Tibetan Plateau
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作者 AN Fuyuan LAI Zhongping +2 位作者 FAN Qishun WEI Haichen MA Haizhou 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期1-2,共2页
1 Introduction The Qarhan Playa of Qaidam Basin is located at the northeastern QinghaiTibetan Plateau(QTP),in which thick lacustrine and evaporate sediments deposited since the late Pleistocene(Chen et al.,1985,1986).... 1 Introduction The Qarhan Playa of Qaidam Basin is located at the northeastern QinghaiTibetan Plateau(QTP),in which thick lacustrine and evaporate sediments deposited since the late Pleistocene(Chen et al.,1985,1986).As surrounded by capacious Gobi and yardang fields and suffered strong westerly-northwesterly wind,abundant aeolian materials were trapped in these sediment sequences in the 展开更多
关键词 Aeolian component in lacustrine sediments Atmospheric circulation East Asian winter monsoon(EAWM) evolution of Qarhan salt lake Qaidam Basin
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Variation in δ^(15)N of a lacustrine sedimentary sequence in the Nanling Mountains and its potential implication for climatic conditions over the past ~16000 years
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作者 钟巍 曹家元 +1 位作者 薛积彬 欧阳军 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第5期1098-1106,共9页
Although extensive studies have been performed on nitrogen isotopes in lake sediments, understanding the complexity of the δ15N variation related to past environmental and climatic conditions still remains unclear. S... Although extensive studies have been performed on nitrogen isotopes in lake sediments, understanding the complexity of the δ15N variation related to past environmental and climatic conditions still remains unclear. Supported by multi-proxy records including litho-units, organic carbon isotopes, ration of total organic carbon and total nitrogen, organic matter content, bulk dry density, the accumulation rate of organic matter, median grain size, magnetic susceptibility, and Rb/Sr and Ca/Mg ratios obtained from a sedimentary sequence in a small lake (i.e., Dahu Swamp) in the eastern Nanling Mountains in South China, we deduce that variation in the δ15N values results primarily from the sources of organic matter, which are significantly influenced by climatic conditions over the past -16 000 years. A low (or high) lake level resulting from dry (or wet) conditions would lead to more (or fewer) vascular plant remains in the sediments and stronger (or weaker) denitrification associated with hypolimnetic anoxia, resulting in lower (or higher) 615N values. In addition, dry (or wet) conditions would favor weakened (or strengthened) biogeochemical activity in the catchment, which could result in less (or more) external input of δ15N-enriched OM, thus leading to decreased (or increased) δ15N values. Our results indicate that the lake sediment δ15N record in the Nanling Mountains has the potential to provide valuable insight into past East Asian monsoon climate- driven environmental changes. 展开更多
关键词 nitrogen isotopes lacustrine sediments climate changes Nanling Mountains
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Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau:Current status and transfer mechanisms
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作者 Rui-ping Liu Fei Liu +3 位作者 Ying Dong Jian-gang Jiao El-Wardany RM Li-feng Zhu 《China Geology》 CAS 2022年第3期421-428,共8页
This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau.The study surveyed the average abundance of microplastics in sediments... This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau.The study surveyed the average abundance of microplastics in sediments.The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22-2643.65 items/kg DW and 0-60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin.The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world.Like microplastics in other lakes of the world,those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA,PET,PE,and PP and are primarily in the shape of fibers and fragments.The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities,and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains.Furthermore,the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments.This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau. 展开更多
关键词 Microplastic pollution Environmental pollution LAKE lacustrine sediment Qinghai Lake Ecological risks Hydrogeological engineering Ecological engineering Qinghai-Tibet Plateau China
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The Mid-Pleistocene Climate Transition Recorded in a 1.6 Myr-Period Lacustrine Sediment Sequence from Mazatage, Tarim Basin
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作者 LIU Jian WU Li +1 位作者 WANG Rujian ZHAO Yue 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第1期312-313,共2页
The mid-Pleistocene climate transition (MPT) has been widely reported in worldwide geological events. As a key issue of the Quaternary geology, it has attracted much attention from the paleoclimate community. MPT re... The mid-Pleistocene climate transition (MPT) has been widely reported in worldwide geological events. As a key issue of the Quaternary geology, it has attracted much attention from the paleoclimate community. MPT refers to a period lasting for several hundreds of thousand years, during which the dominant climate periodicity gradually extended from 41 kyr to 100 kyr (Ruddiman et al., 1989), 展开更多
关键词 Wang Tarim Basin The Mid-Pleistocene Climate Transition Recorded in a 1.6 Myr-Period lacustrine sediment Sequence from Mazatage
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Deformation mechanism and hydrocarbon significance of Eocene organic-rich fine-grained soft sediments in the Leijia Region,Liaohe Depression
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作者 Yijie WEN Jianguo ZHANG +1 位作者 Shu TAO Chenyu CAI 《Frontiers of Earth Science》 SCIE CSCD 2024年第1期83-97,共15页
The deformation structure of soft sediments has always been a research hotspot,which is of great significance for analyzing the tectonic and sedimentary evolution background of a basin,as well as the physical properti... The deformation structure of soft sediments has always been a research hotspot,which is of great significance for analyzing the tectonic and sedimentary evolution background of a basin,as well as the physical properties of reservoirs.Previous studies have reported that a large number of soft sediment deformation structures are developed in the western part of Liaohe depression.In this study,through core observation and thin section identification,various types of deformation structures are identified in the core samples which are collected from the upper Es4 in the Leijia region,western sag of Liaohe depression,such as liquefied dikes,liquefied breccia,convoluted laminae,annular bedding,synsedimentary faults,vein structures,etc.Based on the characteristics of core structure,single well profile and continuous well profile,combined with the regional background,this study clarifies that the deformation structure of soft sediments in the study area is mainly caused by seismic action.It is found that the permeability and porosity of deformation layers in the study area are higher than those of the undeformation layers,which proves that the deformation structure of soft sediments has a good effect on improving the physical properties of reservoirs. 展开更多
关键词 soft sediment deformation structure Liaohe depression organic-rich fine-grained soft sediments hydrocarbon significance
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Discovery of shale oil in alkaline lacustrine basins:The Late Paleozoic Fengcheng Formation,Mahu Sag,Junggar Basin,China 被引量:9
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作者 Yong Tang Jian Cao +3 位作者 Wen-Jun He Xu-Guang Guo Ke-Bin Zhao Wen-Wen Li 《Petroleum Science》 SCIE CAS CSCD 2021年第5期1281-1293,共13页
A new type of shale oil in alkaline lacustrine sediments has been discovered in the Late Paleozoic Fengcheng Formation,Mahu Sag,Junggar Basin,China.The fine-grained sedimentary rocks deposited in this alkaline lacustr... A new type of shale oil in alkaline lacustrine sediments has been discovered in the Late Paleozoic Fengcheng Formation,Mahu Sag,Junggar Basin,China.The fine-grained sedimentary rocks deposited in this alkaline lacustrine environment can be divided into four types and eight sub-types:mudstone(with no alkali minerals),including massive dolomitic mudstone,and massive and laminated calcareous mudstone;dolomite,including massive argillaceous dolomite(with alkali minerals),and massive and laminated argillaceous dolomite(with no alkali minerals);evaporites;and pyroclastic rocks.The massive argillaceous dolomite(with alkali minerals)and pyroclastic rocks have the highest shale oil potential,with average oil saturation index(OSI)values of 344.67 and 124.65 mg HC/g TOC,respectively.Shale oil exploration in the representative well MY1 indicates that the Fengcheng Formation is thick and contains abundant natural fractures,brittle minerals,and mobile oil.The entire Fengcheng Formation is oilbearing and contains three concentrated stratigraphic intervals of shale oil(i.e.,sweet spots).Well MY1 indicates that,compared with source rocks developed in marine and sulfate-type saline basins,the fine-grained sedimentary rocks deposited in alkaline lacustrine environments can also have high shale oil potential.The co-existence and regular distribution of conventional and unconventional reservoirs in the Fengcheng Formation indicate that it is an ideal exploration target for multiple resource types. 展开更多
关键词 Alkaline lake Saline lacustrine basin fine-grained sedimentary rock Argillaceous dolomite Unconventional hydrocarbon
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