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	JOPC 2022 Vol.24 Number 3
	2022, Vol.24 Num.3
	Online: 2022-06-01

	LITHOFACIES PALAEOGEOGRAPHY AND SEDIMENTOLOGY BIOPALAEOGEOGRAPHY AND PALAEOECOLOGY TECTONOPALAEOGEOGRAPHY AND PALAEOTECTONICS GEOCHEMISTRY AND SEDIMENTARY ENVIRONMENTS PALAEOGEOGRAPHY AND MINERAL RESOURCES QUATERNARY PALAEOGEOGRAPHY AND SEDIMENTOLOGY

LITHOFACIES PALAEOGEOGRAPHY AND SEDIMENTOLOGY

	405	Li Sheng-Li, Li Shun-Li, Fu Chao

		Implication of the large-tube settling experiment results on genesis of fine-grained deposition lamination of lacustrine basin
		The study on sedimentary texture and structure is an important aspect in fine-grained sedimentology. At the same time,the genesis of laminar structure of organic mudstone or shale has always been a difficult problem. There are many factors affecting laminar structure of fine-grained deposits in a lacustrine basin,among which salinity and organic matter content are very important factors. Especially,oil shale can be developed in fresh or salt water environment. The relationship between the formation of laminar structure and water salinity needs to be further discussed. In this paper,through large-tube settling experiment,the depositional process and settlementation rate of clay minerals and organic rich argillaceous sediments in fresh water,brackish water and salt water were simulated and observed under hydrostatic conditions. Through experimental observation,the settlement process curve was drawn and the settlement rate was calculated. The research shows that the settlementation rate of organic rich mud in fresh water is significantly higher than that of clay minerals;in brackish water and saline water,the sedimentation rate of clay minerals is significantly higher than that of organic rich mud. At the same time,the sedimentation rates of the two types of fine-grained sediments in the three types of water environment also have different laws. By analyzing the experimental results,it is pointed out that the difference of flocculation type and the influence of buoyancy are the main reasons for the difference of fine particle deposition rate under different water medium conditions. Organic matter,clay minerals and water salinity jointly control the sedimentation rate of fine-grained sediments. Once these conditions change,it is easy to form similar or different laminae. In particular, when the abundance and salinity of organic matter change,it is easier to form laminae with different components. Therefore,in addition to the relatively quiet water environment,the formation of oil shale is also related to the abundance of organic matter,the content of clay minerals,the flocculation process and the comprehensive response to the change of water salinity,rather than the water salinity alone. In addition,in different areas of the lacustrine basin,fine-grained sedimentary structure types are different due to different depositional processes.
		2022 Vol. 24 (3): 405-414 [Abstract] ( 644 ) [HTML 1KB] [PDF 4312KB] ( 381 )

	415	Zhang Ke, Wu Sheng-He, Xu Yun-Jie, Xiong Qi-Cong, Gao Zi-Jie, Yu Ji-Tao

		Sedimentary characteristics of mouth bar within lacustrine fan delta: insights from the Lower Cretaceous Xiguayuan Formation of Sangyuan outcrop,Luanping Basin
		Fan delta is an important hydrocarbon reservoir and its genetic unit type and distribution strongly influence the hydrocarbon distribution and recovery efficiency. Although there is a consensus on the sedimentary characteristics of distributary channels,the sedimentary characteristics of mouth bar,especially the vertical grain-size trend,are still controversial. Field survey and unmanned aerial vehicle(UAV)observation were used to investigate the lacustrine fan delta of the Xiguayuan Formation of Lower Cretaceous in Sangyuan outcrop, Luanping Basin,and flume simulation experiment was done aiming to analyze the sedimentary characteristics of mouth bar and reveal the formation mechanism of vertical grain-size trend. The mouth bars account for 45.27% of glutenite bodies,while the distributary channels and sheet sand account for 53.42% and 1.31% of glutenite bodies,respectively. The mouth bar with a flat bottom and convex top mainly consists of sandy and gravelly accretions. The sandy accretion shows an overall coarsening upward trend,and gravelly accretion shows the fining upward trend. The vertical grain-size trend of mouth bar is controlled by superposition patterns of the accretion bodies,which shows either coarsening upward trend or fining upward trend. Under constant discharge and slope of depositional bedform conditions,finer sediment induces a coarsening upward trend of accretion within the mouth bar dominated by the friction-dominated effluent,while the accretion with coarser sediment results in the coarsening upward accretion controlled by the inertia-dominated effluent diffusion.
		2022 Vol. 24 (3): 415-432 [Abstract] ( 560 ) [HTML 1KB] [PDF 57428KB] ( 652 )

	433	Xia Chang-Fa, Zhang Xia, Lin Chun-Ming, Huang Shu-Ya, Jiang Kai-Xi, Zhou Xue-Qian

		Sedimentary environment and palaeoclimate evolution of the late Quaternary from core SE4 in Qiantang River incised valley
		Based on the analyses of grain size,pollen,AMS ¹⁴C ages etc.,the sedimentary environment and palaeoclimate of the late Quaternary sediments from core SE4 in the Qiantang River incised valley are discussed,and the specific process of sedimentary response to climate change mechanism is revealed. The results show that the late Quaternary sediments in core SE4 consist of five sets of depositional units from bottom to top,including fluvial channel,floodplain,palaeo-estuary,neritic deposits,and modern estuary. The palaeovegetation and palaeoclimate evoluiton of the study area since late Quaternary can be divided into six stages. The first stage is characterized by a mixture of coniferous and broadleaf forest-grassland dominated by broadleaf trees,indicating a mild-humid climatic phase,during which the fluvial channel and floodplain deposits were deposited. The second stage is also represented by a mixture of coniferous and broadleaf forest,but with slightly more deciduous vegetation,suggesting a mild and humid climatic phase,during which palaeo-estuarine and part of shallow marine deposits were deposited. The third stage is dominated by a mixture of coniferous and broadleaf forest,indicating a warm and humid climatic phase when some other shallow marine deposits were formed. From the fourth to sixth stage when modern estuary developed,the vegetation types experienced a transition from coniferous and broadleaf forest-grassland,through coniferous and broadleaf forest,to coniferous and broadleaf forest-grassland,suggestive of a palaeoclimatic shift from mild-dry,through mild-humid,back to mild-dry conditions.
		2022 Vol. 24 (3): 433-448 [Abstract] ( 522 ) [HTML 1KB] [PDF 4710KB] ( 310 )

	449	Xu Wei, Liu Xiao-Hang, Liu Meng, Hu Li-Sha, Xu Jing-Ping, Wang Zhi-Wen

		Turbidite deposition in Manila Trench since 1.4 ka B.P. and its controlling factors
		Turbidity current is an important way for long-distance sediment transport. Submarine turbidity current widely develops in submarine canyons or trenches. The Manila Trench is located at the western Pacific marginal subduction zone and with abundant tectonic activities(earthquake)and extreme climatic events(e.g.,Typhoon),which easily generate turbidity. Because of the complicated abyss topography of the Manila Trench,turbidity currents are rarely reported. In this study,we choose a core collected from 3747 m depth water in northern Manila Trench during 2018 South China Sea Cruise by NSFC for turbidite analyses. The maximum depositional age is 1405 a B.P. High-precision particle size analysis(25 mm per analysis)and sedimentary characteristics show that GEO6 core records at least eleven turbidity flow deposits(T1-T11). Most turbidity deposits show a gradually finning upward grain size,and an erosional surface in the bottom of each turbidite. Only T8 shows an inversely graded sequence,which may be the hyperpycnal flow deposit. Combined with the regional geological data,we found that frequent typhoons in the study area have brought a large amount of terrestrial loose sediments to the upper reaches of the Manila Trench(Gaoping Canyon)since 1.4 ka B.P. These loose deposits collapsed and were transported downstream due to frequent earthquakes,forming recurring turbidity deposits in the Manila Trench.
		2022 Vol. 24 (3): 449-460 [Abstract] ( 460 ) [HTML 1KB] [PDF 2514KB] ( 315 )

BIOPALAEOGEOGRAPHY AND PALAEOECOLOGY

	461	Xing Zhi-Feng, Li Wan-Ying, Qi Yong-An, Zheng Wei, Xu Xin, Zhang Xiang-Yun, Li Da, Wu Pan-Pan

		*Paleoenvironmental significance of ichnogenus Skolithos* in the aftermath of the end-Permian mass extinction: a case study of the Lower Triassic Heshanggou Formation in western Henan Province**
		The Lower Triassic ichnofossils in the western Henan record the evolution of trace-maker communities from remnant to recovery after the Permian-Triassic mass extinction(PTME). Skolithos is characterized by vertical or high angle inclination to the rock layer,and is widely preserved in the Lower Triassic Heshanggou Formation. Macroscopic and microscopic characteristics of Skolithos were studied on abundant,well-developed Skolithos specimens collected from the Heshanggou Formation in Dengfeng and Yiyang areas.We conducted a three dimensional occupation cubes of ecospace utilization and ecosystem engineering by analyzing the motility,feeding strategy,the interaction between organisms and substrate, and the way of biological modification of sediments. We also analyzed the paleoenvironmental significance of Skolithos and explored the high environmental pressure indicated by Skolithos ichnofossils. The results show that Skolithos is mainly affected by high environmental pressures such as high temperatures,dry and hot climate and giant monsoon in the early stage of recovery. As an opportunistic ichnogenus, Skolithos was widely developed in meandering river and shallow lacustrine deposits. The above results may provide a reference for the study of continental sedimentary environment and paleoecological background of the Lower Triassic in the western Henan.
		2022 Vol. 24 (3): 461-478 [Abstract] ( 489 ) [HTML 1KB] [PDF 28463KB] ( 311 )

	479	Zhou Zhi-Qiang, Zhao Jing-Yu, Wang Jia-Shu, Wu Cheng-Yang, Xiao Biao, Huang Pu

		*New material of Zosterophyllum australianum* from the Lower Devonian Mangshan Group in Duyun, Guizhou and its palaeogeographic implications**
		Zosterophyllum is one of the representative taxa of early land plants,and has a worldwide distribution. Z. australianum occurred in South China and Australia,and is a typical species of the Northeastern Gondwana Phytogeographic Unit. New material of Z.australianum from the Mangshan Group of the Baoyang section in Duyun,Guizhou is described here. The plant is characterized by sporangia with a short stalk,which are closely arranged forming a spike,and the sporangia are elliptical or fan-shaped,ca. 2.6~4.1 mm wide and up to 3.9 mm high,and the thickened border is ca. 0.6 mm wide. These features are closely comparable to those of Z. australianum from the Early Devonian Posongchong flora of Wenshan,Yunnan. On the basis of the temporal range of Z. australianum and other plants such as Adoketophyton subverticillatum from the Mangshan Group,the lower part of this group is suggested to be the Pragian of the Early Devonian in age. The discovery of Z. australianum from the Mangshan Group extends the geographic distribution of this species,and adds evidence to a certain relationship between the plant assemblages from the Mangshan Group and the Posongchong flora.
		2022 Vol. 24 (3): 479-492 [Abstract] ( 471 ) [HTML 1KB] [PDF 11949KB] ( 260 )

TECTONOPALAEOGEOGRAPHY AND PALAEOTECTONICS

	493	Zhou Yong, Ji You-Liang, Meng Qi-An, Wan Hong-Feng, Zhang Ge, Ren Yu-Tao, Yan Ke-Xin, Liang Tao, Chen Fu-Yu, Qiang Zhi-Cheng

		Control mechanisms of tectonic paleogeomorphology on the Early Cretaceous sedimentary basin fills in Ta'nan sag,Tamtsag Basin,Mongolia
		The Ta'nan sag is a typical faulted lacustrine basin formed during the Early Cretaceous,which experienced multi-stage episodic faulting activities. Tectonic activities are an important factor for the formation of paleogeomorphology and sand distribution. However,the controls of paleogeomorphologies generated by synsedimentary tectonic activities on sequence architectures,sedimentary system and sand body distribution are still unclear. Based on seismic,well logging and core data,under the guidance of sequence stratigraphy theory and paleogeomorphic sand control theory,the sequence-stratigraphic frameworks of the Lower Cretaceous in the Ta'nan sag are established. Combined with the analysis of the major fault activity during different rifting stages,the controlling effects of different paleogeomorphologies on sedimentary system and sand body distribution are clarified. The investigation of the tectonic evolution and sediment fill of the Ta'nan sag during the Early Cretaceous suggests that the episodic rifting and various activities of major faults created complex paleogeomorphologies including transfer zones and structural slope-break zones,which significantly controlled the development and distribution of both depositional systems and sand bodies. The transfer zones including transverse uplift and relay ramp were the sites for drainage catchment,and controlled the locations of sedimentary provenances,entry points of sedimentary material into the basin,and the resultant development of depositional systems. According to fault geometry and the location of the slope-break zones,the structural slope-break zones of the Ta'nan sag during the climax rifting stage were subdivided into four types: fault scarp zone,fault terrace zone,gentle slope zone and intrabasinal fault break zone,which played significant roles in controlling the changes in accommodation and the distribution of depositional systems and sand bodies. Three syndepostional fault arrangement patterns were identified according to their distribution on the structural map,which are “comb-like”,“fork-like and “parallel”faults. Areas where the structural slope-break zone overlapped with transfer zones are sites for major drainage systems and the optimum locations of fan deltas and sublacustrine fans. The sand bodies deposited here are favorable targets for the exploration of litho-stratigraphic traps in the Ta'nan sag. The results have important theoretical significance and practical value for deepening the theory of source-to-sink system and guiding the prediction of sand body distribution in faulted lacustrine basins.
		2022 Vol. 24 (3): 493-511 [Abstract] ( 481 ) [HTML 1KB] [PDF 12581KB] ( 378 )

	512	Liang Ze-liang, Jiang Yan-liang, Ji Dong-Sheng, Wu Kong-You, Wang Jun, Xiao Li-Xin, Zhao Jin-Yong

		Geological features and genetic evolution of Houxia Basin in North Tianshan Orogenic Belt
		The Houxia Basin,which is a small intermontane basin of the northern Tianshan orogenic belt in the Mesozoic,whose structural characteristics and genetic evolution are critical to understand the tectonic evolution,collision of the landmass,and basin-orogen coupling relationship in the Tianshan region. In this paper,the geological features and genetic evolution of Houxia Basin were systematically studied by means of field survey,seismic interpretation,and balanced section restoration. We found that: (1)the North Tianshan Mountain provided an important provenance to the Houxia Basin during the Jurassic. At that time,the Carboniferous basement was an underwater low bulge,which did not rise into mountains that could have separated the north and south Jurassic strata. The present residual intermountain basin in the Houxia area resulted from the separation of the later tectonics;(2)the Houxia Basin experienced the complex extension-extrusion stresses. Weak extension between early and middle Jurassic resulted in a graben basin. Strong compression in the Late Jurassic and during the Himalayan period resulted in uplift and erosion of strata and structural amplitude changes. The findings are of great significance to clarify the tectonic evolution of the Tianshan orogenic belt and can guide the oil and gas exploration in adjacent sedimentary basins.
		2022 Vol. 24 (3): 512-523 [Abstract] ( 474 ) [HTML 1KB] [PDF 10329KB] ( 457 )

GEOCHEMISTRY AND SEDIMENTARY ENVIRONMENTS

	524	Liu Da-Wei, Cai Chun-Fang, Hu Yong-Jie, Jiang Lei, Li Rui, He Hong, Wang Shi, Peng Yan-Yan, Wei Tian-Yuan, Liu Qi-Yuan

		Variations in analytical results of commonly used major and trace elements and isotopic analyses in carbonate studies:a case study on the Lower Cambrian Longwangmiao Formation in central Sichuan Basin
		There are multiple methods of analyzing trace elements and isotopes in studies on carbonate. Are there any differences in the actual geochemical information obtained by different methods?Are those results possibly to compare with each other?In this paper,we compare the results of the main trace element tests(electron probe micro-analyzer[EPMA], laser ablation-plasma mass spectrometry[LA-ICP-MS], and solution method trace[ICP-OES])and oxygen isotope measurements(in-situ ion probe[in-situ SIMS],and acid soluble powder)commonly used in carbonate studies. Taking the carbonates in the Lower Cambrian Longwangmiao Formation in central Sichuan Basin as an example,we reveal the variability in the results of different test methods,in order to provide references for reducing multi-resolution of geochemical information. The study reveals: (1)the variability among the test means(EPMA,LA-ICP-MS and ICP-OES)objectively exists,but the overall bias of the test results decreases with the increase of concentration of measured elements. For the major elements(>10%),the standard deviation of each test result is less than 2%;For the enriched trace elements(>1000 μg/g),the results are within the test error and the standard deviation of the results is less than 6%;For the concentration range of trace elements(100-1000 μg/g),the standard deviation of each test result increases significantly. The deviations of LA-ICP-MS and ICP-OES results are smaller than that of LA-ICP-MS and EPMA,with the deviations of the former increasing from 6% to 45% and those of the latter increasing from 9.1% to 151%. In the concentration range below 100 μg/g,the deviations of LA-ICP-MS and ICP-OES results can be several times different due to the heterogeneity within the minerals. (2)It was found that the deviation of the EPMA results from the LA-ICP-MS results in the adjacent detection line interval(ranging from 100 to 300 μg/g)gradually increases under the micro-area limitation,and it was speculated that this deviation was caused by the correction compensation mechanism for low content elements in the EPMA result correction process. (3)The in-situ SIMS oxygen isotope values reveal the differences in δ¹⁸O values at the micro-regional scale of minerals,but the overall test results are 0.5‰~2.5‰ V-PDB negative bias. Presumably,this deviation may come from the specimen correction conversion errors. (4)The cathodoluminescence characteristics of the samples are not related to the Fe or Mn contents,and thus it needs to explore the fluid source in conjunction with lithological and geochemical evidence.
		2022 Vol. 24 (3): 524-539 [Abstract] ( 538 ) [HTML 1KB] [PDF 4818KB] ( 320 )

PALAEOGEOGRAPHY AND MINERAL RESOURCES

	540	Huang Yu-Yue, Wang Gui-Wen, Song Lian-Teng, Wang Song, Zhang Yi-Lin, Huang Li-Liang, Lai Jin

		Fracture logging identification and effectiveness analysis of shale reservoir of the Permian Fengcheng Formation in Mahu sag,Junggar Basin
		Shale oil resources have great potential in China. Development of fractures is an important factor affecting shale oil production. Taking the shale reservoir of the Fengcheng Formation in Mahu sag of the Junggar Basin as the research object,the development characteristics of fractures in the study area are summarized through core observation,thin section identification,conventional and imaging logging methods. The comprehensive logging identification method of “conventional+imaging+core” is further proposed,and the logging comprehensive identification chart of typical fracture development types is established. The results show that the natural fractures in Mahu area intensively developed in the P₁f₃, less in the P₁ f₁, and almost none in the middle of the P₁f₂. Fractures mainly developed in felsic shale,dolomitic shale, and mixed shale,mainly high-angle structural fractures and low-angle diagenetic fractures,with high opening degree. A few fractures are filled with carbonate minerals,and the strike is mainly NW-SE. Based on the quantitative calculation results of fracture parameters,combined with lithology,mineral composition and in-situ stress,the effectiveness of reservoir fractures is analyzed. The study shows that the high-angle unfilled fracture development section with high content of brittle mineral components and strike parallel to the current horizontal maximum principal stress has an obvious control effect on reservoir effectiveness,which is consistent with the liquid production data. The comprehensive evaluation method of fracture logging has remarkable effect,and can provide method support for fracture identification and effectiveness evaluation of shale reservoir.
		2022 Vol. 24 (3): 540-555 [Abstract] ( 495 ) [HTML 1KB] [PDF 31216KB] ( 1949 )

	556	Li Ya-Ru, Li Hua, Yang Zhao-Qiang, Zhou Wei, Wang Yu, Liu Sheng-Qian, He You-Bin

		Reservoir architecture of the Huangliu Formation submarine fan in Yinggehai Basin,South China Sea
		Submarine fan on shallow shelf are developed in the Member 1 of the Miocene Huangliu Formation in the Dongfang X Gas Field of the Yinggehai Basin. The sedimentary type in this area is special,and the sand body connectivity is complicated. The research on reservoir architecture of submarine fan is relatively weak,which seriously affects the oil and gas exploration and development in the Dongfang X Gas Field. Under the guidance of sequence stratigraphy,sedimentology,logging geology,seismic sedimentology and other theories,and based on the data of core,drilling,logging,3D seismic and seismic wave impedance inversion,the architecture and sandbody distribution pattern within the submarine fan in this area are studied. The results show that: Submarine fan in the study area is mainly middle fan and characterized by the channel,levee,sheet sand and fan margin sand deposits;Channel and sheet sand are common in the II_b gas group of the first member of the Huangliu Formation. Channels are dominated by sedimentation process and can be divided into two stages of development,which are oriented in NW-SE direction;There are three stacking patterns sand body within the reservoir,layered filling,vertical cut-stacking and lateral cut-stacking;The controlling factors of reservoir architecture include the sediment supply,the slope gradient and the energy of the gravitational flow.
		2022 Vol. 24 (3): 556-567 [Abstract] ( 513 ) [HTML 1KB] [PDF 6838KB] ( 260 )

QUATERNARY PALAEOGEOGRAPHY AND SEDIMENTOLOGY

	568	Lin Xu, Li Ling-Ling, Liu Hai-Jin, Chen Ji-Xin

		Sediments from the upper reaches of Yellow River did not enter into Shanxi-Shaanxi Gorge in the Neogene
		The emergence of rivers is the result of the tectonic activity and climate change in their basins. The Shanxi-Shaanxi Gorge is located at the junction of the upper and middle reaches of the Yellow River,which has irreplaceable geographical advantages for studying when the upper Yellow River enters into Shanxi-Shaanxi Gorge. At present,there is great controversy about when the Yellow River enters the Shanxi-Shaanxi Gorge,e.g.,the Miocene,Pliocene and Pleistocene. In this case,we carried out detrital zircon U-Pb age analysis and sedimentary facies observation on the Late Miocene and Pliocene strata in the northern parts of the Shanxi-Shaanxi Gorge. New 270 detrital zircons U-Pb ages are obtained from the Moshangou,Dayandun and Gaojiayinzi sections. Given the paleocurrent flow direction is from east to west and comparison of U-Pb ages with that of the potential source area,we conclude that the sediments of Moshangou and Dayandun profiles were derived from the proximal source of the northern parts of the Lüliang Mountain. The provenance analysis of the sandstone at the bottom of the Gaojiayinzi section indicate a northward sediment transport direction,and the sediments were mainly derived from the Mesozoic sedimentary strata in the northern Ordos block. Combined with the reported paleomagnetic ages of these strata,the northern section of the Shanxi-Shaanxi Gorge was dominated by near-source accumulation during 6.2~3.7 Ma,which is a response to the remote effect of the uplift of the Tibetan Plateau and the enhancement of the East Asian summer monsoon,and excludes the provenance relationship with the upper reaches of the Yellow River.
		2022 Vol. 24 (3): 568-582 [Abstract] ( 510 ) [HTML 1KB] [PDF 8096KB] ( 264 )

	583	Cai Qing-Song, Yang Guang-Liang, Fan Yu-Xin, Yan Xue-Yu, Gao Min-Min, Zhang Qing-Song, Wang Rong-Hua, Guo Xue-Lian

		Provenance evolution of Quaternary loess/paleosol sequence in Lanzhou, China: evidence from carbonate minerals
		The provenance of loess is of great significance to reveal the climate change and the uplift history of the Qinghai-Tibet Plateau in the Quaternary. In this paper,the main mineral compositions of the loess/paleosol sediments since 1.4 Ma in Lanzhou region,located in the western part of the Chinese Loess Plateau,are analyzed based on X-ray diffraction. Focusing on carbonate mineral content,this paper traces the main immediate provenance region of the loess/paleosol sediments in Lanzhou. The results indicate that: (1)the Qaidam Desert and the Alxa arid area have been the main immediate provenance region of the loess/paleosol sediments in Lanzhou since 1.4 Ma. (2)The relative contribution of potential provenance to dolomite and total carbonate minerals based on the binary mixed model and the feldspar/quartz ratio of the Lanzhou loess/paleosol sediments support that their provenance has changed frequently since 1.4 Ma. The northeastern Tibetan Plateau orogenic belt(Kunlun and Qilian Mountains)and Central Asian Orogenic Belt contributed equally to the loess in Lanzhou in 1.4~1.1 Ma and 0.9~0.3 Ma,while the contribution of the Central Asian Orogenic Belt to the loess in Lanzhou increased in 1.1~0.9 Ma and after 0.3 Ma,which may be a response to the Mid-Pleistocene transition and the enhancement of dry and cold climate in the Tibetan Plateau and its adjacent areas since 0.3 Ma. The high content of dolomite and total carbonate minerals in loess/paleosol sediments of Lanzhou at 1.15 Ma and 0.8 Ma and the rapid increase of feldspar/quartz ratio at 0.8 Ma may be a response to the Kunlun-Huanghe Movement,thus resulting in the increase of the contribution of the Kunlun and Qilian Mountains to the sediments of the Chinese Loess Plateau.
		2022 Vol. 24 (3): 583-598 [Abstract] ( 522 ) [HTML 1KB] [PDF 6344KB] ( 255 )

	599	Shi Wei, Jiang Han-Chao

		Comparison of correlation between magnetic susceptibility and grain size for lacustrine sediments in eastern Tibetan Plateau and loess deposits in Chinese Loess Plateau
		To explore the correlation between magnetic susceptibility(SUS)and grain size of the dust deposits from the tectonically stable and active regions and its implications for environmental events,the grain size and SUS records from the Lantian loess sediments-paleosol of the Chinese Loess Plateau(CLP)were analyzed and compared with that of the lacustrine sediments from the eastern margin of the Tibetan Plateau(TP). Results indicate that the SUS of the loess sediments has the strongest positive correlation with the loess sediments of 2~10 μm grain size in the Chinese Loess Plateau(CLP) and strongest negative in the Tibetan Plateau,respectively,indicating that the 2~10 μm grain size of dust sediments were continuous and stable,which were deposited in the background of the arid to semi-arid regions in the CLP and TP and even in Asia. On the other hand,SUS showed the strongest positive correlation with the 32~63 μm grain size of the loess sediments in the Tibetan Plateau and strongest negative in the Chinese Loess Plateau(CLP),respectively,indicating that the 32~63 μm grain size of the dust sediments were the sensitive indicator not only for the dust storms in the CLP, but also for the seismic events in the eastern margin of the TP. The correlation between SUS and grain size during the beginning period of the seismic event in the eastern part of TP was higher than that of the ending period,indicating that the seismic event brings the fresh sediments in the study area and then decreases due to the gradual recovery of the landscape. The correlation between SUS and grain size is also influenced by the local provenance.
		2022 Vol. 24 (3): 599-610 [Abstract] ( 442 ) [HTML 1KB] [PDF 9619KB] ( 262 )

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