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	JOPC 2020 Vol.22 Number 2
	2020, Vol.22 Num.2
	Online: 2020-04-01

	REVIEW LITHOFACIES PALAEOGEPGRAPHY AND SEDIMENTOLOGY PALAEOGEOGRAPHY AND MINERAL RESOURCES GEOCHEMISTRY AND SEDIMENTARY ENVIRONMENTS PAST AND PRESENT GEOGRAPHY ENVIRONMENTS AND HUMEN CIVILIZATION

REVIEW

	207	Feng Zeng-Zhao

		A review on the definitions of terms of sedimentary facies
		In recent years,in some papers published in and manuscripts submitted to the Journal of Palaeogeography(Chinese Edition and English Edition),the authors named rocks or rock types as “microfacies”or “lithofacies”,named the microfeatures in thin-sections under microscope as “microfacies”,and named the macrofeatures of rocks as “macrofacies”. The author wrote two short papers “Words of the Edition-in-Chief—Rocks are not microfacies”and “Words of the Edition-in-Chief—Rocks are not lithofacies”which were in Chinese and published in the Journal of Palaeogeography (Chinese Edition). However,they did not attract much attention of readers in China and outside China. In addition,in 1980s,some Chinese sedimentologists proposed “subfacies”and “microfacies”based on the macrofeatures of rocks from outcrops and drilling cores. The definition of this “microfacies”is totally different from the “microfacies”proposed by foreign sedimentologists in 1940s based on the microfeatures in thin-sections under microscope. These problems appeared repeatedly and forced the author,as the Editor-in-Chief of the Journal of Palaeogeography(Chinese Edition and English Edition),to observe the policy of “A hundred flowers blossom and a hundred schools of thought contend ”,to write new papers “A review on the definitions of terms of sedimentary facies”both in Chinese and English,to clarify the definitions of the terms of sedimentary facies,i.e.,“facies”,“lithofacies”,two “microfacies”,“macrofacies”,“subfacies”,etc.,and to publish the new papers in the Journal of Palaeogeography(both Chinese Edition and English Edition). I hope that the new papers will attract attention of readers worldwide and they can write papers and participate in the discussion and contending of these problems,strive for getting some common understandings,and therefore promote the progress and development of sedimentology and palaeogeography.
		2020 Vol. 22 (2): 207-220 [Abstract] ( 654 ) [HTML 1KB] [PDF 831KB] ( 818 )

LITHOFACIES PALAEOGEPGRAPHY AND SEDIMENTOLOGY

	221	Xu Shu-Mei, Li Meng, Wang Jin-Duo, Ren Xin-Cheng, Chi Xin-Qi, Shu Peng-Cheng, Wang Jie-Qing, Liu Xian

		Sedimentary cycle pattern and stacked style of sand-body of the Lower Jurassic Sangonghe Formation in belly of Junggar Basin
		The coarse grain braided river delta in Jurassic Sangonghe Formation of Junggar Basin formed the main Mesozoic reservoir system. At present,there are obvious different opinions on the sedimentary cycle characteristics of Jurassic Sangonghe Formation,and there is a lack of research on the driving mechanisms of sedimentary cyclicity,which leads to a great dispute on the stacked style of sand-bodies. Using 38 wells coring and logging data in the belly of Junggar Basin,based on principles and methods of sedimentology and sedimentary basin analysis,the characteristics of sedimentary cycle in Sangonghe Formation are systematically analyzed. The stacked style and combination rule of sand-bodies are studied in detail within sedimentary cyclic framework. The characteristics of basement subsidence and multi-stage uplifting during the Early Jurassic of Junggar Basin are discussed,so as to clear the driving mechanisms of positive sedimentary cycle. The Sangonghe Formation in the study area is divided into four system tract level positive cycles with no reverse cycle deposition,which reflects the sedimentary characteristics of slow lacustrine transgress and fast lacustrine retrogress. The sand-bodies in the braided river delta front of the Sangonghe Formation show five stacking patterns: Strong erosion of superimposed sand-body by subaqueous distributary channel,weak erosion of superimposed sand-body by subaqueous distributary channel,superimposed river-mouth bar on subaqueous distributary channel,distal bar-blanket sand assemblage,beach bar sand-body. The first cycle is the intermittent distribution of beach bar sand-bodies. The second cycle includes continuous distribution of strong erosion of superimposed sand-body by subaqueous distributary channel,weak erosion of superimposed sand-body by subaqueous distributary channel,and superimposed river-mouth bar on subaqueous distributary channel. The third cycle is composed of relatively continuous distribution of weak erosion of superimposed sand-body by subaqueous distributary channel and distal bar-blanket sand assemblage. The fourth cycle is scattered distribution of beach bar sand-body. It is possible because of the slow subsidence and intermittent rapid uplift of the basement of Junggar Basin that regressive superposition and the scour interface between each sedimentary cycle are formed.
		2020 Vol. 22 (2): 221-234 [Abstract] ( 602 ) [HTML 1KB] [PDF 5083KB] ( 378 )

	235	Xu Zhe-Hang, Lan Cai-Jun, Hao Fang, Chen Hao-Ru, Yang Wei-Qiang, Ma Xiao-Lin, Zou Hua-Yao

		Difference of mound-bank complex reservoir under different palaeogeographic environment of the Sinian Dengying Formation in Sichuan Basin
		The mound-bank deposits of the Dengying Formation of the Sinian System are well developed in Sichuan Basin,with good reservoir value. Based on outcrop and core observation,thin section observation,porosity and permeability of samples test,we analyzed the reservoir quality of different mound-bank complexes. During the terminal of Sinian Period,development of the Mianyang-Changning rift affected distribution of sedimentary facies of the 2nd and the 4th Members of Dengying Formation,forming different palaeogeographic units. The high-energy environment,transition environment and low-energy environment of the mound-bank complex rock types are identified,and their reservoir quality is different. The keep-up platform margin mound-bank complex,which is represented by Hujiaba section in the 4th Member of the Dengying Formation mainly deposited high-energy zone rock types. The catch-up platform margin mound-bank complex,which is represented by Yangba section in the 2nd Member of the Dengying Formation,mainly deposited transform zone rock types. The give-up platform interior mound-bank complex,which is represented by Fucheng section in the 4th Member of the Dengying Formation mainly deposited low-energy zone rock types. By comparing reservoir characteristics of three types of mound-bank complex,it is found that the keep-up platform margin mound-bank complex is the‘Sweet spots’ of the Dengying Formation in the Sichuan Basin. The above studies are conducive to find the‘Sweet spots’ of the Sinian Dengying Formation in the Sichuan Basin.
		2020 Vol. 22 (2): 235-250 [Abstract] ( 583 ) [HTML 1KB] [PDF 10178KB] ( 267 )

	251	Yang Wei-Qiang, Liu Zheng, Chen Hao-Ru, Lan Cai-Jun, Xu Zhe-Hang, Lu Chao-Jin, Zou Hua-Yao

		Depositional combination of carbonate grain banks of the Lower Cambrian Longwangmiao Formation in Sichuan Basin and its control on reservoirs
		Rock types, sedimentary subfacies and grain bank properties of the Longwangmiao Formation are studied in detail by outcrop, drilling and logging data, core, thin section and physical property of the Longwangmiao Formation in the Sichuan Basin. The characteristics, development and distribution of grain bank depositional combinations of the Longwangmiao Formation in Sichuan Basin and their control on reservoir development are discussed. The results show that: （1）four main rock types can be identified in the Longwangmiao Formation in Sichuan Basin. Vertically, three upward shallowing depositional combinations associated with carbonate grain bank can be identified: multi-stage vertical overlapping of grain banks, grain bank-tidal flat（mixed tidal flat）, interbank-grain bank（-tidal flat）; (2）the distribution of depositional combinations of grain banks is controlled by paleogeomorphy and sea level fluctuation;and the horizontal distribution is mainly controlled by paleogeomorphy, the vertical overlapping of multi-stage grain banks is mainly developed in the central Sichuan Basin, grain bank-tidal flat（mixed tidal flat）mainly develop in northern and southwestern Sichuan Basin, and interbank-grain bank（-tidal flat）mainly develop in the eastern and southeastern Sichuan Basin;vertically, they are mainly controlled by sea level changes, and have close relationship with their locations in the sequence stratigraphy, and interbank-grain bank（-tidal flat）mostly develop in the middle and lower parts of the sequence, multi-stage vertical overlapping of grain banks and grain bank-tidal flat（mixed tidal flat）develop in the upper part of the sequence; (3）multi-stage vertical overlapping of grain banks is the most favorable for reservoir development, followed by grain bank-tidal flat（mixed tidal flat）combination, and interbank-grain bank（-tidal flat）combination has the poor reservoir physical properties.
		2020 Vol. 22 (2): 251-265 [Abstract] ( 513 ) [HTML 1KB] [PDF 14513KB] ( 250 )

	266	Hu He-Wei, Li Hui-Yong, Yu Hai-Bo, Xiao Shu-Guang, Xu Wei

		Quantitative analysis of source-to-sink system controls on sand-body distribution of the Paleogene in Chengbei low uplift and surrounding areas,Bohai Bay Basin
		In this paper,Chengbei low uplift and the surrounding areas is taken as a whole source-sink system. On the basis of this,utilizing logging,well logging,rock core and 3D seismic data,analysis of sedimentary system types and features of Chengbei low uplift,the quantitative relationship of elements in source-to-sink system is discussed. The results indicate that lithology of basement rock in the Chenbei low uplift is Mesozoic clastic rock during the Paleogene,thin section and the geophysical response data in this study,basement rock is subdivided into nine drainage systems. The corresponding transport pathways including fifteen paleo-valleys and two fault-troughs are identified in the Chenbei low uplift. The paleo-valleys are further subdivided into V shape,U shape,W shape. Fan deltas,semi-deep lacustrine and deep lacustrine is developed in steep slope zone of Chengbei low uplift,which presents isolated lob shape in plane distribution. Braided river delta,shore-shallow,semi-deep lacustrine and deep lacustrine is mainly developed in gentle slope belt,which is featured with wide and continuous plane distribution and superimposed vertical distribution. The characterization of elements in source-to-sink system indicates that volume of depositional systems is closely related to drainage area,length,width,width/length of paleo-valleys. Coupling mode of the source-to-sink system suggests that effective source area controls the size of sedimentary system;sand transporting path controls sedimentary distribution direction and shape.
		2020 Vol. 22 (2): 266-277 [Abstract] ( 498 ) [HTML 1KB] [PDF 9289KB] ( 251 )

	278	Bai Li-Ke, Qiu Long-Wei, Yang Yong-Qiang, Du Shuang-Hu, Yang Bao-Liang, Han Xiao-Tong

		Sedimentary model and controlling factors of modern beach-bar sediments in east coast of Xiashan Lake in Shandong Province
		Beach-bars, one of the important hydrocarbon reservoirs formed in the coastal zone,become the exploration target in terms of subtle reservoirs. In order to figure out the sedimentary model of beach bars deposited in the east coast of Xiashan Lake,a detailed study on sedimentary characteristics and controlling factors of beach-bars was carried out by using ground penetrating radar (GPR) and grain size analysis. The results show that,the east coast of Xiashan Lake has developed two types of sedimentary systems including beach bars and eolian dunes. The eolian sediments in the early stage are well-sorted fine-grained sandstones, which are characterized by large tabular cross-bedding and two-segment pattern on grain size cumulative frequency plot. The beach bars sediments are reverse graded medium-grained sandstone and feature the low-continuity tabular cross-bedding. Plant roots,scouring structure,interbedding of sand and mud and three-segment pattern on on grain size cumulative frequency plot arethe typical characteristics of beach￣bar deposits. The saltation proportion is divided into two different parts indicating high energy hydrodynamic condition. Layered reflecting structures can be confirmed through GPR which implies the eolian sediments depositional pattern. The analyses of environmentally sensitive components of the grain size of eolian sediments suggest two different hydrodynamic environment. In conclusion,eolian sediments and the change of paleogeomorphy environment depend on wind action. The coastal erosion plays an important role in the early stage of the position and sand supply for beach bars. According to the sedimentary model as well as its formation mechanism,we propose a ‘wind transporting-wave modifying’ sedimentary system,which will be helpful for identification of beach bars and the prediction of favorable reservoir.
		2020 Vol. 22 (2): 278-294 [Abstract] ( 567 ) [HTML 1KB] [PDF 5795KB] ( 272 )

PALAEOGEOGRAPHY AND MINERAL RESOURCES

	295	Wang Xiao-Peng, Liu Kun-Peng, Chen Hong-Bin, Gong Bin-Li, Yu Hong-Wei, Gong Qi-Fu, Han Di

		Sedimentary characteristics of the Jurassic Zhiluo Formation and uranium deposits in Zhiluo-Diantou area,southern Ordos Basin
		Diantou uranium deposits and multiple uranium mineralization sites have been discovered in the sandstones in the lower member of the Jurassic Zhiluo Formation in the southern Ordos Basin. However, the study on the sedimentary facies of the Zhiluo Formation, which restricts the prospecting work of sandstone-type uranium deposits. Based on the outcrop measurements and drilling core cataloging, and combined with the geological drilling data of petroleum, coal, and nuclear industry, we have elaborated the sedimentary characteristics of the Zhiluo Formation in the Fuxian area. We have also combined uranium source, structure, post-alteration and other factors to explore the relationship between sedimentary faces and uranium metallogenic conditions in the study area. The study found that in the lower member of the Jurassic Zhiluo Formation, the thickness of the sand body is 30-65 m and sand ratio is 0.6-0.75. It is gravel and sandy braided river deposit. In the upper member of the Jurassic Zhiluo Formation, the thickness of the sand body is 10-38 m, and the sand ratio is 0.15-0.45 and is a meandering river deposit. The study area is located at the center of the lake basin and sedimentary facies is coastal shallow lacustrine in the upper member of the Jurassic Zhiluo Formation. Sedimentary environment, sedimentary facies, the intersection of braided river channels, sand body thickness, sediment particle size and mudstone interlayer play an important role in controlling uranium mineralization. The exploration of uranium deposits in the northern part of the deposit should focus on the intersection or bifurcation of the braided river channel in the lower part of the Zhiluo Formation. The charcoal- and pyrite-bearing sandstone of channel bar can be used as a prospecting indicator for uranium mineralization.
		2020 Vol. 22 (2): 295-308 [Abstract] ( 505 ) [HTML 1KB] [PDF 50863KB] ( 258 )

	309	Song Bai-Rong, Sun Hui, Yang Song-Lin, Han Hong-Dou, Li Qing-Chun, Shi Yu-Hua, Tang Jie-Yun, Liu Yu-Ting

		Characteristics and uranium mineralization of ore-bearing rock series in Qianjiadian sandstone-type uranium deposits, Songliao Basin
		The Qianjiadian sandstone-type uranium deposit in Songliao Basin has become an ultra-large uranium deposit since its exploration and continuous development. The geological and metallogenic characteristics of this area have been studied widely since its discovery,but the detailed petrological features of its ore-bearing construction and favorable metallogenic conditions still require much detailed research. The mineralization of urnium deposit includes various geological processes resulting in the accumulation of uranium element. The source rock with high uranium concentration and much easier for the leaching of uranium is the basis of uranium mineralization. The later oxidation-reduction,mineral alteration are the key for the uranium deposits. In this paper,the petrological characteristic of lithology sandstone-type uranium deposit is studied by using the micro experimental analysis. It is found that the host rocks are primarily composed of medium-fine grained feldspar lithic sandstone,fine grained feldspar lithic sandstone,boulder-clay-bearing sandstone and glutenin. The amount of quartz and feldspar are close to the rock debris. The debris are mainly composed of rhyolite,rhyolitic tuff,and some trochyte,ayenite-aplite,granite,granite porphyry,andesite,silicalite and mudstone etc. the epigenetic alteration includes the carbonatization and kaolinization is general and intense at the local region,followed by the secondary epigenetic alteration includes pyritization,ferrugination and little baratization. Deep oil and gas infiltrate into the oil-bearing strata causing the oil stains,spots and spillage. The symbiosis of pyrite berry globule and micritic pyrite are common. The uranium element exists in the uranium-bearing minerals(e.g.,asphalt and coffinite)as well as the adsorbed state. The multi-genesis and multi-stages of the metallogenic model is established,i.e.,sedimentary preconcentration stage-interlayer infiltration stage-the oil and gas transformation stage-the oil and gas reduction stage.
		2020 Vol. 22 (2): 309-320 [Abstract] ( 438 ) [HTML 1KB] [PDF 9047KB] ( 208 )

	321	Yang Song-Lin

		Geochemical characteristics of interlayer oxidation zone in Qianjiadian sandstone-type uranium deposits,Songliao Basin
		The Qianjiadian sandstone-type uranium deposits is a large uranium deposits discovered in the Songliao Basin. The uranium deposits discovered mainly occur in the Lower Member of the Upper Cretaceous Yaojia Formation. The ore body is tabular and lenticular,mainly controlled by the interlayer oxidation zone. By testing and analyzing the main elements,trace elements and rare earth elements in the oxidation zone of the Qianjiadian sandstone-type uranium deposits(oxidation zone,transition zone and reduction zone),the results show that the geochemical characteristics of each zone vary greatly,where the interlayer oxidation zone can be zoned relatively accurately by Fe₂O₃,FeO,Al₂O₃,SiO₂,Na₂O and K₂O and MgO and CaO have certain indication significance for zoning. From the oxidation zone to the transition zone,the trace elements that tend to be enriched are mainly radioactive elements(U),large ion lithophile elements(Li,Ba),chalcophile elements(Ni),high field strength elements(Nb,Ta),active variable valence elements(Mo),etc.,and LREE,MREE and HREE have different degrees of enrichment,reflecting the long water-rock interaction with large intensity. The significant difference of reducing indexes of organic carbon,St,and ωFe³⁺/ωFe²⁺ in different zones indicates that with the migration of oxygen-uranium containing water in the Yaojia Formation,the reducing components change sharply and have obvious significance of zoning indication.
		2020 Vol. 22 (2): 321-332 [Abstract] ( 506 ) [HTML 1KB] [PDF 1756KB] ( 249 )

GEOCHEMISTRY AND SEDIMENTARY ENVIRONMENTS

	333	Liuzhu Rui-Zhi, He You-Bin, Li Hua, Huang Wei

		Geochemical characteristics of trace elements and tectonic setting of sandstones from the Upper Ordovician Pingliang Formation, southwestern margin of Ordos Basin: A case study of the Duanjiaxia profile, Longxian County
		Due to the lack of reliable sedimentary provenance data,the geological setting and its provenance of the southwestern margin of Ordos Basin in Late Ordovician is uncertain. In this paper,the sandstone of Upper Ordovician Pingliang Formation in Duanjiaxia profile of Longxian area is selected for a systematic study. Using the methods including the comprehensive analysis on the measured geological profile,analysis of microscopic thin section and trace elements,the following results are obtained: (1)the thin section analysis shows that the sandstone is well sorted but poorly rounded. Clastic grains are dominated by quartz,while the rock fragments are mainly composed of polycrystalline quartz,carbonate sand debris,and a little matrix,which means that the turbidite sandstone has been reworked by obvious traction of deep-water;(2)Rare Earth Element(REE)distribution model shows that the sandstone is rich in LREE and is short of HREE and has the negative Eu-anomaly,indicating that the provenance may derive from the intermediate and acid rock in the upper crust;(3)the provenance discrimination diagrams show that the sandstone of the Pingliang Formation is a mixture of sedimentary rock and granite,while the magmatic component is dominated by intermediate and acid rock;(4)Geochemical data of the sandstone suggests that the geological setting significantly belong to continental island arc and passive continental settings. The study area in Longxian during the Late Ordovician period was located in the back arc basin. At that time,the southwestern margin of the North China Craton with the full trench-arc-basin system was changed from the passive continental margin into the active continental margin.
		2020 Vol. 22 (2): 333-348 [Abstract] ( 474 ) [HTML 1KB] [PDF 23369KB] ( 221 )

	349	Guo Xiao-Qiang, Li Hao-Bin, Wei Rong-Zhu, Dong Ai-Guan, Du Yan-Wei, Yang Jun-Cai

		Characteristics of elemental geochemistry of the Cambrian carbonate rocks and their palaeoenvironmental implication in western margin of Qinshui Basin, Shanxi Province
		A set of significant Cambrian carbonate rocks are found in Qinshui Basin of Shanxi Province. On the basis of field investigation,the petrology and element geochemical composition of Cambrian rocks in the western margin of Qinshui Basin are studied. The results show that the Cambrian carbonate rocks are mainly composed of limestone from the Zhangxia and Gushan Formations, and dolostone from the lower part of Sanshanzi Formation. They are mainly shallow platform facies deposits which can be divided into three types: Restricted platform,open platform and platform margin reef and ramp. There are large variation ranges for the authigenic elements(CaO,MgO)and terrestrial elements(SiO₂,Al₂O₃ and Fe₂O₃). They have two vertical upward and downward cycles,reflecting the sedimentary environment with high turbulence. The content of K₂O is high,but the contents of Na₂O and Sr are relatively low. The contents of ΣREE+Y are relatively high and vary widely,and the LREE are much richer than the HREE. A slight negative anomaly of Ce and Eu is found. The normalized curves show a slightly leftward-flat trend,which conforms to the characteristics of the typical marine sediments. The δ¹³C value is in the range of -1.96‰~0.41‰,showing an overall change of initial increase and then decrease trend. The δ¹⁸O value ranges from -9.96‰~-5.33‰,showing a ladder-like upward trend from bottom to top. Related geochemical parameters indicate that the study area was a saltwater marine environment. The paleo-seawater temperature belonged to a warm subtropical climate environment,generally changing from warm to hot and then to cold trends. The paleoclimate experienced a transition of relative humidity-relative dry and heat environmen-relative humidity. The paleo-water depth underwent a variation of shallow-deep-shallow. The ancient sea level experienced a large-scale transgression-regression process. A good coupling relationship between different palaeoenvironment elements is found,showing a certain restriction on the types of sedimentary facies. The results in this paper are very significant for the studies of Cambrian lithofacies palaeogeography and petroleum exploration in the Qinshui Basin and the adjacent regions. It provides a significant theory and practical guidance in the reconstruction of Cambrian palaeoenvironment,palaeotology and palaeoecology evolution of the North China Craton.
		2020 Vol. 22 (2): 349-366 [Abstract] ( 578 ) [HTML 1KB] [PDF 6581KB] ( 281 )

	367	Fan Yu-Chao, Qi Yong-An, Dai Ming-Yue, Qing Guo-Shuai, Liu Bing-Chen, Bai Wan-Bei

		Paleoclimate evolution recorded in the Cambrian Epoch 2 Zhushadong Formation from Dengfeng area, western Henan Province
		The complete early Cambrian Zhushadong Formation is developed in Dengfeng area,Henan Province,which record important information of paleoclimate variation. The lithology,element geochemistry,sedimentology and palaeontology are investigated to have a closer insight into the paleoclimate and environmental variations during deposition of the early Cambrian Zhushadong Formation of the western Henan. The results show that the Zhushadong Formation can be divided into three lithological members: Lower laminated dolomite Member,the upper leopard limestone Member and the top laminated dolomite Member. The paleoclimate variations are reflected by stratified dissolved pores,chert and gypsum in the laminated dolomites,intensive bioturbation in leopard limestones and multiple geochemical parameters,including Mn concentration,and the ratios of Sr/Cu,Rb/Sr and MgO/CaO. It displays a clear change from hot and arid climate of the lower laminated dolomite Member,to warm and humid climate of the upper leopard limestone Member,and back to hot and arid climate of the top laminated dolomite Member. The contemporaneous sediments in North China show the similar paleoclimate variations to the Zhushadong Formation in western Henan Province.
		2020 Vol. 22 (2): 367-376 [Abstract] ( 437 ) [HTML 1KB] [PDF 5011KB] ( 416 )

PAST AND PRESENT GEOGRAPHY ENVIRONMENTS AND HUMEN CIVILIZATION

	377	Che Yin-Ping, Xiao Hai-Yan, Jiang Xiu-Yang, Cai Bing-Gui

		Precise dating of the Dansgaard-Oeschger event 4 and its sub-cycles: Evidence from a stalagmite from Xianyun Cave in Longyan City,Fujian Province
		The Dansgaard-Oeschger event 4(DO4 event) is a significant warming event that occurred in the late Marine Isotope Stage 3. At present,there are different understandings about the detailed characteristics and internal structures of the DO4 event. Based on 6 precisely-dated ²³⁰Th ages and 188 oxygen isotope data of a stalagmite(No.XYⅢ-28)from the Xianyun Cave,Fujian Province,we present δ¹⁸O time series with an average resolution of 7 yr from 29.13 to 27.94 kyr B.P. Our new stalagmites δ¹⁸O records uncover the detailed processes of the DO4 event. The onset and end time of the DO4 event recorded by the stalagmite δ¹⁸O is 28.83±0.06 and 28.46±0.06 kyr B.P.,respectively, and the duration is 0.37±0.06 kyr. Differential with abrupt change of NGRIP ice core δ¹⁸O record at the onset of DO4 based on the GICC05 layer count time scale,the Xianyun Cave δ¹⁸O shows a relatively slow change. The Xianyun stalagmite δ¹⁸O values negatively shift by 0.4‰ within 145±60 yr,which indicates that the Xianyun Cave was likely affected by the ocean-atmosphere coupling of the tropical. In addition,the Xianyun stalagmite δ¹⁸O reveals a series of sub-million-scale summer monsoon enhancement events in and around the DO4 event,corresponding to the NGRIP ice core δ¹⁸O record and the Arabian Sea basin record. Our results suggest that the East Asian summer monsoon is related to the north-high latitude temperature and the ITCZ position changes on the sub-millennium-scale event.
		2020 Vol. 22 (2): 377-384 [Abstract] ( 437 ) [HTML 1KB] [PDF 1919KB] ( 205 )

	385	Wang Xiao-Qing, Zhang David D, Pei Qing, Zhang Sheng-Da, Li Teng

		Relationship between social stability and climate change in the Tang Dynasty
		This paper quantitatively divides the Tang Dynasty into five prosperous and chaotic social periods,and discusses the relationship between the social division and climate change. The criteria for determining prosperity and chaos is refered to a set of systematic war data. In order to verify the reasonableness of the division,we applied 1-way-ANOVA to test the differences of each variable index between prosperity and chaos periods. The results of social division are as follows: from AD 618 to AD 626,and from AD 743 to AD 784,as well as from AD 860 to AD 907 were the chaotic periods;while from AD 627 to A0 742,and from AD 785 to AD 859 were the prosperous periods. The results of 1-way-ANOVA show that,climate change,general wars,rebellions,offensive border wars,defensive border wars,agricultural harvests,and population growth rates are all significantly different between prosperity and chaos,except the general external wars. War data were used to quantitatively represent the social changes in the Tang Dynasty. In chaotic periods,the main types of wars are rebellions and defensive border wars,while the main type of wars in prosperous periods are offensive border wars. To explore the relationship between climate change and social division means to make clear the relationship between climate change and wars. The results of correlation analysis show the decrease of agricultural harvest due to lower temperature and less precipitation leads to the shortage of resources supply,so that the likelihood of rebellions increase;while during the warm periods with abundant rainfall,increasing agricultural harvest stimulates rapid population growth. Due to the limitations of technology and land resources,offensive border wars for expansion are more likely to occur.
		2020 Vol. 22 (2): 385-396 [Abstract] ( 539 ) [HTML 1KB] [PDF 740KB] ( 294 )

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