Pub Date : 2014-03-07DOI: 10.3724/SP.J.1140.2013.02129
S. Yi, Lu Huayu, Yali Zhou, Xianyan Wang, Quanyu Liu
The aeolian silt deposit is a good record of palaeoclimatic and paleoenvironmental changes in Late Quaternary.However,Loess deposition and Palaeoclimatic changes in the Horqin dunefield,Northeastern China,during the late Quaternary remains poorly understood.In this paper,the Rubidium(Rb) and Strontium(Sr) geochemical characteristics of the typical loess sequence in the southern margin of the Horqin dunefield are analyzed.Results show that the variation pattern of Rb-Sr in the Horqin loess are similar to those of the Chinese Loess Plateau,excepted for that the Rb content is lower and the Sr content is higher,probably resulted from the colder and drier climate in this study area,which led to very weak chemical weathering.It further indicates that the variations in Rb/Sr ratio in the Northeastern China loess sequence may represent the alternation of East Asian summer and winter monsoon climates.Based on the Rb-Sr geochemical data,it is suggested that Horqin dunefield had experienced a warmer and wetter climate in the periods of 108-144 ka 86±7 ka,and 233±21 ka,while it was very cold and dry,even worse than the desertification environment in the period of 262±32 ka.The climate changes in this study area are consistent with variations of the East Asian monsoon during Late Quaternary.It could be a footprint of the global glacial-interglacial climatic variations in northeastern China.
{"title":"Rb/Sr GEOCHEMISTRY OF LOESS DEPOSITS IN THE HORQIN DUNEFIELD, NORTHEASTERN CHINA, AND ITS IMPLICATIONS FOR CLIMATE CHANGE DURING LATE QUATERNARY: Rb/Sr GEOCHEMISTRY OF LOESS DEPOSITS IN THE HORQIN DUNEFIELD, NORTHEASTERN CHINA, AND ITS IMPLICATIONS FOR CLIMATE CHANGE DURING LATE QUATERNARY","authors":"S. Yi, Lu Huayu, Yali Zhou, Xianyan Wang, Quanyu Liu","doi":"10.3724/SP.J.1140.2013.02129","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02129","url":null,"abstract":"The aeolian silt deposit is a good record of palaeoclimatic and paleoenvironmental changes in Late Quaternary.However,Loess deposition and Palaeoclimatic changes in the Horqin dunefield,Northeastern China,during the late Quaternary remains poorly understood.In this paper,the Rubidium(Rb) and Strontium(Sr) geochemical characteristics of the typical loess sequence in the southern margin of the Horqin dunefield are analyzed.Results show that the variation pattern of Rb-Sr in the Horqin loess are similar to those of the Chinese Loess Plateau,excepted for that the Rb content is lower and the Sr content is higher,probably resulted from the colder and drier climate in this study area,which led to very weak chemical weathering.It further indicates that the variations in Rb/Sr ratio in the Northeastern China loess sequence may represent the alternation of East Asian summer and winter monsoon climates.Based on the Rb-Sr geochemical data,it is suggested that Horqin dunefield had experienced a warmer and wetter climate in the periods of 108-144 ka 86±7 ka,and 233±21 ka,while it was very cold and dry,even worse than the desertification environment in the period of 262±32 ka.The climate changes in this study area are consistent with variations of the East Asian monsoon during Late Quaternary.It could be a footprint of the global glacial-interglacial climatic variations in northeastern China.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"129-136"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-07DOI: 10.3724/SP.J.1140.2013.02121
Jiaxiong He, Wen Yan, Youhai Zhu, Yang Hu, Jingru Zhang, Xiaofeng Gong
As a special kind of unconventional gas resources with great resource potential,gas hydrate is not only an important supplement and substitute for conventional natural fossil gas,but also a new low-carbon green and efficient energy.In order to better understand the special geological formation conditions and distribution pattern of the gas hydrate,the geological and geochemical characteristics of the global gas hydrate and their sources were studied in-depth by the authors.According to the statistical results of the geochemical compositions of natural gas hydrate explored in the world so far and their geological formation conditions,the main genetic types of gas hydrate are biogenetic and biogenetic-pyrolytic mixed,followed by matured pyrolytic gases in terms of the sources of gases.The formation of gas hydrate deposits depends on the sources for gas supply in addition to a high-pressure and low-temperature environment.
{"title":"GENETIC TYPES OF GAS HYDRATE IN THE WORLD AND THEIR MAIN CONTROLLING FACTORS: GENETIC TYPES OF GAS HYDRATE IN THE WORLD AND THEIR MAIN CONTROLLING FACTORS","authors":"Jiaxiong He, Wen Yan, Youhai Zhu, Yang Hu, Jingru Zhang, Xiaofeng Gong","doi":"10.3724/SP.J.1140.2013.02121","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02121","url":null,"abstract":"As a special kind of unconventional gas resources with great resource potential,gas hydrate is not only an important supplement and substitute for conventional natural fossil gas,but also a new low-carbon green and efficient energy.In order to better understand the special geological formation conditions and distribution pattern of the gas hydrate,the geological and geochemical characteristics of the global gas hydrate and their sources were studied in-depth by the authors.According to the statistical results of the geochemical compositions of natural gas hydrate explored in the world so far and their geological formation conditions,the main genetic types of gas hydrate are biogenetic and biogenetic-pyrolytic mixed,followed by matured pyrolytic gases in terms of the sources of gases.The formation of gas hydrate deposits depends on the sources for gas supply in addition to a high-pressure and low-temperature environment.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"121-128"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-07DOI: 10.3724/SP.J.1140.2013.02143
Hong Ye, Tao Yang, Guorong Zhu, Shaoyong Jiang
Various models,including two conceptual models and several numerical models for gas hydrate formation,accumulation,transportation and dissociation,were reviewed in this paper.These models can be classified into three groups,namely,low flux model,high flux model and mixed flux model,according to different conceptual models.After careful comparison,the hydro-dynamical model from the transport-dispersion theory in porous media is recommended for their rationality and applicability.The model has the capability to reveal the growth behavior of gas hydrate.The development potential of gas hydrate modeling is also discussed.
{"title":"ADVANCES IN NUMERICAL MODELING OF GAS HYDRATE FORMATION IN MARINE SEDIMENTS: ADVANCES IN NUMERICAL MODELING OF GAS HYDRATE FORMATION IN MARINE SEDIMENTS","authors":"Hong Ye, Tao Yang, Guorong Zhu, Shaoyong Jiang","doi":"10.3724/SP.J.1140.2013.02143","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02143","url":null,"abstract":"Various models,including two conceptual models and several numerical models for gas hydrate formation,accumulation,transportation and dissociation,were reviewed in this paper.These models can be classified into three groups,namely,low flux model,high flux model and mixed flux model,according to different conceptual models.After careful comparison,the hydro-dynamical model from the transport-dispersion theory in porous media is recommended for their rationality and applicability.The model has the capability to reveal the growth behavior of gas hydrate.The development potential of gas hydrate modeling is also discussed.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"143-152"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-07DOI: 10.3724/SP.J.1140.2013.02137
Longsheng Xu, Jing-lu Wu
Through the determinations of δ13C,δ15N,total organic C,total N,total P in sediments of Dapu area in the Taihu Lake,this paper analyzed the eutrophication process of this area.The results showed that δ13C,δ15N in sediments had a significant change in patferns with the water evolution from low nutrition to eutrophication.Before 1950s,primary productivity of the lake was low and the water environment was good.Moreover,the impact of human activities was weak,and the lake sediments record showed a high value of δ13C and low values of δ15N,TOC,TN,TP.In 1990s,the lake environment changed significantly and the primary productivity increased substantially.As the result,the water environment deteriorated and the nutrition level increased rapidly resulting in eutrophication.Accordingly,the value of δ13C decreased rapidly,but δ15N increased,and the correlation showed significant reverse(R=-0.81).However,the correlation between δ13C and δ15N was significantly positive(R=0.96).This phenomenon reflected that the isotopic elements of different lakes responded differently to environmental changes,and the eutrophication patterns of grass-type lake and algae-type lake were initially established.
{"title":"LAKE ENVIRONMENTAL CHARACTERISTICS RECOREDED BY ISOTOPES IN SEDIMENTS OF DAPU AREA IN LAKE TAIHU: LAKE ENVIRONMENTAL CHARACTERISTICS RECOREDED BY ISOTOPES IN SEDIMENTS OF DAPU AREA IN LAKE TAIHU","authors":"Longsheng Xu, Jing-lu Wu","doi":"10.3724/SP.J.1140.2013.02137","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02137","url":null,"abstract":"Through the determinations of δ13C,δ15N,total organic C,total N,total P in sediments of Dapu area in the Taihu Lake,this paper analyzed the eutrophication process of this area.The results showed that δ13C,δ15N in sediments had a significant change in patferns with the water evolution from low nutrition to eutrophication.Before 1950s,primary productivity of the lake was low and the water environment was good.Moreover,the impact of human activities was weak,and the lake sediments record showed a high value of δ13C and low values of δ15N,TOC,TN,TP.In 1990s,the lake environment changed significantly and the primary productivity increased substantially.As the result,the water environment deteriorated and the nutrition level increased rapidly resulting in eutrophication.Accordingly,the value of δ13C decreased rapidly,but δ15N increased,and the correlation showed significant reverse(R=-0.81).However,the correlation between δ13C and δ15N was significantly positive(R=0.96).This phenomenon reflected that the isotopic elements of different lakes responded differently to environmental changes,and the eutrophication patterns of grass-type lake and algae-type lake were initially established.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"137-142"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-06DOI: 10.3724/SP.J.1140.2013.02087
Shuai Zhang, Tiegang Li, F. Chang, Haixia Wang, Z. Xiong, Zhoufei Yu
The Core KX97322-4 was taken from the Ontong Java Plateau,western equatorial Pacific.Quantitative analysis of planktonic foraminifera,combined with oxygen isotope data and spectral analyses of each index,revealed the glacial-interglacial variations of the oxygen isotope of planktonic foraminifera and the vertical structure of the upper water in the center of the West Pacific Warm Pool(WPWP) during the last 360kyr.Our results indicate that,since MIS10,the oxygen isotopes of both the surface dwelling species G.ruber and subsurface dwelling species N.dutertrei's showed obvious glacial-interglacial cycles.The surface and subsurface waters were influenced by the volume change of high latitude ice sheets in a large scale generally,and the subsurface water is even more sensitive.The variation in upper water structure also imitates the glacial-interglacial cycle.The thermocline(DOT) was getting deeper during MIS10 to MIS8,but abruptly became shallower in MIS8-MIS7/8,then deepened again after MIS7/8 and turned to stable fluctuation when entered the last glacial stage.The spectral analyses indicate that the joint effect of high latitude forcing and tropic-driving caused the variation in the upper water characters.Of course,ocean circulation has also impact on the variation in the upper water structures.
{"title":"THE EVOLUTION OF UPPER WATER IN THE CENTER OF WEST PACIFIC WARM POOL DURING THE LAST 360KYR","authors":"Shuai Zhang, Tiegang Li, F. Chang, Haixia Wang, Z. Xiong, Zhoufei Yu","doi":"10.3724/SP.J.1140.2013.02087","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02087","url":null,"abstract":"The Core KX97322-4 was taken from the Ontong Java Plateau,western equatorial Pacific.Quantitative analysis of planktonic foraminifera,combined with oxygen isotope data and spectral analyses of each index,revealed the glacial-interglacial variations of the oxygen isotope of planktonic foraminifera and the vertical structure of the upper water in the center of the West Pacific Warm Pool(WPWP) during the last 360kyr.Our results indicate that,since MIS10,the oxygen isotopes of both the surface dwelling species G.ruber and subsurface dwelling species N.dutertrei's showed obvious glacial-interglacial cycles.The surface and subsurface waters were influenced by the volume change of high latitude ice sheets in a large scale generally,and the subsurface water is even more sensitive.The variation in upper water structure also imitates the glacial-interglacial cycle.The thermocline(DOT) was getting deeper during MIS10 to MIS8,but abruptly became shallower in MIS8-MIS7/8,then deepened again after MIS7/8 and turned to stable fluctuation when entered the last glacial stage.The spectral analyses indicate that the joint effect of high latitude forcing and tropic-driving caused the variation in the upper water characters.Of course,ocean circulation has also impact on the variation in the upper water structures.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"1 1","pages":"87-96"},"PeriodicalIF":0.0,"publicationDate":"2014-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69772758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-06DOI: 10.3724/SP.J.1140.2013.01161
Xiao Wei, Ya Wang, Yang Yang, Jian Chen, J. Gao, Aijun Wang, Dong-yi Li, G. Hu
Various methods were used to measure the suspended sediment concentrations(SSCs) in the Jiulong Estuary in March,2010 and in the North Branch of Yangtze Estuary in February,2011.The synchronous acoustics and optical data including OBS,LISST-100X,ADCP,ADP and ADV were obtained by profiling and seabed tripod measurements.During these surveys,water samples were collected from the water columns form the sea surface down to the bottom,and then the SSC was retrieved by filtration in the lab.Distinctions were discerned among the above methods.Firstly,the seawater filtration is a benchmark method.Secondly,SSCs could be successfully and accurately estimated from acoustic and optical instruments installed at the same height above the seabed,with small measurement errors.Hence,they can be replaced each other,as a case of complementary measurement.Finally,the settling method may overestimate the SSCs,comparing to the filtration method due to the saline substance remained in the sediments.Thus,in order to estimate better SSCs,a suitable method should be selected according to the study purpose and local SSC background.
{"title":"Suspended Sediment Concentrations in Shallow Sea: Comparative Study of Methods","authors":"Xiao Wei, Ya Wang, Yang Yang, Jian Chen, J. Gao, Aijun Wang, Dong-yi Li, G. Hu","doi":"10.3724/SP.J.1140.2013.01161","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.01161","url":null,"abstract":"Various methods were used to measure the suspended sediment concentrations(SSCs) in the Jiulong Estuary in March,2010 and in the North Branch of Yangtze Estuary in February,2011.The synchronous acoustics and optical data including OBS,LISST-100X,ADCP,ADP and ADV were obtained by profiling and seabed tripod measurements.During these surveys,water samples were collected from the water columns form the sea surface down to the bottom,and then the SSC was retrieved by filtration in the lab.Distinctions were discerned among the above methods.Firstly,the seawater filtration is a benchmark method.Secondly,SSCs could be successfully and accurately estimated from acoustic and optical instruments installed at the same height above the seabed,with small measurement errors.Hence,they can be replaced each other,as a case of complementary measurement.Finally,the settling method may overestimate the SSCs,comparing to the filtration method due to the saline substance remained in the sediments.Thus,in order to estimate better SSCs,a suitable method should be selected according to the study purpose and local SSC background.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"161-170"},"PeriodicalIF":0.0,"publicationDate":"2014-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69772959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-06DOI: 10.3724/SP.J.1140.2013.01121
Shengzhu Wang
{"title":"CHARACTERISTICS AND QUALITY ASSESSMENT OF LATE PALEOZOIC CARBONATE RESERVOIRS IN NANPANJIANG DEPRESSION: CHARACTERISTICS AND QUALITY ASSESSMENT OF LATE PALEOZOIC CARBONATE RESERVOIRS IN NANPANJIANG DEPRESSION","authors":"Shengzhu Wang","doi":"10.3724/SP.J.1140.2013.01121","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.01121","url":null,"abstract":"","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"121-128"},"PeriodicalIF":0.0,"publicationDate":"2014-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-03-06DOI: 10.3724/SP.J.1140.2013.02009
W. Li, Shiguo Wu, Xiujuan Wang, Dawei Wang, F. Zhao
2D/3D seismic data and coherence of 3D seismic data in the deepwater area of Qiongdongnan Basin reveal the occurrence of multi-stage mass transport deposits(MTDs) in the Central Canyon of the basin.The MTDs of this region consist of three units,namely the headwall domain,the translational domain and the toe domain characterized by different seismic characteristics.Being regarded as an important part of deepwater deposition in the Central Canyon of Qiongdongnan Basin since Neogene,the large-scale MTDs have an important effect on the spatial distribution of sediment in the deepwater basin.The Pliocene MTDs are distributed in an area of 300 km2,with a thickness up to 240 m in a fan shape in planar distribution.The rapid sedimentary discharge and active tectonic movement may be the main reasons for the development of the MTDs in Central Canyon of Qiongdongnan Basin..In addition,earthquakes and fluctuation of sea level have a significant effect on the formation of the MTDs.
{"title":"SEISMIC CHARACTERISTICS AND DISTRIBUTION OF PLIOCENE MASS TRANSPORT DEPOSITS IN CENTRAL CANYON OF QIONGDONGNAN BASIN: SEISMIC CHARACTERISTICS AND DISTRIBUTION OF PLIOCENE MASS TRANSPORT DEPOSITS IN CENTRAL CANYON OF QIONGDONGNAN BASIN","authors":"W. Li, Shiguo Wu, Xiujuan Wang, Dawei Wang, F. Zhao","doi":"10.3724/SP.J.1140.2013.02009","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02009","url":null,"abstract":"2D/3D seismic data and coherence of 3D seismic data in the deepwater area of Qiongdongnan Basin reveal the occurrence of multi-stage mass transport deposits(MTDs) in the Central Canyon of the basin.The MTDs of this region consist of three units,namely the headwall domain,the translational domain and the toe domain characterized by different seismic characteristics.Being regarded as an important part of deepwater deposition in the Central Canyon of Qiongdongnan Basin since Neogene,the large-scale MTDs have an important effect on the spatial distribution of sediment in the deepwater basin.The Pliocene MTDs are distributed in an area of 300 km2,with a thickness up to 240 m in a fan shape in planar distribution.The rapid sedimentary discharge and active tectonic movement may be the main reasons for the development of the MTDs in Central Canyon of Qiongdongnan Basin..In addition,earthquakes and fluctuation of sea level have a significant effect on the formation of the MTDs.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"9-16"},"PeriodicalIF":0.0,"publicationDate":"2014-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Cenozoic Beibuwan Basin is located in the southwest margin of the South China Block.Many depositional breaks and unconformities have been found in the Cenozoic sequence.The characteristics and distribution pattern of these conformities are described in details in this paper.According to their scale and behaviors,these unconformities can be divided into three orders.And based on ages and their relationship with the rifting stages of the basin,there are three main types of unconformities,i.e.rifting phase unconformity,rifting-depression phase unconformity and inversion phase angular unconformity.The basal unconformity of the basin recorded the initial rifting event of the basin.Being the first-order unconformity,it formed in the rifting phase,and was in conjunction with the sudden decrease in the subduction rate of the Pacific Plate.The unconformity beneath the Weizhou Formation was interpreted in this paper as a rifting phase third-order unconformity formed by the Zhuqiong Movement.It is regionally associated with the collision of the Indian Plate to the Eurasian Plate and the turn of the subduction direction of the Pacific Plate.The unconformity at the bottom of the Xiayang Formation is the transitional interface of the basin structural systes.As a second-order unconformity,it corresponds to the continuous opening of the South China Sea Basin.The unconformity at the bottom of the Dengloujiao Formation is considered as the result of the tectonic inversion of the basin in the later stage.It is a third-order angular unconformity formed in the inversion phase.From a regional point of view,it is related to the Indian-Australian Plate,rather than the subduction of the Philippine Sea Basin.It is concluded that the formation of unconformities is closely related to the rifting of the South China continental margin and the multiple-order and multiple-phase transtension or transpression.It is believed that the intensively strike-slip faulting along the South China continental margin is the result from the reorganization of the regional plate tectonic pattern.
{"title":"UNCONFORMITIES IN THE BEIBUWAN BASIN AND THEIR IMPLICATIONS FOR TECTONIC EVOLUTION: UNCONFORMITIES IN THE BEIBUWAN BASIN AND THEIR IMPLICATIONS FOR TECTONIC EVOLUTION","authors":"Yun Ma, Li Sanzhong, Bingkun Zhang, Shuyun Gong, Xin Liu, Shan Yu, Xiaofei Wang, Shujuan Zhao","doi":"10.3724/SP.J.1140.2013.02063","DOIUrl":"https://doi.org/10.3724/SP.J.1140.2013.02063","url":null,"abstract":"The Cenozoic Beibuwan Basin is located in the southwest margin of the South China Block.Many depositional breaks and unconformities have been found in the Cenozoic sequence.The characteristics and distribution pattern of these conformities are described in details in this paper.According to their scale and behaviors,these unconformities can be divided into three orders.And based on ages and their relationship with the rifting stages of the basin,there are three main types of unconformities,i.e.rifting phase unconformity,rifting-depression phase unconformity and inversion phase angular unconformity.The basal unconformity of the basin recorded the initial rifting event of the basin.Being the first-order unconformity,it formed in the rifting phase,and was in conjunction with the sudden decrease in the subduction rate of the Pacific Plate.The unconformity beneath the Weizhou Formation was interpreted in this paper as a rifting phase third-order unconformity formed by the Zhuqiong Movement.It is regionally associated with the collision of the Indian Plate to the Eurasian Plate and the turn of the subduction direction of the Pacific Plate.The unconformity at the bottom of the Xiayang Formation is the transitional interface of the basin structural systes.As a second-order unconformity,it corresponds to the continuous opening of the South China Sea Basin.The unconformity at the bottom of the Dengloujiao Formation is considered as the result of the tectonic inversion of the basin in the later stage.It is a third-order angular unconformity formed in the inversion phase.From a regional point of view,it is related to the Indian-Australian Plate,rather than the subduction of the Philippine Sea Basin.It is concluded that the formation of unconformities is closely related to the rifting of the South China continental margin and the multiple-order and multiple-phase transtension or transpression.It is believed that the intensively strike-slip faulting along the South China continental margin is the result from the reorganization of the regional plate tectonic pattern.","PeriodicalId":18188,"journal":{"name":"Marine Geology & Quaternary Geology","volume":"33 1","pages":"63-72"},"PeriodicalIF":0.0,"publicationDate":"2014-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69773097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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