The Xigaze ophiolite crops out in the central segment of the Yarlung Zangbo suture zone,southern Tibet(Fig.1).It is characterized by large amounts of ultramafic units with minor mafic rocks.The mafic rocks consist of ...The Xigaze ophiolite crops out in the central segment of the Yarlung Zangbo suture zone,southern Tibet(Fig.1).It is characterized by large amounts of ultramafic units with minor mafic rocks.The mafic rocks consist of gabbros,展开更多
Objective There has been considerable debate about the definition of the lower boundary of Nanhua System by far.One definition is based on sedimentary sequence of different stages of basin evolution,focusing on whethe...Objective There has been considerable debate about the definition of the lower boundary of Nanhua System by far.One definition is based on sedimentary sequence of different stages of basin evolution,focusing on whether deposits of the Banxi Period should be classified as Nanhua System.Another is the onset time of Nanhua glacial period.展开更多
The Dongping gold deposit is located on the northern margin of the North China Craton,and is the largest alkaline pluton-related gold deposit in China(Bao et al.,2014),which is characterized by its large amounts of te...The Dongping gold deposit is located on the northern margin of the North China Craton,and is the largest alkaline pluton-related gold deposit in China(Bao et al.,2014),which is characterized by its large amounts of tellurides.The deposit is largely hosted in the Shuiquangou syenitic complex and consists of auriferous quartz veins and disseminated sulfide ores.It has been extensively studied since its discovery in the 1980s;however the geochronology and genesis of the deposit are still controversial.Nie(1998)considered that the deposit was formed in the Devonian.展开更多
Objective The Susong complex zone（SCZ）is a relatively lowgrade metamorphic unit mostly with an epidoteamphibolite facies,located in the southernmost part of the Dabie orogen.However,its rock compositions,ages,
The North China Craton,one of the oldest continental nuclei on Earth,is bounded to the north by the Central Asian Orogenic Belt and to the south by the Qinling–Dabie ultrahigh-pressure metamorphic belt.The Liaodong
To understand the forming and tectonic evolution of the South China Sea basin, new data of the structural styles and geochronology were obtained from the Dulong-Song Chay dome, southeastern Yunnan and northern Vietnam...To understand the forming and tectonic evolution of the South China Sea basin, new data of the structural styles and geochronology were obtained from the Dulong-Song Chay dome, southeastern Yunnan and northern Vietnam. The structural styles were acquired through field investigation and geo-chronological dating was carried out using zircon SHRIMP Ⅱ U-P and argon isotopic analyses. The South China Sea basin extension occurred firstly at Late Mesozoic to Early Cenozoic, and then at Late Oligocene to Middle Miocene （32-17 Ma）. The second stage of extension formed immediately after the first stage, and both extensions have a consistent forming mechanism. New structural analysis and geo-chronological data do not support the models of ＂backarc spreading＂ and ＂strike-slip faults producing the extension＂. Then what mechanism resulted in the extension of South China Sea basin？ The data indicate that at least two episodes of major extensional tectonics, i.e. , the D1 deformation at 237-228 Ma resulted in the rising and exhumation of the dome, and D2 deformation at 86-78 Ma overprinted and redeformed the dome. Of them, the D2 shows a consistent forming time, extensional direction and tectonic regime among Dulong-Song Chay dome, South China block and the northern margin of the South China Sea basin. Regional geology has proved that the northern margin of the South China Sea basin belongs to the South China block, therefore, we interpreted that the Late Mesozoic to Early Cenozoic extensional tectonics occurred in the northern margin of the South China Sea basin due to the intraplate deformation of the South China block, while the Ailaoshan-Red River sinistral slip strengthened the Cenozoic extension in the South China Sea basin.展开更多
The Liao-Ji belt(LJB)is one of the Paleoproterozoic tectonic belts located in the North China Craton.A large number of Paleoproterozoic meta-volcanic-sedimentary rock and intrusive rocks are preserved in the LJB,which...The Liao-Ji belt(LJB)is one of the Paleoproterozoic tectonic belts located in the North China Craton.A large number of Paleoproterozoic meta-volcanic-sedimentary rock and intrusive rocks are preserved in the LJB,which provide reliable carriers for the study of the Paleoproterozoic tectonic evolution of the North China Craton.The Paleoproterozoic intrusive rock in the LJB can be divided into the following seven types:syenogranite,quartz diorite,porphyry granite,migmatitic granite,sye-nite,metamorphic plutonic rock,and granitic pegmatite and metagabbro(metamorphic diabase).Zir-con U-Pb dating of 15 samples from intrusive rocks was carried out in this study.The chronology framework of the Paleoproterozoic intrusive rock in the LJB was established,and the magmatism of intrusive rocks can be divided into three stages:2200 to 2110,2010 to 1937,1900 to 1820 Ma.The chronological framework supported the evolution model of subduction accretionary arc-continent colli-sion in the LJB effectively.Combined with previous geochemical work,it was a passive continental margin environment at approximately 2200 Ma,and then transformed into and active continental margin.The bimodal intrusive rocks between 2180 and 2150 Ma indicated a back-arc tension envi-ronment which lasted until approximately 2110 Ma with a large number of basic intrusive rocks.And then the back-arc basin began to contract and the magmatic activities were reduced,with only a small number of intrusive rock activities occurring at approximately 2040,2010 and 1937 Ma.After the orogenic activities,there was a post-orogenic extension stage from 1900 to 1820 Ma.Magmatic activi-ties caused by the environmental extension started to occur more frequently and subsequently resulted in the large-scale intrusive rocks in eastern Liaoning.展开更多
To unravel the geochemical heterogeneity and its origin in different terranes of North China,we conducted geochronological and geochemical analyses of the meta-mafic rocks from the Lüliang–Zhongtiao rift zone(Sh...To unravel the geochemical heterogeneity and its origin in different terranes of North China,we conducted geochronological and geochemical analyses of the meta-mafic rocks from the Lüliang–Zhongtiao rift zone(Shanxi Province).LA-ICP-MS zircon U–Pb dating yielded mostly End-Neoarchean to Proterozoic ages for the basement rocks(Sushui Complex:2516±26 Ma;Metamafic rocks:2494±31 Ma),Jiangxian Group(~2213 Ma),Zhongtiao Group(2077±29 Ma),Jiehekou Group(1998±23 Ma),and Lüliang Group(2152±52 Ma).Petrographic characteristics show that the meta-mafic rocks from the Neoarchean–Paleoproterozoic Zhongtiaoshan(Sushui Complex)have similar geochemical characteristics to the overlying Jiangxian and Zhongtiao Groups.The Paleoproterozoic Lüliang andYejishan Group meta-mafic rocks from Lüliangshan also have similar geochemical characteristics but are geochemically different from similar-age rocks from Zhongtiaoshan.This shows that the late-stage rocks have a geochemical inheritance from the early-stage rocks in the same region and that the geochemical heterogeneity of rocks from different areas was originated from the inherited heterogeneity of the magma source.展开更多
This paper presents the results of geochronological(40Ar-39Ar,U-Pb SHRIMP Ⅱ),petrological and geochemical studies of the Late Paleozoic complexes of alkaline rocks(Zimovechinsky,Tuchinsky and Koma) located within the...This paper presents the results of geochronological(40Ar-39Ar,U-Pb SHRIMP Ⅱ),petrological and geochemical studies of the Late Paleozoic complexes of alkaline rocks(Zimovechinsky,Tuchinsky and Koma) located within the Vitim Plateau(the western part of the Mongol-Okhotsk Orogenic Belt).The rocks were formed at 310-280 Ma.It is coeval with Late Paleozoic magmatism within the Central Asian Orogenic Belt.The εNd(T) values show large variations from-2.1 to +3.3 as well as the initial Sr(I) isotopic ratios from 0.7042 to 0.7138,that demonstrate strong isotopic heterogeneity of the magmatic source.The geochemical characteristics of the rocks show pronounced positive Pb and negative Ti,Zr-Hf anomalies that can be explained by involvement of the subducted component in primary melts.The rocks intruded in a setting of extension at the active continental margin of the Siberian Craton during subduction of Mongol-Okhotsk oceanic crust under the Siberian Craton.展开更多
文摘The Xigaze ophiolite crops out in the central segment of the Yarlung Zangbo suture zone,southern Tibet(Fig.1).It is characterized by large amounts of ultramafic units with minor mafic rocks.The mafic rocks consist of gabbros,
基金supported by the National Natural Science Foundation of China(grants No.41372124,41402103 and 41302091)
文摘Objective There has been considerable debate about the definition of the lower boundary of Nanhua System by far.One definition is based on sedimentary sequence of different stages of basin evolution,focusing on whether deposits of the Banxi Period should be classified as Nanhua System.Another is the onset time of Nanhua glacial period.
基金financially supported by the National Natural Science Foundation of China (grant 41573036)the Fundamental Research Funds for the Central Universities, China University of Geosciences (grant No. 2652017262)
文摘The Dongping gold deposit is located on the northern margin of the North China Craton,and is the largest alkaline pluton-related gold deposit in China(Bao et al.,2014),which is characterized by its large amounts of tellurides.The deposit is largely hosted in the Shuiquangou syenitic complex and consists of auriferous quartz veins and disseminated sulfide ores.It has been extensively studied since its discovery in the 1980s;however the geochronology and genesis of the deposit are still controversial.Nie(1998)considered that the deposit was formed in the Devonian.
基金financially supported by the National Basic Research Program of China(grant No.2015CB856104)the National Natural Science Foundation of China(grant No.41773020)
文摘Objective The Susong complex zone（SCZ）is a relatively lowgrade metamorphic unit mostly with an epidoteamphibolite facies,located in the southernmost part of the Dabie orogen.However,its rock compositions,ages,
基金financially supported by the National Key Basic Research Program of China (Grant No. 2012CB416603)the National Natural Science Foundation of China (Grant No. 90914001)
文摘The North China Craton,one of the oldest continental nuclei on Earth,is bounded to the north by the Central Asian Orogenic Belt and to the south by the Qinling–Dabie ultrahigh-pressure metamorphic belt.The Liaodong
文摘To understand the forming and tectonic evolution of the South China Sea basin, new data of the structural styles and geochronology were obtained from the Dulong-Song Chay dome, southeastern Yunnan and northern Vietnam. The structural styles were acquired through field investigation and geo-chronological dating was carried out using zircon SHRIMP Ⅱ U-P and argon isotopic analyses. The South China Sea basin extension occurred firstly at Late Mesozoic to Early Cenozoic, and then at Late Oligocene to Middle Miocene （32-17 Ma）. The second stage of extension formed immediately after the first stage, and both extensions have a consistent forming mechanism. New structural analysis and geo-chronological data do not support the models of ＂backarc spreading＂ and ＂strike-slip faults producing the extension＂. Then what mechanism resulted in the extension of South China Sea basin？ The data indicate that at least two episodes of major extensional tectonics, i.e. , the D1 deformation at 237-228 Ma resulted in the rising and exhumation of the dome, and D2 deformation at 86-78 Ma overprinted and redeformed the dome. Of them, the D2 shows a consistent forming time, extensional direction and tectonic regime among Dulong-Song Chay dome, South China block and the northern margin of the South China Sea basin. Regional geology has proved that the northern margin of the South China Sea basin belongs to the South China block, therefore, we interpreted that the Late Mesozoic to Early Cenozoic extensional tectonics occurred in the northern margin of the South China Sea basin due to the intraplate deformation of the South China block, while the Ailaoshan-Red River sinistral slip strengthened the Cenozoic extension in the South China Sea basin.
基金This study was financially supported by the National Key Research and Development Program(No.2018YFC0603804)the China Geological Survey(Nos.DD20190042,DD20190039 and DD20160048-05).
文摘The Liao-Ji belt(LJB)is one of the Paleoproterozoic tectonic belts located in the North China Craton.A large number of Paleoproterozoic meta-volcanic-sedimentary rock and intrusive rocks are preserved in the LJB,which provide reliable carriers for the study of the Paleoproterozoic tectonic evolution of the North China Craton.The Paleoproterozoic intrusive rock in the LJB can be divided into the following seven types:syenogranite,quartz diorite,porphyry granite,migmatitic granite,sye-nite,metamorphic plutonic rock,and granitic pegmatite and metagabbro(metamorphic diabase).Zir-con U-Pb dating of 15 samples from intrusive rocks was carried out in this study.The chronology framework of the Paleoproterozoic intrusive rock in the LJB was established,and the magmatism of intrusive rocks can be divided into three stages:2200 to 2110,2010 to 1937,1900 to 1820 Ma.The chronological framework supported the evolution model of subduction accretionary arc-continent colli-sion in the LJB effectively.Combined with previous geochemical work,it was a passive continental margin environment at approximately 2200 Ma,and then transformed into and active continental margin.The bimodal intrusive rocks between 2180 and 2150 Ma indicated a back-arc tension envi-ronment which lasted until approximately 2110 Ma with a large number of basic intrusive rocks.And then the back-arc basin began to contract and the magmatic activities were reduced,with only a small number of intrusive rock activities occurring at approximately 2040,2010 and 1937 Ma.After the orogenic activities,there was a post-orogenic extension stage from 1900 to 1820 Ma.Magmatic activi-ties caused by the environmental extension started to occur more frequently and subsequently resulted in the large-scale intrusive rocks in eastern Liaoning.
基金supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences (Grant No.XDB18010105)the Talent start-up fund of Guiyang University(2019039510821)。
文摘To unravel the geochemical heterogeneity and its origin in different terranes of North China,we conducted geochronological and geochemical analyses of the meta-mafic rocks from the Lüliang–Zhongtiao rift zone(Shanxi Province).LA-ICP-MS zircon U–Pb dating yielded mostly End-Neoarchean to Proterozoic ages for the basement rocks(Sushui Complex:2516±26 Ma;Metamafic rocks:2494±31 Ma),Jiangxian Group(~2213 Ma),Zhongtiao Group(2077±29 Ma),Jiehekou Group(1998±23 Ma),and Lüliang Group(2152±52 Ma).Petrographic characteristics show that the meta-mafic rocks from the Neoarchean–Paleoproterozoic Zhongtiaoshan(Sushui Complex)have similar geochemical characteristics to the overlying Jiangxian and Zhongtiao Groups.The Paleoproterozoic Lüliang andYejishan Group meta-mafic rocks from Lüliangshan also have similar geochemical characteristics but are geochemically different from similar-age rocks from Zhongtiaoshan.This shows that the late-stage rocks have a geochemical inheritance from the early-stage rocks in the same region and that the geochemical heterogeneity of rocks from different areas was originated from the inherited heterogeneity of the magma source.
基金Mineralogical investigations were carried out using research project of the Geology Institute of SB RAS,NoAAAA-A16-116122110027-2supported by the Russian Foundation for Basic Research (Project No.17-05-00309-a)supported by the Russian Science Foundation (Grant 19-17-00019)
文摘This paper presents the results of geochronological(40Ar-39Ar,U-Pb SHRIMP Ⅱ),petrological and geochemical studies of the Late Paleozoic complexes of alkaline rocks(Zimovechinsky,Tuchinsky and Koma) located within the Vitim Plateau(the western part of the Mongol-Okhotsk Orogenic Belt).The rocks were formed at 310-280 Ma.It is coeval with Late Paleozoic magmatism within the Central Asian Orogenic Belt.The εNd(T) values show large variations from-2.1 to +3.3 as well as the initial Sr(I) isotopic ratios from 0.7042 to 0.7138,that demonstrate strong isotopic heterogeneity of the magmatic source.The geochemical characteristics of the rocks show pronounced positive Pb and negative Ti,Zr-Hf anomalies that can be explained by involvement of the subducted component in primary melts.The rocks intruded in a setting of extension at the active continental margin of the Siberian Craton during subduction of Mongol-Okhotsk oceanic crust under the Siberian Craton.
