The newly obtained Sm-Nd isochron ages are 1034 Ma and 935 Ma for ophiolites from northeasternJiangxi and Fuchuan, southern Anhui respectively. There exist two unconformity surfaces under the initialLate Proterozoic v...The newly obtained Sm-Nd isochron ages are 1034 Ma and 935 Ma for ophiolites from northeasternJiangxi and Fuchuan, southern Anhui respectively. There exist two unconformity surfaces under the initialLate Proterozoic volcanics as well as the Sinian rocks. The Xiuning intrusive body which was intruded into theShangxi Group in southern Anhui yields a whole-rock Rb-Sr isochron age of 963 Ma. There occurs a belt ofLate Proterozoic calc-alkali volcanic rocks extending from northeastern Jiangxi to northwestern Zhejiang. Inthe light of the above facts, the authors consider that the southeastern margin of Jiangnania is an ancient islandarc. At about 1000 Ma ago, the Huanan (South China) oceanic crust was subducted along the line linking Dex-ing and Hangzhou, thus starting the accretion of the island arc system to Jiangnania. At 800 Ma ago Cathaysiaand Jiangnania converged together along the Jiangshan-Shaoxing line, marking the end of the accretion.展开更多
Proterozoic rocks in the northeastern Jiangxi-southern Anhui may fall into three rock associations whichbelong to different but interrelated tectono-palaeogeographic units. The field geological and petrochemicalcharac...Proterozoic rocks in the northeastern Jiangxi-southern Anhui may fall into three rock associations whichbelong to different but interrelated tectono-palaeogeographic units. The field geological and petrochemicalcharacteristics of the northeastern Jiangxi-western Zhejiang volcanic zone indicate that it was once an islandarc zone. An analysis of the sedimentary characteristics of Proterozoic turbidites lying north of the zone has re-vealed the history of development of a back-arc basin. According to the type of the Proterozoic rock formationsouth of the zone, it may be deduced that the formation might represent the fore-arc and trench areas. Bymeans of various tectono-palaeogeographic analyses, the relation between the island arc zone and the back-arcbasin is inferred and the Late Proterozoic tectono-palaeogeographic development is discussed by using themodel of the trench-arc-basin system.展开更多
On the basis of a study of the acanthomorphic acritarchs discovered in the Late Proterozoicto Early Cambrian Meishucunian Stage in different regions of China, especially in southernShaanxi and the Yangtze Platform, co...On the basis of a study of the acanthomorphic acritarchs discovered in the Late Proterozoicto Early Cambrian Meishucunian Stage in different regions of China, especially in southernShaanxi and the Yangtze Platform, coupled with a study of the assemblages, morphological cor-relation, microstructure, and evolutional relations of the acanthorphic acritarchs, as well as awide correlation with those found in different regions of the world, the authors discuss the earlyevolutionary stages of the acanthomorphs, features of their assemblages in various stages, theirbiostratigraphical significance, and their evolutionary trend in China.展开更多
文摘The newly obtained Sm-Nd isochron ages are 1034 Ma and 935 Ma for ophiolites from northeasternJiangxi and Fuchuan, southern Anhui respectively. There exist two unconformity surfaces under the initialLate Proterozoic volcanics as well as the Sinian rocks. The Xiuning intrusive body which was intruded into theShangxi Group in southern Anhui yields a whole-rock Rb-Sr isochron age of 963 Ma. There occurs a belt ofLate Proterozoic calc-alkali volcanic rocks extending from northeastern Jiangxi to northwestern Zhejiang. Inthe light of the above facts, the authors consider that the southeastern margin of Jiangnania is an ancient islandarc. At about 1000 Ma ago, the Huanan (South China) oceanic crust was subducted along the line linking Dex-ing and Hangzhou, thus starting the accretion of the island arc system to Jiangnania. At 800 Ma ago Cathaysiaand Jiangnania converged together along the Jiangshan-Shaoxing line, marking the end of the accretion.
文摘Proterozoic rocks in the northeastern Jiangxi-southern Anhui may fall into three rock associations whichbelong to different but interrelated tectono-palaeogeographic units. The field geological and petrochemicalcharacteristics of the northeastern Jiangxi-western Zhejiang volcanic zone indicate that it was once an islandarc zone. An analysis of the sedimentary characteristics of Proterozoic turbidites lying north of the zone has re-vealed the history of development of a back-arc basin. According to the type of the Proterozoic rock formationsouth of the zone, it may be deduced that the formation might represent the fore-arc and trench areas. Bymeans of various tectono-palaeogeographic analyses, the relation between the island arc zone and the back-arcbasin is inferred and the Late Proterozoic tectono-palaeogeographic development is discussed by using themodel of the trench-arc-basin system.
基金Note:This study was supported by the China National Natural Science Foundation Grant No.49172071 and the Foundation for Development of Geological Science and Technology of the Ministry of Geology and Mineral Resources
文摘On the basis of a study of the acanthomorphic acritarchs discovered in the Late Proterozoicto Early Cambrian Meishucunian Stage in different regions of China, especially in southernShaanxi and the Yangtze Platform, coupled with a study of the assemblages, morphological cor-relation, microstructure, and evolutional relations of the acanthorphic acritarchs, as well as awide correlation with those found in different regions of the world, the authors discuss the earlyevolutionary stages of the acanthomorphs, features of their assemblages in various stages, theirbiostratigraphical significance, and their evolutionary trend in China.
