TY - JOUR
T1 - Composition variations of the Sinian-Cambrian sedimentary rocks in Hunan and Guangxi provinces and their tectonic significance
AU - Wang, Peng Ming
AU - Yu, Jin Hai
AU - Sun, Tao
AU - Shi, Yu
AU - Chen, Pei Rong
AU - Zhao, Kui Dong
AU - Chen, Wei Feng
AU - Liu, Qian
PY - 2013/11
Y1 - 2013/11
N2 - This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area, Guangxi Province and the Jinjiling area, Hunan Province. Petrographic and geochemical features indicate that protoliths of these metamorphic rocks are clastic sedimentary rocks with medium weathering, which were formed in the passive continental margin. Geochemistry and zircon U-Pb ages indicate that the Sinian and Cambrian sedimentary rocks in the Jinjiling area have similar detritus components, which are characterized by abundant Grenvillian detrital zircons, suggesting a close affinity with the Cathaysia Block. The Cambrian sedimentary rocks in the Miaoer Mountain area have similar geochemistry and zircon geochronology to those in the Jinjiling area, showing an affinity with the Cathaysia Block. However, the Sinian sedimentary rocks in the Miaoer Mountain area show different geochemical features from the Cambrian sedimentary rocks and those in the Jinjiling area, and are characterized by abundant 840-700 Ma detrital zircons and less ~2.0 Ga ones, showing a close affinity with the Yangtze Block. These variations suggest that the Jinjiling area continuously accepted the fragments from the Cathaysia from the Sinian to the Cambrian, whereas the provenance of the Miaoer Mountain sedimentary basin changed from the Yangtze Block to the Cathaysia Block during this interval. This change implies a tectonic movement, which caused the further sinking of the basin in the Miaoer Mountain area and northwestward transferring of the basin center before the Middle Cambrian, so that the Miaoer Mountain basin received the detritus from the Cathaysia Block in the Middle Cambrian. This fact also proves that the Yangtze and Cathaysia blocks have converged at least in Middle Cambrian, and the southwestern boundary between them is located between the Miaoer Mountain and Jinjiling areas.
AB - This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area, Guangxi Province and the Jinjiling area, Hunan Province. Petrographic and geochemical features indicate that protoliths of these metamorphic rocks are clastic sedimentary rocks with medium weathering, which were formed in the passive continental margin. Geochemistry and zircon U-Pb ages indicate that the Sinian and Cambrian sedimentary rocks in the Jinjiling area have similar detritus components, which are characterized by abundant Grenvillian detrital zircons, suggesting a close affinity with the Cathaysia Block. The Cambrian sedimentary rocks in the Miaoer Mountain area have similar geochemistry and zircon geochronology to those in the Jinjiling area, showing an affinity with the Cathaysia Block. However, the Sinian sedimentary rocks in the Miaoer Mountain area show different geochemical features from the Cambrian sedimentary rocks and those in the Jinjiling area, and are characterized by abundant 840-700 Ma detrital zircons and less ~2.0 Ga ones, showing a close affinity with the Yangtze Block. These variations suggest that the Jinjiling area continuously accepted the fragments from the Cathaysia from the Sinian to the Cambrian, whereas the provenance of the Miaoer Mountain sedimentary basin changed from the Yangtze Block to the Cathaysia Block during this interval. This change implies a tectonic movement, which caused the further sinking of the basin in the Miaoer Mountain area and northwestward transferring of the basin center before the Middle Cambrian, so that the Miaoer Mountain basin received the detritus from the Cathaysia Block in the Middle Cambrian. This fact also proves that the Yangtze and Cathaysia blocks have converged at least in Middle Cambrian, and the southwestern boundary between them is located between the Miaoer Mountain and Jinjiling areas.
KW - boundary of Yangtze and Cathaysia blocks
KW - Cambrian sedimentary rocks
KW - geochemistry
KW - Sinian sedimentary rocks
KW - zircon U-Pb geochronology
UR - http://www.scopus.com/inward/record.url?scp=84886753325&partnerID=8YFLogxK
U2 - 10.1007/s11430-013-4634-1
DO - 10.1007/s11430-013-4634-1
M3 - Article
AN - SCOPUS:84886753325
SN - 1674-7313
VL - 56
SP - 1899
EP - 1917
JO - Science China Earth Sciences
JF - Science China Earth Sciences
IS - 11
ER -