Feldspar Lead Isotopic Composition of Granitoids from the Eastern Qinling Orogenic Belt and Their Tectonic Significance |
| |
作者姓名: | Zhang Hongfei Zhang Benren Zhao Zhidan Luo Tingchuan and Chen Yuelong |
| |
作者单位: | Zhang Hongfei;Zhang Benren;Zhao Zhidan;Luo Tingchuan and Chen Yuelong Department of Geochemistry,China University of Geosciences,Wuhan,Hubei |
| |
基金项目: | This study was supported by the National Natural Science Foundation of China Grant No.49290102. |
| |
摘 要: | This paper reports 48 feldspar lead isotope analyses from 27 granitic intrusions,which formed from the Late Proterozic to Mesozoic within the Eastern Qinling oregenic belt. Itis found that the granitic rocks of South Qinling are characterized by a strong block-effect anddepletion in U-Pb and Th-Pb, showing that these rocks came from the same lead isotopetectono-geochemical province, while those of North Qinling are characterized by higher U-Pband Th-Pb for Late Proterozoic to Early Paleozoic ones and lower U-Pb and Th-Pb forLate-Palaeozoic and younger ones in their feldspar lead isotopic composition. In the NorthQinling block, lead isotopic signatures reflect that the source of granitic magma had changedsince the Late Palaeozoic. Comparison of feldspar lead isotopic composition between SouthQinling and North Qinling shows that there is marked difference in lead isotopic compositionfor pre-Palaeozoic granitoids, indicating that the South Qinling and the North Qinling blocksbelong to different tectonic units, but the similarities in lead isotopic composition are quiteclear, which indicates that the South Qinling block had been welded with the North Qinlingblock and that the magma sources of both blocks were identical. The analysis provides directevidence for underplating of the continental crust of South Qinling beneath the North Qinlingblock in the continent-continent interaction stage of the Eastern Qinling oregenic belt.
|
Feldspar Lead Isotopic Composition of Granitoids from the Eastern Qinling Orogenic Belt and Their Tectonic Significance |
| |
Authors: | Zhang Hongfei Zhang Benren Zhao Zhidan Luo Tingchuan and Chen Yuelong |
| |
Institution: | Zhang Hongfei,Zhang Benren,Zhao Zhidan,Luo Tingchuan and Chen Yuelong Department of Geochemistry,China University of Geosciences,Wuhan,Hubei |
| |
Abstract: | This paper reports 48 feldspar lead isotope analyses from 27 granitic intrusions,which formed from the Late Proterozic to Mesozoic within the Eastern Qinling oregenic belt. Itis found that the granitic rocks of South Qinling are characterized by a strong block-effect anddepletion in U-Pb and Th-Pb, showing that these rocks came from the same lead isotopetectono-geochemical province, while those of North Qinling are characterized by higher U-Pband Th-Pb for Late Proterozoic to Early Paleozoic ones and lower U-Pb and Th-Pb forLate-Palaeozoic and younger ones in their feldspar lead isotopic composition. In the NorthQinling block, lead isotopic signatures reflect that the source of granitic magma had changedsince the Late Palaeozoic. Comparison of feldspar lead isotopic composition between SouthQinling and North Qinling shows that there is marked difference in lead isotopic compositionfor pre-Palaeozoic granitoids, indicating that the South Qinling and the North Qinling blocksbelong to different tectonic units, but the similarities in lead isotopic composition are quiteclear, which indicates that the South Qinling block had been welded with the North Qinlingblock and that the magma sources of both blocks were identical. The analysis provides directevidence for underplating of the continental crust of South Qinling beneath the North Qinlingblock in the continent-continent interaction stage of the Eastern Qinling oregenic belt. |
| |
Keywords: | Eastern Qinling orogenic belt granitic rock feldspar Pb isotopic composition tectonic significance |
本文献已被 CNKI 等数据库收录! |
| 点击此处可从《Acta Geologica Sinica》浏览原始摘要信息 |
| 点击此处可从《Acta Geologica Sinica》下载免费的PDF全文 |