江西武功山地区老虎塘组碎屑锆石U-Pb年龄和Hf同位素: 沉积时代厘定及其源区特征 |
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关键词:detrital zircons LA-ICP-MS U-Pb age sedimentary age Laohutang Formation Wugongshan |
基金项目:国家自然科学基金项目(编号: 41272220);国家重点研发计划(编号: 2016YCF0600202);中国地质调查局地质调查项目(编号: DD20160201) |
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摘要: |
U-Pb and Hf Isotopic Data of Detrital Zircons from the Laohutang Formation in the Wugongshan Area, Central Jiangxi Province:Constraint on Sedimentary Age and Material Source |
The Sinian Laohutang Formation, outcropped in the Wugongshan area on the northern margin of the Cathaysia plate, is composed of thin bedded sandstone, siltstone and chert. The sedimentary rocks have undergone strong deformation and metamorphism. There is some controversy on the age of the sedimentary rock due to the lack of paleontological evidence. This study shows that the ages of detrital zircons from the sandstones are predominantly Early Paleozoic, and the youngest detrital zircon grains clearly show that the maximum depositional age of the Laohutang Formation is ca. (432.7±1.8) Ma. The ages of the detrital zircons can be dominantly divided into two groups: 423~537 Ma and 660~1 280 Ma. The zircons in the 423~537 Ma age population show approximately the same εHf(t) values from –20 to +5, suggesting that the source rocks were the igneous rocks formed on the northern margin of the Cathisian block in the Caledonian period. Zircon with ages from 660 Ma to 1 280 Ma shows the Hf values ranging from –20 to + 5. The age data are comparable with the ages of zircons in the Neoproterozic granites and volcanic rocks in the Qinhang belt. The small Paleoproterozoic and Archean zircon population implies the probably derivation of the materials from the basement of the Cathaysia plate. A comprehensive analysis shows that there was a collision-orogenic event on the northern margin of the Cathaysia plate in the Caledonian period, and the orogenic belt contributed abundant materials to the sedimentary basin. |
WANG Tao,WANG Zong-qi,WANG Dong-sheng,WU Fu-jiang,WANG Ming-qian,MA Zhen-hui.2018.U-Pb and Hf Isotopic Data of Detrital Zircons from the Laohutang Formation in the Wugongshan Area, Central Jiangxi Province:Constraint on Sedimentary Age and Material Source[J].Acta Geoscientica Sinica,39(2):167-178. |
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