Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes
Changtang rhyolite is the acidic end-member of asymmetric bimodal volcanic rock association, which is composed mainly of amounts of rhyolite and minor basalt. It is considered to be the youngest Yanshanian rhyolite in southern China (SHRIMP age of 96.8 Ma), but the petrological and geochemical chara...
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Science Press, PR China
2016-09-01
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| Series: | Yankuang ceshi |
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| Online Access: | http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.2016.05.015 |
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| author | LAO Yu-jun WU Jian-hua XU Xun-sheng |
| author_facet | LAO Yu-jun WU Jian-hua XU Xun-sheng |
| author_sort | LAO Yu-jun |
| collection | DOAJ |
| description | Changtang rhyolite is the acidic end-member of asymmetric bimodal volcanic rock association, which is composed mainly of amounts of rhyolite and minor basalt. It is considered to be the youngest Yanshanian rhyolite in southern China (SHRIMP age of 96.8 Ma), but the petrological and geochemical characteristics are, as yet unclear. In this paper, the focus is on the whole rock major elements, Sr-Nd-Pb-O isotopes and zircon Hf isotopes. Rhyolite belongs to weakly sub-alkaline peraluminous rock. It is enriched in rare earth elements with strong light and heavy REE fractionation with obvious europium depletions. Rhyolite has low (87Sr/86Sr)i, hight εNd(t), low (206Pb/204Pb)i, (207Pb/204Pb)i and (208Pb/204Pb)i values. The zircon has high Hf isotopes and δ18O values. Whole rock TDM2(Hf) values are similar to TDM2(Nd), indicating the derivation of juvenile lower crust. Combined with regional geological data, it is suggested that the Changtang rhyolite was formed by melting of Neoproterozoic lower crust which was derived from EMⅡ mantle source mixed with minor crustal materials. The primary magma experienced fractional crystallization during eruption. Petrogenesis of early stage of the Late Cretaceous rhyolite in South China provides the time evidence for crustal extensional thinness to normal thickness. |
| first_indexed | 2024-04-10T16:27:40Z |
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| language | English |
| last_indexed | 2024-04-10T16:27:40Z |
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| series | Yankuang ceshi |
| spelling | doaj.art-15c8cb0dd9134eb8b6c11107af0fd7c92023-02-09T01:25:49ZengScience Press, PR ChinaYankuang ceshi0254-53572016-09-0135555856710.15898/j.cnki.11-2131/td.2016.05.015ykcs-35-5-558Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O IsotopesLAO Yu-jun0WU Jian-hua1XU Xun-sheng2College of Earth Science, East China Institute of Technology, Nanchang 330013, ChinaCollege of Earth Science, East China Institute of Technology, Nanchang 330013, ChinaNo. 270 Research Institute, China National Nuclear Cooperation, Nanchang 330200, ChinaChangtang rhyolite is the acidic end-member of asymmetric bimodal volcanic rock association, which is composed mainly of amounts of rhyolite and minor basalt. It is considered to be the youngest Yanshanian rhyolite in southern China (SHRIMP age of 96.8 Ma), but the petrological and geochemical characteristics are, as yet unclear. In this paper, the focus is on the whole rock major elements, Sr-Nd-Pb-O isotopes and zircon Hf isotopes. Rhyolite belongs to weakly sub-alkaline peraluminous rock. It is enriched in rare earth elements with strong light and heavy REE fractionation with obvious europium depletions. Rhyolite has low (87Sr/86Sr)i, hight εNd(t), low (206Pb/204Pb)i, (207Pb/204Pb)i and (208Pb/204Pb)i values. The zircon has high Hf isotopes and δ18O values. Whole rock TDM2(Hf) values are similar to TDM2(Nd), indicating the derivation of juvenile lower crust. Combined with regional geological data, it is suggested that the Changtang rhyolite was formed by melting of Neoproterozoic lower crust which was derived from EMⅡ mantle source mixed with minor crustal materials. The primary magma experienced fractional crystallization during eruption. Petrogenesis of early stage of the Late Cretaceous rhyolite in South China provides the time evidence for crustal extensional thinness to normal thickness.http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.2016.05.015rhyoliteearly late cretaceoussr-nd-pb-hf-o isotopesyoung lower crustchangtang basins |
| spellingShingle | LAO Yu-jun WU Jian-hua XU Xun-sheng Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes Yankuang ceshi rhyolite early late cretaceous sr-nd-pb-hf-o isotopes young lower crust changtang basins |
| title | Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes |
| title_full | Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes |
| title_fullStr | Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes |
| title_full_unstemmed | Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes |
| title_short | Petrogenesis of the Late Cretaceous Rhyolites in the Changtang Basin, Northern Guangdong: Constraints from Geochemistry and Sr-Nd-Pb-Hf-O Isotopes |
| title_sort | petrogenesis of the late cretaceous rhyolites in the changtang basin northern guangdong constraints from geochemistry and sr nd pb hf o isotopes |
| topic | rhyolite early late cretaceous sr-nd-pb-hf-o isotopes young lower crust changtang basins |
| url | http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.2016.05.015 |
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