Geochronology and geochemistry of volcanic rocks from the Jingtan Formation in the eastern Jiangnan orogen, South China: Constraints on petrogenesis and tectonic implications
Geochronology and geochemistry of volcanic rocks from the Jingtan Formation in the eastern Jiangnan orogen, South China: Constraints on petrogenesis and tectonic implications
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江南造山带东部镜坛组火山岩年代学和地球化学：岩石成因制约及构造意义
DOI：
10.1016/j.precamres.2017.02.012
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发表时间：
2017-02
影响因子：
3.8
通讯作者：
Xia Xiaoping
中科院分区：
文献类型：
--
作者：
Li Longming;Lin Shoufa;Xing Guangfu;Jiang Yang;Xia Xiaoping
对江南造山带东段靖潭组流纹岩和流纹岩凝灰岩进行了锆石U-Pb年代学和地球化学综合研究，并结合Nd-Hf同位素进行了研究。两个样品的锆石U-Pb年龄分别为784±6 Ma和788±6 Ma。地球化学上，它们是过铝质（A/CNK大多在1.2左右），其特征是Rb、Th、ree和hfse（如Zr和Y）富集，Ba、Sr、P、Eu和Ti贫缺。火山岩具有明显的a型花岗岩地球化学特征，总碱度高（K2O + Na2O = 5.3 ~ 7.64 wt%）， FeOt/MgO比值高，CaO、MgO和tio2含量低。它们的全岩ε nd (t)为负（−4.2 ~−1），锆石ε hf (t)为正（+1.26 ~ +11.6），表明Nd-Hf同位素解耦，可能与它们的成岩过程有关。锆石的正ε hf (t)值和幼期ethfdm1 （0.89 ~ 1.3 Ga）表明，该火山岩可能来源于新元古代至中元古代晚期地壳物质的部分熔融作用。结合江南造山带东段大量现代双峰型火山岩的赋存，推断景潭长英质火山岩是在扬子和华夏两块陆块最终合并后不久的碰撞后伸展时期形成的。
An integrated study of zircon U-Pb geochronology and geochemistry, together with Nd-Hf isotopes, have been carried out on the rhyodacite and rhyolitic tuff of the Jingtan Formation in the eastern part of the Jiangnan orogen. SIMS zircon U-Pb dating of two samples yielded weighted mean206Pb/238U ages of 784 ± 6 Ma and 788 ± 6 Ma, respectively. Geochemically, they are peraluminous (A/CNK mostly around 1.2) and are characterized by enrichments in Rb, Th, REEs and HFSEs (e.g. Zr and Y) but depletions in Ba, Sr, P, Eu and Ti. The volcanic rocks show a clear A-type granite geochemical signature with high total alkalis (K2O + Na2O = 5.3–7.64 wt%), FeOt/MgO ratios and low CaO, MgO and TiO2contents. They have negative whole-rockεNd(t) (−4.2 to −1) and positive zirconεHf(t) (+1.26 to +11.6) values, illustrating decoupled Nd-Hf isotopes which may be genetically related to their petrogenesis process. The positiveεHf(t) values and juvenileTHfDM1(0.89–1.3 Ga) of zircons indicate that the volcanic rocks may have been derived from the partial melting of the Neoproterozoic to late Mesoproterozoic crustal materials. Combined with the occurrence of significant volumes of contemporary bimodal volcanic rocks in eastern section of the Jiangnan orogen, it is inferred that the Jingtan felsic volcanic rocks formed during post-collisional extension shortly after the final amalgamation of Yangtze and Cathaysia blocks.
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影响因子：
5
作者：
M. Garçon;C. Chauvel;C. France‐Lanord;P. Huyghe;J. Lavé
通讯作者：
M. Garçon;C. Chauvel;C. France‐Lanord;P. Huyghe;J. Lavé
影响因子：
2.4
作者：
Chuan-Lin Zhang;Huaibin Li;M. Santosh
通讯作者：
Chuan-Lin Zhang;Huaibin Li;M. Santosh
DOI：
10.1016/0024-4937(92)90029-x
发表时间：
1992-07
期刊：
--
影响因子：
--
作者：
S. Turner;J. Foden;R. S. Morrison
通讯作者：
S. Turner;J. Foden;R. S. Morrison
影响因子：
5
作者：
M. Whitehouse;S. Claesson;T. Sunde;J. Vestin
通讯作者：
M. Whitehouse;S. Claesson;T. Sunde;J. Vestin
影响因子：
3.9
作者：
Frisby, Carl;Bizimis, Michael;Mallick, Soumen
通讯作者：
Mallick, Soumen