Petrogenesis of Late Cretaceous I-type granites in the southern Yidun Terrane: New constraints on the Late Mesozoic tectonic evolution of the eastern Tibetan Plateau

	Petrogenesis of Late Cretaceous I-type granites in the southern Yidun Terrane: New constraints on the Late Mesozoic tectonic evolution of the eastern Tibetan Plateau
	Xin-Song Wang; Rui-Zhong Hu; Xian-Wu Bi; Cheng-Biao Leng; Li-Chuan Pan
	2014
发表期刊	Lithos
卷号	208 期号:1 页码:202-219
摘要	The collision between the Lhasa and Qiangtang terranes, prior to the Indo-Asian collision, is a critical aspect in terms of development of the Tibetan Plateau. It has been demonstrated that the occurrence of the Late Cretaceous granites (110-80 Ma) in the Yidun Terrane, eastern Tibetan Plateau (ETP) associates with the Lhasa-Qiangtang collision. The Xiuwacu Late Cretaceous pluton in the southern Yidun Terrane, consists three phases including biotite granitic porphyry (phase 1), monzogranite (phase 2), and alkali-feldspar leucogranite (phase 3), which have zircon U-Pb ages ranging from 85.5 Ma to 84.4 Ma. All these three phases are metaluminous or slightly peraluminous granites (A/CNK = 0.96-1.07), with high SiO2 (70.0-76.0 wt.%), K2O + Na2O (7.5-10.7 wt.%), and Ga/AI (2.5-4.7), and relatively low CaO (0.39-1.67 wt.%), MgO (0.01-0.57 wt.%), and P2O5 (0.01-0.17 wt%). The granites are enriched in light rare earth elements (LREEs), Rb, Th, U and Ta, but depleted in heavy REEs (HREEs), Ba, Sr, P, and Ti, with significantly negative Eu anomalies (Eu/Eu* = 0.24-0.59). Comparing to classic A-type granites, these samples present higher Sr (10.1-256 ppm, mostly >100 ppm) and lower FeO*/MgO ratios (12-9.9) and Zr + Nb + Ce + Y (248-483 ppm, mostly <350 ppm). However, they show highly fractionated I-type granites affinities. All these phases have relatively high (Sr-87/Sr-86), (0.7075-0.7098), negative epsilon(Nd)(t) (-8.0 to -6.9) and epsilon(Hf)(t) (-7.6 to -3.2) values, and ancient Nd and Hf model ages (1.7-1.3 Ga), which indicates similar origins predominately through partial melting of ancient mafic-intermediate lower continental crust. Besides, variable zircon delta O-18 values (5.9 parts per thousand to 8.4 parts per thousand, partly <6.5 parts per thousand) and the occurrences of mafic microgranular enclaves (MMEs) within the granites probably indicate a contribution of mantle components. Although the Xiuwacu Late Cretaceous intrusions show higher SiO2 values and lower Sr/Y ratios comparing to other three high Sr/Y I-type intrusions (Relin, Hongshan, and Tongchanggou) in the southern Yidun Terrane, similar (Sr-87/Sr-86)(i), epsilon(Nd)(t), epsilon(Hf)(t), and delta O-18 contents in all of these four intrusions point to a common source. We propose that both the Xiuwacu intrusions and the other three intrusions in the southern Yidun Terrane were generated under a late- or post-collision environment related to the Lhasa-Qiangtang collision during the Late Cretaceous. Decompression induced upwelling of mantle-derived magmas to underplate and provided heat for the anatexis of thickened lower crust. Then, those Late Cretaceous magmas were brought into the southern Yidun Terrane by mixing of lower continental crust-derived melts and minor mantle-derived magmas, and the following fractional crystallization. Occurrence of these late- or post-collision magmas probably indicates that the timing of both the Lhasa-Qiangtang collision and the eastern Tibetan Plateau uplifting was earlier than the late Cretaceous, and that the Lhasa-Qiangtang collision did not cease at least until ca. 80 Ma. Afterwards, tectonic setting of the eastern Tibetan Plateau was progressively to be under a control mainly of the subduction of the Neo-Tethys Ocean and subsequent Indo-Asian collision.
关键词	Granites Sr–nd–hf–o Isotopes Meso-tethys Yidun Terrane Eastern Tibetan Plateau
学科领域	矿床地球化学
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/6029
专题	矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文矿床地球化学国家重点实验室
通讯作者	Rui-Zhong Hu
推荐引用方式 GB/T 7714	Xin-Song Wang,Rui-Zhong Hu,Xian-Wu Bi,et al. Petrogenesis of Late Cretaceous I-type granites in the southern Yidun Terrane: New constraints on the Late Mesozoic tectonic evolution of the eastern Tibetan Plateau[J]. Lithos,2014,208(1):202-219.
APA	Xin-Song Wang,Rui-Zhong Hu,Xian-Wu Bi,Cheng-Biao Leng,&Li-Chuan Pan.(2014).Petrogenesis of Late Cretaceous I-type granites in the southern Yidun Terrane: New constraints on the Late Mesozoic tectonic evolution of the eastern Tibetan Plateau.Lithos,208(1),202-219.
MLA	Xin-Song Wang,et al."Petrogenesis of Late Cretaceous I-type granites in the southern Yidun Terrane: New constraints on the Late Mesozoic tectonic evolution of the eastern Tibetan Plateau".Lithos 208.1(2014):202-219.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
Petrogenesis of Late（4185KB）			开放获取	使用许可	浏览请求全文