The Bulk Crustal Composition of the Southeastern Lhasa Terrane and Its Origin

被引：3
|
作者：
Guo J. [1 ,2 ]
Zhang H. [1 ,2 ]
Xu W. [1 ,2 ]
Guo L. [1 ,2 ]
Wu Y. [2 ]
Cui D. [1 ,2 ]
机构：
[1] School of Earth Sciences, China University of Geosciences, Wuhan
[2] State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan
来源：
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2019年 / 44卷 / 06期
关键词：
Chemical differentiation; Continental crust; Foundering; Gangdese; Nd isotopes; Petrology; Tibetan Plateau;
D O I：
10.3799/dqkx.2019.050
中图分类号：
学科分类号：
摘要：
The structure and composition of orogenic belts are important for understanding the chemical evolution of the continental crust and the background for metallogenesis. This study integrates previously published crustal seismic structures, experimentally determined petrophysical properties of various rock types, and geochemical data of magmatic rocks from the southeastern Lhasa Terrane, in order to discuss the compositional features of the continental crust in this region and their possible causes. The average crustal seismic velocity in this region is lower than the average values of global continental crust and orogenic belts, suggesting a more felsic composition for the bulk continental crust. Moreover, the lower crust could also be composed of intermediate rocks (restitic intermediate garnet granulite). The felsic bulk crustal composition of the southeastern Lhasa terrane is supposed to be related to multiple episodes of felsification, including the pre-collisional continental arc evolution stage (mainly by delamination of cumulate or restitic lower crust) and the post-collisional plateau collapsing stage (mainly by delamination of thickened lower crust, which is accompanied by the relamination/tectonic underthrusting of felsic materials from the ancient Indian continental crust). The Lhasa terrane is one of the best places to study the chemical differentiation of continental crust, which demands further comprehensive studies of multiple disciplines. © 2019, Editorial Department of Earth Science. All right reserved.
引用
收藏
页码：1809 / 1821
页数：12
相关论文
共 89 条
  • [1] Abers G.A., Hacker B.R., A MATLAB Toolbox and Excel Workbook for Calculating the Densities, Seismic Wave Speeds, and Major Element Composition of Minerals and Rocks at Pressure and Temperature, Geochemistry, Geophysics, Geosystems, 17, 2, pp. 616-624, (2016)
  • [2] Bai Z.M., Zhang S.F., Braitenberg C., Crustal Density Structure from 3D Gravity Modeling beneath Himalaya and Lhasa Blocks, Tibet, Journal of Asian Earth Sciences, 78, pp. 301-317, (2013)
  • [3] Beck S.L., Zandt G., The Nature of Orogenic Crust in the Central Andes, Journal of Geophysical Research(Solid Earth), 107, B10, pp. ESE 7-1-ESE 7-16, (2002)
  • [4] Becker M., Le Roex A.P., Geochemistry of South African on- and off-Craton, Group I and Group II Kimberlites: Petrogenesis and Source Region Evolution, Journal of Petrology, 47, 4, pp. 673-703, (2006)
  • [5] Chan G.N., Waters D.J., Searle M.P., Et al., Probing the Basement of Southern Tibet: Evidence from Crustal Xenoliths Entrained in a Miocene Ultrapotassic Dyke, Journal of the Geological Society, 166, 1, pp. 45-52, (2009)
  • [6] Chapman A.D., Ducea M.N., Kidder S., Et al., Geochemical Constraints on the Petrogenesis of the Salinian Arc, Central California: Implications for the Origin of Intermediate Magmas, Lithos, 200-201, pp. 126-141, (2014)
  • [7] Chapman J.B., Ducea M.N., Kapp P., Et al., Spatial and Temporal Radiogenic Isotopic Trends of Magmatism in Cordilleran Orogens, Gondwana Research, 48, pp. 189-204, (2017)
  • [8] Chapman J.B., Kapp P., Tibetan Magmatism Database, Geochemistry, Geophysics, Geosystems, 18, 11, pp. 4229-4234, (2017)
  • [9] Christensen N.I., Mooney W.D., Seismic Velocity Structure and Composition of the Continental Crust: A Global View, Journal of Geophysical Research: Solid Earth, 100, B6, pp. 9761-9788, (1995)
  • [10] Chu M.F., Chung S.L., O'Reilly S.Y., Et al., India's Hidden Inputs to Tibetan Orogeny Revealed by Hf Isotopes of Transhimalayan Zircons and Host Rocks, Earth and Planetary Science Letters, 307, 3-4, pp. 479-486, (2011)
123456789