期刊
LITHOS
卷 300, 期 -, 页码 212-226出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.lithos2017.11.023
关键词
Early Cretaceous; Aluminous A-type granite; Crust-mantle interaction; Lithospheric extension; Large Igneous Province
资金
- National Key Research and Development Project of China [2016YFC0600309, 2016YFC0600407]
- Key Program of the Chinese Academy of Sciences [QYZDJ-SSW-DQC026]
- National Natural Science Foundation of China [41402048, 41606076, 41630208]
- talent project of Guangdong Province [2014TX01Z079]
- Key Program of Guangzhou City [201707020032]
- State Scholarship Fund of China [201604910124]
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGCAS 135 project) [135TP201601]
A-type granites have been the focus of considerable research due to their distinctive major- and trace-element signatures and tectonic significance. However, their petrogenesis, magmatic source and tectonic setting remain controversial, particularly for aluminous A-type granites. The earliest Cretaceous (ca. 140 Ma) Comei granite in the eastern Tethyan Himalaya is associated with coeval oceanic island basalt (OIB)-type mafic lava, and has A-type granite geochemical characteristics including high 10,000 x Ga/AI (up to 6), FeOtotal/MgO (4.6-6.1) and (Na2O + K2O)/Al2O3 (0.50-0.61) ratios but low CaO (0.6-1.6 wt%) and Na2O (1.8-2.6 wt%) contents. The Comei granite also has variable peraluminous compositions (A/CNK = 1.00-1.36) along with zircon 8180, epsilon(Nd)(t) and initial Sr-87/Sr-86 values of 8.2%. to 9.3%., -13.0 to -12.4 and 0.7238 to 0.7295, respectively. This range of compositions can be interpreted as the interaction between high-temperature upwelling OIB type basaltic magmas and a shallow crustal (<5 kbar) metapelitic source. The Comei granite and coeval OIB type basaltic rock could represent the earliest stage (145-140 Ma) of a large igneous event in eastern Tethyan Himalaya, which may well have been triggered by pre-breakup lithospheric extension prior to the arrival of the Kerguelen plume head. (C) 2017 Elsevier B.V. All rights reserved.
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