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Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province

Wang, Yaying and Zeng, Lingsen and Asimow, Paul D. and Gao, Li-E and Ma, Chi and Antoshechkina, Paula M. and Guo, Chunli and Hou, Kejun and Tang, Suohan (2018) Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province. Lithos, 296-299 . pp. 396-411. ISSN 0024-4937. http://resolver.caltech.edu/CaltechAUTHORS:20171116-093457188

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Abstract

The Dala diabase intrusion, at the southeastern margin of the Yardoi gneiss dome, is located within the outcrop area of the ~ 132 Ma Comei Large Igneous Province (LIP), the result of initial activity of the Kerguelen plume. We present new zircon U-Pb geochronology results to show that the Dala diabase was emplaced at ~ 132 Ma and geochemical data (whole-rock element and Sr-Nd isotope ratios, zircon Hf isotopes and Fe-Ti oxide mineral chemistry) to confirm that the Dala diabase intrusion is part of the Comei LIP. The Dala diabase can be divided into a high-Mg/low-Ti series and a low-Mg/high-Ti series. The high-Mg/low-Ti series represents more primitive mafic magma compositions that we demonstrate are parental to the low-Mg/high-Ti series. Fractionation of olivine and clinopyroxene, followed by plagioclase within the low-Mg series, lead to systematic changes in concentrations of mantle compatible elements (Cr, Co, Ni, and V), REEs, HFSEs, and major elements such as Ti and P. Some Dala samples from the low-Mg/high-Ti series contain large ilmenite clusters and show extreme enrichment of Ti with elevated Ti/Y ratios, likely due to settling and accumulation of ilmenite during the magma chamber evolution. However, most samples from throughout the Comei LIP follow the Ti-evolution trend of the typical liquid line of descent (LLD) of primary OIB compositions, showing strong evidence of control of Ti contents by differentiation processes. In many other localities, however, primitive magmas are absent and observed Ti contents of evolved magmas cannot be quantitatively related to source processes. Careful examination of the petrogenetic relationship between co-existing low-Ti and high-Ti mafic rocks is essential to using observed rock chemistry to infer source composition, location, and degree of melting.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.lithos.2017.11.014DOIArticle
http://www.sciencedirect.com/science/article/pii/S0024493717303973PublisherArticle
ORCID:
AuthorORCID
Asimow, Paul D.0000-0001-6025-8925
Additional Information:© 2017 Elsevier B.V. Received 5 May 2017, Accepted 12 November 2017, Available online 15 November 2017. This study was supported by Special Scientific Research Fund of Public Welfare Profession of China (Grant No. 201511022), China Geological Survey Project (Grant No. 12120115027101), and National Science Foundation of China (Grant Nos. 41425010, 41503023). PDA's participation was supported by the US National Science Foundation, award EAR-1550934.
Funders:
Funding AgencyGrant Number
Special Scientific Research Fund of Public Welfare Profession of China201511022
China Geological Survey12120115027101
National Science Foundation of China41425010
National Science Foundation of China41503023
NSFEAR-1550934
Subject Keywords:Comei Large Igneous Province; Mafic magmatic evolution; LLD; Low-Ti and high-Ti mafic rocks; Tethyan Himalaya
Record Number:CaltechAUTHORS:20171116-093457188
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20171116-093457188
Official Citation:Yaying Wang, Lingsen Zeng, Paul D. Asimow, Li-E Gao, Chi Ma, Paula M. Antoshechkina, Chunli Guo, Kejun Hou, Suohan Tang, Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province, In Lithos, Volumes 296–299, 2018, Pages 396-411, ISSN 0024-4937, https://doi.org/10.1016/j.lithos.2017.11.014. (http://www.sciencedirect.com/science/article/pii/S0024493717303973)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83250
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:16 Nov 2017 17:43
Last Modified:13 Dec 2017 17:13

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