SUN, T., QIAN, Z., THAKURTA, J., YANG, S., XU, G., DUAN, J., GAO, B. and WANG, J. (2018), Geochemical and Petrological Studies on the Early Carboniferous Sidingheishan Mafic–Ultramafic Iintrusion in the Southern Margin of the Central Asian Orogenic Belt, NW China. Acta Geologica Sinica ‐ English Edition, 92: 952-971. doi:10.1111/1755-6724.13585
Geochemical and petrological studies on the early carboniferous Sidingheishan mafic-ultramafic intrusion in the southern margin of the Central Asian Orogenic Belt, NW China
|Author:||Sun, Tao1; Qian, Zhuangzhi2; Thakurta, Joyashish3;|
1School of Resource Environment and Earth Sciences, Yunnan University, Kunming 650091 China
2MOE Key Laboratory of Western China's Mineral Resources and Geological Engineering, College of Earth Science and Recourses, Chang'an University, Xi'an 710054 China
3Department of Geosciences, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, Ml 49008 USA
4Department of Geosciences, University of Oulu, P.O. Box 3000, 90014 Oulu Finland
5Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 China
|Online Access:||PDF Full Text (PDF, 0.4 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe202001233173
John Wiley & Sons,
|Publish Date:|| 2020-01-23
The Sidingheishan mafic–ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine‐free unit and the second pulse produced an olivine–bearing unit. The magmas intruded the Devonian granites and granodiorites. An age of 351.4±5.8 Ma (Early Carboniferous) for the Sidingheishan intrusion has been determined by U‐Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U‐Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA‐ICP‐MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine‐liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately 10.43wt% and 13.14wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The εNd (t) values in the rock units vary from +6.70 to +9.64, and initial 87Sr/86Sr ratios range between 0.7035 and 0.7042. Initial 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values fall in the ranges of 17.23–17.91, 15.45–15.54 and 37.54–38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low (La/Gd)PM values between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel–peridotite mantle. (Th/Nb)PM ratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust. Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10vol% contamination from a granitic melt. This was followed by about 5vol% assimilation of upper crustal rocks. Thus, the high‐Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break‐off of a subducted slab.
Acta geologica sinica. English edition
|Pages:||952 - 971|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
This study was financially supported by the National Science Foundation of China (41402070, 41372101, 41602082), Chang’an University (310826151138) and China Geological Survey (DD20160346).
© 2018 Geological Society of China. This is the peer reviewed version of the following article: SUN, T., QIAN, Z., THAKURTA, J., YANG, S., XU, G., DUAN, J., GAO, B. and WANG, J. (2018), Geochemical and Petrological Studies on the Early Carboniferous Sidingheishan Mafic–Ultramafic Iintrusion in the Southern Margin of the Central Asian Orogenic Belt, NW China. Acta Geologica Sinica ‐ English Edition, 92: 952-971, which has been published in final form at https://doi.org/10.1111/1755-6724.13585. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."