Geochemical characteristics and tectonic significance of OIB-type basalts in the Nagong area, southern Tibet

The basalts of the Sangxiu Formation are widely distributed across the Nagong area of southern Tibet, particularly along the Rongbu–Gudui fault and its secondary faults. High-precision testing and analysis of the basalts reveal SiO 2 contents ranging from 43.7 to 47.71%, and initial 87 Sr/ 86 Sr and...

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Bibliographic Details
Published in:Arabian journal of geosciences 2021-11, Vol.14 (21), Article 2189
Main Authors: Gao, Jianguo, Ding, Feng, Li, Ying, Jiang, Xiufang
Format: Article
Language:English
Subjects:
Asthenosphere
Basalt
Comparative analysis
Earth and Environmental Science
Earth science
Earth Sciences
Field strength
Hot spots
Hot spots (geology)
Isotopes
Lava
Mantle plumes
Neodymium isotopes
Original Paper
Rubidium
Silica
Silicon dioxide
Strontium 87
Strontium isotopes
Tectonics
Zirconium
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Summary:The basalts of the Sangxiu Formation are widely distributed across the Nagong area of southern Tibet, particularly along the Rongbu–Gudui fault and its secondary faults. High-precision testing and analysis of the basalts reveal SiO 2 contents ranging from 43.7 to 47.71%, and initial 87 Sr/ 86 Sr and 143 Nd/ 144 Nd ratios of 0.706135–0.708093 and 0.512521–0.512706, respectively; εNd(t) values are − 1.18 to + 2.57. These data are consistent with the characteristics of ocean island basalts (OIB) and Emeishan high-Ti basalts. Large ion lithophile elements (LILEs) such as Rb and Ba, as well as high field strength elements (HFSEs) such as Nb, Ta, and Zr, are enriched, and there is no obvious Eu negative anomaly. These results indicate that the Sangxiu basalts are OIB-type alkaline basalts formed through interactions with the lithospheric mantle as well as partial melting of the asthenospheric mantle in relation to a mantle plume. Additional comparative analysis of the regional Cuomei Large Igneous Province (CLIP) and other rocks related to the Kerguelen hotspot suggests that the Nagong basalts belong to the CLIP in relation to the earliest Kerguelen hotspot activity.
ISSN:1866-7511
1866-7538
DOI:10.1007/s12517-021-08578-y