Geochemical characteristics and geological significance of basalts in the Sangxiu formation, Rongbu area, southern Tibet
- PDF / 7,993,644 Bytes
- 16 Pages / 595.276 x 790.866 pts Page_size
- 43 Downloads / 218 Views
ORIGINAL PAPER
Geochemical characteristics and geological significance of basalts in the Sangxiu formation, Rongbu area, southern Tibet Ying Li 1 & Feng Ding 1 & Lei Yang 1 & Xiangang Xie 1 & Kunzhi Xu 1 & Qing Li 2,3 & Wenlong Yu 1 & Yao Sun 1 Received: 15 December 2018 / Accepted: 9 October 2019 # Saudi Society for Geosciences 2019
Abstract The Upper Jurassic–Lower Cretaceous Sangxiu Formation in the Rongbu area of Tibet is dominated by large–scale exposed basalts. This paper characterizes the geochemistry and magmatic activities of the Sangxiu Formation basalts in a geochemical analysis. The Sangxiu basalt has higher content of TiO2, TFeO and P2O5 (average content is 3.68%, 11.16% and 0.51%, respectively). The total amount of rare earth elements (REEs) in the Sangxiu Formation basalt is high and largely variable (ranging from 174.6 × 10−6 to 235.3 × 10−6). The light-to-heavy REE ratio ranges from 6.19 to 8.36. These characteristics and the REE fractionation degree of the samples indicate an origin from the same magma. The Zr/Nb ratio of the trace elements lies between 7.96 and 13.15, and the Hf/Th ratio is 1.73–6.67, similar to those of intraplate basalts. And the basalts have the characteristics of elements similar to OIB-type basalt. The magma experienced a large degree of separation and crystallization. During the low-level partial melting of the source material, the basaltic magma of the Sangxiu Formation were isolated and crystallized by olivine, clinopyroxene and other iron–magnesium minerals but were not contaminated by the crust during their evolution. After comparison, it is found that the Sangxiu basalts have similar trace elements and Sr–Nd isotopes with the T7090 diabase and the Laguila magnesite in the Jiangya–Kangma area. It is believed that the Sangxiu basalt is the early stage of the Kerguelen mantle. The hot spot is formed by mixing with the lithospheric mantle and quickly cascade to the edge of the passive continental rift. Keywords Rongbu area . Sangxiu formation . Basalts . Geochemical characteristics . Geological significance
Introduction Magmatic rocks play an important role in the study of the dynamics of the Qinghai–Tibet continent. They are both a
probe and a window for detecting depth, as well as a record of tectonic evolution. The Sangxiu Formation volcanic rock is an important part of the geological unit in the Rangbu area of southern Tibet. It is characterized by bimodal volcanic rock
Responsible Editor: Domenico M. Doronzo * Feng Ding [email protected]; [email protected]
Wenlong Yu [email protected]
Ying Li [email protected] Lei Yang [email protected]
Yao Sun [email protected] 1
College of Earth Sciences, Chengdu University of Technology, No.1, East 3rd street, Erxian bridge, Chenghua Distinct, Chengdu 610059, Sichuan, China
2
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
3
University of Chinese Academy of Sciences, Beijing 100049, China
Xiangang Xie [email protected] Kunzhi Xu [email protected] Qing Li [email protected]
Data Loading...
