Premium
Geochemical characteristics of Late Carboniferous volcanic rocks in South‐eastern Heishanling, Beishan area, Xinjiang, China
Author(s) -
He Hujun,
An Le,
Yang Xingke,
Li Yuhang,
Zhang Jian,
Yang Longwei,
Han Ke
Publication year - 2018
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3146
Subject(s) - geology , geochemistry , carboniferous , volcanic rock , rift , permian , trace element , basalt , lithophile , igneous rock , volcano , partial melting , paleontology , tectonics , structural basin
The Palaeozoic Beishan Rift Valley zone in Xinjiang, China, is located between the Dunhuang and Kuluketage blocks, in the north‐eastern margin of the Tarim Plate. Carboniferous–Permian volcanism is evident in this area. The Ganquan cycle, the main eruptive event of the Late Carboniferous in the Beishan region, produced large volumes of lava and was related to Carboniferous–Permian volcanism in the rift valley. Major element, rare earth element (REE), and trace element compositions of volcanic rocks were determined, with results indicating that volcanic rocks of the Ganquan cycle are mainly an association of sodic calc‐alkaline rocks, with some alkaline compositions. The REE characteristics of all rock types indicate a continuous and progressive evolution, with a gradual increase in light REE enrichment, and positive to negative Eu anomalies reflecting crystallization of plagioclase. Trace element compositions show obvious depletion in Nb and Ta, and high abundances of large‐ion lithophile elements, indicative of a subduction‐related origin. It is concluded that the Late Carboniferous Beishan Rift Valley of the Ganquan cycle formed in a compressional tectonic environment, which generated a set of volcanic rock assemblages and sedimentary formations. Subsequent Early Permian volcanic activity was caused by large‐scale delamination of the orogenic belt and thickened lithosphere, which resulted in large‐scale ascent of partial melt from the mantle.