Late Cretaceous adakitic rocks from the western Tibetan Plateau: implications for the subduction of the Neo-Tethys Ocean
Journal
International Geology Review
Journal Volume
63
Journal Issue
15
Pages
1884-1899
Date Issued
2021
Author(s)
Abstract
It is still hotly debated whether the subduction of the Indus-Yarlung Zangbo Tethyan oceanic lithosphere led to Cretaceous magmatism in the north Lhasa terrane or not. Here, we provide new data on adakitic dacite in the Rutog area, western Tibetan Plateau. Zircon U-Pb dating and Lu-Hf analyses yielded a weighted-mean 206Pb/238U age of ca. 97?Ma for a dacite sample, and corresponding positive zircon εHf(t) values of +5.3 to +10.1. All samples have high Sr (796–1091ppm), but low Y (10.4–11.9 ppm) and Yb (0.68–0.79 ppm) contents, with pronounced high Sr/Y (72.5–97.6) ratios. Furthermore, they have low K2O (1.11–1.49?wt.%) and Th (4.18–4.54 ppm) contents, and low K2O/Na2O (0.18–0.28) and Th/La (0.22–0.24) ratios. These geochemical features are most simialr to those of adakite derived from partial melting of subducted oceanic slab. These new data, in combination with regional geology, enable us to suggest that the Late Cretaceous arc-affinity magmatic rocks were probably triggered by northward subduction of the Indus-Yarlung Zangbo oceanic lithosphere. This will give new insights into the geodynamic evolution of the Indus-Yarlung Zangbo Neo-Tethys Ocean. ? 2020 Informa UK Limited, trading as Taylor & Francis Group.
Subjects
adakite
late cretaceous
neo-tethys ocean
subduction
Tibetan plateau
Cretaceous
geodynamics
magmatism
oceanic lithosphere
paleoceanography
partial melting
regional geology
tectonic evolution
Tethys
China
Indus-Yarlung Suture Zone
Qinghai-Xizang Plateau
Type
journal article