The Coupling Relationship between the Uplift of Longmen Shan and the Subsidence of Foreland Basin, Sichuan, China

Abstract

Depending on the analysis of the coeval sedimentary geometry and subsidence mechanism in the Longmen Shan foreland basin, three models about the coupling relationship between Longmen Shan uplift and foreland basin subsidence since the Indosinian have been proposed: (1) crustal shortening and its related wide wedge‐shaped foreland basin, (2) crustal isostatic rebound and its related tabular foreland basin, and (3) lower crustal flow and its related narrow wedge‐shaped foreland basin. Based on the narrow wedge‐shaped foreland basin developed since 4 Ma, it is believed that the narrow crustal shortening and tectonic load driven by lower crustal flow is a primary driver for the present Longmen Shan uplift and the Wenchuan (Ms 8.0) earthquake.

Geochemistry, Paleoenvironment and Mechanism of Organic‐Matter Enrichment in the Lower Silurian Longmaxi Formation Shale in the Sichuan Basin, China

“…During the Late Ordovician-Early Silurian period, Chuanzhong uplift in the northwest of the Upper Yangtze Platform, Qianzhong uplift in the south of the Upper Yangtze Platform and Jiangnan-Xuefeng uplift in the southeast of the Upper Yangtze Platform extended under the intensive compression of the Caledonian orogeny (Chen et al, 2004;Liang et al, 2009;Xu et al, 2012;Li et al, 2017). Coincident climate warming and the global melting of ice sheets resulted in rapid sea level rises that lead to global transgressions (Yan et al, 2010;Zhang et al, 2012).…”

“…9. Ni-Zn-Co ternary diagram for the Lower Longmaxi Formation in the Jiaoshiba, Zhaotong and Weiyuan areas, Sichuan Basin, distinguishing hydrothermal and hydrogenic sediments (modified from Choi and Hariya, 1992;Wu et al, 2017). This might have been because of the paleogeography of the Weiyuan area, which placed it near the Chuanzhong uplift, where enhanced tectonic activity took place (Xu et al, 2012;Li et al, 2017). The Caledonian orogeny movement not only extended the Chuanzhong uplift but also activated basement faults around the uplift, providing vents for deep-hydrothermal-fluid upwelling.…”