Abstract: Paleo-uplift is the positive structural unit on the Earth's surface due to the interaction between the internal and exotic geodynamic processes. Its structural restoration is important for understanding the Earth's evolutionary history as well as supporting energy exploration. In this paper, taking the Tianjingshan paleo-uplift as an example, we discussed the geological structure and formation and modification of paleo-uplift, and put forward a structural restoration methodology. Although the Tianjingshan paleo-uplift was discovered in the early 1980s, its geological structure and formation and evolutionary history have been controversial owing to its distinctive geographic location. Based on stratigraphic and structural distribution data, we constructed the near-surface geological cross-section and reconstructed the formation and evolutionary history of the paleo-uplift using the structural restoration method. The Tianjingshan paleo-uplift developed several structural layers including the Sinian, the Cambrian to Silurian, the Devonian to Carboniferous, the Permian to Triassic, and the Jurassic to Quaternary. Along its strike, the paleo-uplift can be divided into the northern, central and southern segments, which consist of two anticlines intercalating with a syncline, a tight anticline, and a gradually overturned anticline, respectively. The Tianjingshan paleo-uplift underwent four-stage tectonic evolution, i.e. episodic uplifting during the Cambrian to Silurian, continual uplifting during the Devonian to Carboniferous, total burial during the Permian to Triassic, and modification and transformation during the Jurassic to Quaternary. The tectonic evolution resulted in a southeastward axial migration. The Tianjingshan paleo-uplift is a remnant uplift with extensive modification, demonstrating the effect of multi-phase extension and compression in the northern Longmenshan Mountains.

Key words: northern segment of Longmenshan Mountains, Tianjingshan paleo-uplift, geological structure, structural restoration, extension and compression cycle