Sedimentary characteristics and main controlling factors of the Middle-Upper Permian and Middle-Upper Triassic around Bogda Mountain of Xinjiang, NW China

Abstract

Based on field geological survey, interpretation of seismic data and analysis of drilling and logging data, the evolution of geological structures, stratigraphic sedimentary filling sequence and sedimentary system around the Bogda Mountain were analyzed according to the idea of “structure controlling basin, basin controlling facies and facies controlling assemblages”. The tectonic evolution of the basin around the Bogda Mountain can be divided into nine stages. The Middle-Late Permian–Middle-Late Triassic was the development stage of intracontinental rift, foreland basin and inland depression basin when lake, fan delta and braided river delta sedimentary facies developed. Early intracontinental rifting, late Permian tectonic uplift, and middle-late Triassic tectonic subsidence controlled the shape, type, subsidence rate and sedimentary system evolution of the basin. The Bogda Mountain area was the subsidence center and deposition center of the deep water lake basin in the Middle Permian with mainly deep-water deposition and local gravity flow deposition. This area had tectonic inversion in the Late Permian, when the Bogda Mountain uplifted to form a low bulge and a series of fan delta sand bodies. In the Middle-Late Triassic, subsidence occurred in the Bogda low uplift, characterized by extensive development of braided river delta deposits.

Keywords

• Junggar Basin
• Bogda Mountain
• Fukang fault zone
• Permian
• Lucaogou Formation
• Triassic