Permian Source-to-Sink Processes and Paleogeographic Reconstruction in the Northern Ordos Basin and Its Periphery

Key words: 
• Detrital zircon /
• provenance analysis /
• northern Ordos Basin /
• paleogeographic framework /
• Permian

Abstract: 

[Objective] The Permian represents a critical period of tectonic-sedimentary transition in the northern Ordos Basin. A detailed characterization of its complex source-to-sink processes is essential for revealing multi-provenance differential supply patterns and paleogeographic evolution.[Methods] This study systematically analyzes provenance signals and sedimentary filling processes in the northern Ordos Basin through outcrop observations, well-logging data, and detrital zircon U-Pb geochronology, aiming to clarify the paleogeographic framework constrained by source-to-sink systems and its implications for the closure of the Paleo-Asian Ocean. [Results](1) Detrital zircon U-Pb ages reveal that the Alxa Block, Xing-Meng Orogenic Belt, and North China Craton contributed differentially during the Permian, with marked east-west variations. Multidimensional scaling (MDS) analysis divides the northern basin into three provenance zones: Alxa, western Yinshan, and eastern Yinshan. (2) The Permian depositional systems evolved from tide-dominated deltas to braided-river deltas, with sediment thickness and sandbody distribution showing a "thicker in the west and stronger in the north" pattern. Provenance supply intensity closely correlated with environmental changes. Enhanced lateral continuity of sandbodies in the Shanxi and Shihezi Formations reflects braided channel development under strong sediment supply.(3) Source-to-sink analysis indicates:Taiyuan Stage: Dominated by proximal weak supply.Shanxi Stage: Increased provenance mixing formed an east-west differentiated depositional pattern.Shihezi Stage: Significant uplift of the North China Craton basement led to dominant distal supply, with maximum sandbody thickness and spatial extent. [Conclusions]The inhomogeneity of the subduction/closure of the Paleo-Asian Ocean drove the differential uplift characterized by "strong in the west and weak in the east" in the Xing'an-Mongolian Orogenic Belt and "strong in the east and weak in the west" in the basement of the North China Craton. This controlled the east-west differentiation pattern and evolution of the provenance in the northern part of the basin, which showed "mixed provenance in the west and cratonic basement in the east". The sedimentary system transformed from a tide-dominated delta in the marine-continental transitional environment to a continental braided river delta from the Taiyuan Stage to the Shihezi Stage. [Significance] The established paleogeographic evolution model, based on source-to-sink processes, provides a dynamic coupling framework for understanding multi-provenance-sedimentation responses and hydrocarbon exploration in large cratonic basins.