255-3 Thermochronological insight and review on the Meso-Cenozoic morphotectonic evolution of the Western North China Craton

Session: Broad Applications of Thermochronology to Understanding Geologic Rates and Processes Through the Sedimentary Record

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Abstract:

The surface uplift and deformation of the Western North China Craton have led to differential geological, climatic, and geomorphological evolution across western and central China. However, a systematic understanding of the tectonic events affecting the western North China Craton since the Mesozoic, as well as the structural differences between the craton margin and its interior, remains lacking. In this study, we integrate nearly one hundred new and previously published low-temperature thermochronological data. Apatite fission-track (AFT) and apatite (U–Th)/He analyses on drilling cores from the Western North China Craton enable us to reconstruct the region's exhumation and cooling history, revealing pronounced spatial variations in both the timing and intensity of thermal events. AFT ages and Mean Track Length (MTCL) distribution maps show considerable heterogeneity along the craton margin, indicating significant regional differences in cooling histories. New thermal history modeling identifies four major cooling episodes that initiated during the Late Jurassic, late Early Cretaceous, Late Cretaceous, and the Cenozoic, respectively. The study of low-temperature thermochronology at plate edges provides favorable constraints for regional tectonic evolution and surface processes. We propose that the timing and distribution of these events, as recorded in the thermochronological age patterns, reflect long-lived, complex fault activity and the reactivation of the craton. The Late Jurassic exhumation corresponds to the development of the fold-and-thrust belt along the western margin of the craton, with earlier initiation in the northern and southern segments and slightly delayed activity in the central part. Furthermore, exhumation timing across different fault blocks generally becomes younger from the basin margin toward the interior, following an east–west trend. This pattern reflects variations in tectonic evolution and stress regimes across the region.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7125

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