Thermal History Reconstruction of the Yaziluo Aulacogen, Paleo-Tethyan Complex Tectonic Domain: Coupled Constraints from Multitype Thermal Indicators

The Yaziluo Aulacogen, developed on the northern margin of the Paleo-Tethys Ocean, has become a strategic breakthrough area for shale gas exploration in southern China's complex tectonic regions due to the discovery of Carboniferous industrial gas flow. However, prior to this study, the region had been poorly studied, with limited thermal indicator data, well-developed carbonate strata, and was affected by the superimposed effects of multi-phase tectonic movements. A single type of thermal indicator could not accurately reconstruct its thermal history, leading to uncertainties in hydrocarbon source rock maturity evolution and hydrocarbon generation phases, thus hindering the evaluation of shale gas potential. To address the challenge of accurately reconstructing thermal history in complex tectonic regions, this study focused on the Yaziluo Aulacogen, which preserves abundant stratigraphic records. We reconstructed the thermal history of the aulacogen since the Late Paleozoic using a multi-method coupling approach, including the combination of carbonate clumped isotope with U-Pb dating, low-temperature thermochronology, and organic thermal indicators. This work established a thermal history reconstruction technique for complex tectonic regions and quantitatively analyzed the spatio-temporal superimposition effects of multi-phase tectono-thermal events. Furthermore, we identified the controlling factors influencing the maturity evolution of the Lower Carboniferous source rocks and clarified the relationship between regional tectono-thermal evolution and critical hydrocarbon generation periods. The results have provided geothermal constraints for geodynamic studies of passive continental margin rift basins along the northern Paleo-Tethys margin and offered key technical support for hydrocarbon resource assessment in similar complex tectonic regions across the Paleo-Tethyan domain.