Hydrocarbon generation driven by thermal pulses, Tarim Basin, Central Asia

Deciphering the thermal footprint of large igneous provinces (LIPs) within sedimentary basins is critical for understanding fluid evolution and deep carbon cycling, yet capturing transient thermal pulses remains methodologically challenging. In the northwestern Tarim Basin, Central Asia, Lower Cambrian strata produce high-temperature thermogenic dry gas, presenting a paradox: Conventional models suggest a peak burial temperature of only ∼130 °C, insufficient to explain the observed maturity. We reconstructed a high-resolution thermal history by integrating U-Pb geochronology, zircon (U-Th)/He thermochronology, and clumped isotope analysis of stage-constrained carbonates. Modeling reveals a previously unrecognized Early Permian thermal anomaly reaching ∼200 °C. Fluid inclusion analyses identify two hydrocarbon generation episodes: a Devonian oil peak (ca. 398−350 Ma) and an Early Permian gas peak (ca. 287−285 Ma). In situ U-Pb dating of calcite veins hosting primary methane inclusions yields 287 ± 8 Ma, coincident with the Tarim LIP eruption. Coeval aqueous inclusions record homogenization temperatures of 178.4−206.9 °C, corroborating the thermal model. We propose that mantle plume−induced heating drove rapid in situ pyrolysis of paleo-oil. These findings challenge conventional burial-driven paradigms, demonstrating that transient magmatic pulses can act as a primary driver for episodic hydrocarbon generation in global cratonic basins. Furthermore, this mechanism triggers massive sedimentary carbon release, potentially influencing Early Permian climate dynamics.