The origins of natural hydrogen in natural gas systems of sedimentary basins and the capacity of these systems to store hydrogen remain inadequately understood, posing crucial questions for the large-scale exploration of natural hydrogen. This study reports on the natural gas composition, stable carbon and hydrogen isotopic values, and helium isotopic values of gas samples collected from the Qingshen gas deposit within volcanic rocks of the Songliao Basin. Natural hydrogen primarily originates from water radiolysis, water-rock interactions (WRI), and mantle. The Qingshen gas deposit contains 95.23 × 10 ⁹ cubic meters of abiotic CH ₄ , of which 15.24 × 10 ⁹ cubic meters was generated through hydrogen conversion via Fischer-Tropsch synthesis, with the maximum original hydrogen reserves calculated to be approximately 61.9 × 10 ⁹ cubic meters. We estimated that the study area has generated a maximum total of 572 × 10 ⁹ cubic meters of radiolytic hydrogen, 248 × 10 ⁹ cubic meters of WRI hydrogen, and 127 × 10 ⁹ cubic meters of mantle-derived hydrogen.

The Late Triassic Carnian Pluvial Episode (CPE) witnessed enormous climate change closely associated with volcanic activity. However, the coupling relationship between volcanic activity and climate change, which may be linked to chemical weathering, has not yet been fully uncovered. We used lithium contents and isotopes of volcanic ash (VA)–bearing lacustrine shale to constrain their deposition pathways and response to climate changes, i.e., weathering intensity, during the Late Triassic era. Elevated δ ⁷ Li (i.e., >2.5‰) and low Li contents (i.e., 135 microgram per gram), alongside relatively low δ ⁷ Li (i.e., <0‰), likely implying waterborne VA dominated by intensified weathering under a super humidity climate. Hence, this study provides evidence for the differential VA-rich shale deposition model related to chemical weathering states synchronous with climate changes during the CPE period.