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The boundary between the Triassic and Jurassic periods is a key moment in Earth history, which is distinguished by one of the five biggest mass extinctions, Pangea progressively breaking apart with the opening of the central Atlantic Ocean, eruption of Central Atlantic Magma Province, and a dramatic increase in the CO2 concentration. However, the major occurrence of terrestrial sediments in China has been difficult to bio-stratigraphically correlate with the Global Stratotype Section and Point (GSSP) defined in marine strata from the Triassic-Jurassic boundary (TJB). Two new <5I3C wood stratigraphic curves in the Kuqa River section were generated from two independent samplings, focusing on the materials within the charcoal and coalified fossil wood and representing the synchronous evolution of <5I3C in atmospheric CO2. The consistency of the two results proves the repeatability of this study, verifying the method of carbon-isotope stratigraphic sampling. The terrestrial Kuqa River section in the Tarim Basin is well correlated with the TJB of GSSP in Austria and other typical global sections, as constrained by the biostratigraphy of sporo-pollen assemblages and mega-plant fossils. The end-Triassic mass extinction (ETE) beginning horizon and synchronous TJB of GSSP are located near the bottom of Beds 38 and 41, respectively. The obvious negative carbon isotope excursion took place at the of the ETE beginning horizon and TJB. The significant fluctuations of carbon-isotope records in both marine and terrestrial strata across the ETE and TJB have been discovered globally, suggesting a global perturbation of carbon reservoirs within Earth surface cycles during this period. [ABSTRACT FROM AUTHOR]

Despite the upsurge in hydrocarbon exploration in the Lake Albert Rift Basin (LARB) over the past three decades, systematic characterization of hydrocarbon compositions remains lacking, leading to uncertainties in source rock and oil generation determination. We characterized crude oil compositions and oil sand samples in the northern and southern subbasins of LARB. The relative abundance of normal and branched linear alkanes, hopanes, steranes, and aromatic hydrocarbon suggest that northern and southern hydrocarbons were deposited in anoxic to suboxic lacustrine environments and share similar biological source compositions (i.e., a mixture of plants and aquatic algae and bacteria). Relative to southern samples, northern samples show more negative δ13C values for oils, saturates and aromatics, indicating longer migration paths, and exhibit higher MPI‐1, DNR‐1 and 4‐/1‐MDBT ratios, indicating higher maturity. Between the two possible sets of source rocks (upper Miocene and Jurassic strata), the positive δ13C values of saturated hydrocarbons (average = –20.5‰) suggest that the upper Miocene lacustrine shale is the most likely candidate. Oleanane index (<5% in our samples) does not exclude either source rock possibility, and C28/C29 regular sterane (average = 0.63) may be biased by high terrestrial inputs in a lacustrine setting. Together, our data show that northern and southern oils originate from the same source rocks but different oil kitchens. Given the similar geochemical characteristics of southern and northern oils, previous exploration successes in the northern subbasin likely suggest similar potential in the southern sector, while other elements influencing exploration success must be also evaluated. [ABSTRACT FROM AUTHOR]