The Neoproterozoic–Cambrian is an important period of Earth’s biological evolution and environmental change, highlighted by remarkable major geological events, such as the Neoproterozoic Snowball Earth, the deposition of cap carbonate, the extreme negative carbon isotope excursion, and the Cambrian explosion. The study of the tectonic-sedimentary responses to major geological events is of great scientific significance for identifying the development mechanism of ultradeep source rocks and revealing the potential of oil and gas resources at depths greater than 10,000 m. During this period, three sets of globally distributed organic-rich black shales were deposited (i.e., Cryogenian, Ediacaran, and lower Cambrian), which were important source rocks. With the discovery of high-quality source rocks formed during the Nanhua (Cryogenian) interglacial period, we revealed the mechanisms of biological recovery and organic matter accumulation under the warming conditions during the interglacial period by nitrogen isotopes. This research also demonstrated the control of highly stratified redox conditions of the Ediacaran on the formation of high-quality source rocks. Metal isotopes have unveiled the presence of early Cambrian transgression events and oceanic redox conditions dominated by continuous ferruginous and intermittent sulfidic conditions and their impacts on the high-quality lower Cambrian source rocks. This research has reconstructed paleogeographic patterns of cratonic basins in China from the Neoproterozoic to the Cambrian. It is found that the paleogeographic pattern of the Tarim Basin from the Neoproterozoic to the Cambrian has a good preservation. This was used to delineate the distribution patterns of the Cryogenian, Ediacaran, and Cambrian source rocks and to calculate gas generation intensity and generated hydrocarbons during key geological periods. The total generated gas in the South China and Tarim cratonic basins is 6551 × 1012 and 2332 × 1012 m3, respectively, laying the foundation for ultradeep oil and gas exploration at depths more than 10,000 m and prediction of gas fields with reserves in the range of trillions of cubic meters.

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