The Neoproterozoic Earth witnessed major global glaciation events with significant impact on paleoclimate and life evolution. The Tarim Craton in China preserves the records of four glaciation events during the Neoproterozoic which were correlated with the global glaciations, the nature and impact of these with respect to Neoproterozoic paleoclimatic - paleogeographic reconstructions remain unresolved. Here we report the - discovery of a suite of source rocks from northeastern Tarim in which the strata formed during 655 635 Ma, corresponding to the interglacial period between the Sturtian and Marinoan diamictites. These source rocks are dominated by black shales and mudstones of up to 300 mthickness, and are characterized by high content of R organic matter with TOC (total organic carbon) of 0.46% - 3.5% (average 1.64%), vitrinite reflectance of o 13 1.28% -1.60%, and kerogen carbon isotope δ C value between -28.58‰ and -31.89‰. Biomarker compounds indicate that the organic matter in these saprolite source rocks are made up of microorganisms such as algae and bacteria. The Pr and Ph values indicate a weak reducing - oxidizing environment, and most values of CIA (Chemical Index of Alteration) are >68, suggesting an interglacial temperate paleoclimate. The La/Th - Hf and Co/Th - La/Sc relationship suggests that the provenance of these rocks is mainly mixed felsic/mafic rocks. In the 2 Tarim basin, these source rocks comprise an area of up to 90,000 km within Cryogenian rifts as inferred from seismic reflection profiles. Based on zircon U-Pb ages of volcanic rocks underlying the shale units, it is inferred the source rock formed during the temperate Sturtian glaciation events with subsequent extensive biotic recovery and high productivity.

Zhu, J.-C., Zou, C.-N., Feng, Y.-L., Jiang, S., Wu, W.-A., Zhu, R.-x., Yuan, M., 2020. Distribution and controls of petroliferous plays in subtle traps within a Paleogene lacustrine sequence stratigraphic framework, Dongying Depression, Bohai Bay Basin, Eastern China. Petroleum Science 17, 1-22.

https://doi.org/10.1007/s12182-019-00387-z The characteristics of petroliferous plays in subtle traps within a sequence stratigraphic framework in the Dongying Depression are investigated in this study. Sand bodies within lowstand systems tracts (LSTs) of sequences, comprising incised-channel fills, sublacustrine fans, deltas in LSTs, controlled by syndepositional normal faults, and sand bodies within transgressive systems tracts (TSTs) to early highstand systems tracts (HSTs), consisting of beach bars, and turbidites, controlled by the prodelta slope, paleorelief, and syndepositional normal faults, are good subtle reservoirs. Mudstones and shale of deep lake subfacies in TSTs to early HSTs of sequences are source and cap rocks. Abnormal overpressure is the dominant dynamic factor for hydrocarbon migration from source rock to the subtle traps. Normal faults, sand bodies, and unconformities function as conduit systems. Sand bodies distributed in the abnormal overpressure source rocks within LSTs to early HSTs are petroliferous plays in lithologic traps. The petroliferous plays in stratigraphic traps are controlled by unconformities at margins of the Depression.

Zhu, L., Zhang, C., Zhang, C., Zhang, Z., Zhou, X., Liu, W., Zhu, B., 2020. A new and reliable dual model- and data-driven TOC prediction concept: ATOC logging evaluation method using multiple overlapping methods integrated with semi-supervised deep learning. Journal of Petroleum Science and Engineering 188, 106944.

http://www.sciencedirect.com/science/article/pii/S0920410520300425 The total organic carbon content (TOC) is the most important parameter when determining the source rock quality. At present, there are two main types of TOC well logging calculation methods: model-driven and data- driven methods. However, research on the these two types of methods has slowed over the past ten years, and the ongoing research is very limited; thus, it is difficult to improve the TOC calculation accuracy. This paper analyses the advantages and disadvantages of current methods and proposes a new model- and data-driven TOC prediction concept to improve the TOC prediction accuracy. The proposed concept takes the curve obtained with the overlap method as an input instead of using a conventional log curve; we believe that deep learning is best suited to accomplish this task. We propose a new integrated semi-supervised deep learning network - the integrated deep semi-supervised ladder network (IDLN) algorithm - for small-sample well logging interpretation problems based on the proposed approach. A two-step method consisting of intelligent curve overlapping and automatic TOC prediction is employed to better interpret logging data and core data; this method can predict the TOC without manually overlapping curves. Testing the data from 12 wells in 3 blocks revealed that the proposed concept and IDLN algorithm greatly improve the TOC prediction accuracy, and the