Cloudinids have long been considered the earliest biomineralizing metazoans, but their affinities have remained contentious and undetermined. Based on well-preserved ultrastructures of two taxa, we here propose new interpretations regarding both their extent of original biomineralization and their phylogenetic affinity. One of Zuunia chimidtsereni these taxa is a new cloudinid from Mongolia, gen. et sp. nov., which exhibits key characteristics of submicrometric kerogenous lamellae, plastic tube-wall deformation, and tube-wall Cloudina delamination. Multiple carbonaceous lamellae are also discovered in from Namibia and Paraguay, which we interpret to have originated from chitinous or collagenous fabrics. We deduce that these cloudinids were predominantly originally organic (chitinous or collagenous), and postmortem decay and taphonomic mineralization resulted in the formation of aragonite and/or calcite. Further, based on our ultrastructural characterization and other morphological similarities, we suggest that the cloudinids should most parsimoniously be assigned to annelids with originally organic tubes.

Yang, F., Zhou, X., Peng, Y., Song, B., Kou, X., 2020. Evolution of Neoproterozoic basins within the Yangtze Craton and its significance for oil and gas exploration in South China: An overview. Precambrian Research 337, 105563.

http://www.sciencedirect.com/science/article/pii/S0301926819302190 Based on a comprehensive review of published results, the plate tectonic setting of the Neoproterozoic basins in the Yangtze Craton can be summarized as evolving from the Qingbaikou convergent continental margin to the Nanhua-Sinian divergent continental margin. Four phases of basin evolution are identified in the Neoproterozoic Yangtze Craton based on the prototype basin classification scheme: a) the early Qingbaikou period (ca. 1000 - 820 Ma), with back-arc spreading basins on the western and northern Yangtze margins and the interior, and a retro-arc foreland basin on the southeastern Yangtze margin; b) the late Qingbaikou period (ca. 820 - 720 Ma), with back-arc spreading basins on the western and northern Yangtze margins and extensional down-faulted basins on the southeastern Yangtze margin and the interior of the carton; c) the Nanhua period (ca. 720 - 635 Ma), with rift basins on the southeastern, western, and northern Yangtze margins and the interior; and d) the Sinian period (ca. 635 - 541 Ma), with intracratonic rift basins in the interior of Yangtze Craton and divergent marginal subsidence basins on the southeastern and northern Yangtze margins. The temporal sequence and spatial distribution of the major prototype basins associated with the four stages of basin evolution in the Yangtze Craton were further identified. By comparing the petroleum exploration practices in China and abroad, this paper concludes that the Nanhua rift basins on the southeastern and northern Yangtze margins, the Sinian divergent marginal subsidence basins on the southeastern and northern Yangtze margins and the intracratonic rift basins in the interior Yangtze Craton were most conducive to source rock formation and are target regions for future oil and gas exploration.

Yang, H., Zhao, S., Liu, Y., Wu, W., Xia, Z., Wu, T., Luo, C., Fan, T., Yu, L., 2019. Main controlling factors of enrichment and high-yield of deep shale gas in the Luzhou Block, southern Sichuan Basin. Natural Gas Industry 39, 55-63.

http://oversea.cnki.net/kcms/detail/detail.aspx?dbCode=cjfd&QueryID=14&CurRec=13&filename=TRQG2019 11013&dbname=CJFDLAST2019 In Chinese. The key to the scale development of deep shale gas lies in a better understanding of the main controlling factors for its enrichment and high-yield. In this regard, the high-quality shale of the Upper Ordovician Wufeng - Longmaxi Formations in the Luzhou Block, southern Sichuan Basin, was taken as the research object. Based on drilling, logging, seismic and analytical test data of a typical core well there, an in- depth study was conducted on the tectonic, sedimentary, and reservoir characteristics and compressibility of shale in this study area. On this basis, combined with production performance, the main controlling factors of a （ ） high-yield shale gas well were discussed. The following findings were achieved. 1 There are two sets of type-I reservoirs with high gas saturation, high total gas content and high brittle mineral content vertically. One （ 1 - 3 4 is S l sub-layers with a thickness of 10 - 20 m, the other is S l sub-layer with a thickness of 3 - 10 m. 2 1 11 1 11 ） The thicker the type-I reservoir, the longer the targeted horizontal sections, and the higher initial production rate of a horizontal shale gas well. Under the same scenario, the trial test production rate of a shale gas well in