气候变化领域集成服务门户(CCPortal): Polybessurus-like fossils as key contributors to Permian–Triassic boundary microbialites in South China

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DOI	10.1016/j.palaeo.2020.109770
	Polybessurus-like fossils as key contributors to Permian–Triassic boundary microbialites in South China
	Zhang X.-Y.; Zheng Q.-F.; Li Y.; Yang H.-Q.; Zhang H.; Wang W.-Q.; Shen S.-Z.
发表日期	2020
ISSN	0031-0182
卷号	552
英文摘要	Massive occurrences of microbialites near the Permian–Triassic boundary have been interpreted as being due to benthic microbial proliferation in unusual marine conditions after the end-Permian mass extinction. Here, we present large populations of Polybessurus-like microfossils in the microbialites of the South China Craton to reveal their morphological structures, growth patterns, and ecological implications. These distinctive microfossils are composed of layered stalks and spherical endpoints. The spheroids, 20–40 μm in diameter, comprising external thin micritic walls and internal sparry parts, are interpreted as coccoid cyanobacteria. The stalks consist of multiple “stacked-cup” micritic envelopes consisting of micron-sized magnesian calcite/dolomite grains and are catalogued as calcified remains of coccoid cyanobacterial extracellular polymeric substances (EPS). Early microbially mediated calcification of EPS increased the preservation potential of microfossils. The microfossils stand upright as coccoid unicells supported by the highly unidirectional secretion of EPS, revealing their benthic behaviours. The successively secreted EPS lift the cells away from the substrate, expanding their ecological niches to gain more sunlight for photosynthesis in the barren marine floor. The distinctive Polybessurus-like microfossils can be viewed both in laminae of stromatolites and in spotted/digitate clots of thrombolites, suggesting their critical roles in microbe-dominated reefs in the aftermath of the end-Permian mass extinction. The morphological features and growth patterns of the Polybessurus-like fossils resemble their Proterozoic counterpart—Polybessurus bipartitus Fairchild ex Green et al. (1987). The widespread Polybessurus-like fossils in the Permian–Triassic boundary microbialites of the South China Craton suggest pervasive retrogressive ecosystems on carbonate platforms after the largest extinction event during the Earth's history. © 2020 Elsevier B.V.
英文关键词	Calcified EPS; Coccoid cyanobacteria; End-Permian extinction; Microbialite; South China Craton
语种	英语
scopus关键词	carbonate platform; cyanobacterium; fossil record; marine environment; mass extinction; microbialite; microfacies; microfossil; morphology; Permian-Triassic boundary; Proterozoic; China; Coccoidea; Cyanobacteria
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150471
作者单位	CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xin'gang Road, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 511400, China; State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
推荐引用方式 GB/T 7714	Zhang X.-Y.,Zheng Q.-F.,Li Y.,等. Polybessurus-like fossils as key contributors to Permian–Triassic boundary microbialites in South China[J],2020,552.
APA	Zhang X.-Y..,Zheng Q.-F..,Li Y..,Yang H.-Q..,Zhang H..,...&Shen S.-Z..(2020).Polybessurus-like fossils as key contributors to Permian–Triassic boundary microbialites in South China.Palaeogeography, Palaeoclimatology, Palaeoecology,552.
MLA	Zhang X.-Y.,et al."Polybessurus-like fossils as key contributors to Permian–Triassic boundary microbialites in South China".Palaeogeography, Palaeoclimatology, Palaeoecology 552(2020).