气候变化领域集成服务门户(CCPortal): Small microbialites from the basal Triassic mudstone (Tieshikou; Jiangxi; South China): Geobiologic features; biogenicity; and paleoenvironmental implications

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DOI	10.1016/j.palaeo.2018.06.030
	Small microbialites from the basal Triassic mudstone (Tieshikou; Jiangxi; South China): Geobiologic features; biogenicity; and paleoenvironmental implications
	Yang H.; Chen Z.-Q.; Kershaw S.; Liao W.; Lü E.; Huang Y.
发表日期	2019
ISSN	0031-0182
起始页码	221
结束页码	235
卷号	519
英文摘要	We report small microbialites from the calcareous mudstone slightly above the Permian–Triassic boundary (PTB) in the Tieshikou section, southern Jiangxi Province, South China. The newly found microbialite is a bowl-like structure, which contrasts with the surrounding calcareous mudstone. The small microbialite is composed of columnar forms and fan-shaped structures. Mini-columnar structures resemble mini stromatolites. In plane view, most branches are patchy or strip-shaped, with clotted structures, resembling that of a thrombolite. Fan-shaped cement precipitates are comprised of multiple crystal fans that have a radiating texture and that show distinct growth laminae. The radiating fabrics are represented by rod-shaped filaments under SEM, which are interpreted as calcified trichomes/filaments. Prominent micropores occur within the rods, and they may be the plane views of multiple sheaths of the false branching zone of trichomes. Thus, both the columnar forms and radiating fans are probably microbial in origin. Moreover, three types of nano-sized structures: intraparticle micropores, fibrous biofilms, and filamentous sheaths are also pronounced in both the columnar structures and cement fans of the Tieshikou microbialite, all suggestive of biogenicity. These well-preserved fibrous biofilms probably represent calcified extracellular polymeric substances (EPS), and linear sheaths are interpreted as the traces of bacterial activities during the precipitation of dolomite crystals. The Tieshikou microbialite therefore shares similar biogenetic mechanisms with other PTB microbialites. The combination of the absence of pyrite framboids, slightly negative carbon isotope values, and an association with abundant ammonoids, bivalves, and gastropods indicates oxic conditions during the growth of the Tieshikou microbialite. Moreover, the nodular preservational state resembles widely distributed nodular mudstones or muddy limestones of the Lower Triassic successions worldwide. This implies that nodular mudstone or argillaceous limestones may also have been deposited in microbe-rich environments, in which terrigenous supply was abundant. © 2018 Elsevier B.V.
英文关键词	Clotted structure; Early Triassic; Limestone nodule; Mass extinction; Microbial bloom
语种	英语
scopus关键词	exopolymer; growth; invertebrate; limestone; mass extinction; microbialite; mudstone; paleoenvironment; precipitation (chemistry); stromatolite; Triassic; China; Ammonoidea; Bacteria (microorganisms); Bivalvia; Gastropoda
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/151042
作者单位	State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; Department of Life Sciences, Brunel University, Kingston Lane, Uxbridge, UB8 3PH, United Kingdom
推荐引用方式 GB/T 7714	Yang H.,Chen Z.-Q.,Kershaw S.,et al. Small microbialites from the basal Triassic mudstone (Tieshikou; Jiangxi; South China): Geobiologic features; biogenicity; and paleoenvironmental implications[J],2019,519.
APA	Yang H.,Chen Z.-Q.,Kershaw S.,Liao W.,Lü E.,&Huang Y..(2019).Small microbialites from the basal Triassic mudstone (Tieshikou; Jiangxi; South China): Geobiologic features; biogenicity; and paleoenvironmental implications.Palaeogeography, Palaeoclimatology, Palaeoecology,519.
MLA	Yang H.,et al."Small microbialites from the basal Triassic mudstone (Tieshikou; Jiangxi; South China): Geobiologic features; biogenicity; and paleoenvironmental implications".Palaeogeography, Palaeoclimatology, Palaeoecology 519(2019).