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Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/744

Title: Earliest Triassic microbialites in the South China Block and other areas; controls on their growth and distribution
Authors: Kershaw, S
Li, Y
Crasquin-Soleau, S
Feng, Q
Mu, X
Collin, PY
Reynolds, A
Guo, L
Keywords: Microbialite
Dendrolite
Thrombolite
Permian–Triassic boundary
Anoxia
Mass extinction
Publication Date: 2007
Publisher: Springer Berlin
Citation: Facies 53(2007): 409
Abstract: Earliest Triassic microbialites (ETMs) and inorganic carbonate crystal fans formed after the end-Permian mass extinction (ca. 251.4 Ma) within the basal Triassic Hindeodus parvus conodont zone. ETMs are distinguished from rarer, and more regional, subsequent Triassic microbialites. Large differences in ETMs between northern and southern areas of the South China block suggest geographic provinces, and ETMs are most abundant throughout the equatorial Tethys Ocean with further geographic variation. ETMs occur in shallow-marine shelves in a superanoxic stratified ocean and form the only widespread Phanerozoic microbialites with structures similar to those of the Cambro-Ordovician, and briefly after the latest Ordovician, Late Silurian and Late Devonian extinctions. ETMs disappeared long before the mid-Triassic biotic recovery, but it is not clear why, if they are interpreted as disaster taxa. In general, ETM occurrence suggests that microbially mediated calcification occurred where upwelled carbonate-rich anoxic waters mixed with warm aerated surface waters, forming regional dysoxia, so that extreme carbonate supersaturation and dysoxic conditions were both required for their growth. Long-term oceanic and atmospheric changes may have contributed to a trigger for ETM formation. In equatorial western Pangea, the earliest microbialites are late Early Triassic, but it is possible that ETMs could exist in western Pangea, if well-preserved earliest Triassic facies are discovered in future work.
URI: http://bura.brunel.ac.uk/handle/2438/744
DOI: http://dx.doi.org/10.1007/s10347-007-0105-5
ISSN: 0172-9179
Appears in Collections:The Experimental Techniques Centre

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