MICROBIALLY INDUCED SEDIMENTARY STRUCTURES AS SEQUENCE STRATIGRAPHIC TOOLS IN SILICICLASTIC DEPOSITS

‘Microbially induced sedimentary structures – MISS' are formed in siliciclastic, shallow-marine environments by the mechanical interaction of microbial mats with erosion and deposition (Noffke et al. 2003a). The benthic microbiota respond to the sedimentary dynamics for example by biostabilization, or baffling, trapping and binding. Because of their unique biotic-physical modes of formations, the structures have been categorized as own group in the classification of primary sedimentary structures sensu Pettijohn and Potter 1964 (Noffke et al. 2003a). Prominent examples for MISS are ‘wrinkle structures', ‘erosional remnants and pockets', or ‘multidirected ripple marks' (Hagadorn et al. 1999; Noffke et al. 2003a).

MISS have been detected in siliciclastic deposits of the Paleo-Archean age to the Pleistocene, where they record extensive ancient microbial mats covering large areas of the sea floor (Noffke et al. 2003b). This study presents facies and sequence analyses conducted on data sets from sandstone successions of the Paleo- and Meso-Archean of South Africa, the Neo-Proterozoic of Namibia, and the Ordovician of the Montagne Noire, France. The analyses show that the occurrences of MISS correlate with the turning points between regressions and transgressions. Especially for the investigation of very homogeneous lithologies, the MISS are helpful tools for the identification of sequence stratigraphic patterns.

The study is funded by the National Science Foundation, Geology and Paleontology Program, EAR-0345149.

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