Selected Publications

Abstract:   Microbially induced sedimentary structures, including
spectacular siliciclastic domal stromatolites, up to 80 cm wide and 30
cm high, have been found in coastal quartzites of the Lower Devonian
Muth Formation (Pin Valley, NW Himalayas). The microbial structures
occur in intervals of the formation associated with physical sedimentary
structures that indicate, at least temporally, emergent conditions.
These observations support the interpretation of a peritidal
setting for the microbial structures within the wave-dominated, barrier-
island depositional environment of the Muth Formation. The siliciclastic
domal stromatolites probably formed in a shallow subtidal to
intertidal environment with high hydraulic energy, where periods of
high sedimentation rates are interrupted by periods of low or zero
sedimentation. Microbial gas pits and microbial gas domes were produced
by ascending gas from degrading buried organic material in a
lower supratidal zone, influenced by tidal flushing. Multidirected ripple
marks document a series of erosion events interfering with microbial
stabilization in lower supratidal settings. Polygonal shrinkage cracks
from supratidal environments indicate a semiarid paleoclimate. The
replacement textures of the microquartz matrix in the stromatolites
indicates the former existence of syngenetic carbonate cements, which
may explain the preservation of the domal stromatolites in the highenergy,
siliciclastic environments of the Muth Formation. The Muth
stromatolites, commonly containing more than 60 vol. % siliciclastic
grains, prove the existence of microbial activity in environments of
higher sedimentary stress than generally thought and extend our
knowledge of the capability of benthic microbial organisms to settle in
siliciclastic shallow marine environments.

Keywords:   Noffke, microbial mat; M.I.S.S.; MISS; wrinkle structures. physical-microbial interaction

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