Controls on Morphology of Upper Cambrian Elongate Stromatolites
Earth and Biological Sciences, Loma Linda University, Highland, CA, USA
Upper Cambrian elongate stromatolites exhibit consistent long-axis orientation over an extensive area of at least 20 square kilometers. My objective will be to construct a depositional model that accounts for this unique elongate morphology. In order to achieve this, I will:
- Limit the lateral extent of the elongate bed by applying general mapping techniques.
- Determine overall morphology at the macro, meso and micro scale. At the macro scale, stromatolite dimensions as well as interspatial zones will be measured. In order to ascertain meso scale fabrics, rock samples will be cut, polished, etched and stained in the lab. At the micro scale, thin section data will provide crucial information on stomatolite fabrics, grain types, grain size, depositional texture, packing and porosity. SEM will be used to capture high resolution, high magnification images of stromatolite/interspatial fabrics in the hope of finding fossil bacteria. SEM and XRD techniques will be utilized to ascertain mineral composition.
- Conduct a detailed facies analysis of the stromatolite bearing unit.
Since a tidal model is proposed for the elongate morphology, a concomitant tidal facies should be an expected result. Other expected results should include the correlation of stromatolite long-axis orientation with paleo-current indicators, and the presence of microbial fossils in association with fossil stromatolites.
This research will shed light on the problem of fossil microbialite biogenicity, assist in the paleoenvironmental reconstruction of Western Laurentia and contribute valuable data to the oil and gas industry.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects