Influences of Biologic Modification on Sedimentology, Porosity, and Permeability of Shallow-Marine Carbonate: Crooked-Acklins Platform, Southern
Geology, University of Kansas, Lawrence, KS, USA
Ichnofossils are indicators of depositional environment, useful for determining the physicochemical conditions at the time of deposition. Although ichnofossil trends are well understood in siliciclastic depositional systems, the nature, distribution and impact of biologic modification in carbonate systems are not well constrained. Carbonate depositional systems are spatially and temporally variable, as grains can be produced in situ, and grain fabrics vary with both biota and hydrodynamic conditions. This study proposes a comparative analysis of ichnologic trends in Pleistocene, Holocene, and modern shallow marine carbonate successions on Crooked-Acklins Platform, southern Bahamas, testing the following hypotheses: 1) ichnofossil associations are similar in Pleistocene, Holocene, and modern carbonate strata from the same environment; and 2) ichnologic trends (e.g., abundance and diversity of ichnogenera, depth and tiering of traces) and ichnofossil associations in carbonate successions are similar in pattern to those of ichnofacies in siliciclastic settings. This study will integrate sedimentological and ichnological data collected from petrography, phi/k analysis, computed tomography scans, and field observations of ancient and modern successions to evaluate the effect of biota on carbonate depositional textures. Collectively, these results will provide a conceptual model that will aid in understanding and predicting the distribution and effects of biologic modification on strata, and porosity and permeability within carbonate systems.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects