ABSTRACT

Coastal geomorphic-depositional systems represent the dynamic response of
sediments to forcing mechanisms that operate across a range of spatio-temporal scales.
Characterizing these systems is important for meaningful prediction in both modern coastal
systems and for accurate stratigraphic interpretation of ancient analogs. In carbonate
depositional systems, general sedimentologic criteria indicative of different facies are well
documented, as are the general factors that control the regional distribution of these facies on
carbonate platforms. What remains unclear are the details of the landscape-scale geomorphic
and sedimentologic patterns within individual facies belts and bodies, the processes that
influence these patterns, and possible feedbacks between process and product. In examining
how sediments build into geomorphologic features which eventually may become the
stratigraphic record, this intermediate scale represents a fundamental .missing link. between
documentation of carbonate sediments and study of carbonate stratigraphy.
To begin to fill this basic gap in understanding, this study proposes quantitatively
examining the landscape-scale patterns and processes within some Bahamian ooid shoals, one
carbonate depositional environment. Beyond the fact that these systems and the ooids forming
them are inherently interesting, the locations chosen for this study also: a) have ancient analogs
that form important water and hydrocarbon reservoirs; b) include ubiquitous lobate forms,
geometries broadly analogous to some siliciclastic environments, allowing explicit comparison;
and c) include lobes in both open-shelf and tidal delta settings, to permit assessing the generality
of process-response dynamics in different conditions.
We outline data collection and experiments to test several linked hypotheses related to
modern carbonate ooid shoals and deltas, including: 1) at the landscape scale, the
geomorphology of shoals is closely linked to spatial patterns of fluid flow; 2) the grain size,
sorting, and type varies systematically and predictably within this hydro-geomorphic framework;
and 3) lobes are a dynamically stable geomorphic configuration in many tide-dominated
carbonate sand bodies in both tidal deltaic and more open shelf tide-dominated conditions.
To address these hypotheses, this research will integrate remote sensing, bathymetric,
grain size and sorting, grain type, and fluid flow data in a GIS,. In providing for quantitative
characterization of these landscape-scale patterns and links to processes, these data will represent
some of the first such analyses in carbonate systems. In exploring patterns and processes within
oolitic tidal systems, this study will provide first-order predictive trends in morphodynamic
evolution of shoals (.creating geobodies.) and quantitative links between geomorphic framework
and grains (size, sorting) within shoals (.grains within geobodies.).

Broader impacts. The application of new remote sensing, bathymetric and fluid flow analytical
tools and quantitative integration of these data in a GIS represents a novel approach to study of
landscape-scale sedimentologic-geomorphic systems. This approach should be broadly
applicable to other environments, and we expect it will lead to a deeper understanding of
geomorphic-depositional systems in general.
In addition to training a Ph.D. student, this project includes educating underserved high
school minority students about science, enhancing understanding of technology and environment
in the local Bahamian community, and providing new learning tools and experiences for
University of Miami students.

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