Landscape-Scale Morphology and Dynamics of Some Bahamian Ooid Shoals

海岸地貌-沉积系统代表了沉积物对在一系列时空尺度上运行的强迫机制的动态响应。确定这些系统的特征对于在现代沿海系统中有意义的预测和对古代类似物的准确地层解释都是重要的。在碳酸盐沉积体系中，指示不同相的一般沉积学标准被很好地记录下来，控制这些相在碳酸盐台地上的区域分布的一般因素也是如此。尚不清楚的是个别相带和主体内的景观尺度地貌和沉积模式的细节，影响这些模式的过程，以及过程和产品之间可能的反馈。在研究沉积物如何形成最终可能成为地层记录的地貌特征时，这个中间尺度代表了一个基本的、缺失的环节。在碳酸盐沉积记录和碳酸盐地层研究之间。为了开始填补这一认识上的基本空白，这项研究建议定量地研究一些巴哈马奥陶质浅滩--一个碳酸盐沉积环境--内的景观尺度模式和过程。除了这些系统和形成它们的卵母细胞本身就很有趣这一事实之外，本研究选择的地点还包括：a)具有形成重要水和碳氢化合物储集层的古代类似物；b)包括无处不在的分叶形式，其几何形状广泛类似于一些硅质碎屑环境，允许进行明确的比较；以及c)包括开架和潮汐三角洲环境中的分叶，以便能够评估不同条件下过程-反应动力学的一般性。我们概述了数据收集和实验，以检验几个与现代碳酸盐泥滩和三角洲相关的假设，包括：1)在景观尺度上，浅滩地貌与流体流动的空间模式密切相关；2)在这个水文地貌框架内，颗粒大小、分选和类型发生系统和可预测的变化；3)在潮汐三角洲和更开放的陆架潮汐控制条件下，许多潮汐控制的碳酸盐砂体中的叶状物是一种动态稳定的地貌形态。为了解决这些假设，这项研究将在一个地理信息系统中集成遥感、水深测量、颗粒大小和分类、颗粒类型和流体流动数据。在提供这些景观尺度模式的量化特征和与过程的联系方面，这些数据将代表碳酸盐系统中的一些首批此类分析。这项研究将提供滩涂地貌动力演化的一阶预测趋势，以探索蚝粒潮汐体系内的模式和过程。地貌框架与浅滩内颗粒(地体内颗粒)之间的定量联系。更广泛的影响。新的遥感、水深和水流分析工具的应用，以及这些数据在地理信息系统中的定量集成，为研究景观尺度的沉积-地貌系统提供了一种新的途径。这种方法应该广泛适用于其他环境，我们预计它将导致对一般地貌沉积系统的更深层次的理解。除了培训博士生外，该项目还包括对未得到充分服务的少数民族高中学生进行科学教育，增强当地巴哈马社区对技术和环境的了解，并为迈阿密大学的学生提供新的学习工具和体验。

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.