Landscape-Scale Morphology and Dynamics of Some Bahamian Ooid Shoals

一些巴哈马乌伊德浅滩的景观尺度形态和动力学

• 批准号: 0418815
• 负责人: Eugene Rankey
• 金额: $ 27.16万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0418815&HistoricalAwards=false
• 关键词: Landscape; Scale; Morphology; Dynamics; Some

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.

沿海地貌-沉积系统代表了沉积物对在一系列时空尺度上运作的强迫机制的动态响应。 表征这些系统对于现代沿海系统的有意义的预测和古代类似物的准确地层解释非常重要。 在碳酸盐沉积系统中，指示不同相的一般沉积学标准以及控制碳酸盐台地上这些相区域分布的一般因素都有详细记录。 目前尚不清楚的是各个相带和体内的景观尺度地貌和沉积学模式的细节、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，这种中间尺度代表了一个基本的缺失环节。碳酸盐沉积物记录与碳酸盐地层学研究之间的关系。 为了开始填补这一基本认识空白，本研究建议定量研究一些巴哈马鲕滩（一种碳酸盐沉积环境）内的景观规模模式和过程。 除了这些系统和形成它们的鲕系本质上很有趣之外，本研究选择的地点还：a）具有形成重要水和碳氢化合物储层的古代类似物； b) 包括普遍存在的叶状形式、与某些硅质碎屑环境大致相似的几何形状，允许明确的比较； c) 包括开陆架和潮汐三角洲环境中的波瓣，以允许评估不同条件下过程响应动态的普遍性。 我们概述了数据收集和实验，以测试与现代碳酸盐鲕滩和三角洲相关的几个相关假设，包括：1）在景观尺度上，浅滩的地貌与流体流动的空间模式密切相关； 2) 在此水文地貌框架内，粒度、排序和类型系统地、可预测地变化； 3）在潮汐三角洲和更开放的陆架潮汐主导条件下，波瓣是许多潮汐主导碳酸盐岩砂体中动态稳定的地貌配置。 为了解决这些假设，本研究将在 GIS 中集成遥感、测深、粒度和排序、颗粒类型和流体流动数据。 在提供这些景观规模模式的定量特征和过程链接时，这些数据将代表碳酸盐系统中的一些首次此类分析。 在探索鲕粒潮汐系统内的模式和过程时，本研究将提供浅滩形态动力学演化的一阶预测趋势（创建地质体）以及浅滩内地貌框架和颗粒（大小、排序）之间的定量联系（地质体内的颗粒）。 更广泛的影响。 新的遥感、测深和流体流动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代表了研究景观尺度沉积地貌系统的一种新方法。 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入理解。 除了培养博士学位。学生，该项目包括对服务不足的高中少数族裔学生进行科学教育，增强对巴哈马当地社区技术和环境的了解，以及为迈阿密大学学生提供新的学习工具和体验。