Shallow Stratigraphy, Structure, and Modern Depositional Processes along Margins of Small Detached Carbonate Platforms in an Active Tectonic Setting

尼加拉瓜隆起是一个主要的构造/构造特征，由分离的碳酸盐岩台地组成，分隔了加勒比海的西南和西北盆地。在1987年3 - 4月和1988年5月的研究巡航期间，收集了大量数据集，包括单通道地震反射剖面数据、海底样本、水肺潜水员观测、遥控车辆和海底照相机颜料数据。在头两年的研究中，海因和哈洛克-穆勒发现了台地深度（平均岸顶深度从东向西增加）、沉积相（从绿藻到绿藻沉积类型的梯度）、底栖生物群落（藻类-海绵优势向西增加）和生物色素浓度（从东向西增加一倍）的相应东西梯度。这些梯度的记录对于了解地质记录中的碳酸盐台地淹没具有重要意义。此外，它们的地震反射数据还为研究海道的充填、碳酸盐斜坡的侵蚀/沉积以及构造对碳酸盐滩发育的影响提供了新的见解。他们还在加勒比海发现了第一批被描述的哈利梅达生物。大约三分之二的数据仍有待分析。这笔续期拨款将使该项目能够完成对一个重要但鲜为人知的现代碳酸盐台地系统的沉积控制过程的研究。

The Nicaraguan Rise is a major structural/tectonic feature, consisting of detached carbonate platforms, that separates the southwestern and northwestern basins of the Caribbean Sea. During research cruises in March-April 1987 and May 1988, a large data set was collected that includes single-channel seismic reflection profiling data, bottom samples, SCUBA diver observations, remote operated vehicle and bottom camera pigment data. In their first two years of research, Hine and Hallock- Muller have discovered corresponding east-west gradients in platform depth (average bank top depth increases east to west), sediment facies (gradients from chlorozoan to chloralgal sediment types), benthic communities (algal-sponge dominance increases to the west), and biotic pigment concentrations (doubling east to west). Documentation of these gradients has important implications for understanding carbonate platform drownings in the geologic record. In addition, their seismic reflection data have provided new insights concerning the infilling of seaways, erosion/deposition on carbonate slopes, and tectonic influences on carbonate bank development. They have also discovered the first Halimeda bioherms to be described from the Caribbean. About two thirds of the data remain to be analyzed. This renewal grant will enable completion of this project examining processes controlling deposition on an important, but poorly known system of modern carbonate platforms.