REU: SeaMARC II and Seismic Reflection Study of the Southeast Bahamas-Hispaniola Collision Zone

增生的浅水碳酸盐岩地体是许多古山带的共同特征，但大多数这些地体的构造历史仍然知之甚少。在许多情况下，这是因为与初始增生有关的早期变形构造已被增生后的构造和变质事件覆盖和湮没。为了充分认识这些浅水碳酸盐岩地体的形成机制，必须研究包括浅水碳酸盐岩滩在内的活动碰撞带。将使用巴哈马东南部和伊斯帕尼奥拉岛之间的活跃碰撞的详细测绘和地震反射研究。在这里，巴哈马群岛的小而孤立的海岸与伊斯帕尼奥拉岛的北缘发生了斜碰撞，成为北美-加勒比板块边界的一部分。巴哈马东南部的碰撞环境与巴哈马西北部的构造静止、被动边缘环境形成鲜明对比，为比较和对比不同构造制度下浅水碳酸盐岩滩的发展提供了无与伦比的机会。建议使用SeaMARC II海底测绘系统，结合数字记录的单通道地震反射剖面，为我们提出的研究提供了一个理想的系统，该系统将专注于记录碰撞区内的浅层结构和表层沉积特征。山带中的碳酸盐矿床通常与构造时期冲至大陆的浅海沉积有关。该项目将研究伊斯帕尼奥拉岛边缘的碳酸盐岩沉积物，作为构造活跃地区碳酸盐岩地形类型的现代模拟物。沉积学和构造环境将使用取心、地震地层学和侧面扫描声纳成像（SeaMarc II）相结合的方法进行检查。结果可用于解释在许多发现碳酸盐沉积物的积层地形中的碳酸盐沉积物。

Accreted shallow-water carbonate terranes are a common feature of many ancient mountain belts, yet the tectonic history of the majority these terranes remains poorly understood. In many cases, this is because early deformational structures associated with initial accretion have been overprinted and obliterated by post-accretion structural and metamorphic events. In order to fully understand the mechanism(s) of these shallow- water carbonate terranes, an active collision zone involving a shallow-water carbonate bank must be studied. A detailed swath mapping and seismic reflection study of the active collision between the southeastern Bahamas and the island of Hispaniola will be used. Here, the small, isolated banks of the Bahamas are colliding obliquely with the northern margin of Hispaniola, as part of the broad, transpressional North American-Caribbean Plate boundary. The collisional setting of the southeast Bahamas contrasts markedly with the tectonically quiescent, passive-margin setting of the northwest Bahamas, providing an unparalleled opportunity to compare and contrast the development of shallow-water carbonate banks in widely differing tectonic regimes. proposed use of the SeaMARC II seafloor mapping system, in conjunction with digitally recorded single-channel seismic reflection profiles, provides a system that is ideally suited for our proposed studies, which will focus on documenting shallow structures and surficial sedimentary features within the collision zone. %%% Carbonate deposits in mountain belts are commonly associated with shallow marine sediments that have been thrust onto the continent during tectonic episodes. This project will study carbonate sediments on the Hispaniola margin as a modern analog of the type of carbonate terrains that are found in tectonically active regions. The sedimentology and structural setting will be examined using a combination of coring, seismic stratigraphy, and side-scan sonar imaging (SeaMarc II). Results may be used to interpret carbonate sediments in the many accreted terrains where such deposits are found.