SeaMARK II and Seismic Reflection Study of the Southeast Bahamas-Hispaniola Collision Zone

堆积的浅水碳酸盐地体是许多古老山脉的共同特征，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，这是因为与初始吸积有关的早期变形构造已经被吸积后的构造和变质事件所覆盖和抹去。为了全面了解这些浅水碳酸盐岩地体的形成机制(S)，必须研究涉及浅水碳酸盐岩滩的活动碰撞带。将对巴哈马东南部和伊斯帕尼奥拉岛之间的活动碰撞进行详细的带状测绘和地震反射研究。在这里，巴哈马群岛与世隔绝的小河岸与伊斯帕尼奥拉的北缘倾斜相撞，这是北美-加勒比海板块广阔的跨压力边界的一部分。巴哈马东南部的碰撞环境与巴哈马西北部的构造静止、被动边缘环境形成了鲜明的对比，这为我们提供了一个无与伦比的机会，可以比较和对比不同构造体制下浅水碳酸盐岩的发育情况。拟议使用SeaMARC II海底测绘系统，结合数字记录的单通道地震反射剖面，提供了一个非常适合我们拟议研究的系统，该系统将侧重于记录碰撞带内的浅层结构和表面沉积特征。山带中的碳酸盐矿床通常与浅海沉积有关，这些沉积是在构造事件期间被推入大陆的。该项目将研究伊斯帕尼奥拉边缘的碳酸盐沉积，将其作为构造活动区中发现的碳酸盐地形类型的现代模拟。将结合取心、地震地层学和侧扫声纳成像(SeaMarc II)检查沉积学和构造背景。结果可以用来解释在许多发现碳酸盐沉积的吸积地形中的碳酸盐沉积。

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 strtigraphy, 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.