RUI: Arc-Continent Interaction and Evolution of the Caribbean-South American Plate Boundary

RUI：弧大陆相互作用和加勒比-南美板块边界的演化

• 批准号: 8720366
• 负责人: Rudolph Torrini
• 金额: $ 2万
• 依托单位: University of Puerto Rico Mayaguez
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-10-15 至 1989-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8720366&HistoricalAwards=false
• 关键词: RUI; Arc; Continent; Interaction; Evolution

This project involves study of multichannel marine seismic profiles to resolve the structural and tectonic history of the southern Lesser Antilles arc and adjacent parts of the continental margin of South America. Objectives of the study are the identification of terrane boundaries based on lateral discordance and change in seismic character (amplitude, coherency, continuity) and velocity of reflectors, and the identification of structures and determination of their timing in layered sequences based on correlation with wells. The ultimate goal is to interpret existing, newly obtained data, leading to an improved understanding of: (1) arc-continent interaction processes leading to the accretionary growth of continents, and (2) the structural and tectonic history of the eastern reach of the Caribbean-South American boundary zone. Two principal models have been proposed for the nature of the plate boundary: (A) a margin-parallel, east-striking strike-slip boundary with large, distributed, right-lateral (easterly) displacement of the southern Lesser Antilles, and (B) an oblique collision zone with small easterly displacement of the southern Lesser Antilles. A broad zone of deformation, perhaps hundereds of kilometers wide, is postulated by both of the plate boundary models. Because such a deformation zone is largely submerged, marine seismic profiles offer the only means besides seismicity and potential field data to study its structure in the offshore. The study may permit discrimination between the two aforementioned models or lead to the development of a new alternative model.

该项目涉及研究多通道海洋地震剖面，以解决小安的列斯群岛南部弧和南美洲大陆边缘邻近部分的结构和构造历史。研究的目的是根据横向不一致和反射波的地震特征（振幅、相干性、连续性）和速度的变化来识别地层边界，以及根据与井的对比来识别层状层序中的构造和确定它们的时间。最终目标是解释现有的新获得的数据，从而更好地理解：(1)导致大陆增生的弧-大陆相互作用过程，以及(2)加勒比-南美边界带东段的构造和构造历史。对于板块边界的性质，提出了两种主要模式：(A)一个边缘平行的、向东的走滑边界，其南部小安的列斯群岛具有较大的、分布的、右向（东向）位移；(B)一个倾斜碰撞带，其南部小安的列斯群岛具有较小的东向位移。两种板块边界模型都假定有一个宽达数百公里的变形带。由于这种变形带大部分被淹没，除了地震活动性和势场数据外，海洋地震剖面是研究其海上结构的唯一手段。该研究可能允许在上述两种模型之间进行区分，或导致开发一种新的替代模型。