Correlation of Geologic and Seismic Structures in the Southern MARK Area: Surface Manifestations of Normal Faulting on the Mid-Atlantic Ridge

缓慢扩张的中大西洋海岭（MAR）由两部分组成。 对称和不对称裂谷段或扩张 通过转换断层和“非- 转换偏移”或调节区，并类似于 许多大陆裂谷的结构。的各种部件的 MAR结构最重要的断层发生在主要的 不对称（半地堑）扩张单元的边界断层， 将它们与相邻细胞连接起来的适应区。典型 这些特征的示例存在于标记区域（23“N上， 1992年，阿尔文对这一现象进行了研究。 美国/法语（F.A.R.A.）20次潜水的计划将是 试图研究伸展运动的表面表现， MARK地区南部约100公里处的构造 凯恩变形两个主要的几何定义结构 将被调查。1.）的人。首要目标是 沿沿着陡峭的东部 在大约22'30' N处的中间谷壁（Toomey等人，1985; 1988）。 这被解释为一个地震活跃的断层带， 一个幼稚的分离错误。2.）的情况。第二个目标是 同一扩张单元北端的适应带。 该区域位于 同样的细胞扩散。 它位于 最近发现的一个主要的北倾地壳内反射体 多道地震反射研究，可能是一个低角度 断层滑动（侧向斜坡）。 阿尔文号潜水将允许详细的绘图和结构 测量各种特征（断层表面，剪切带， 叶理、线理、岩脉和水流等）在露出地面的 变形的基底岩石我们的目标是利用 地震和地质数据，以帮助桥梁之间的差距构造 这一进程和近轴测深特征的创建。

The slow-spreading Mid-Atlantic Ridge (MAR) consists of both symmetrical and asymmetrical rift valley segments or spreading cells that are linked end-to-end by transform faults and "non- transform offsets" or accommodation zones and is similar to the structure of many continental rifts. Of the various components of MAR architecture the most important faulting occurs at the major border faults of asymmetrical (half-graben) spreading cells and at the accommodation zones that link them to adjacent cells. Typical examples of these feature are present in the MARK Area (23"N on the Mid-Atlantic Ridge) and can be investigated by Alvin in 1992. A joint U.S./French (F.A.R.A.) program of 20 dives to will be attempted investigate the surface manifestations of extensional tectonics in the southern part of the MARK Area about 100 km south of the Kane Transform. Two major geophysically defined structures will be investigated. 1.) The primary target will be the zone teleseismic and microseismic activity along the steep eastern median valley wall at about 22'30'N (Toomey et al., 1985; 1988). This is interpreted as a seismically active fault zone and perhaps a juvenile detachment fault. 2.) The secondary target will be the accommodation zone at the north end of the same spreading cell. This lies at the surface intersection of a zone at the north end of the same spreading cell. This lies at the surface intersection of a major north-dipping intra-crustal reflector identified in recent multichannel seismic reflection studies that may be a low-angle oblique-slip fault (lateral ramp). The Alvin dives will permit detailed mapping and structural measurement of various features (fault surfaces, shear zones, foliations, lineations, dikes and flows, etc.) in outcrops of deformed basement rocks. The goal is to use the correlation between seismic and geologic data to help bridge the gap between tectonic processes and the creation of near-axial bathymetric features.