A Towed Electromagnetic Survey Across the Kane Megamullion: Mapping the Uppermost Gabbro/Serpentinite Contact

知识优势：海洋核杂岩（OCC）是沿大西洋中脊和其他缓慢和超缓慢扩张脊分布广泛的特征。它们经常出现在山脊不连续面的内部角落，最近已观察到它们在海底大片区域上成群出现。对这些构造的采样表明，它们是暴露在海底的低角度滑脱断层，使下地壳和地幔的部分开裂和暴露。这些断层通过一段时间内的有效应变积累来容纳大量的变形，有时超过1兆尔。地幔橄榄岩的隆升和露出是隆升过程所固有的。浅层橄榄岩的存在促进了整个特征的蛇纹石化，至少在一个实例中，与蛇纹石化相关的放热反应导致了中等温度的热液喷口。仅根据地震速度很难区分蛇纹岩和辉长岩。我们建议电导率作为识别OCCs内蛇纹岩的替代方法。这个项目是一个概念验证。试点实验，拖曳海底电磁系统穿过凯恩和阿贝尔圆顶内的OCC在凯恩转换断层南部的大西洋中脊。这将测试我们根据电导率进行区分的能力：a)横跨丘顶的蛇纹岩和辉长岩之间（横向）最上面（~0-30m）的接触几何形状；b)在板块分离过程中容纳大部分应变的断层核的性质和几何形状的变化。这将是同类实验中的第一次。更广泛的影响：该项目标志着pi与巴黎IPGP科学家之间国际合作的开始。我们预计将开展一些联合活动，包括为PI在巴黎的活动以及为巴黎的同事访问WHOI寻求资金。在这个试点研究中收集的数据集将适合于一个小型的一般考试项目或作为暑期学生研究员的项目。WHOI举办了一个暑期学生项目，每年约有20名学生参加，为期12周，让他们接触自己的研究项目和广泛的教育经验。这些学生中有许多人继续读研究生。该机构还支持并开展了一个少数族裔培训项目，旨在让来自代表性不足背景的学生接触海洋科学。如果合适的候选人申请，那么暑期学生可以从这个池子里出来。

Intellectual Merit: Oceanic core complexes (OCC) are widespread features along the mid-Atlantic Ridge and other slow and ultra-slow spreading ridges. They are often found in inside corners of ridge discontinuities, and recently have been observed to occur in clusters over large areas of the seafloor. Sampling of these structures has shown that they are low-angle detachment faults exposed at the seafloor that unroof and expose sections of lower crust and mantle. These faults accommodate large amounts of deformation through effective strain accumulation over periods of time, sometime in excess of 1 Myrs. The uplift and exposure of mantle peridotite is inherent to the uplift process. The presence of shallow peridotite promotes serpentinization across the features that, in at least one instance, results in moderate temperature hydrothermal venting fueled by exothermic reactions associated with the serpentinization. Discrimination of serpentinite from gabbro is difficult on the basis of seismic velocities alone. We suggest electrical conductivity as an alternative approach to identifying serpentinite within OCCs. This project is a ?proof-of-concept? pilot experiment, towing a seafloor EM system across the Cain and Abel domes within the OCC south of the Kane transform fault on the Mid-Atlantic Ridge. This will test our ability to discriminate, on the basis of electrical conductivity: a) the uppermost (~0-30m) contact geometry (laterally) between serpentinite and gabbro across the dome of the mound; and b) the variations in the nature and geometry of the fault core that accommodates most of the strain during plate separation. This experiment will be the first of its kind.Broader Impacts: This project marks the start of an international collaboration between the P.I. and scientists at IPGP in Paris. We anticipate a number of joint activities that will include seeking funds for the PI to spend time in Paris, and for Paris colleagues to visit WHOI. The data set collected in this pilot study will be appropriate for a small general examination project or as a project for a summer student fellow. WHOI runs a summer student program which annually brings around 20 students for 12 weeks and exposes them to their own research project and to a wide range of educational experiences. Many of these students go on to graduate school. The institution also supports and runs a minority trainee program which seeks to expose students from underrepresented backgrounds to ocean science. If appropriate candidates apply, then a summer student could come from this pool.