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

知识专长：大洋核心复合体是沿着大西洋中脊和其他缓慢和超缓慢扩张脊的广泛特征。它们经常出现在海脊不连续面的内角，最近观察到它们成簇出现在大面积的海底。对这些结构的取样表明，它们是暴露在海底的低角度拆离断层，使下地壳和地幔的部分揭顶和暴露出来。这些断层在一段时间内通过有效应变积累容纳了大量的变形，有时超过100万年。地幔橄榄岩的抬升和出露是隆升过程所固有的。浅橄榄岩的存在促进了整个特征的蛇纹化，在至少一种情况下，导致由与蛇纹化相关的放热反应引起的中温热液喷发。单凭地震速度很难区分蛇纹岩和辉长岩。我们建议电导率作为一种替代方法来识别蛇纹岩内OCC。这个项目是一个？概念验证在中大西洋海岭凯恩转换断层以南OCC内的凯恩和阿贝尔圆顶上拖曳海底EM系统进行试点实验。这将测试我们的能力，区分的基础上的导电性：a）蛇纹岩和辉长岩之间的最高（~0- 30米）接触几何形状（横向）横跨圆顶的丘;和B）的性质和几何形状的变化的故障核心，容纳大部分的应变在板块分离。更广泛的影响：该项目标志着P.I.和科学家们在巴黎的IPGP。我们预计将开展一系列联合活动，包括为PI在巴黎的时间和巴黎同事访问WHOI寻求资金。在这项试点研究中收集的数据集将是一个小的一般性考试项目或作为一个项目的暑期学生研究员适当。WHOI运行一个暑期学生计划，每年带来约20名学生12周，并让他们接触到自己的研究项目和广泛的教育经验。这些学生中的许多人继续读研究生。该机构还支持和运行少数民族实习生计划，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。

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.