Magnetic and Structural Study of Sub-Volcanic Oceanic Lithosphere Exposed in Kane Megamullion, Mid-Atlantic Ridge, 23deg30min N

拟议中的项目将研究凯恩巨型断层，它被解释为大西洋中部海脊凯恩断裂带附近一个长期存在的正常滑脱断层的下盘。断层似乎暴露了一个深部地壳，可能还有上地幔，这是岩石圈的一部分，使其能够进行调查、采样和最终钻探。拟议的现场方案将使用自主水下机器人(ABE)、ROV JASON和DREDING，以及实验室分析，以解决以下问题：1)如何在地壳中部和更深层次记录地球磁场的磁化和极性反转历史？2)裂谷轴线上的岩浆活动条件与巨型巨石的形成有关，以及由此产生的地壳中部和更深层次的组成和侵入关系是什么？(3)大洋地壳主要正断层剪切带应变调节的性质和应变局部化的演化。这是一个独特的可进入的区域，调查和采样将使人们能够对缓慢扩张的地壳的沉积和解剖过程有重要的新见解。调查数据将提供数据，以扩展和限制从钻探到巨型钻探到三维的解释。

Abstract of Tivey 0118445The proposed project will study the Kane megamullion, which is interpreted to be the exhumed footwall of a long-lived normal detachment fault near the Kane Fracture Zone on the Mid-Atlantic Ridge. The faulting appears to have exposed a deep-crustal and possibly upper mantle, section of lithosphere, making it accessible to survey, sampling and eventual drilling. The proposed field program will use the autonomous underwater vehicle (ABE), ROV Jason and dredging, together with laboratory analyses to address the questions of 1) how are magnetization and polarity -reversal history of Earth's magnetic field recorded at mid-crustal and deeper levels?, 2) what conditions of magmatism at the rift axis attend formation of megamullions,and what are the resulting composition and intrusive relations at mid-crustal and deeper levels? and 3) what are the nature of strain accomodation and evolution of strain localization in the shear zone of a major normal fault in ocean crust? This is a uniquely accessible section where survey and sampling will allow significant new insights into the processes of accretion and dissection of slow-spreading crust. The survey data will provide data to extend and constrain interpretations from drilling into megamullions, into three dimensions.