Crustal Block Rotation in a Migrating Transform Zone: Oriented Piston Cores Study

克莱恩罗克博士的大部分研究都集中在东太平洋海隆西经95.9‘的典型传播中心的力学上。奇怪的是，当“活跃的”扩散轴进入并分裂“老的”地壳时，洋壳从一个岩石圈板块转移到另一个板块。已知在活动和不活动的扩展中心之间会形成复杂的变形模式。有两种理论可以解释这种变形：1)预测位移的“纸牌模型”是沿着普遍存在的山脊-正断层进行的；2)预测变形的“书架构造”模型是通过地壳块体绕垂直轴旋转来进行的。克莱恩罗克博士将通过检查活塞芯相对于地球磁场的下芯自转来测试后者。在最近的一次巡航中，他监督在95.5‘W系统的疑似变形区域内获取了6个活塞芯。每一个都配备了一个芯头相机来记录取心过程中发生的绝对定向、旋转和偏离垂直方向的情况。斯克里普斯公司的丽莎·托克斯博士将对这些岩芯进行全面、透彻的低温磁强计测量。拆分时，将分析子样品的剩余磁化强度，从这些分析得出的倾斜值和倾斜值将提供给KleinRock博士，他随后将结合岩芯头信息来去除岩芯伪影，以构建每个岩心的绝对旋转历史。他估计，该地区至少发生了45‘的地块旋转，这里提出的技术将能够解决大约10’的旋转。

Much of Dr. Kleinrock's research has focused on mechanics ofthe now-classic propagating spreading center at 95.9'W on the East Pacific Rise. An oddity of this and all propagators is the ocean crust gets transferred from one lithospheric plate to another as the "active" spreading axis advances into and splits the "old" crust. Complex deformation patterns are known to develop between the active and inactive spreading centers. Two theories exist to explain this deformation: 1) the "deck of cards model" that predicts displacement is accomodated along pervasive ridge-normal faults: and 2) the "bookshelf tectonics" model that predicts deformation is taken up by crustal block rotation about vertical axes. Dr. Kleinrock will test the latter by examining piston cores for down-core rotation relative to the earth's magnetic field. During a recent cruise, he supervised the acquisition of 6 piston cores within the regions of suspected deformation at the 95.5'W system. Each was equipped with a corehead camera to record obsolute orientation, rotation, and departures from vertical that occured during the coring process. Dr. Lisa Tauxe at Scripps will conduct full-core, pass-thorough cryogenic magnetometer measurements on these cores. When split, subsamples will be analyzed for remnant magnetization, Inclination and declination values derived from these analyses will be provided to Dr. Kleinrock who will then incorporate the corehead information to remove corring artifacts to construct a down-core history of absolute rotation for each core. He estimates that at least 45' of block rotation has occurred in the region, and the technique proposed here will be able to resolve rotations of roughly 10'.