Multichannel Seismic Investigation of Velocity Structure of Megamullions on the Mid-Atlantic Ridge

OCE99-87004Tucholke奖是对中大西洋海脊两侧三个发育良好的地壳深成和上地幔超镁铁质岩石的多道地震(MCS)反射测量。这些光滑圆顶的“龟背形”暴露，被称为巨球，显然代表与附近扩张山脊的伸展过程有关的拆离断层表面，其特征是广泛而突出的波纹(隆起结构)。这些MCS调查应该建立这些巨球在横向和垂直方向上的上地震速度结构，并将使我们深入了解这些巨球所暴露的洋壳和上地幔的深部性质，并更好地了解巨球是如何形成的以及为什么形成。这项调查还将作为大洋钻探计划(ODP)提案512-Full和532-Full的基础现场调查，并解决大洋钻探计划长期计划的几个地壳目标。

OCE 99-87004TucholkeAward is for a multichannel seismic (MCS) reflection survey of three well-developed structural exposures of deep-crustal plutonic and upper-mantle ultramafic rock that occur on the flanks of the Mid-Atlantic Ridge. These smoothly-domed, "turtleback" shaped exposures, termed megamullions, apparently represent detachment fault surfaces associated with extensional processes at the nearby spreading ridge, and are characterized by extensive and prominent corrugations (mullion structures). These MCS surveys should establish the upper seismic velocity structure of these megamullions both laterally and vertically, and will give insight both into the deep nature of the oceanic crust and upper mantle now exposed in these megamullions as well as give a better understanding of how and why megamullions form. This survey would also serve as a foundational site survey to Ocean Drilling Program (ODP) proposals 512-Full and 532-Full and addresses several crustal objectives of the ODP Long Range Plan.***