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

OCE 99- 87004 Tucholke奖是对大西洋中脊两侧深地壳深成岩和上地幔超镁铁岩的三个发育良好的结构暴露进行的多通道地震（MCS）反射勘测。 这些光滑的圆顶，“龟背”形的曝光，被称为megamullions，显然是代表剥离断层表面与伸展过程在附近的扩展脊，其特点是广泛和突出的波纹（竖框结构）。 这些MCS调查应建立这些巨球的上部地震速度结构的横向和纵向，并将深入了解海洋地壳和上地幔现在暴露在这些巨球的深层性质，以及更好地了解如何和为什么巨球的形成。这项调查还将作为大洋钻探计划512-Full和532-Full提案的基础现场调查，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.***