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

OCE 99-87004TucholkeAward是对中大西洋洋脊两侧三个发育良好的深地壳深部和上地幔超基性岩石构造暴露的多通道地震（MCS）反射调查。这些光滑的圆顶，“龟背”形状的暴露，被称为巨型断层，显然代表了与附近伸展脊的伸展作用相关的滑脱断层面，其特征是广泛而突出的波纹（巨型构造）。这些MCS调查将在横向和纵向上建立这些巨节块的上部地震速度结构，并将深入了解现在暴露在这些巨节块中的海洋地壳和上地幔的深层性质，并更好地理解巨节块的形成方式和原因。该调查还将作为海洋钻探计划（ODP） 512-Full和532-Full提案的基础现场调查，并解决ODP长期计划中的几个地壳目标

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.***