ALVIN Diving in the Intra-Transform Spreading Centers of theSiqueiros Transform

该项目将侧重于Siqueiros变换断层内变换扩展中心的岩石学和地球化学特征，通过ALVIN场成像确定变换域的构造历史，从每个断崖壁上恢复的变形岩石的结构研究，以及对过去4 Ma影响Siqueiros转变发展的构造过程的理解。“阿尔文”号将在转换过程中进行18次潜水，并在夜间进行岩石取心和疏浚项目，以提供沿扩展轴和沿走滑断层的各个地点的额外样本。SeaBeam将在夜间使用，为每个扩展轴制作详细的10米等高线地图。需要解决的问题包括：哪些过程负责启动转换内部传播？当一个新的扩散中心开始时，熔岩类型的演化顺序是什么？地幔中主要转换相关的成分不连续的性质是什么？地幔中化学非均质性的尺度是什么？沿转换断层是否产生了独特的岩浆类型？

This program will focus on a petrological and geochemical characterization of the intra-transform spreading centers in the Siqueiros transform fault, on determining the structural histroy along the transform domain through ALVIN field mapping, structural studies of deformed rocks recovered from the walls of each fault scarp, and on understanding the tectonci processess that have influenced the development of the Siqueiros tranform for the past 4 Ma. There will be eighteen ALVIN dives in the transfrom and a night-time program of rock coring and dredging that will provide additional samples from along the spreading axis and at various sites along the strike- slip faults. SeaBeam will be used at night to produce detailed 10 m contour maps of each spreading axis. Questions to be addressed include: What processes are responsible for initiating intra-transform spreading? What is the evolutionary sequence of lava types erupted when a new spreading center start? What is the nature of major transform-affiliated compositional discontinuities in the mantle? What is the scale of chemical heterogeneity in the mantle? Are unique magma types generated along transform faults?