Segment-Scale Melt Storage and Transport Processes at Mediumto Fast-Spreading Ridges: Case Study at the EPR, 9 Degrees 30' Norh Area

岩浆在活动中轴线以下向快速扩张脊的储存和搬运过程，对认识轴向火山的脊分割和动力学行为具有重要意义。对经过充分研究和采样的脊段进行详细的岩石学和地球化学研究，可以对这些过程的性质和几何形状提供强有力的约束。该项目将分析北纬9度20分至北纬9度53分之间东太平洋洋面的微量元素、矿物化学和晶体尺寸分布数据，以测试岩浆运输和岩浆房过程模型。洋中脊火山作用的一种模式认为火山作用是深部上升流的结果，向上退化成多个底辟和导管。在浅层，岩浆明显地经历了分馏，岩石由形成于局部脊峰高点的高温熔体结晶，岩石由形成于脊峰低点的低温熔体结晶。这个模型将通过比较从大量的疏浚运输中得到的分析结果和从一个或多个母岩浆的分馏中得到的岩石成分的计算结果来检验。

Magma storage and transport processes below the axes of active medium to fast spreading ridges is of fundamental importance to understanding ridge segmentation and the dynamic behavior of axial volcanoes. Detailed petrologic and geochemical studies of well-studied and well-sampled ridge segments can provides strong constraints on the nature and geometry of these processes. This project will analyze trace element, mineral chemistry, and crystal size distribution data from the East Pacific Rise between 9 degree 20 minutes North and 9 degrees 53 minutes North to test models of magma transport and magma chamber processes. One model of mid-ocean ridge volcanism considers the volcanism to be the result of deep upwelling which degenerates upward into multiple diapirs and conduits. At shallow levels magmas apparently undergo fractionation with rocks crystallized from high-temperature melts forming at local ridge-crest highs and rocks crystallizing form low-temperature melts found at ridge-crest lows. This model will be tested by comparing analyses from extensive dredge hauls to calculations of rock compositions that would be expected from a fractionation of one or more parent magmas.