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

中速扩张山脊的分段规模熔体储存和运输过程：EPR、北纬 9 度 30 地区的案例研究

• 批准号: 9000193
• 负责人: Rodey Batiza
• 金额: $ 6.5万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-03-15 至 1992-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9000193&HistoricalAwards=false
• 关键词: Segment; Scale; Melt; Storage; Transport

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.

岩浆在活动中至快速扩张山脊轴线以下的储存和运移过程对于理解山脊分段和轴向火山的动力学行为具有重要意义。对经过充分研究和采样的海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限制。该项目将分析东太平洋隆起北纬9度20分至9度53分之间的微量元素、矿物化学和晶体尺寸分布数据，以测试岩浆运移和岩浆室过程的模型。大洋中脊火山作用的一种模型认为，火山作用是深上涌的结果，它向上退化为多个底辟和管道。在浅层，岩浆显然经历了分馏，岩石由形成于局部山脊峰顶的高温熔体结晶而成，岩石结晶形成于山脊低谷处的低温熔体。这一模型将通过将大量挖泥船的分析与岩石成分的计算进行比较来检验，这些分析预计来自一种或多种母岩浆的分馏。