A Submersible Study of Axial Processes, East Pacific Rise 10-12'N

轴向过程的潜水研究，东太平洋海隆 10-12N

• 批准号: 8712098
• 负责人: Geoffrey Thompson
• 金额: $ 50.26万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-11-01 至 1990-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8712098&HistoricalAwards=false
• 关键词: Submersible; Study; Axial; Processes; East

A major emphasis of recent marine geological studies has been to relate the detailed geochemistry and petrology of crustal rocks to the fine-scale features present along mid-ocean ridges. Initial models of the sea-floor spreading process had assumed that crust was created from long, fairly continuous, axial magma chambers. Although minor variations in chemistry were allowed in these models, the composition of the erupted lavas was assumed to be fairly constant. With the advent of detailed mapping systems such as Seabeam and Seamarc, a whole new class of processes were revealed in ridge crest bathymetry. New models emerging from these data indicate that the ridge axis is composed of a series of small, discrete magmatic segments or individual volcanoes. The lavas produced from these volcanoes appears in many cases to be chemically distinct. The objective of the present project is to examine the chemistry of basalts in several of these segments along the East Pacific Rise using the research submersible Alvin. Previous surface ship sampling has defined the gross changes in basalt chemistry related to features such as overlapping spreading centers, off-set ridge axis, and transform faults. Alvin will now be used to sample in detail at boundaries between such features. These data will be used to constrain the nature and distribution of subsurface magma chambers and their relation to the individual morphological segments along the ridge axis. The principal investigators are well qualified to complete the proposed project.

最近海洋地质学研究的一个主要重点是将地壳岩石的详细地球化学和岩石学与大洋中脊沿线的精细特征联系起来。海底扩张过程的最初模型假定地壳是由长的、相当连续的轴向岩浆室形成的。虽然在这些模型中允许化学成分的微小变化，但喷发的熔岩的成分被认为是相当恒定的。随着SEABEAM和SeamArc等详细测绘系统的出现，脊峰测深揭示了一类全新的过程。从这些数据中出现的新模型表明，山脊轴是由一系列小的、离散的岩浆段或单个火山组成的。在许多情况下，这些火山产生的熔岩在化学上似乎是不同的。本项目的目标是利用阿尔文号潜水器研究东太平洋隆起沿线几个部分的玄武岩的化学成分。以前的水面舰船取样已经确定了玄武岩化学的总体变化，这些变化与重叠的扩张中心、错开的脊轴和转换断层等特征有关。阿尔文现在将被用来在这些特征之间的边界上进行详细采样。这些数据将被用来限制地下岩浆室的性质和分布，以及它们与沿山脊轴线的个别形态段的关系。主要调查人员完全有资格完成拟议的项目。