Collaborative Research: Petrologic and Geochemical Investigations of Low Temperature Fluid-Rock Interactions within a Hot Spot, Oceanic Island Volcano from Study of the HSDP Core

该项目将重点对夏威夷大岛希洛附近的一个深钻孔中回收的蚀变岩心进行岩石学和地球化学的综合分析。其中一些材料来自于夏威夷科学钻探项目（HSDP）于1999年9月完成的一个3公里深的钻孔。从2003年初开始，当现有的洞被加深时，将从新的样本中回收这些样本，以提醒人们。该项目的主要目标是利用综合分析方法研究回收的岩心材料，开发和测试岩石蚀变模型。需要解决的主要问题是：(1)构成莫纳克亚火山的玄武岩物质的蚀变历史是怎样的？它是如何受到各种蚀变过程的影响的？这些蚀变过程与其他形式的海底蚀变过程有何区别？(2)这种蚀变如何影响这些材料的矿物组成和物理性质？(3)变化对莫纳克亚山海底部分化学成分的影响有多大？(4)关于（提出的模型）该火山内部地下水深层循环的证据是什么？问题1和问题2将通过对蚀变矿物学的系统研究来解决。问题#3和4将通过与玄武岩矿物和玻璃转化为巴拉哥化玻璃、层硅酸盐和沸石相关的元素和同位素特征的详细地球化学调查来解决。微量元素和同位素分析将为评价蚀变过程中玄武岩、海水和大气成分的交换提供手段。对蚀变矿物的稳定同位素分析将使我们能够测试一个水文模型，该模型表明，大气流体在莫纳克亚山内部深处循环。

0125666SchiffmanThe project will focus on combined petrographic and geochemical analyses of altered rock core recovered from a deep drill hole near Hilo, on the Big Island of Hawaii. Some of this material comes from a 3 km-deep drill hole completed by the Hawaii Scientific Drilling Project (HSDP) in September, 1999. The reminder will come from new samples that will be recovered when the existing hole is deepened, beginning in early 2003. The primary objective of this project will be to develop and test models for rock alteration using an integrated analytical approach for studying the recovered core materials. Major questions to be addressed are: (1) What is the alteration history of the basaltic material which underlies Mauna Kea volcano, how has it been influenced by various types of alteration processes, and are these distinct from other forms of seafloor alteration? (2) How has this alteration affected the mineral composition and physical properties of these materials? (3) How significantly has alteration affected the chemical composition of the submarine portions of the Mauna Kea? and (4) What is the evidence regarding (proposed models invoking) deep circulation of ground waters within the interior of this volcano? Questions # 1 and 2 will be addressed through the systematic study of the alteration mineralogy. Question #3 and 4 will be addressed by detailed geochemical investigations of elemental and isotopic signatures associated with the conversion of basaltic minerals and glass to palagonitized glass, layer silicates, and zeolites. Trace element and isotopic analyses will provide the means of evaluating the exchange of basaltic, seawater, meteoric components during alteration. Stable isotopic analyses of alteration minerals should allow us to test a hydrologic model suggesting that meteoric fluids have circulated deep within the interior of Mauna Kea.