Accretion of superfast spreading oceanic crust: Participation in IODP Expedition 335

超快扩张洋壳的堆积：参与 IODP 335 号探险

基本信息

批准号：
NE/J005592/1
负责人：
Cornelis Lissenberg
金额：
$ 1.03万
依托单位：
CARDIFF UNIVERSITY
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ005592%2F1
关键词：
Accretion superfast spreading oceanic crust

项目摘要

Oceanic crust covers nearly two thirds of the Earth's surface. It is generated at mid-ocean ridges by the solidification of magmas formed in the upwelling mantle. These magmas are stored in magma chambers below the ridge axis, where they crystallise to yield the lower oceanic crust. The heat provided by magma input and crystallisation drives seafloor hydrothermal systems, which control ocean chemistry through lithosphere-hydrosphere exchange, and provide energy for chemosynthetic ecosystems. Reconstructing the magmatic processes in the lower crust has proven challenging, however, primarily due to severely limited accessibility. Only lower crustal sections from dismembered crust have been studied to date, and it remains uncertain to which extent these sections are representative for intact crust. Thus, in order to understand the formation of a large part of the Earth's crust, the recovery of intact lower oceanic crust would be a major step forward.Scientific ocean drilling in the Equatorial Pacific Ocean (IODP Hole 1256D) has penetrated the upper crust, reaching the upper crust-lower crust boundary. IODP Expedition 335 is set to deepen the hole, recovering the first section of intact lower oceanic crust. This section will yield an unprecedented view of lower crustal evolution, from magma chamber processes and the resulting formation of the crust to its subsequent cooling and alteration by ocean-derived hydrothermal fluids.This proposal seeks funding for the PI to join Expedition 335, where he will serve as igneous petrologist. He will describe and interpret the plutonic rocks, which represent the building blocks of the lower crust, using their composition and textures to make first-order observations about the magma chamber processes during crustal accretion. In addition, he will define hypotheses to test during post-cruise research, and take the necessary samples to achieve the postcruise research objectives.

洋壳覆盖了地球表面近三分之二的面积。它是由洋中脊上涌的地幔中形成的岩浆凝固而产生的。这些岩浆储存在山脊轴下方的岩浆室中，在那里结晶形成下洋壳。岩浆输入和结晶提供的热量驱动海底热液系统，该系统通过岩石圈-水圈交换控制海洋化学，并为化学合成生态系统提供能量。然而，重建下地壳的岩浆过程已被证明具有挑战性，这主要是由于可及性严重受限。迄今为止，仅研究了肢解地壳的下地壳部分，并且仍不确定这些部分在多大程度上代表完整的地壳。因此，为了了解大部分地壳的形成，恢复完整的下洋地壳将是向前迈出的一大步。赤道太平洋的科学海洋钻探（IODP Hole 1256D）已经穿透了上地壳，到达上地壳-下地壳边界。 IODP 335 号探险队将加深该洞，恢复第一部分完整的下洋地壳。本节将对下地壳演化提供前所未有的视角，从岩浆房过程和由此产生的地壳形成，到随后由海洋热液引起的冷却和改变。本提案为 PI 寻求资金加入 335 号探险队，他在那里将担任火成岩岩石学家。他将描述和解释代表下地壳组成部分的深成岩，利用它们的成分和纹理对地壳增生过程中的岩浆房过程进行一级观测。此外，他还将定义在巡航后研究期间测试的假设，并采集必要的样本以实现巡航后研究目标。