The magmatic and geochemical evolution of oceanic intraplate volcanoes: constraints from the Louisville Seamounts (IODP Leg 330) and other Pacific hotspots

海洋板内火山的岩浆和地球化学演化：来自路易斯维尔海山（IODP Leg 330）和其他太平洋热点的限制

• 批准号: 242297404
• 负责人: Professor Dr. Christoph Beier
• 金额: --
• 依托单位: Geotieteiden ja maantieteen osasto
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/242297404?language=en
• 关键词: magmatic; geochemical; evolution; oceanic; intraplate

The volcanoes of long-lived, age-progressive seamount chains are likely the result of mantle plumes rising from the upper and possibly even lower mantle underneath moving lithosphere plates. The volcanoes evolve through distinct stages from a shield-building to a post-shield or even post-erosional stages over a period of several millions of years. Typically, the major element compositions range from tholeiitic to SiO2-undersaturated magmas with decreasing age of the lava. The geochemical variability observed is influenced by changes of depth and degree of partial melting but may also be influenced by the mineralogical and geochemical composition of the mantle source. These parameters likely depend on the positioning of the mantle plume relative to the lithospheric plate. The impact of mantle plume temperature, dynamics and composition on these geochemical changes is only poorly understood. This project aims at analysing volcanic glasses and olivines from seamounts of the Louisville Seamount Chain (IODP Leg 330) and other Pacific Hotspots ((Macdonald, Society, Pitcairn, Juan Fernandez) to investigate the compositional variability of primitive melts erupted on old, fast moving lithosphere. The samples are readily available in Erlangen and Kiel. The composition of the glasses allows to better constrain the composition of the primary melt compared to whole rock analyses. In addition, the O isotope composition of glasses and olivines from different hotspots will be measured to determine the O isotope variability in mantle plumes. Combined with published ages and geochemical data this is the first systematic study on the variability of mantle melts in different hotspot settings and its relationship with the mantle plume positioning relative to the lithospheric plate.

长寿的、随年龄发展的海山链火山很可能是从移动的岩石圈板块下面的上层甚至下层地幔升起的地幔羽流的结果。在数百万年的时间里，这些火山经历了从建造盾牌到盾牌后甚至侵蚀后的不同阶段。通常，随着熔岩年龄的下降，主要元素组成范围从拉斑玄武岩到SiO_2不饱和岩浆。观测到的地球化学变异性受深度和部分熔融程度变化的影响，但也可能受到地幔来源的矿物学和地球化学成分的影响。这些参数可能取决于地幔热柱相对于岩石圈板块的位置。地幔热柱的温度、动力学和组成对这些地球化学变化的影响还知之甚少。该项目旨在分析路易斯维尔海山链海山(IODP第330段)和其他太平洋热点地区(Macdonald，Society，Pitcairn，Juan Fernandez)的火山玻璃和橄榄石，以调查在古老的快速移动的岩石圈上喷发的原始熔体的成分变异性。这些样品在埃尔兰根和基尔随处可见。与全岩分析相比，玻璃的成分可以更好地约束原始熔体的成分。此外，还将测量来自不同热点地区的玻璃和橄榄石的氧同位素组成，以确定地幔热柱中的氧同位素变异性。结合已发表的年龄和地球化学数据，首次系统地研究了不同热点背景下地幔熔体的变异性及其与地幔热柱相对于岩石圈板块位置的关系。

项目成果

Geochemistry of volcanic glasses from the Louisville Seamount Trail (IODP Expedition 330): Implications for eruption environments and mantle melting

路易斯维尔海山小道（IODP Expedition 330）火山玻璃的地球化学：对喷发环境和地幔融化的影响

• DOI: 10.1002/2013gc005086
• 发表时间: 2014
• 期刊: Geochemistry
• 影响因子: 3.7
• 作者: Nichols;Brandl
• 通讯作者: Brandl

Louisville Seamount Chain: Petrogenetic processes and geochemical evolution of the mantle source

• DOI: 10.1002/2014gc005288
• 发表时间: 2014-06
• 期刊: Geochemistry
• 影响因子: 3.7
• 作者: L. Vanderkluysen;J. Mahoney;A. Koppers;C. Beier;M. Regelous;J. Gee;P. Lonsdale