Evolution of the Kerguelen Plume: Constraints from Geochemical Studies of Lava Sequences in the Kerguelen Archipelago

本研究的长期目标是了解与Kerguelen地幔柱有关的~115 Ma火山活动记录的起源和演化。克格伦羽流特别重要，因为：1)它的寿命很长；2)与羽流有关的火山活动的各个方面都可供研究；3)熔岩具有独特的地球化学特征，可能反映了地壳向深部地幔的再循环；d)在新形成的印度洋中形成的大火成岩省（克格伦高原）可能使这些羽流地球化学特征扩散到印度洋软流圈。该提案旨在扩展当前的项目，以包括最近（40 Ma）的火山历史，这些火山历史记录在厚的洪水玄武岩序列中，这些玄武岩是Kerguelen群岛的主要体积单位。这些熔岩的化学组成（主要元素和微量元素丰度）和同位素（He, Sr, Nd， Pb和Os）特征将被确定，以显示熔岩组成如何随时间变化（在40Ar-39Ar测年控制下的相对和绝对基础上）和群岛的位置。

9614532 Frey The long-term goal of this research is to understand the origin and evolution of the ~115 Ma record of volcanism related to the Kerguelen mantle plume. The Kerguelen plume is particularly important because:1) it is long-lived; 2) all aspects of plume-related volcanism are accessible for study; 3) lavas have a distinctive geochemical signature that may reflect recycling of crust into the deep mantle; and d) formation of the large igneous province (Kerguelen Plateau) in the newly formed Indian Ocean may have enabled dispersal of these plume geochemical characteristics into the Indian Ocean asthenosphere. This proposal seeks to extend the current project to include the recent (40 Ma) volcanic history of this plume that is recorded in a thick sequence of flood basalts which are the major volumetric unit of the Kerguelen archipelago. The chemical composition (major and trace element abundances) and isotopic (He, Sr, Nd, Pb, and Os) characteristics of these lavas will be determined to show how the lava compositions have changed with time (both on a relative and absolute basis with control by 40Ar-39Ar dating) and location in the archipelago.