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

9614532弗雷，这项研究的长期目标是了解与科尔盖伦地幔热柱有关的~115 Ma火山活动记录的起源和演化。科尔盖伦热柱之所以特别重要，是因为：1)它的寿命很长；2)与热柱有关的火山活动的方方面面都可以进行研究；3)熔岩具有独特的地球化学特征，可能反映了地壳向地幔深处的再循环；以及d)在新形成的印度洋上形成的大型火成岩省(科尔盖伦高原)可能使这些热柱的地球化学特征得以扩散到印度洋软流圈。这项提议旨在扩大目前的项目，以包括该烟柱最近(40 Ma)的火山史，它记录在一个厚厚的溢流玄武岩序列中，这些玄武岩是科尔盖伦群岛的主要体积单位。这些熔岩的化学成分(主量元素和微量元素丰度)和同位素(氦、锶、钕、铅和铯)特征将被确定，以显示熔岩成分如何随时间(在40Ar-39Ar测年控制下的相对和绝对基础上)和在群岛中的位置而变化。

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.