REU: Evolution of the Kerguelen Plume: Studies of Mafic Rocks From the Northern Kerguelen Plateau

REU：凯尔盖朗地幔柱的演化：凯尔盖朗高原北部镁铁质岩石的研究

• 批准号: 9814313
• 负责人: Frederick Frey
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814313&HistoricalAwards=false
• 关键词: REU; Evolution; Kerguelen; Plume; Studies

9814313FreyOver the past 115 My a significant fraction of the eastern Indian Ocean seafloor was formed by magmas derived from the Kerguelen mantle plume. The overall goal of this research is to use this volcanic record to understand the origin and evolution of the Kerguelen mantle plume. This is an important objective because magmas derived from mantle plumes provide information about physical and chemical processes occurring in the earth's mantle that cannot be obtained from study of volcanism associated with diverging and converging plates. Specifically, mantle plumes provide information about convection processes in the mantle, and the effects of long-term recycling of crust into the mantle. The Kerguelen Plume is particularly important because: (a) it is long-lived; (b) all aspects of plume-related volcanism are accessible for study; i.e., a very large igneous province (Kerguelen Plateau) which is commonly associated with plume initiation, a long hotspot track of volcanoes (Ninetyeast Ridge) which formed as the Indian plate migrated rapidly northwards over the plume, and a large, recently active oceanic island (Kerguelen Archipelago) located on the Antarctic Plate; (c) lavas associated with this plume have a distinctive geochemical signature which reflect recycling of crust into the deep mantle; (d) formation of the large igneous province in the newly formed relatively small Indian Ocean may have enabled dispersal of these plume geochemical characteristics into the Indian Ocean asthenosphere, thereby creating the distinctive geochemical characteristics of basalts erupted at currently active seafloor spreading centers in the Indian Ocean; and (e) the high magma flux reflected by the mid-Cretaceous formation of the Southern Kerguelen Plateau may have significantly affected the earth's hydrosphere/atmosphere system. Geochemical and age data for igneous rocks from the Kerguelen Archipelago and submarine Northern Kerguelen Plateau will be obtained in order to understand the source and evolution of the 40 My volcanism related to the Kerguelen Plume.

9814313Frey过去 115 东印度洋海底的很大一部分是由来自凯尔盖朗地幔柱的岩浆形成的。 这项研究的总体目标是利用这一火山记录来了解凯尔盖朗地幔柱的起源和演化。 这是一个重要的目标，因为源自地幔柱的岩浆提供了有关地幔中发生的物理和化学过程的信息，而这些信息无法通过与发散和聚合板块相关的火山活动研究来获得。 具体来说，地幔羽流提供了有关地幔对流过程以及地壳长期循环进入地幔的影响的信息。 凯尔盖朗羽流特别重要，因为： (a) 它寿命长； (b) 与羽流相关的火山活动的所有方面都可供研究；即，一个非常大的火成岩省（凯尔盖朗高原），通常与羽流的形成有关，一条长长的火山热点轨迹（九十东岭），是随着印度板块在羽流上快速向北迁移而形成的，以及一个最近活跃的大型海洋岛屿（凯尔盖朗群岛）位于南极板块； (c) 与该羽流相关的熔岩具有独特的地球化学特征，反映了地壳再循环到地幔深处； (d) 在新形成的相对较小的印度洋中形成的大型火成岩省可能使这些羽流地球化学特征扩散到印度洋软流圈中，从而产生了印度洋目前活跃的海底扩张中心喷发的玄武岩的独特地球化学特征海洋; (e) 南凯尔盖朗高原的白垩纪中期地层所反映的高岩浆通量可能对地球的水圈/大气系统产生了重大影响。将获得凯尔盖朗群岛和北凯尔盖朗高原海底火成岩的地球化学和年龄数据，以了解与凯尔盖朗火山喷发相关的40 My火山活动的来源和演化。