Collaborative Research: A Geochemical Investigation of the Tortugal Komatiites of Costa Rica

合作研究：哥斯达黎加托图加尔科马提岩的地球化学调查

• 批准号: 9725454
• 负责人: Christopher Sinton
• 金额: --
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9725454&HistoricalAwards=false
• 关键词: Collaborative; Research; Geochemical; Investigation; Tortugal

9725454 Sinton High MgO lavas (komatiites and picrites) are a rare but important component of the mid-Cretaceous Caribbean plateau large igneous province (LIP). These lava types are critical to understanding mantle temperature and dynamics that lead to their production but are inaccessible in other oceanic LIP provinces. This project is an integrated field, petrological and geochemical study of the recently discovered Tortugal ultramafic/mafic lavas of Costa Rica. Major element, trace element, platinum group element and Sr-Nd-Pb-Os isotope analyses, combined with 40Ar-39Ar dating, will be used to characterize the Tortugal lavas in order to further document the spatial and temporal variability in petrogenesis related to LIP formation in the region. The Tortugal suite is temporally related to the Gorgona Island komatiites, picrites and basalts 1000 km to the southeast, however preliminary data show significant differences in mantle source and thermal regime between the two areas. Understanding the spatial variability in high MgO lavas will help distinguish between rapid decompression melting or plume head models for the creation of the Caribbean plateau.

辛顿高MgO熔岩（科马提岩和苦橄岩）是白垩纪中期加勒比海高原大火成岩省（LIP）的一种罕见但重要的组成部分。这些熔岩类型对于了解导致其产生的地幔温度和动力学至关重要，但在其他海洋LIP省无法访问。该项目是对最近在哥斯达黎加发现的托尔图加尔超镁铁质/镁铁质熔岩进行的综合实地、岩石学和地球化学研究。主要元素，微量元素，铂族元素和Sr-Nd-Pb-Os同位素分析，结合40 Ar-39 Ar定年，将被用来表征Tortugal熔岩，以进一步记录在该地区的LIP形成有关的岩石成因的空间和时间的变化。Tortugal套件在时间上与东南1000 km的戈尔戈纳岛科马提岩，苦橄岩和玄武岩有关，但初步数据显示，这两个地区之间的地幔来源和热状况存在显着差异。了解高镁熔岩的空间变异性将有助于区分快速减压融化或羽头模型的加勒比海高原的创建。