Collaborative Research: Geochemistry of Arc Magmas from Luzon and Marinduque Islands, Philippines.

合作研究：菲律宾吕宋岛和马林杜克群岛弧岩浆的地球化学。

• 批准号: 8721418
• 负责人: Marc Defant
• 金额: $ 6.53万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-04-15 至 1991-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8721418&HistoricalAwards=false
• 关键词: Collaborative; Research; Geochemistry; Arc; Magmas

The island of Luzon is bounded by a simple system of opposed subduction zones. Contrasting slabs of "oceanic" Philippine Sea and "marginal" South China Basin lithosphere are injected into the mantle, where they appear to impact distinctive imprints on magma sources. This project will attempt to model subduction- induced source evolution through geochemical/isotopic study of post-Miocene lavas from calc-alkalic Bicol and Bataan volcanic lineaments, and the alkalic Taal-Banahaw group in southern Luzon. Data for major and trace elements, and Be-10, Sr, Nd, Pb, H, and O isotopes will be used to contrast effects of subducting (sparse) pelagic sediment and MORB basement with (voluminous) continental sediment and variable MORB "transitional" basement. Thus it should be possible to asses the influence of subducted sial on the genesis of alkalic magma. Several specific questions will be addressed including: 1. The long term history of the suprasubduction mantle: was this of the MORB, OIB, or sub-continental type? 2. The nature of mantle metasomatism beneath the Bataan and Bicol arcs. 3. The significance of accessory phase stabilities; do they compositionally buffer second-stage metasomatic melts? 4. The role of subduction-derived H2O. The project will involve sampling twelve active or dormant volcanoes, and is coordinated with research by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), and research groups in West Germany and France.

吕宋岛的边界是一个简单的相对俯冲带系统。 “海洋”菲律宾海和“边缘”华南盆地岩石圈形成对比的板块被注入地幔中，它们似乎在岩浆源上留下了独特的印记。 该项目将尝试通过对来自钙碱性比科尔和巴丹火山地貌以及吕宋岛南部碱性 Taal-Banahaw 群的中新世后熔岩的地球化学/同位素研究来模拟俯冲引起的源演化。 主要元素和微量元素以及Be-10、Sr、Nd、Pb、H和O同位素的数据将用于对比俯冲（稀疏）远洋沉积物和MORB基底与（大量）大陆沉积物和可变MORB“过渡”基底的影响。 因此，应该可以评估俯冲硅藻土对碱性岩浆成因的影响。 将讨论几个具体问题，包括： 1. 超俯冲地幔的长期历史：是 MORB、OIB 还是次大陆类型？ 2. 巴丹岛弧和比科尔岛弧下方地幔交代作用的性质。 3、副相稳定性的意义；它们在成分上缓冲第二阶段交代融化吗？ 4.俯冲产生的H2O的作用。 该项目将涉及对 12 座活火山或休眠火山进行采样，并与菲律宾火山和地震研究所 (PHIVOLCS) 以及西德和法国的研究小组的研究进行协调。