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

吕宋岛被一个简单的相对俯冲带系统所包围。对比鲜明的“大洋”菲律宾海板块和“边缘”华南盆地岩石圈板块注入地幔，在那里它们似乎对岩浆来源产生了独特的影响。本项目将尝试通过对吕宋岛南部钙碱性Bicol和Bataan火山线以及碱性Taal-Banahaw群中新世后熔岩的地球化学/同位素研究，模拟俯冲诱导的烃源演化。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）大陆沉积物和变化的MORB“过渡”基底的影响。因此，有可能评估俯冲岩浆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型、OIB型还是次大陆型？2. 巴丹和比科尔弧下地幔交代作用的性质。3. 副相稳定性的意义；它们是否在成分上缓冲第二阶段的交代熔体？4. 俯冲产生的水的作用。该项目将包括对12座活火山或休眠火山进行采样，并与菲律宾火山学和地震学研究所（PHIVOLCS）以及西德和法国的研究小组进行协调。

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.