Collaborative Research: Geochemical Studies of the Southern Lesser Antilles

这是康奈尔大学和布朗大学的一个合作项目 高校 我们建议研究岩浆成因， 圣卢西亚、圣文森特和格林纳达的演变， 多学科方法，包括实地工作， 岩石学研究，主量元素，微量元素，Sr，Nd，Pb 氧同位素测定和K-Ar定年。 岩相 研究将包括微探针和激光烧蚀- 电感耦合等离子体质谱研究。 的 本研究的直接目标是：（1）确定 弧壳对地幔演化的贡献 衍生岩浆在格林纳达和圣卢西亚，（2）使用最多 这些岩浆中的镁，其中一些只是轻微的 自地幔楔产生以来， 熔融程度和源富集，以及（3）确定 岩浆的成分是如何随着时间的推移而变化的 群岛 实现这些目标使我们能够解决 几个更广泛的目标。 它们是：增强 对（1）岩浆生成和演化的认识 岛弧的构造演化过程; 加勒比地区，（3）地壳的必要条件 同化发生或不发生，（4）物质运输 从俯冲板片到岛弧岩浆;（5）岩体 不相容元素向深部地幔的通量 俯冲带 通过集中在几个地方， 完善的实验知识基础，并具有广泛的 我们相信我们可以大大提高 早期的模型

This is a collaborative project between Cornell and Brown Universities. We propose to study magma genesis and evolution in St. Lucia, St. Vincent, and Grenada through a multi-disciplinary approach that will include field work, petrographic study, major element, trace element, Sr, Nd, Pb and O isotope determination, and K-Ar dating. Petrographic study will include both micro probe and laser-ablation- inductively-coupled-plasma-mass-spectrometry studies. The immediate objectives of this study are to: (1) determine the contribution of arc crust to the evolution of mantle- derived magmas in Grenada and St. Lucia, (2) use the most magnesian of these magmas, some of which are only slightly evolved since production in the mantle wedge, to investigate degree of melting and source enrichment, and (3) determine how magma composition has changed through time on these islands. Achieving these objectives allows us to address several broader objectives. These are: enhanced understanding of (1) magma generation and evolution processes in island arcs, (2) tectonic evolution of the Caribbean region, (3) the conditions necessary for crustal assimilation to occur or not to occur, (4) mass transport from the subducting slab to island arc magmas, and (5) mass fluxes of incompatible elements to the deep mantle from subduction zones. By focusing on a few localities with an improved experimental knowledge base, and having a wide range of data, we believe we can substantially improve earlier models.