Investigating Magma Chamber Evolution Using Crystal Isotope Stratigraphy

该项目将使用传统的微采样技术和新的原位激光烧蚀技术来获得高精度和分辨率的矿物相同位素数据，从而显著提高我们对岩浆分异的理解。晶体同位素地层学（CIS）的简单原理是，生长在分异的开放岩浆系统中的晶体记录了它们结晶的液体同位素组成的长期变化。当结合结构和矿物成分数据时，可以重建详细的分异历史。这一理念将在两个密切相关的调查中发展；1)研究了苏格兰Rhum地区受污染和再补给岩浆房的层状堆积序列；2)详细研究了新西兰Ngauruhoe火山开放体系分异喷发产物的年代。第一项研究将允许检查比火山岩组所代表的更持久和完整的分化历史，而第二项研究，由于极好的时间限制，可以通过时间来校准开放系统的分化。

9805023DavidsonThis project will use both conventional microsampling techniques, together with new in situ laser ablation techniques to obtain high precision and resolution isotope data on mineral phases, and to thereby significantly improve our understanding of magmatic differentiation. The simple principle of crystal isotope stratigraphy (CIS) is that crystals growing in a differentiating open magma system record secular changes in the isotope composition of the liquid from which they crystallize. When combined with textural and mineral composition data a detailed history of differentiation can be reconstructed. This philosophy will be developed in two closely related investigations; 1) an examination of the layered cumulate sequence from a contaminated and recharged magma chamber at Rhum, Scotland, and 2) detailed studies of the dated eruption products of open system differentiation at Ngauruhoe volcano, New Zealand. The first study will allow examination of a far more protracted and complete differentiation history than is represented by volcanic rock suites, while the second, by virtue of the excellent time constraints, may enable calibration of open system differentiation through time.