Petrology and Geochemistry of the Stillwater Complex, Montana

9406243麦卡勒姆这项研究将提供对层状镁铁质侵入岩，特别是静水杂岩形成过程的更深入的了解。建议的研究包括三个子项目：(1)铂族元素(PGE)矿带的岩石成因；(2)辉长闪长岩中宏观韵律分层的起源；(3)岩浆流入演化岩浆室的影响。矿带的研究将利用电子和离子探针分析以及铅同位素研究，以阐明寄主岩性与地层层序之间的关系。第二个项目将把建模方法与通过微探针和图像分析方法获得的描述性纹理和矿物学数据结合起来，以测试成层定量模型的预测能力。第三个项目将利用电子和离子探针测定的矿物成分以及辉石的Nd同位素比率来确定特定接触带是岩浆流入的结果，还是分离结晶的结果。对Stillwater复合体的研究意义重大，因为它是西半球最大的前列腺素E(PGE)和铬储量的储存库。

9406243 McCallum This research will provide a deeper understanding of the processes that operate in the formation of layered mafic intrusions, especially the Stillwater complex. The proposed research includes three subprograms: (1) petrogenesis of the platinum group element (PGE) ore zone, (2) origin of macro rhythmic layering in gabbronorites, and (3) effects of influxes of magmas into an evolving magma chamber. The study of the ore zone will utilize electron and ion probe analyses and Pb isotopic studies to elucidate the relationship between the host lithologies and the stratigraphic sequence. The second project will combine a modeling approach with descriptive textural and mineralogical data obtained by microprobe and image analysis methods to test the predictive capacity of quantitative models of layer formation. The third project will utilize mineral compositions determined by electron and ion probe and Nd isotopic ratios of pyroxenes to determine whether specific contact zones are the result of magmatic influxes rather than fractional crystallization. Study of the Stillwater Complex is significant because it is the repository of the largest reserves of (PGE) and chromium in the western hemisphere.