Processes of Isotopic Resetting in the Contact Aureole of the Laramie Anorthosite Complex

本研究项目的主要目的是了解拉勒米斜长杂岩接触光圈中矿物中U-Pb和Sm- Nd体系的同位素重置过程。利用常规相平衡法、氧同位素测温法和Ar-Ar黑云母和角闪石冷却年龄对光圈的时间-温度剖面进行了细化。然后，所得剖面将用于限制钛铁矿、榍石、磷灰石、石榴石和独居石等矿物中U-Pb和Sm-Nd系统的闭合温度和重置过程。通过比较光晕中来自反应性和非反应性岩石类型的矿物中U-Pb和Sm-Nd年龄重置的温度，可以检查矿物反应和体积扩散对各种同位素系统再平衡的影响。

The principal objective of this research project is to understand isotopic resetting processes for the U-Pb and Sm- Nd systems in minerals in the contact aureole of the Laramie Anorthosite Complex. The time-temperature profile of the aureole will be refined using conventional phase equilibria, oxygen isotope thermometry and Ar-Ar biotite and hornblende cooling ages. The resulting profile will then be used to place constraints on the closure temperatures and resetting processes for the U-Pb and Sm-Nd systematics in minerals such as ilmenite, sphene, apatite, garnet and monazite. Comparison of the temperatures at which the U-Pb and Sm-Nd ages reset in minerals from reactive and non-reactive rock types in the aureole will permit examination of the effects of mineral reactions and volume diffusion on reequilibration of the various isotopic sytems.