The Evolution of Mantle Melting During Development of the Southernmost Basin and Range Province, Mexico

这是一个持续的项目，在这个项目中，已经对圣路易斯波托西较年轻的地幔衍生玄武岩进行了详细的综合研究，包括测量Sr和Nd同位素比率。这些数据表明至少有三个地幔源成分。该合同将使PIs能够对相同的样品进行Pb同位素分析，并将现场调查扩展到Durango地区和这两个地区更古老、富含岩浆的基长岩。他们还将尝试推断出捕虏体中Nd和Sr的总预算。这样就有可能在整个极端构造运动时期，追踪横跨最南端盆地和山脉省的500公里横断面的地幔融化历史。通过K-Ar和Ar-Ar方法进行年龄测定将在加州大学伯克利分校进行。在同位素分析之前，将对斜辉石进行探针研究和浸出。

This is a continuing project in which detailed, integrated studies have already been conducted of the younger, mantle- derived basanites of San Luis Potosi, including measurement of Sr and Nd isotope ratios. These data indicate at least three mantle source components. This award will enable the PIs to perform Pb isotopic analyses on the same samples, and to expand field based investigations to include the Durango area and the older, magacryst-rich basenites from both areas. They will also attempt to deduce total Nd and Sr budgets in the xenoliths. It should then be possible to trace the history of mantle melting for a 500-km transect across the southernmost Basin and Range Province throughout the period of extreme tectonism. Age dating by both K-Ar and Ar-Ar methods will be done at Cal-Berkeley. Probe studies and leaching of clinopyroxenes from lherzolites will be carried out prior to isotopic analysis.