Geochemistry and U-Pb Zircon Geochronology of the Central Mexican Lower Crust

5月，在美国国家科学基金会赞助的墨西哥中部含捕虏体玄武岩调查期间，卢尔、研究生格雷格·普尔和我们的墨西哥同事豪尔赫·阿兰达-戈麦斯访问了墨西哥中部两个主要的下地壳捕虏体所在地。详细调查了每个喷口的地壳和地幔包体的空间丰度，并试图根据手工取样观测来量化露头中捕虏体类型的相对丰度。Aranda-Gomez将在墨西哥国立大学的一项岩石学研究中继续这项统计工作，使用50-60个具有代表性的地壳包体的小碎片的薄片。这一项目构成了格雷格·普尔的A.M.论文题目。当他完成论文时，这笔助学金将支持他秋季学期的学习。这笔赠款提供的资金将通过仪器中子活化提供额外的微量元素分析。U-Pb年代学研究将集中在每个喷口的几个正片麻岩包体中的锆石。

In may 1989, during NSF-sponsored investigations of the xenolith- bearing basanites of central Mexico, Luhr, graduate student Greg Pool, and our Mexican colleague Jorge Aranda-Gomez visited two of the principal localities of lower-crustal xenoliths in central Mexico. Each vent was investigated in detail with regard to the spatial abundance of crustal and mantle xenoliths, and attempts were made to quantify the relative abundances of xenolith types in outcrop based on hand-sample observations. Aranda-Gomez will continue with this statistical work in a petrographic study at the Mexican National University using thin sections from small fragments of 50-60 representative crustal xenoliths. This project constitutes the A.M. thesis topic of Greg Pool. Funds from this grant will support him for the fall semester as he completes his thesis. Funds provided by this grant will provide additional trace element analyses by instrumental neutron activation. U-Pb geochronological investigations will concentrate on zircons in several orthogneiss xenoliths from each vent.