U.S.-Mexico Collaborative Research: Plio-Quaternary uplift and tectonism of western Mexico from geologic studies and 36Cl cosmogenic isotopes

这项美国-墨西哥奖将资助亚利桑那大学的Kevin Righter博士与墨西哥瓜达拉哈拉大学的Jose Rosas-Elguera博士合作的一个合作项目。研究人员的目的是研究墨西哥西部的新生代火山和构造演化。该项目将有助于确定墨西哥西部最近火山活动的年龄，并提高我们对火山活动时空分布的理解。地球科学司也将为该项目提供部分支持。墨西哥西部的新生代火山和构造演化受到加利福尼亚湾张开的伸展和里维拉板块俯冲到北美板块之下的挤压两个过程的影响。尽管在墨西哥西部有一些隆起的证据，但隆起的时间是不确定的。它可能很年轻，完全与当前的俯冲环境有关。或者可以追溯到中生代中期，由于下加利福尼亚向太平洋板块的转移，该地区开始发生变化。为了了解该地区的隆起历史，研究人员建议使用新的同位素方法确定墨西哥西部Atenguillo地区的区域隆起率。这项技术已经在一小批样品上得到了成功的测试。此外，还将对墨西哥西部地区的一组非常年轻的火山岩进行年代测定。这项研究的结果将与该地区的地质研究，以及最近和正在进行的区域板块运动和GPS研究的结果相结合。

0123000RighterThis US-Mexico award will fund a collaborative project between Dr. Kevin Righter, of the University of Arizona, in collaboration with Dr. Jose Rosas-Elguera of the University of Guadalajara, Mexico. The researchers aim to study the Cenozoic volcanic and tectonic evolution of western Mexico. The project will help to determine ages of more recent volcanic activity in western Mexico, and improve our understanding of the spatial and temporal distribution of volcanism. The Division of Earth Sciences will also contribute partial support for this project. The Cenozoic volcanic and tectonic evolution of western Mexico has been influenced by two processes - extension from opening of the Gulf of California, and compression from the subduction of the Rivera Plate beneath the North American Plate. Although there is some evidence for uplift in western Mexico, the timing of that uplift is uncertain. It may be young and related entirely to the current subduction environment. Or it could date back to the mid-Cenozoic, when the region started undergoing change as a result of the transfer of Baja California to the Pacific Plate. In order to understand the uplift history of this region, the researchers propose to determine regional uplift rates in the Atenguillo region of western Mexico, using new isotopic methods. The technique has been tested successfully on a small suite of samples. In addition, a selected suite of very young volcanic rocks will be dated from the western Mexico region. Results of this study will be integrated with geologic studies of the area, and also with the results of recent and ongoing regional plate motion and GPS studies.