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

这个美国-墨西哥奖项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博士合作的一个项目。研究人员的目标是研究墨西哥西部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。墨西哥西部新生代火山和构造演化受到两个过程的影响--加利福尼亚州海湾的张开和里维拉板块俯冲到北美板块之下的挤压。尽管有一些证据表明墨西哥西部出现了隆升，但这种隆升的时间尚不确定。它可能是年轻的，完全与当前的俯冲环境有关。或者它可以追溯到中新生代，当时该地区开始经历变化，作为下加利福尼亚转移到太平洋板块的结果。为了了解该地区的隆升历史，研究人员建议使用新的同位素方法确定墨西哥西部阿滕吉洛地区的区域隆升速率。这项技术已经在一小套样本上成功测试。此外，选定的一套非常年轻的火山岩将来自墨西哥西部地区。这项研究的结果将与该地区的地质研究相结合，并与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.