From Cones to Clusters: Evolution of a Monogenetic Volcanic Field

点击翻译按钮获取中文摘要

Monogenetic volcanoes, those that erupt only once, are the most common expression of magmatism on the Earth's surface, and they are found in every tectonic setting, yet key aspects of the behavior and evolution of monogenetic volcanic systems remain poorly understood. Understanding the processes that govern evolution of monogenetic volcanoes, and the time scales over which these processes operate, is critical for hazard and risk assessment in active monogenetic volcanic fields. In particular, it is important to understand whether magmas ascend rapidly from the mantle to the surface, or instead undergo prolonged residence in the shallow crust, as this will influence the nature and timing of potential eruptive precursors that might be monitored, including seismicity, ground deformation, hydrologic changes, or gas emission. This project will provide key constraints on the sources, processes, and time scales of magma ascent and storage leading to eruption of monogenetic volcanoes in the Trans-Mexican Volcanic Belt - the largest monogenetic volcanic field in the world - and will provide an important framework for better understanding the behavior of monogenetic volcanic fields globally. The project will support the thesis work of a female graduate student in a STEM field where females are underrepresented. Two female high school students will be recruited to participate via internships. A colleague of Mexican heritage is co-PI an will work directly mentoring students.This project will investigate recent, individual monogenetic cones and cone clusters linked closely in space and time, to address the processes and timescales governing magma evolution and temporal-compositional variations in the Michoac?n-Guanajuato Volcanic Field (MGVF) in the central Trans-Mexican Volcanic Belt. Primary objectives of the project include assessing the relative importance of mantle versus crustal control on magmatism producing MGVF monogenetic clusters, and evaluating the similarities and differences that lead to formation of successive individual cinder cones versus small shield volcanoes. Specific questions include: 1) are multiple magma sources tapped in single eruptions?; 2) are the same magmas tapped in successive eruptions?; 3) are magmas stored at crustal levels, and if so, for how long?; 4) do different clusters exhibit common compositional progressions?; and 5) how do the processes and timescales of small shield volcano evolution compare to those of cinder cones? Target study areas include Late Pleistocene and Holocene cinder cone clusters in the Tac?mbaro, Tanc?taro and Zacapu areas, and the Holocene El Metate small shield volcano, all of which have recently been mapped in detail and dated. These questions will be addressed through geochemical and isotopic analysis at the mineral and whole-rock scales. The project will support the research of a female graduate student and several undergraduate students, including collaboration with a minority-recruiting organization on campus. Two female high school students will be recruited to participate in a STEM outreach effort. A colleague of Mexican heritage is co-PI an will work directly mentoring students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.