Testing contrasting models for the distribution of hydrothermal circulation in subducting crust

GSTDTAP

项目编号	1551587
	Testing contrasting models for the distribution of hydrothermal circulation in subducting crust
	Glenn Spinelli
主持机构	New Mexico Institute of Mining and Technology
项目开始年	2016
	2016-06-01
项目结束日期	2019-05-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	203427(USD)
国家	美国
语种	英语
英文摘要	Subduction zones are where one of Earth's tectonic plates moves under another resulting in many of the world's largest earthquakes and damaging tsunamis. One example is the 2011 earthquake and tsunami in northern Japan that killed more than 20,000 people and crippled the Fukushima Daiichi nuclear complex. These earthquakes arise from friction on the subduction zone fault that separates the two tectonic plates. The temperature of the subduction fault zone affects this friction and can control the size and distribution of earthquakes. In addition, subduction zone temperatures affect a wide range of other physical and chemical processes, including the generation of magma that supplies nearby volcanoes. To understand these processes, it is important to accurately estimate subduction zone temperatures. Recent discoveries show that seawater circulating within the subducting tectonic plates is an important control on subduction zone temperatures. This project will examine how fractures that open in the upper part of a tectonic plate as it bends down into a subduction zone affect seawater circulation in the system and how that affects subduction zone temperatures. The project will develop numerical thermal models for seven subduction zones. Application of the results of this research has direct societal benefit, by informing earthquake hazard estimates. In addition, the project will enhance education at New Mexico Tech, a STEM-focused Hispanic-serving institution. A graduate student will be trained in geophysics and hydrogeology. Results of the project will be incorporated into "using data in the classroom" efforts, improving hands-on experience in undergraduate courses. Accurate subduction zone thermal models are necessary to understand frictional behavior, metamorphic reaction progress, release of volatiles from the subducting slab, mantle wedge hydration, subduction dynamics, and melt generation. Fluid circulation in an oceanic crustal aquifer is an important control on subduction zone temperatures. However, there are contrasting hypotheses for how much of the oceanic crust can host vigorous hydrothermal circulation. Both thickening of the oceanic crustal aquifer via plate bending normal faults and fluid circulation between subducted crust and the crust seaward of the trench may contribute to the advective redistribution of heat that affects subduction zone temperatures. This project will test the hypothesis that the thermal effects of aquifer thickening prior to subduction are greater for slabs with a greater degree of curvature. This project will exploit the fact that aquifer thickening from the outer rise to the trench and continued fluid circulation in subducting crust are expected to produce distinct surface heat flux anomalies (a broad low amplitude anomaly for aquifer thickening; a narrow high amplitude anomaly for fluid circulation in subducting crust) in order to constrain the thermal effects of each process. This will advance our understanding of the fluid circulation process that is an important control on subduction zone temperatures, improving subduction zone thermal models for the seven margins examined in this project and others.
来源学科分类	Geosciences - Ocean Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69587
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Glenn Spinelli.Testing contrasting models for the distribution of hydrothermal circulation in subducting crust.2016.