Evaluating Mantle and Crustal Processes in Off-axis Volcanism on Iceland

GSTDTAP

项目编号	1550415
	Evaluating Mantle and Crustal Processes in Off-axis Volcanism on Iceland
	David Peate
主持机构	University of Iowa
项目开始年	2016
	2016-08-01
项目结束日期	2019-07-31
资助机构	US-NSF
项目类别	Continuing grant
项目经费	154059(USD)
国家	美国
语种	英语
英文摘要	Most volcanoes in Iceland are concentrated in a NE-SW rift that traverses the center of the island. This rift marks where two tectonic plates are drifting apart, which causes the underlying mantle rocks to rise and melt, forming magma that creates volcanic eruptions at the surface. However, the reasons are less clear why some volcanoes are found in the Snaefellsnes Peninsula in the western part of Iceland (including Snaefellsjökull - made famous in Jules Verne's novel as the place where travellers could 'Journey to the Center of the Earth'). This project aims to understand why and how the mantle melts in this region by analysing the chemical composition of the lavas. From the size distribution and chemical composition of crystals of specific minerals in lavas, it is possible to determine how and where the crystals were formed, thereby revealing details of what was happening at depth beneath each volcano prior to lavas eruption. College-level teaching resources will be developed based on these samples that integrate chemical data sets with field photographs and a web-based digital virtual microscope, and made available to other educators. Public outreach activities will be coordinated through the University of Iowa Museum of Natural History, with the creation of a "Discovery Trunk" on Volcanoes for local schools to use, and participation in the Museum's public lecture series. More attention has been given to melt generation and storage in the Iceland rift zones because of their dominance on melt production, but the reasons for melt generation at large (~100km+) distances from the rifts, like at Snaefellsnes, remain uncertain. This project will be the first in-depth study of primitive lavas in this off-axis zone that focuses on how melts are generated and transported to the surface, to investigate the underlying cause of melting and how details of melt aggregation and transport through thick lithosphere contrasts with the extensional setting and thinner lithosphere of the rift zones. Crystallization depths will be estimated from glass analyses (using ol-cpx-plag saturation) and clinopyroxene thermobarometry, and melt diversity will be characterized with olivine-hosted melt inclusions and clinopyroxene compositions. Radiogenic isotopes and U-series disequilibria will be used to provide insights into the compositional heterogeneity and melting behavior of mantle sources and the process of melt extraction, and additional constraints on the details of melting will come from REE inversion models. The potential of high-precision minor element analyses of olivines to show involvement of non-peridotite sources for off-axis magmas will also be evaluated. The project will provide training in research methods and data acquisition/interpretation for a Ph.D. student, and research experiences for undergraduates. Results will be disseminated through journal articles and conference presentations.
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文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69908
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	David Peate.Evaluating Mantle and Crustal Processes in Off-axis Volcanism on Iceland.2016.