Continental flood basalts are the products of events in which very large volumes of magma (105 - 107 km3) are erupted in geologically short periods of time (=106 years). Although there is widespread agreement that rising deep-rooted mantle plumes provide the heat source for such intense volcanism, other mantle and crustal rocks may melt under the thermal impact of the plume to contribute some, perhaps most, of the total erupted mass of flood basalt. Assessing the relative contributions of magma from these different sources to continental flood basalt lavas is a long-standing problem. This project will apply modern approaches of small-scale sampling, targeting key geochemical tracers (chiefly isotope ratios) within and between single crystals and basalt matrix, to the Columbia River flood basalts. Because this approach is based on rock textures that grow sequentially, this research will enable reconstruction of how and in what order the magmas were assembled from different sources. In addition, residence times of crystals in their host magmas can be obtained by diffusion modeling of spatial variations in isotope abundance ratios in crystals, allowing constraints to be placed on the durations of individual eruptions, which is an important parameter in assessing the potential these events have for global climate and ecological disruption. Over the next few years, the techniques to be employed will enter the mainstream of geochemical investigations into volcanism, and training research students to meet this need is a further benefit of the project.

Agency
National Science Foundation (NSF)
Institute
Division of Earth Sciences (EAR)
Application #
0440336
Program Officer
Sonia Esperanca
Project Start
Project End
Budget Start
2005-01-01
Budget End
2008-12-31
Support Year
Fiscal Year
2004
Total Cost
$182,888
Indirect Cost
Name
Washington State University
Department
Type
DUNS #
City
Pullman
State
WA
Country
United States
Zip Code
99164