Earth Sciences Postdoctoral Research Fellowship Award

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; R o o t E n t r y F % @ C o m p O b j b W o r d D o c u m e n t O b j e c t P o o l & ' ( ) * + , - . / 0 F Microsoft Word 6.0 Document MSWordDoc Word.Document.6 ; ; o o ; Bohrson, Wendy A. EAR-9505228 This is a carefully thought-out proposal to document changes in crust and mantle structures during high-magnitude extension by integrating structural, geochemical, and geochronological data in a well-exposed section of the Basin-and-Range. Over 4.5 km of volcanic rocks characterized by heterogeneous compositions and structural histories render the northern Eldorado Mountains of Nevada a remarkable target for investigating the interdependence of magma composition, magma volume, time, and extension rates. The data permit the PI to (1) address the genetic link between extension and magmatism, (2) to quantify the changing roles that crust, lithosphere, and asthenosphere have during rifting, and (3) document the magmatic evolution of a continental rift zone. By focusing on a restricted locality, the approach minimizes the complexities inherent in regional studies that compare areas with diachronous tectono-magmatic histories. The work will provide constraints on the evolution of mantle source regions, the contribution of the crust to magma genesis, and the thermal and chemical consequences of extension on crust and lithosphere. It represents one of the few studies that explicitly links rates of extension with changes in eruptive style, magma volume, and composition, and thus will provide fundamental constraints for understanding the tectono-magmatic history of areas affected by large-magnitude extension. Oh +' 0 $ H l D h S u m m a r y I n f o r m a t i o n ( % R:\WWUSER\TEMPLATE\NORMAL.DOT Bohrson, Wendy A. National Science Foundation Judy Hannah @ # @ @ k @ Microsoft Word 6.0 2 ; ; e = e Q @ @ @ y T X K p Bohrson, Wendy A. EAR-9505228 This is a carefully thought-out proposal to document changes in crust and mantle structures during high-magnitude extension by integrating structural, geochemical, and geochronological data in a well-exposed section of the Basin-and-Range. Over 4.5 km of volcanic rocks characterized by heterogeneous compositions and structural histories render the northern Eldorado Mountains of Nevada a remarkable target for investigating the interdependence of magma composition, magma volume, time, and extension rates. The data permit the PI to (1) address the genetic link between extension and magmatism, (2) to quantify the changing roles that crust, lithosphere, and asthenosphere have during rifting, and (3) document the magmatic evolution of a continental rift zone. By focusing on a restricted locality, the approach minimizes the complexities inherent in regional studies that compare areas with diachronous tectono-magmatic histories. The work will provide constraints on the evolution of mantle source regions, the contribution of the crust to mag