Steven B. Shirey

Research staff, geochemistry

 
 

    The goal of my research is to understand the evolution of the continents from top to bottom, from the Hadean to the present, and on a range of spatial scales (see figures below). The formation of the continents is the only chemical differentiation process to span nearly all of Earth history and to record, in its rock record, changes in geodynamic and magmatic processes over time. A recurring theme has been the demonstration that ancient episodes of magmatism and crust formation operated differently from those operating today. This broad topic which leaves the latitude to study continental volcanic rocks, subduction zone mechanisms for new crust creation, mantle evolution -especially changes related to continental crust creation, continental rifting, and the deep mantle keels to the continents. The latter subject has led to recent focus on the age and petrogenesis of diamonds. Diamonds bring up the deepest, oldest, and most pristine mineral inclusions from the mantle that are known on Earth. The chief tools for this research are radiogenic isotope systems such as Re-Os, Sm-Nd, and Pb-Pb and trace elements such as the highly siderophile elements (HSE) and the large ion lithophile elements (LILE).

Research Statement

PhD 1984, Geochemistry, SUNY Stony Brook

MSc 1975, Geology, University of Massachusetts, Amherst

AB 1972, Geology, Dartmouth College

Department of Terrestrial Magnetism

Carnegie Institution of Washington

5241 Broad Branch Road, NW

Washington, DC 20015 USA

Office: 114 Cyclotron Building

Office phone: (202) 478-8473

Cell phone:  (301) 792-9083

FAX number:  (202) 478-8821

E-mail address:  shirey_at_dtm_dot_ciw_dot_edu

Skype name: stevenshirey

Featured Publications  (November, 2010)

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These figures represent the wide range in scale that this research involves, from the continental scale to the microscopic. The left panel shows correspondence of diamond paragenesis with seismic structure of the Kaapvaal craton. The middle panel is a field photograph of an Archean mantle xenolith hosted in diamondiferous lamprophyre from Wawa, Ontario. The right panel is a sulfide inclusion in rough diamond (~3 mm across) from Orapa, Botswana. Click on the ‘Research’ tab above for more details on these images. A gallery of sulfide inclusion photos can be seen here.

Press Releases from the Department of Terrestrial Magnetism