Graham Harper Edwards, PhD

Graham Harper Edwards, PhD

he | him
Cosmochemistry
Geochronology
NSF Postdoctoral Fellow

graham.h.edwards at dartmouth.edu

Publications

Ice retreat in Wilkes Basin of East Antarctica during a warm interglacial

T. Blackburn, G.H. Edwards, S. Tulaczyk, M. Scudder, G. Piccione, B. Hallet, N. McLean, J.C. Zachos, B. Cheney, & J.T. Babbe
Nature, 2020       PDF       Web

Press coverage in National Geographic
U-series isotopics of subglacial precipitates from beneath the East Antarctic Ice Sheet (EAIS) record an open-system event ca. 400,000 years ago in the subglacial Wilkes Basin. Our data and models support ice retreat and seawater incursion during this time, suggesting that the Pleistocene EAIS was not as stable as previously assumed. These findings bear important implications for future EAIS stability in a warming climate.

Detecting the extent of ca. 1.1 Ga Midcontinent Rift plume heating using U-Pb thermochronology of the lower crust

Graham Harper Edwards and Terrence Blackburn
Geology, 2018       PDF       Web

We combine U-Pb thermochronology of rutile and apatite from middle-to-lower crustal xenoliths form an Attawapiskat kimberlite with paired crustal thermal and Pb-production diffusion models to ascertain the timescales of plume heating beneath the Superior Craton in midwestern Canada. Thermochronologic data are best fit by model simulations in which the Attawapiskat lithosphere experienced a ca. 1.1 Ga heating event triggered by partial lithosphere removal and mantle temperatures >200 °C in excess of that of ambient mantle, consistent with a model of ∼100 m.y. plume head residence beneath the Attawapiskat region.