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Detailed Reference Information |
Hutchinson, D.R., White, R.S., Cannon, W.F. and Schulz, K.J. (1990). Keweenaw hot spot: Geophysical evidence for a 1.1 Ga mantle plume beneath the Midcontinent Rift system. Journal of Geophysical Research 95: doi: 10.1029/90JB00135. issn: 0148-0227. |
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The Proterozoic Midcontinent Rift System of North America is remarkably similar to Phanerozoic rifted continental margins and flood basalt provinces. Like the younger analogues, the volcanism within this older rift can be explained by decompression melting and rapid extrusion of igneous material during lithospheric extension above a broad, asthenospheric, thermal anomaly which we call the Keweenaw hot spot. Great Lakes International Multidisciplinary Program on Crustal Evolution seismic reflection profiles constrain end-member models of melt thickness and stretching factors, which yield an inferred mantle potential temperature of 1500¿--1570 ¿C during rifting. Combined gravity modeling and subsidence calculations are consistent with stretching factors that reached 3 or 4 before rifting ceased, and much of the lower crust beneath the rift consists of relatively high density intruded or underplaced synrift igneous material. The isotopic signature of Keweenawan volcanic rocks, presented in a companion paper by Nicholson and Shirey (this issue), is consistent with our model of passive rifting above an asthenospheric mantle plume. ¿ American Geophysical Union 1990 |
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Abstract |
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Keywords
Tectonophysics, Heat generation and transport, Information Related to Geologic Time, Precambrian, Information Related to Geographic Region, North America |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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