HR: 11:05h
AN: T22B-04 INVITED    [Abstracts]
TI: A Reference Heat Generation Model for the Continental Lithosphere Constrained by Heat Flow and Elevation
AU: * Hasterok, D
EM: dhasterok@earth.utah.edu
AF: University of Utah, Dept. of Geology and Geophysics 135 S 1460 E WBB 719, Salt Lake City, UT 84112, United States
AU: Chapman, D S
EM: David.Chapman@gradschool.utah.edu
AF: University of Utah, Dept. of Geology and Geophysics 135 S 1460 E WBB 719, Salt Lake City, UT 84112, United States
AB: We propose a new general heat generation model within the continental lithosphere. Heat generation within the upper crust (~16~km) is parameterized as a percentage of the surface heat flow to account for the general decrease in heat flow and heat generation with crustal age. We explore constant, linear and exponential heat production relations as viable models. The best-fitting thermal isostatic model suggests ~30% of the surface heat flow is due to heat generation within this layer. Our model assumes a lower crustal heat generation of 0.4~μW-m^-3, consistent with observations from exposed granulite terranes (0.15--2.08~μW- m^-3, median 0.4~μW-m^-3) but somewhat higher than mafic lower crustal xenoliths (0.13~μW-m^-3). We estimate mantle heat generation as 0.02~μW-m^-3, consistent with estimates of non-kimberlite hosted cratonic xenoliths (0.019~μW-m^-3) and previous modeling studies (0 - 0.03~μW-m^-3). Tests of elevation sensitivity to heat generation variations show that much of the scatter about the best-fitting thermal isostatic relationship may be due to deviations from the reference heat generation. Continental elevation provides a new constraint to improve lithospheric heat generation estimates, thus allowing more accurate determination of lithospheric and boundary temperatures and heat flow, all of which have important geodynamic implications.
DE: 1020 Composition of the continental crust
DE: 5418 Heat flow
DE: 7218 Lithosphere (1236)
DE: 8125 Evolution of the Earth (0325)
DE: 8130 Heat generation and transport
SC: Tectonophysics [T]
MN: 2007 Fall Meeting