On the radiogenic heat production of metamorphic,igneous,and sedimentary rocks

作     者：D.Hasterok M.Gard J.Webb 

作者机构：Department of Earth SciencesUniversity of AdelaideNorth TerraceSA5005Australia Centre for Tectonics Research and Exploration(TRaX)University of AdelaideNorth TerraceSA5005Australia Ramelius Resources Ltd.East PerthWA 6005Australia 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2018年第9卷第6期

页      面：1777-1794页

核心收录：

学科分类：07[理学] 

基　　金：supported by Australian Government Research Training Program Scholarship 

主　　题：Heat generation Density Metamorphic rocks Sedimentary rocks Igneous rocks Continental lithosphere 

摘      要：Sedimentary rocks cover-73% of the Earth s surface and metamorphic rocks account for approximately91% of the crust by volume. Understanding the average behavior and variability of heat production for these rock types are vitally important for developing accurate models of lithospheric temperature. We analyze the heat production of ～204,000 whole rock geochemical data to quantify how heat production of these rocks varies with respect to chemistry and their evolution during metamorphism. The heat production of metaigneous and metasedimentary rocks are similar to their respective protoliths. Igneous and metaigneous samples increase in heat production with increasing SiO_2 and K_2 O, but decrease with increasing FeO, MgO and CaO. Sedimentary and metasedimentary rocks increase in heat production with increasing Al_2 O_3, FeO, TiO_2, and K_2 O but decrease with increasing CaO. For both igneous and sedimentary rocks, the heat production variations are largely correlated with processes that affect K_2 O concentration and covary with other major oxides as a consequence. Among sedimentary rocks,aluminous shales are the highest heat producing(2.9 μW^(-3)) whereas more common iron shales are lower heat producing(1.7 μW m^(-3)). Pure quartzites and carbonates are the lowest heat producing sedimentary rocks. Globally, there is little definitive evidence for a decrease in heat production with increasing metamorphic grade. However, there remains the need for high resolution studies of heat production variations within individual protoliths that vary in metamorphic grade. These results improve estimates of heat production and natural variability of rocks that will allow for more accurate temperature models of the lithosphere.