DOI: 10.1016/j.epsl.2021.117091
论文题名: Heat flow constraints on the mafic character of Archean continental crust
作者: Hawkesworth C. ; Jaupart C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 571 语种: 英语
中文关键词: bulk Archaean continental crust
; heat flow
; heat production
; proportion of mafic crust
英文关键词: Binary alloys
; Gallium
; Magnesia
; Silica
; Structural geology
; Archaean
; Bulk archean continental crust
; Crustals
; Heat flow value
; Heat production
; Heat-flow
; Production value
; Proportion of mafic crust
; SiO$-2$
; Surface heat flow
; Heat transfer
英文摘要: The bulk composition of the continental crust can be constrained from its surface heat flow. Published values of heat flow and heat production from 17 areas ranging in age from 3.3 to 0.4 Ga are compared. In the Superior province, the ca. 2.7 Ga accreted belts have a heat flow of 41mWm−2, significantly higher than that in the older, ca. 3.0 Ga, craton core (32mWm−2) (Jaupart et al., 2014). The mean surface heat flow values are 40±1.2mWm−2 for the Archaean areas, and 53±1.9mWm−2 for the post-Archaean. Heat flow values into the base of the crust are constrained from P-T estimates in lithospheric mantle xenoliths, and subtracted from the surface heat flow to calculate the bulk crustal heat production, whereupon there is a strong correlation between the surface heat flow data and the calculated average bulk crustal heat production values. Average crustal heat production values are described in terms of two component mixtures of felsic crust with >57% SiO2, and mafic crust with <57% SiO2, which is suggested to be more robust than relying on an average seismic model, given the complexity of the crustal structure and how it varies between provinces, and sometimes within a single province. The proportions of the mafic crustal component required to account for the regional bulk heat production values in 5 areas older than 2.8 Ga range from 60–78% consistent with a fixed mafic proportion of ∼70%. This is higher than the proportion of lower, mafic crust in the present bulk crust of Rudnick and Gao (2014), which is 43%, and the estimated bulk crust MgO values change from 10–6.6% in areas older than 2.8 Ga, to ∼5% MgO for the younger areas. The bulk crust in the late Archaean was on average more mafic than the bulk crust at the present day, and it had a bulk crust Rb/Sr value of 0.12±0.04. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165501
Appears in Collections: 气候变化与战略
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作者单位: University of Bristol, School of Earth Sciences, Queens Road, Bristol, UK, United Kingdom; Université de Paris, Institut de physique du globe de Paris, CNRS, Paris, F-75005, France
Recommended Citation:
Hawkesworth C.,Jaupart C.. Heat flow constraints on the mafic character of Archean continental crust[J]. Earth and Planetary Science Letters,2021-01-01,571