DOI: 10.1016/j.epsl.2018.03.018
Scopus记录号: 2-s2.0-85044595689
论文题名: Seismic evidence for depth-dependent metasomatism in cratons
作者: Eeken T. ; Goes S. ; Pedersen H.A. ; Arndt N.T. ; Bouilhol P.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 491 起始页码: 148
结束页码: 159
语种: 英语
英文关键词: cratons
; geothermal structure
; lithosphere
; metasomatism
; Rayleigh wave dispersion
Scopus关键词: Carbon dioxide
; Heat flux
; Heat transfer
; Kaolinite
; Mica
; Mineralogy
; Rayleigh waves
; Seismic waves
; Seismology
; Serpentine
; Structural geology
; cratons
; Geothermal structure
; lithosphere
; metasomatism
; Rayleigh-wave dispersion
; Dispersion (waves)
; craton
; geothermal system
; lithosphere
; metasomatism
; Moho
; Rayleigh wave
; seismic data
; wave dispersion
; Australia
; Baltic Shield
; Canada
; East European Craton
; Slave Province
; Western Australia
; Yilgarn Block
; Calluna vulgaris
英文摘要: The long-term stability of cratons has been attributed to low temperatures and depletion in iron and water, which decrease density and increase viscosity. However, steady-state thermal models based on heat flow and xenolith constraints systematically overpredict the seismic velocity-depth gradients in cratonic lithospheric mantle. Here we invert for the 1-D thermal structure and a depth distribution of metasomatic minerals that fit average Rayleigh-wave dispersion curves for the Archean Kaapvaal, Yilgarn and Slave cratons and the Proterozoic Baltic Shield below Finland. To match the seismic profiles, we need a significant amount of hydrous and/or carbonate minerals in the shallow lithospheric mantle, starting between the Moho and 70 km depth and extending down to at least 100–150 km. The metasomatic component can consist of 0.5–1 wt% water bound in amphibole, antigorite and chlorite, ∼0.2 wt% water plus potassium to form phlogopite, or ∼5 wt% CO2 plus Ca for carbonate, or a combination of these. Lithospheric temperatures that fit the seismic data are consistent with heat flow constraints, but most are lower than those inferred from xenolith geothermobarometry. The dispersion data require differences in Moho heat flux between individual cratons, and sublithospheric mantle temperatures that are 100–200 °C less beneath Yilgarn, Slave and Finland than beneath Kaapvaal. Significant upward-increasing metasomatism by water and CO2-rich fluids is not only a plausible mechanism to explain the average seismic structure of cratonic lithosphere but such metasomatism may also lead to the formation of mid-lithospheric discontinuities and would contribute to the positive chemical buoyancy of cratonic roots. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109927
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Earth Science and Engineering, Imperial College, London, United Kingdom; LGIT, Université Joseph Fourier, Grenoble, France; CRPG, Université de Lorraine, UMR 7358, Vandoeuvre-Lès-Nancy, F-54501, France
Recommended Citation:
Eeken T.,Goes S.,Pedersen H.A.,et al. Seismic evidence for depth-dependent metasomatism in cratons[J]. Earth and Planetary Science Letters,2018-01-01,491