DOI: 10.1016/j.epsl.2018.05.027
Scopus记录号: 2-s2.0-85047986192
论文题名: An experimental investigation of C–O–H fluid-driven carbonation of serpentinites under forearc conditions
作者: Sieber M.J. ; Hermann J. ; Yaxley G.M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 496 起始页码: 178
结束页码: 188
语种: 英语
英文关键词: carbonation
; C–O–H fluid
; deep carbon cycle
; forearc
; partitioning
; serpentinites
Scopus关键词: Budget control
; Carbon
; Carbon dioxide
; Gas chromatography
; Kaolinite
; Lithology
; Magnesite
; Quartz
; Serpentine
; Structural geology
; Talc
; Deep carbon cycles
; Experimental investigations
; Forearc
; Hydrated mantle wedges
; partitioning
; serpentinites
; Thermodynamic calculations
; Time-series experiments
; Carbonation
; carbon cycle
; experimental study
; forearc basin
; partitioning
; serpentinite
; subduction zone
英文摘要: The carbonation of serpentinites in the forearc region of the mantle wedge in subduction zones and of serpentinites within the subducting slab by fluids derived from prograde dehydration and decarbonation has important implications for the deep Earth carbon cycle. This study shows that the carbonation of serpentinites under the forearc can establish, over time, a significant reservoir for carbon within a partially hydrated mantle wedge and that carbonation of (ultra-) mafic rocks within the subducting slab contributes to C-transfer to greater depths and might supply carbon for arc volcanism or the deep mantle. We report a new high pressure experimental investigation of the interactions between oxidised C–O–H fluids and serpentinite and model the reaction progress with time series experiments. The CO2, H2O and alkane (CnH2n+2, n=1–6; e.g. methane, ethane) contents in the fluid phase from quenched experimental run products have been analysed by gas chromatography and the results are compared with thermodynamic calculations. With progressive carbonation, the formation of magnesite + chlorite together with quartz, quartz + talc or talc at 1–2 GPa and 500–650 °C was observed. At temperatures above antigorite stability (T≳700 °C and 2 GPa) magnesite + chlorite is stable together with talc, talc + enstatite, enstatite or enstatite + forsterite for decreasing CO2-content in the fluid. Carbonation of serpentinite is a rapid process where magnesite forms within the first hour of the experiments, filtering CO2 from the fluid effectively and equilibrium is approached within 48 h. The CO2-sequestration and magnesite production are less pronounced at higher temperatures. Therefore, C–O–H fluids released under subarc conditions might migrate through the mantle with only minor changes in their carbon budget whereas significant carbonation likely occurs under the forearc. Furthermore, partition coefficients for Ca, Ba, Sr and Pb between magnesite and a C-poor aqueous fluid have been established to demonstrate the potential of newly formed magnesite to sequester fluid mobile elements. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109787
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: Research School of Earth Science, The Australian National University, Canberra, 2601, Australia; Institute of Geological Sciences, University of Bern, Bern, 3012, Switzerland
Recommended Citation:
Sieber M.J.,Hermann J.,Yaxley G.M.. An experimental investigation of C–O–H fluid-driven carbonation of serpentinites under forearc conditions[J]. Earth and Planetary Science Letters,2018-01-01,496