DOI: 10.1016/j.epsl.2018.02.028
Scopus记录号: 2-s2.0-85042914866
论文题名: Infiltration-driven metamorphism, New England, USA: Regional CO2 fluxes and implications for Devonian climate and extinctions
作者: Stewart E.M. ; Ague J.J.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 489 起始页码: 123
结束页码: 134
语种: 英语
英文关键词: fluid infiltration
; metamorphic carbon flux
; metamorphic decarbonation
; thermodynamic modeling
Scopus关键词: Carbon
; Global warming
; Sea level
; Amphibolite facies
; Carbon fluxes
; Decarbonation
; Fluid composition
; Mineral composition
; New England , USA
; Reaction temperature
; Thermodynamic model
; Carbon dioxide
英文摘要: We undertake thermodynamic pseudosection modeling of metacarbonate rocks in the Wepawaug Schist, Connecticut, USA, and examine the implications for CO2 outgassing from collisional orogenic belts. Two broad types of pseudosections are calculated: (1) a fully closed-system model with no fluid infiltration and (2) a fluid-buffered model including an H2O–CO2 fluid of a fixed composition. This fluid-buffered model is used to approximate a system open to infiltration by a water-bearing fluid. In all cases the fully closed-system model fails to reproduce the observed major mineral zones, mineral compositions, reaction temperatures, and fluid compositions. The fluid-infiltrated models, on the other hand, successfully reproduce these observations when the XCO2 of the fluid is in the range ∼0.05 to ∼0.15. Fluid-infiltrated models predict significant progressive CO2 loss, peaking at ∼50% decarbonation at amphibolite facies. The closed-system models dramatically underestimate the degree of decarbonation, predicting only ∼15% CO2 loss at peak conditions, and, remarkably, <1% CO2 loss below ∼600 °C. We propagate the results of fluid-infiltrated pseudosections to determine an areal CO2 flux for the Wepawaug Schist. This yields ∼1012 mol CO2 km−2 Myr−1, consistent with multiple independent estimates of the metamorphic CO2 flux, and comparable in magnitude to fluxes from mid-ocean ridges and volcanic arcs. Extrapolating to the area of the Acadian orogenic belt, we suggest that metamorphic CO2 degassing is a plausible driver of global warming, sea level rise, and, perhaps, extinction in the mid- to late-Devonian. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109958
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: Yale University Department of Geology & Geophysics, P.O. Box 208109, New Haven, CT 06520-8109, United States
Recommended Citation:
Stewart E.M.,Ague J.J.. Infiltration-driven metamorphism, New England, USA: Regional CO2 fluxes and implications for Devonian climate and extinctions[J]. Earth and Planetary Science Letters,2018-01-01,489