DOI: 10.1016/j.epsl.2017.10.010
Scopus记录号: 2-s2.0-85033678533
论文题名: Carbon dioxide generation and drawdown during active orogenesis of siliciclastic rocks in the Southern Alps, New Zealand
作者: Menzies C.D. ; Wright S.L. ; Craw D. ; James R.H. ; Alt J.C. ; Cox S.C. ; Pitcairn I.K. ; Teagle D.A.H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 481 起始页码: 305
结束页码: 315
语种: 英语
英文关键词: carbon cycle
; carbon isotopes
; chemical weathering
; CO2
; metamorphism
; mountain building
Scopus关键词: Atmospheric chemistry
; Budget control
; Calcite
; Carbonation
; Dissolution
; Geochemistry
; Graphite
; Hot springs
; Isotopes
; Landforms
; Metamorphic rocks
; Weathering
; Carbon cycles
; Carbon isotopes
; Chemical weathering
; metamorphism
; Mountain building
; Carbon dioxide
; carbon budget
; carbon cycle
; carbon dioxide
; carbon isotope
; chemical weathering
; host rock
; metamorphism
; orogeny
; siliciclastic deposit
; thermal spring
; vein (geology)
; New Zealand
; South Island
; Southern Alps
英文摘要: Collisional mountain building influences the global carbon cycle through release of CO2 liberated by metamorphic reactions and promoting mechanical erosion that in turn increases chemical weathering and drawdown of atmospheric CO2. The Southern Alps is a carbonate-poor, siliciclastic mountain belt associated with the active Australian Pacific plate boundary. On-going, rapid tectonic uplift, metamorphism and hydrothermal activity are mobilising carbon. Here we use carbon isotope measurements of hot spring fluids and gases, metamorphic host rocks, and carbonate veins to establish a metamorphic carbon budget. We identify three major sources for CO2 within the Southern Alps: (1) the oxidation of graphite; (2) consumption of calcite by metamorphic reactions at the greenschist–amphibolite facies boundary, and (3) the dissolution of groundmass and vein-hosted calcite. There is only a minor component of mantle CO2 arising on the Alpine Fault. Hot springs have molar HCO3 −/Ca2+ ∼9, which is substantially higher than produced by the dissolution of calcite indicating that deeper metamorphic processes must dominate. The total CO2 flux to the near surface environment in the high uplift region of the Southern Alps is estimated to be ∼6.4 × 108 mol/yr. Approximately 87% of this CO2 is sourced from coupled graphite oxidation (25%) and disseminated calcite decarbonation (62%) reactions during prograde metamorphism. Dissolution of calcite and mantle-derived CO2 contribute ∼10% and ∼3% respectively. In carbonate-rich orogens CO2 production is dominated by metamorphic decarbonation of limestones. The CO2 flux to the atmosphere from degassing of hot springs in the Southern Alps is 1.9 to 3.2 × 108 mol/yr, which is 30–50% of the flux to the near surface environment. By contrast, the drawdown of CO2 through surficial chemical weathering ranges between 2.7 and 20 × 109 mol/yr, at least an order of magnitude greater than the CO2 flux to the atmosphere from this orogenic belt. Thus, siliciclastic mountain belts like the Southern Alps are net sinks for atmospheric CO2, in contrast to orogens involving abundant carbonate rocks, such as the Himalaya, that are net CO2 sources. © 2017 The Author(s) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110184
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, United Kingdom; Department of Geology, University of Otago, Dunedin, 9016, New Zealand; Department of Earth and Environmental Science, The University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109-1005, United States; GNS Science, Private Bag 1930, Dunedin, 9054, New Zealand; Department of Geological Sciences, Stockholm University, Stockholm, SE-10691, Sweden
Recommended Citation:
Menzies C.D.,Wright S.L.,Craw D.,et al. Carbon dioxide generation and drawdown during active orogenesis of siliciclastic rocks in the Southern Alps, New Zealand[J]. Earth and Planetary Science Letters,2018-01-01,481