Release of CO2 from carbonate rocks during regional metamorphism of lithologically heterogeneous crust
2000; Geological Society of America; Volume: 28; Issue: 12 Linguagem: Inglês
10.1130/0091-7613(2000)28 2.0.co;2
ISSN1943-2682
Autores Tópico(s)Paleontology and Stratigraphy of Fossils
ResumoResearch Article| December 01, 2000 Release of CO2 from carbonate rocks during regional metamorphism of lithologically heterogeneous crust Jay J. Ague Jay J. Ague 1Department of Geology and Geophysics, Yale University, P.O. Box 208109, New Haven, Connecticut 06520-8109, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Jay J. Ague 1Department of Geology and Geophysics, Yale University, P.O. Box 208109, New Haven, Connecticut 06520-8109, USA Publisher: Geological Society of America Received: 31 Mar 2000 Revision Received: 13 Sep 2000 Accepted: 15 Sep 2000 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2000) 28 (12): 1123–1126. https://doi.org/10.1130/0091-7613(2000)28 2.0.CO;2 Article history Received: 31 Mar 2000 Revision Received: 13 Sep 2000 Accepted: 15 Sep 2000 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jay J. Ague; Release of CO2 from carbonate rocks during regional metamorphism of lithologically heterogeneous crust. Geology 2000;; 28 (12): 1123–1126. doi: https://doi.org/10.1130/0091-7613(2000)28 2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Prograde regional metamorphism drives CO2 from carbonate rock to crustal fluids that ascend and ultimately interact with the atmosphere and oceans. The observed loss of CO2 from metamorphic belts remains problematic, however, because the cooling that accompanies fluid ascent favors reactions that add CO2 to metacarbonate rock by removing CO2 from fluids. A new two-dimensional model of coupled mass transfer, chemical reaction, and heat transport was developed to assess how rock devolatilization proceeds along the upward escape paths of crustal fluids during prograde metamorphism. The model is based on upper greenschist to lower amphibolite facies growth of amphibole in metacarbonate layers and garnet and biotite in intercalated metapelite layers of the Wepawaug Schist, Connecticut (Acadian orogeny). The modeling indicates that during heating, CO2 concentrations were larger in metacarbonate layers than in adjacent metapelite layers because amphibole growth in metacarbonates produced CO2, whereas garnet and biotite growth in metapelites produced H2O. The resulting cross-layer concentration gradients drove H2O into the metacarbonate layers and CO2 out by diffusion and the transverse component of mechanical dispersion. Such cross-layer mass transfer can continually force rock decarbonation while fluids ascend, dominating the effects of cooling, unless fluid fluxes are large and prograde heating rates are small. Consequently, prograde metamorphism of carbonate-bearing sedimentary sequences containing significant amounts of pelitic rock will release CO2 to regionally migrating fluids in a wide range of orogenic settings, regardless of whether flow is in a direction of increasing or decreasing temperature. Regional CO2 release can be driven by outcrop-scale processes of volatile exchange between contrasting lithologies. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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