Back to Search
Start Over
CO 2 -Degassing Carbonate Conduits in Early Pleistocene Marine Clayey Deposits in Southwestern Umbria (Central Italy).
- Source :
- Minerals (2075-163X); Jul2022, Vol. 12 Issue 7, pN.PAG-N.PAG, 24p
- Publication Year :
- 2022
-
Abstract
- Early Pleistocene marine deposits in southwestern Umbria (Orvieto–Allerona area, Italy) recently revealed the presence of more than forty carbonate conduits distributed over 2 km along the Paglia riverbed. In order to investigate their origins, analyses of their mineralogy, δ<superscript>18</superscript>O and δ<superscript>13</superscript>C stable isotopes, and organic geochemistry were conducted. All the carbonate conduits are made of euhedral microcrystals of dolomite with subordinate quartz, plagioclases, and micas. The stable carbon and oxygen isotope values of the bulk concretionary carbonates range from −0.57 to +4.79‰ (δ<superscript>13</superscript>C) and from +1.58 to +4.07‰ (δ<superscript>18</superscript>O), respectively. The lack of organic geochemical biomarkers of anaerobic methane oxidation (AOM) and the very low values of extractable organic matter suggest a non-biological origin for the dolomite precipitation. The latter is probably related to the rise of volcanic carbon dioxide due to the incipient Vulsini magmatism recorded in Early Pleistocene marine deposits all around the study site. The spatial distribution of the structures indicates that the upward migration of the CO<subscript>2</subscript> was controlled by the fault system, while the vertical development of the conduits suggests that carbon dioxide degassing occurred, with multiple events. Carbon dioxide was probably stored in pockets within the clayey sediments until the pressure exceeded the eruptive threshold. These structures represent the first documentation of a volcanic carbon dioxide marine seepage event in the Umbria region. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 2075163X
- Volume :
- 12
- Issue :
- 7
- Database :
- Complementary Index
- Journal :
- Minerals (2075-163X)
- Publication Type :
- Academic Journal
- Accession number :
- 158299278
- Full Text :
- https://doi.org/10.3390/min12070819