Authigenic carbonates linked to hydrocarbon enriched fluid escape

Natural hydrocarbon emissions occur in a wide range of geologic and geodynamic settings, with seepage sites being steadily discovered all around the world, and their role in the degassing of deeply buried sediments is assessed. Methane is the most important greenhouse gas and the formation of authigenic carbonates represents its sink in marine sediments. The process of authigenic carbonate precipitation is due to microbe consortia that promote the Anaerobic Oxidation of Methane together with Sulphate Reduction (AOM-SR). The research focuses various aspects related to the genesis of hydrocarbon-derived carbonate concretions in marine sequences and provides new insights on the processes involved in the carbonate precipitation:

1) definition of hydrocarbon-saturated horizons by interpreting high-resolution seismic profiles and by sampling stratigraphic sections;

2) comparison of fluid migration pathways in relation to the tectono-stratigrafic and geologic evolution;

3) investigation of biogeochemical processes and mineralogical phases that characterize the authigenic carbonates;

4) detailed study of authigenic precipitation concerning petrography, stable isotopic composition, elemental composition that would lead to define if carbonate formation occurred in the deep subsurface and thus partially preventing fluid flow at the sea floor.

The accurate reconstruction of paleoenvironments through proper descriptors such as biological legacy, geochemical characters and sedimentary facies supports the interpretation if carbonate bodies formed at the seabed or exhumed by erosional events.

Selected publications

Oppo, D., Capozzi, R., Picotti, V., Ponza, A., 2015. A genetic model of hydrocarbon-derived carbonate chimneys in shelfal fine-grained sediments: The Enza River field, Northern Apennines (Italy). Marine and Petroleum Geology,  66, pp. 555 – 565.

Capozzi, R., Negri, A., Reitner, J., Taviani, M., 2015. Carbonate Conduits linked to Hydrocarbon-enriched Fluid Escape. Marine and Petroleum Geology,  66, pp. 497 – 500.

Viola, I., Oppo, D., Franchi, F., Capozzi, R., Dinelli, E., Liverani, B., Taviani, M., 2015. Mineralogy, geochemistry and petrography of methane-derived authigenic carbonates from Enza River, Northern Apennines (Italy), Marine and Petroleum Geology, 66, pp. 566 – 581

Research project:

Capozzi, R., PRIN 2009 Coordinatore nazionale del progetto (PI):  Condotti carbonatici legati all'espulsione di fluidi ricchi in idrocarburi.