Abstract
A remarkable exposure of carbonate pipe-like and slab concretions occurs along the Enza riverbanks on the Northern Apennines foothills (Italy). Based upon geochemical and field evidences, their genesis has been attributed to microbial-governed carbonate precipitation from hydrocarbon-enriched fluids. The pipe-like concretions are thus interpreted as former conduits (chimneys) marking sites of methane ascent onto the seafloor. The resulting Enza River chimney field is arranged in a palisade fashion, a rare example of such. Mineralogical and petrographic analyses of some chimneys and slabs document that the dominant cement is dolomite. Although the chimneys show a rather homogeneous texture, a clear zonation is observed in the relative distribution of major and minor elements in their internal and external parts. The occurrence of sulphide minerals in the stratigraphically upper samples indicates possible renewal of fluids leakage after a major erosive event.
Original language | English |
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Pages (from-to) | 566-581 |
Number of pages | 16 |
Journal | Marine and Petroleum Geology |
Volume | 66 |
Issue number | 3 |
Early online date | 20 Mar 2015 |
DOIs | |
Publication status | Published - Sept 2015 |
Bibliographical note
AcknowledgementsFunding was provided by the national project PRIN 2009 “Carbonate conduits linked to hydrocarbons enriched seepages” (PI R. Capozzi) of the Italian Ministry of University and Research (MIUR). Thanks are due to C. Mazzoli (University of Padua) for the access at the cathodoluminescence facilities. The authors are indebted with two anonymous reviewers for their constructive criticism. This is ISMAR-Bologna scientific contribution number 1851.
Keywords
- carbonate chimneys
- hydrocarbon migration
- anaerobic methane oxidation
- Apennine chain