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Authigenic seep-carbonates cementing coarse-grained deposits in a fan-delta depositional system (middle Miocene, Marnoso-arenacea Formation, central Italy).
- Source :
-
Sedimentology . Apr2008, Vol. 55 Issue 2, p471-486. 16p. 2 Color Photographs, 2 Black and White Photographs, 1 Diagram, 1 Chart, 1 Graph, 3 Maps. - Publication Year :
- 2008
-
Abstract
- Seep-carbonates (13C-depleted) are present at different levels within the Miocene terrigenous succession of Deruta (Marnoso-arenacea Formation, central Italy); they are associated with pebbly sandstones and conglomerates in a tectonically active fan-delta slope depositional system. Most of these seep-carbonates are included in slide/slump horizons as scattered blocks. The occurrence of seep-carbonates is clear evidence of the flow of methane-rich fluids pervading the sediments. Fluids, probably of biogenic origin, may have reached the sea-bottom through thrust faults and selectively infiltrated the more permeable coarse-grained horizons deposited along the slope. Different stages of fluid emissions are documented: slow flux stage, corresponding to the development of large carbonate bodies and dense chemosynthetic communities; and fast fluid flow associated with intense carbonate brecciation, pipes and veins. Large amounts of authigenic carbonates are reworked by slope failures triggered by tectonics and fluids reducing sediment strength; in situ cementation of slide blocks may also have occurred due to remobilization of methane-rich fluids by mass-wasting processes. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00370746
- Volume :
- 55
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Sedimentology
- Publication Type :
- Academic Journal
- Accession number :
- 31225094
- Full Text :
- https://doi.org/10.1111/j.1365-3091.2007.00910.x