Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy
Bottom nepheloid layers (BNL) are deep dense waters transporting suspended clay, silt or fine sand with organic matter particles in the central part of basins, with usual suspended sediment concentrations of <0.1 mg/l above background levels, reaching higher concentrations close to the continenta...
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ftuniperugiairis:oai:research.unipg.it:11391/1377750 2024-02-11T10:06:46+01:00 Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy MONACO, Paolo F. J. Rodríquez Tovar A. Uchman T. Trecci Neto de Carvalho Monaco, Paolo F. J., Rodríquez Tovar A., Uchman T., Trecci 2016 ELETTRONICO http://hdl.handle.net/11391/1377750 http://ichnia2016.org eng eng Neto de Carvalho et al. country:PRT ispartofbook:ICHNIA 2016 ICHNIA 2016 http://hdl.handle.net/11391/1377750 http://ichnia2016.org Ichnology info:eu-repo/semantics/conferenceObject 2016 ftuniperugiairis 2024-01-17T17:42:22Z Bottom nepheloid layers (BNL) are deep dense waters transporting suspended clay, silt or fine sand with organic matter particles in the central part of basins, with usual suspended sediment concentrations of <0.1 mg/l above background levels, reaching higher concentrations close to the continental rises, with near-bottom peaks >1 mg/l and lesser concentrations < 1 mg/l progressively towards the basin plain (Puig et al., 2013). BNL are very common in recent basin margins (e.g. the continental rise of French Mediterranean, North Atlantic), but poorly studied in the geological record. Some authors think that turbulent flow in BNL is more responsible for deposition of mud in flat basin plains than fine-grained turbidites (P. Pilgrim, personal communication 2010). The thickness of BNL deposits depends on bottom current velocity and the balance between gravitational settling of particles, basin plain morphology and turbulence of the current. Burrowing organisms intensively exploit the organic matter deposited in the sea floor by BNL; in Canadian Atlantic basin plain, the upper surface is extremely bioturbated with hundreds of burrow openings per m2 (Hunkins et al., 1969, figs 3, 4). In the Paleogene Scaglia Toscana Formation (central Italy; Trasimeno area, Montanare, M. Solare, M. Maggio, Fig. 1), grey to red mudstones occur in beds which are 40 to 60 cm thick (Fig. 2). They are much thicker than typical mud turbidites of overlying Macigno Formation (Amendola et al. 2015). A typical increasing upward density of trace fossils (Monaco et al., 2012) has been detected. In lower tiers dominate deep endichnia (Zoophycos, Taenidium, Planolites); in middle and shallow tiers dominate very common Avetoichnus luisae, Chondrites targionii, C. intricatus, and Cladichnus. Then, utilizing ichnocoenoses is possible differentiate turbulent flow deposits (see Shanmugam, 2002; turbidites versus BNL deposits), because currents caused variation in food resources and the presence or absence of nutrient-rich fine-grained ... Conference Object North Atlantic IRIS Università degli Studi di Perugia |
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IRIS Università degli Studi di Perugia |
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English |
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Ichnology |
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Ichnology MONACO, Paolo F. J. Rodríquez Tovar A. Uchman T. Trecci Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy |
topic_facet |
Ichnology |
description |
Bottom nepheloid layers (BNL) are deep dense waters transporting suspended clay, silt or fine sand with organic matter particles in the central part of basins, with usual suspended sediment concentrations of <0.1 mg/l above background levels, reaching higher concentrations close to the continental rises, with near-bottom peaks >1 mg/l and lesser concentrations < 1 mg/l progressively towards the basin plain (Puig et al., 2013). BNL are very common in recent basin margins (e.g. the continental rise of French Mediterranean, North Atlantic), but poorly studied in the geological record. Some authors think that turbulent flow in BNL is more responsible for deposition of mud in flat basin plains than fine-grained turbidites (P. Pilgrim, personal communication 2010). The thickness of BNL deposits depends on bottom current velocity and the balance between gravitational settling of particles, basin plain morphology and turbulence of the current. Burrowing organisms intensively exploit the organic matter deposited in the sea floor by BNL; in Canadian Atlantic basin plain, the upper surface is extremely bioturbated with hundreds of burrow openings per m2 (Hunkins et al., 1969, figs 3, 4). In the Paleogene Scaglia Toscana Formation (central Italy; Trasimeno area, Montanare, M. Solare, M. Maggio, Fig. 1), grey to red mudstones occur in beds which are 40 to 60 cm thick (Fig. 2). They are much thicker than typical mud turbidites of overlying Macigno Formation (Amendola et al. 2015). A typical increasing upward density of trace fossils (Monaco et al., 2012) has been detected. In lower tiers dominate deep endichnia (Zoophycos, Taenidium, Planolites); in middle and shallow tiers dominate very common Avetoichnus luisae, Chondrites targionii, C. intricatus, and Cladichnus. Then, utilizing ichnocoenoses is possible differentiate turbulent flow deposits (see Shanmugam, 2002; turbidites versus BNL deposits), because currents caused variation in food resources and the presence or absence of nutrient-rich fine-grained ... |
author2 |
Neto de Carvalho Monaco, Paolo F. J., Rodríquez Tovar A., Uchman T., Trecci |
format |
Conference Object |
author |
MONACO, Paolo F. J. Rodríquez Tovar A. Uchman T. Trecci |
author_facet |
MONACO, Paolo F. J. Rodríquez Tovar A. Uchman T. Trecci |
author_sort |
MONACO, Paolo |
title |
Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy |
title_short |
Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy |
title_full |
Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy |
title_fullStr |
Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy |
title_full_unstemmed |
Avetoichnus luisae ichnocoenosis in Paleogene bottom nepheloid layer deposits, Scaglia Toscana Formation, central Italy |
title_sort |
avetoichnus luisae ichnocoenosis in paleogene bottom nepheloid layer deposits, scaglia toscana formation, central italy |
publisher |
Neto de Carvalho et al. |
publishDate |
2016 |
url |
http://hdl.handle.net/11391/1377750 http://ichnia2016.org |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
ispartofbook:ICHNIA 2016 ICHNIA 2016 http://hdl.handle.net/11391/1377750 http://ichnia2016.org |
_version_ |
1790604709863620608 |