Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain.
The examination of about eighty exposures of lucinid deposits of the Apennine chain based on new field analyses and previous data, and the compositional study of one hundred samples representative of the different geological settings in which lucinid assemblages are found, enable us to distinguish f...
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Dipartimento di Geologia e Palentologia Geofisica:Univ. Sigra Todesco via Giotto 1, 35137 Padua Italy:011 39 49 664828
1998
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ftunivmodena:oai:iris.unimore.it:11380/450209 2024-01-21T10:09:51+01:00 Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. CONTI, Stefano FONTANA, Daniela Conti, Stefano Fontana, Daniela 1998 STAMPA http://hdl.handle.net/11380/450209 eng eng Dipartimento di Geologia e Palentologia Geofisica:Univ. Sigra Todesco via Giotto 1, 35137 Padua Italy:011 39 49 664828 volume:50 firstpage:101 lastpage:131 journal:MEMORIE DI SCIENZE GEOLOGICHE http://hdl.handle.net/11380/450209 info:eu-repo/semantics/closedAccess lucinid-like clam chemoherm Miocene Apennine brecciated structure diapirism methane fluid venting info:eu-repo/semantics/article 1998 ftunivmodena 2023-12-26T23:12:46Z The examination of about eighty exposures of lucinid deposits of the Apennine chain based on new field analyses and previous data, and the compositional study of one hundred samples representative of the different geological settings in which lucinid assemblages are found, enable us to distinguish four types of deposits. Type 1 and type 2 are primary (autochthonous) deposits whereas type 3 and type 4 are secondary (allochthonous) deposits. Type 1 deposits consist of marly-calcareous and calcarenitic lenses or columnar bodies, jammed with articulated lucinid-like shells, usually belonging to oligotypic communities and grading into the surrounding pelitic sediments. Most of the samples are made of homogeneous micrites, biomiocrites and fossiliferous micrites, containing variable amounts of biogenic particles, chiefly planktonic foraminifera. Type 2 deposits are made up of lucinid shells, either isolated or associated with a more diverse fauna, in mudstones, marls, arenitic and calcareous marls. Type 3 deposits are constituted of carbonate olistoliths enclosed as blocks within chaotic horizons in turbiditic and hemipelagic formations of the Miocene foredeep. Type 4 deposits are represented by coquina debris, isolated articulated or disarticulated shells in resedimented arenites, calcarenites, carbonate breccias with biogenic debris. Samples of secondary deposits show a noticeable variety of lithologies and textures and are very heterogeneous even at the microscopic scale. The most common lithotypes include fine to medium grained arenites characterized by a loosely detrital fabric and by a pervasive micrite cement. Fossiliferous micrites and biomicrites with brecciated textures are common. The detrital framework show striking similarities to the composition of the host turbidites. Carbonate intraclasts and clasts deriving from lithotypes of the ligurian domain are present. Most of the type 1 and 3 deposits are strongly 13C depleted and are interpreted as chemosynthetic communities (chemoherms), with authigenic ... Article in Journal/Newspaper Planktonic foraminifera Archivio della ricerca dell'Università di Modena e Reggio Emilia (Unimore: IRIS) |
institution |
Open Polar |
collection |
Archivio della ricerca dell'Università di Modena e Reggio Emilia (Unimore: IRIS) |
op_collection_id |
ftunivmodena |
language |
English |
topic |
lucinid-like clam chemoherm Miocene Apennine brecciated structure diapirism methane fluid venting |
spellingShingle |
lucinid-like clam chemoherm Miocene Apennine brecciated structure diapirism methane fluid venting CONTI, Stefano FONTANA, Daniela Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. |
topic_facet |
lucinid-like clam chemoherm Miocene Apennine brecciated structure diapirism methane fluid venting |
description |
The examination of about eighty exposures of lucinid deposits of the Apennine chain based on new field analyses and previous data, and the compositional study of one hundred samples representative of the different geological settings in which lucinid assemblages are found, enable us to distinguish four types of deposits. Type 1 and type 2 are primary (autochthonous) deposits whereas type 3 and type 4 are secondary (allochthonous) deposits. Type 1 deposits consist of marly-calcareous and calcarenitic lenses or columnar bodies, jammed with articulated lucinid-like shells, usually belonging to oligotypic communities and grading into the surrounding pelitic sediments. Most of the samples are made of homogeneous micrites, biomiocrites and fossiliferous micrites, containing variable amounts of biogenic particles, chiefly planktonic foraminifera. Type 2 deposits are made up of lucinid shells, either isolated or associated with a more diverse fauna, in mudstones, marls, arenitic and calcareous marls. Type 3 deposits are constituted of carbonate olistoliths enclosed as blocks within chaotic horizons in turbiditic and hemipelagic formations of the Miocene foredeep. Type 4 deposits are represented by coquina debris, isolated articulated or disarticulated shells in resedimented arenites, calcarenites, carbonate breccias with biogenic debris. Samples of secondary deposits show a noticeable variety of lithologies and textures and are very heterogeneous even at the microscopic scale. The most common lithotypes include fine to medium grained arenites characterized by a loosely detrital fabric and by a pervasive micrite cement. Fossiliferous micrites and biomicrites with brecciated textures are common. The detrital framework show striking similarities to the composition of the host turbidites. Carbonate intraclasts and clasts deriving from lithotypes of the ligurian domain are present. Most of the type 1 and 3 deposits are strongly 13C depleted and are interpreted as chemosynthetic communities (chemoherms), with authigenic ... |
author2 |
Conti, Stefano Fontana, Daniela |
format |
Article in Journal/Newspaper |
author |
CONTI, Stefano FONTANA, Daniela |
author_facet |
CONTI, Stefano FONTANA, Daniela |
author_sort |
CONTI, Stefano |
title |
Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. |
title_short |
Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. |
title_full |
Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. |
title_fullStr |
Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. |
title_full_unstemmed |
Recognition of primary and secondary Miocene lucinid deposits in the Apennine chain. |
title_sort |
recognition of primary and secondary miocene lucinid deposits in the apennine chain. |
publisher |
Dipartimento di Geologia e Palentologia Geofisica:Univ. Sigra Todesco via Giotto 1, 35137 Padua Italy:011 39 49 664828 |
publishDate |
1998 |
url |
http://hdl.handle.net/11380/450209 |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_relation |
volume:50 firstpage:101 lastpage:131 journal:MEMORIE DI SCIENZE GEOLOGICHE http://hdl.handle.net/11380/450209 |
op_rights |
info:eu-repo/semantics/closedAccess |
_version_ |
1788700997604868096 |