Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay

The Cretaceous (Mercedes Formation) and Paleogene (Queguay Formation) deposits cropping out inWand S Uruguay comprise two terrestrial limestone units that are very rich in trace fossils. The study of these units permits to propose a sedimentological model for palustrine limestones and calcretes in w...

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Detalhes bibliográficos
Autores: Alonso Zarza, Ana María, Genise, Jorge F., Verde Cataldo, Mariano
Formato: artículo
Fecha de publicación:2011
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/44166
Acesso em linha:https://hdl.handle.net/20.500.14352/44166
Access Level:acceso abierto
Palavra-chave:56.012
552.5
Calcretes
Lacustrine carbonates
Trace fossils
Silicification
Chaco–Paranense Basin
Uruguay
Paleontología
Petrología
2416 Paleontología
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oai_identifier_str oai:docta.ucm.es:20.500.14352/44166
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spelling Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from UruguayAlonso Zarza, Ana MaríaGenise, Jorge F.Verde Cataldo, Mariano56.012552.5CalcretesLacustrine carbonatesTrace fossilsSilicificationChaco–Paranense BasinUruguayPaleontologíaPetrología2416 PaleontologíaThe Cretaceous (Mercedes Formation) and Paleogene (Queguay Formation) deposits cropping out inWand S Uruguay comprise two terrestrial limestone units that are very rich in trace fossils. The study of these units permits to propose a sedimentological model for palustrine limestones and calcretes in which the distribution of different types of trace fossils is considered. The study units include three main types of deposit: lacustrine limestones, palustrine limestones and calcretes. The lacustrine limestones are relatively homogeneous and contain gastropods, charophytes and ostracods, but no trace fossils. They were deposited in a relatively more perennial lacustrine environment. The palustrine limestones include four different facies: desiccated mudstones, nodular limestones, granular limestones and gravel-sheets. The desiccated mudstones indicate a lesser degree of pedogenic modification and the granular limestones a higher degree. The gravel-sheets are an indication of the reworking of previous limestones deposits during low lakewater levels. Most of the palustrine limestones (except the gravel sheets) contain the same bioclasts as the lacustrine limestones plus a variety of trace fossils such as Rebuffoichnus sciuttoi, Fictovichnus gobiensis and different ichnospecies of Celliforma. The calcretes are either massive (groundwater) or laminar. The massive calcretes are sandy limestones made up of a carbonate matrix and cements. The laminar calcretes (root mats), which contain alveolar septal structures, occur as centimetre-thick layers and can be seen in all types of deposit. They contain the same trace fossil association as the palustrine limestones; the massive calcretes are poorer in such fossils. The distribution of trace fossils in these environments is under strong facies control and provides good evidence of subaerial exposure and semi-arid climates. All the limestones are partially replaced and cemented by opal and quartz, but in all cases the primary structure is preserved. Silicification occurred under groundwater meteoric conditions. Overall, the limestones facies (calcretes, palustrine and lacustrine) and their lateral distribution likely reflect the existence of wetland environments in semiarid to sub-humid climates. These climatic conditions were interrupted by a period of increased precipitations, probably the Early Eocene Climatic Optimum.ElsevierUniversidad Complutense de Madrid20112011-01-0120112011-01-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/44166reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/441662026-06-02T12:44:21Z
dc.title.none.fl_str_mv Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
title Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
spellingShingle Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
Alonso Zarza, Ana María
56.012
552.5
Calcretes
Lacustrine carbonates
Trace fossils
Silicification
Chaco–Paranense Basin
Uruguay
Paleontología
Petrología
2416 Paleontología
title_short Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
title_full Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
title_fullStr Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
title_full_unstemmed Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
title_sort Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
dc.creator.none.fl_str_mv Alonso Zarza, Ana María
Genise, Jorge F.
Verde Cataldo, Mariano
author Alonso Zarza, Ana María
author_facet Alonso Zarza, Ana María
Genise, Jorge F.
Verde Cataldo, Mariano
author_role author
author2 Genise, Jorge F.
Verde Cataldo, Mariano
author2_role author
author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 56.012
552.5
Calcretes
Lacustrine carbonates
Trace fossils
Silicification
Chaco–Paranense Basin
Uruguay
Paleontología
Petrología
2416 Paleontología
topic 56.012
552.5
Calcretes
Lacustrine carbonates
Trace fossils
Silicification
Chaco–Paranense Basin
Uruguay
Paleontología
Petrología
2416 Paleontología
description The Cretaceous (Mercedes Formation) and Paleogene (Queguay Formation) deposits cropping out inWand S Uruguay comprise two terrestrial limestone units that are very rich in trace fossils. The study of these units permits to propose a sedimentological model for palustrine limestones and calcretes in which the distribution of different types of trace fossils is considered. The study units include three main types of deposit: lacustrine limestones, palustrine limestones and calcretes. The lacustrine limestones are relatively homogeneous and contain gastropods, charophytes and ostracods, but no trace fossils. They were deposited in a relatively more perennial lacustrine environment. The palustrine limestones include four different facies: desiccated mudstones, nodular limestones, granular limestones and gravel-sheets. The desiccated mudstones indicate a lesser degree of pedogenic modification and the granular limestones a higher degree. The gravel-sheets are an indication of the reworking of previous limestones deposits during low lakewater levels. Most of the palustrine limestones (except the gravel sheets) contain the same bioclasts as the lacustrine limestones plus a variety of trace fossils such as Rebuffoichnus sciuttoi, Fictovichnus gobiensis and different ichnospecies of Celliforma. The calcretes are either massive (groundwater) or laminar. The massive calcretes are sandy limestones made up of a carbonate matrix and cements. The laminar calcretes (root mats), which contain alveolar septal structures, occur as centimetre-thick layers and can be seen in all types of deposit. They contain the same trace fossil association as the palustrine limestones; the massive calcretes are poorer in such fossils. The distribution of trace fossils in these environments is under strong facies control and provides good evidence of subaerial exposure and semi-arid climates. All the limestones are partially replaced and cemented by opal and quartz, but in all cases the primary structure is preserved. Silicification occurred under groundwater meteoric conditions. Overall, the limestones facies (calcretes, palustrine and lacustrine) and their lateral distribution likely reflect the existence of wetland environments in semiarid to sub-humid climates. These climatic conditions were interrupted by a period of increased precipitations, probably the Early Eocene Climatic Optimum.
publishDate 2011
dc.date.none.fl_str_mv 2011
2011-01-01
2011
2011-01-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/44166
url https://hdl.handle.net/20.500.14352/44166
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.301629

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