Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)

Autores
Giachetti, Luciana María; Richiano, Sebastián Miguel; Fernández, Diana Elizabeth
Año de publicación
2023
Idioma
inglés
Tipo de recurso
documento de conferencia
Estado
versión publicada
Descripción
Cabo Raso is located in the north of Bahía Camarones, in Central Patagonia, Argentina. The marine Quaternary deposits from this area are poorly studied and scarce paleontological and geological studies have been made. These deposits are preserved as parallel beach ridges with mollusc shells, one of the principal substrates of bioerosion traces. In the last year, an ichnological analysis was made from these deposits. Here, we describe the preliminary results of this study.The outcropping Pleistocene deposits are approximately 90 cm thick. They begin with a sandy matrix-supported conglomerate with mollusc shells, followed by a level of fine-grained sandstones to medium-grained conglomerates with sporadic mollusc shells and the uppermost part is similar to the base. Regarding the Holocene deposit, represented by fine to medium-grained conglomerates with mollusc shells, an excavation of 50 cm was made to collect a bulk sample.A total of 489 mollusc shells were analysed and 61.5% are bioeroded. In the Pleistocene sample, 70.4% of the shells show bioerosion and 12 ichnotaxa were distinguished. The most dominant ichnogenera were Iramena (borings with circular to oval aperture produced by cheilostome bryozoans), Maeandropolydora (a trace produced by annelids), Oichnus (a predatory trace produced by gastropods) and Podichnus (attachment trace produced by articulated brachiopods). In the Holocene samples, the bioeroded shells decreased (51.3%) and only four ichnogenera were observed: Iramena, Maeandropolydora, Oichnus and Podichnus. The Modern sample presents a major number of ichnogenera (13), where Iramena, Finichnus (attachment scars produced by cheilostome bryozoans) Podichnus and Maeandropolydora are the most abundant ichnotaxa.In the last years, it has been demonstrated that the mollusc shells (and the associated traces) preserved in the marine Quaternary deposits of Patagonia represent a proxy of paleoenvironmental conditions. According to previous studies, the bryozoan biodiversity is higher in colder waters of high chlorophyll-a concentration. Therefore, the dominance of bioerosion traces produced by cheilostome bryozoans in the Pleistocene might be associated with the colder waters present at that time. The bioerosion pattern observed in the modern samples is very similar to the Pleistocene. This could be indicating that both present similar environmental conditions. The cold Malvinas current presents a more extensive and intensified position at the present day. This causes a decrease in the sea surface temperature (SST) and high productivity on the Patagonia coast. Therefore, it is probable that the Pleistocene coast also presented high productivity. In the mid-Holocene, a period of maximum warming called the Hypsithermal event occurred. This event increased the SST and weakened the oceanic anticyclones that provoked the increase in the energy of marine storms. The rise of the temperature might impact in the marine community changing the ontogenetic stages and interaction predatory-prey while the storm waves have implications for intertidal and shallow subtidal systems (vulnerable to hydrodynamic disturbance). Also, these climatic changes could modify the nutrient supply and, therefore, productivity. This might be the cause of the low number of ichnogenera in the Holocene sample.This study represents the first ichnological characterization of the Quaternary deposits in the Cabo Raso locality.
Fil: Giachetti, Luciana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina
Fil: Richiano, Sebastián Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina
Fil: Fernández, Diana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina
XVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de Sedimentología
La Plata
Argentina
Asociación Argentina de Sedimentología
Materia
Trace fossils
Ichnology
Quaternary
Coastal marine
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/248487

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network_name_str CONICET Digital (CONICET)
spelling Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)Giachetti, Luciana MaríaRichiano, Sebastián MiguelFernández, Diana ElizabethTrace fossilsIchnologyQuaternaryCoastal marinehttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Cabo Raso is located in the north of Bahía Camarones, in Central Patagonia, Argentina. The marine Quaternary deposits from this area are poorly studied and scarce paleontological and geological studies have been made. These deposits are preserved as parallel beach ridges with mollusc shells, one of the principal substrates of bioerosion traces. In the last year, an ichnological analysis was made from these deposits. Here, we describe the preliminary results of this study.The outcropping Pleistocene deposits are approximately 90 cm thick. They begin with a sandy matrix-supported conglomerate with mollusc shells, followed by a level of fine-grained sandstones to medium-grained conglomerates with sporadic mollusc shells and the uppermost part is similar to the base. Regarding the Holocene deposit, represented by fine to medium-grained conglomerates with mollusc shells, an excavation of 50 cm was made to collect a bulk sample.A total of 489 mollusc shells were analysed and 61.5% are bioeroded. In the Pleistocene sample, 70.4% of the shells show bioerosion and 12 ichnotaxa were distinguished. The most dominant ichnogenera were Iramena (borings with circular to oval aperture produced by cheilostome bryozoans), Maeandropolydora (a trace produced by annelids), Oichnus (a predatory trace produced by gastropods) and Podichnus (attachment trace produced by articulated brachiopods). In the Holocene samples, the bioeroded shells decreased (51.3%) and only four ichnogenera were observed: Iramena, Maeandropolydora, Oichnus and Podichnus. The Modern sample presents a major number of ichnogenera (13), where Iramena, Finichnus (attachment scars produced by cheilostome bryozoans) Podichnus and Maeandropolydora are the most abundant ichnotaxa.In the last years, it has been demonstrated that the mollusc shells (and the associated traces) preserved in the marine Quaternary deposits of Patagonia represent a proxy of paleoenvironmental conditions. According to previous studies, the bryozoan biodiversity is higher in colder waters of high chlorophyll-a concentration. Therefore, the dominance of bioerosion traces produced by cheilostome bryozoans in the Pleistocene might be associated with the colder waters present at that time. The bioerosion pattern observed in the modern samples is very similar to the Pleistocene. This could be indicating that both present similar environmental conditions. The cold Malvinas current presents a more extensive and intensified position at the present day. This causes a decrease in the sea surface temperature (SST) and high productivity on the Patagonia coast. Therefore, it is probable that the Pleistocene coast also presented high productivity. In the mid-Holocene, a period of maximum warming called the Hypsithermal event occurred. This event increased the SST and weakened the oceanic anticyclones that provoked the increase in the energy of marine storms. The rise of the temperature might impact in the marine community changing the ontogenetic stages and interaction predatory-prey while the storm waves have implications for intertidal and shallow subtidal systems (vulnerable to hydrodynamic disturbance). Also, these climatic changes could modify the nutrient supply and, therefore, productivity. This might be the cause of the low number of ichnogenera in the Holocene sample.This study represents the first ichnological characterization of the Quaternary deposits in the Cabo Raso locality.Fil: Giachetti, Luciana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Richiano, Sebastián Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Fernández, Diana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaXVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de SedimentologíaLa PlataArgentinaAsociación Argentina de SedimentologíaAsociación Argentina de Sedimentología2023info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObjectCongresoBookhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/248487Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina); XVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de Sedimentología; La Plata; Argentina; 2023; 213-213978-631-90299-0-1CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://libros.unlp.edu.ar/index.php/unlp/catalog/book/2374Internacionalinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:33:25Zoai:ri.conicet.gov.ar:11336/248487instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:33:25.483CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
title Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
spellingShingle Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
Giachetti, Luciana María
Trace fossils
Ichnology
Quaternary
Coastal marine
title_short Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
title_full Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
title_fullStr Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
title_full_unstemmed Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
title_sort Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina)
dc.creator.none.fl_str_mv Giachetti, Luciana María
Richiano, Sebastián Miguel
Fernández, Diana Elizabeth
author Giachetti, Luciana María
author_facet Giachetti, Luciana María
Richiano, Sebastián Miguel
Fernández, Diana Elizabeth
author_role author
author2 Richiano, Sebastián Miguel
Fernández, Diana Elizabeth
author2_role author
author
dc.subject.none.fl_str_mv Trace fossils
Ichnology
Quaternary
Coastal marine
topic Trace fossils
Ichnology
Quaternary
Coastal marine
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Cabo Raso is located in the north of Bahía Camarones, in Central Patagonia, Argentina. The marine Quaternary deposits from this area are poorly studied and scarce paleontological and geological studies have been made. These deposits are preserved as parallel beach ridges with mollusc shells, one of the principal substrates of bioerosion traces. In the last year, an ichnological analysis was made from these deposits. Here, we describe the preliminary results of this study.The outcropping Pleistocene deposits are approximately 90 cm thick. They begin with a sandy matrix-supported conglomerate with mollusc shells, followed by a level of fine-grained sandstones to medium-grained conglomerates with sporadic mollusc shells and the uppermost part is similar to the base. Regarding the Holocene deposit, represented by fine to medium-grained conglomerates with mollusc shells, an excavation of 50 cm was made to collect a bulk sample.A total of 489 mollusc shells were analysed and 61.5% are bioeroded. In the Pleistocene sample, 70.4% of the shells show bioerosion and 12 ichnotaxa were distinguished. The most dominant ichnogenera were Iramena (borings with circular to oval aperture produced by cheilostome bryozoans), Maeandropolydora (a trace produced by annelids), Oichnus (a predatory trace produced by gastropods) and Podichnus (attachment trace produced by articulated brachiopods). In the Holocene samples, the bioeroded shells decreased (51.3%) and only four ichnogenera were observed: Iramena, Maeandropolydora, Oichnus and Podichnus. The Modern sample presents a major number of ichnogenera (13), where Iramena, Finichnus (attachment scars produced by cheilostome bryozoans) Podichnus and Maeandropolydora are the most abundant ichnotaxa.In the last years, it has been demonstrated that the mollusc shells (and the associated traces) preserved in the marine Quaternary deposits of Patagonia represent a proxy of paleoenvironmental conditions. According to previous studies, the bryozoan biodiversity is higher in colder waters of high chlorophyll-a concentration. Therefore, the dominance of bioerosion traces produced by cheilostome bryozoans in the Pleistocene might be associated with the colder waters present at that time. The bioerosion pattern observed in the modern samples is very similar to the Pleistocene. This could be indicating that both present similar environmental conditions. The cold Malvinas current presents a more extensive and intensified position at the present day. This causes a decrease in the sea surface temperature (SST) and high productivity on the Patagonia coast. Therefore, it is probable that the Pleistocene coast also presented high productivity. In the mid-Holocene, a period of maximum warming called the Hypsithermal event occurred. This event increased the SST and weakened the oceanic anticyclones that provoked the increase in the energy of marine storms. The rise of the temperature might impact in the marine community changing the ontogenetic stages and interaction predatory-prey while the storm waves have implications for intertidal and shallow subtidal systems (vulnerable to hydrodynamic disturbance). Also, these climatic changes could modify the nutrient supply and, therefore, productivity. This might be the cause of the low number of ichnogenera in the Holocene sample.This study represents the first ichnological characterization of the Quaternary deposits in the Cabo Raso locality.
Fil: Giachetti, Luciana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina
Fil: Richiano, Sebastián Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina
Fil: Fernández, Diana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina
XVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de Sedimentología
La Plata
Argentina
Asociación Argentina de Sedimentología
description Cabo Raso is located in the north of Bahía Camarones, in Central Patagonia, Argentina. The marine Quaternary deposits from this area are poorly studied and scarce paleontological and geological studies have been made. These deposits are preserved as parallel beach ridges with mollusc shells, one of the principal substrates of bioerosion traces. In the last year, an ichnological analysis was made from these deposits. Here, we describe the preliminary results of this study.The outcropping Pleistocene deposits are approximately 90 cm thick. They begin with a sandy matrix-supported conglomerate with mollusc shells, followed by a level of fine-grained sandstones to medium-grained conglomerates with sporadic mollusc shells and the uppermost part is similar to the base. Regarding the Holocene deposit, represented by fine to medium-grained conglomerates with mollusc shells, an excavation of 50 cm was made to collect a bulk sample.A total of 489 mollusc shells were analysed and 61.5% are bioeroded. In the Pleistocene sample, 70.4% of the shells show bioerosion and 12 ichnotaxa were distinguished. The most dominant ichnogenera were Iramena (borings with circular to oval aperture produced by cheilostome bryozoans), Maeandropolydora (a trace produced by annelids), Oichnus (a predatory trace produced by gastropods) and Podichnus (attachment trace produced by articulated brachiopods). In the Holocene samples, the bioeroded shells decreased (51.3%) and only four ichnogenera were observed: Iramena, Maeandropolydora, Oichnus and Podichnus. The Modern sample presents a major number of ichnogenera (13), where Iramena, Finichnus (attachment scars produced by cheilostome bryozoans) Podichnus and Maeandropolydora are the most abundant ichnotaxa.In the last years, it has been demonstrated that the mollusc shells (and the associated traces) preserved in the marine Quaternary deposits of Patagonia represent a proxy of paleoenvironmental conditions. According to previous studies, the bryozoan biodiversity is higher in colder waters of high chlorophyll-a concentration. Therefore, the dominance of bioerosion traces produced by cheilostome bryozoans in the Pleistocene might be associated with the colder waters present at that time. The bioerosion pattern observed in the modern samples is very similar to the Pleistocene. This could be indicating that both present similar environmental conditions. The cold Malvinas current presents a more extensive and intensified position at the present day. This causes a decrease in the sea surface temperature (SST) and high productivity on the Patagonia coast. Therefore, it is probable that the Pleistocene coast also presented high productivity. In the mid-Holocene, a period of maximum warming called the Hypsithermal event occurred. This event increased the SST and weakened the oceanic anticyclones that provoked the increase in the energy of marine storms. The rise of the temperature might impact in the marine community changing the ontogenetic stages and interaction predatory-prey while the storm waves have implications for intertidal and shallow subtidal systems (vulnerable to hydrodynamic disturbance). Also, these climatic changes could modify the nutrient supply and, therefore, productivity. This might be the cause of the low number of ichnogenera in the Holocene sample.This study represents the first ichnological characterization of the Quaternary deposits in the Cabo Raso locality.
publishDate 2023
dc.date.none.fl_str_mv 2023
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/conferenceObject
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http://purl.org/coar/resource_type/c_5794
info:ar-repo/semantics/documentoDeConferencia
status_str publishedVersion
format conferenceObject
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/248487
Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina); XVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de Sedimentología; La Plata; Argentina; 2023; 213-213
978-631-90299-0-1
CONICET Digital
CONICET
url http://hdl.handle.net/11336/248487
identifier_str_mv Bioerosion pattern as a tool to environmental interpretation: a case of study of Cabo Raso (Patagonia, Argentina); XVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de Sedimentología; La Plata; Argentina; 2023; 213-213
978-631-90299-0-1
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://libros.unlp.edu.ar/index.php/unlp/catalog/book/2374
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eu_rights_str_mv openAccess
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dc.coverage.none.fl_str_mv Internacional
dc.publisher.none.fl_str_mv Asociación Argentina de Sedimentología
publisher.none.fl_str_mv Asociación Argentina de Sedimentología
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