Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza

Microbial oncoids have been found in the Oxfordian limestones of the La Manga Formation in the La Vaina section at Potimalal River, Mendoza province. The oncoids ocurr either in packstone or floatstone-rudstone or are scattered in the wackestones. They are mostly elliptical, ameboidal and subordinat...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Palma, Ricardo Manuel, Bressan, Graciela Susana, Kietzmann, Diego Alejandro
Publicado: 2007
Materias:
Jurassic
La Manga Formation
Oncoids
bivalve
echinoderm
growth rate
lamination
limestone
microorganism
micropaleontology
morphology
oncolite
paleoecology
paleoenvironment
sedimentation rate
Argentina
Mendoza
South America
Bivalvia
Echinodermata
Echinoida
Foraminifera
Mollusca
Nubeculariidae
Serpulidae
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v62_n1_p116_Palma
http://hdl.handle.net/20.500.12110/paper_00044822_v62_n1_p116_Palma
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00044822_v62_n1_p116_Palma
record_format dspace
spelling paper:paper_00044822_v62_n1_p116_Palma2023-06-08T14:26:02Z Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza Palma, Ricardo Manuel Bressan, Graciela Susana Kietzmann, Diego Alejandro Jurassic La Manga Formation Oncoids bivalve echinoderm growth rate Jurassic lamination limestone microorganism micropaleontology morphology oncolite paleoecology paleoenvironment sedimentation rate Argentina Mendoza South America Bivalvia Echinodermata Echinoida Foraminifera Mollusca Nubeculariidae Serpulidae Microbial oncoids have been found in the Oxfordian limestones of the La Manga Formation in the La Vaina section at Potimalal River, Mendoza province. The oncoids ocurr either in packstone or floatstone-rudstone or are scattered in the wackestones. They are mostly elliptical, ameboidal and subordinately spherical in shape. Different types of oncoids were recognized, according to their features of envelopes: (1) micritic laminations, (2) grumose laminations, and (3) organism-bearing laminations. Molluscs and echinoid fragments, peloids, and intraclasts acted as oncoid nuclei. Laminae follow the shape of nuclei, especially in the inner zone of the cortices. However, in the outer zones the laminae contain encrusting organisms dominated by nubeculariids and serpulids. Some oncoids, especially the ameboidal or elliptical forms, are characterized by multiple nuclei, represented by small oncoids. The oncoids are associated with bivalves, echinoderms, forams, and serpulids. The fauna is indicative of calm, shallow conditions and the excellent preservation of echinoderms suggests minimal transport prior to burial. Growth histories are in evidence. The oncoids grew in a shallow, low energy, slightly to moderate agitated subtidal normal sea water environment. The limited rolling growth oncoids was probably accompanished by intermittent currents that reoriented the oncoids parallel to stratification. The discontinuous organisms-bearing laminations reflect periods of non-agitation and litification, which facilitated the growth of encrusting organisms on static oncoid particles during a period of low sedimentation rate. Deposition of the oncoid-bearing limestones took place during shallowing of the carbonate interval and associated with emersion, subaerial exposition and paleokarst as consequence of sea level fluctuations. Fil:Palma, R.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Bressan, G.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Kietzmann, D.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v62_n1_p116_Palma http://hdl.handle.net/20.500.12110/paper_00044822_v62_n1_p116_Palma
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Jurassic
La Manga Formation
Oncoids
bivalve
echinoderm
growth rate
Jurassic
lamination
limestone
microorganism
micropaleontology
morphology
oncolite
paleoecology
paleoenvironment
sedimentation rate
Argentina
Mendoza
South America
Bivalvia
Echinodermata
Echinoida
Foraminifera
Mollusca
Nubeculariidae
Serpulidae
spellingShingle Jurassic
La Manga Formation
Oncoids
bivalve
echinoderm
growth rate
Jurassic
lamination
limestone
microorganism
micropaleontology
morphology
oncolite
paleoecology
paleoenvironment
sedimentation rate
Argentina
Mendoza
South America
Bivalvia
Echinodermata
Echinoida
Foraminifera
Mollusca
Nubeculariidae
Serpulidae
Palma, Ricardo Manuel
Bressan, Graciela Susana
Kietzmann, Diego Alejandro
Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza
topic_facet Jurassic
La Manga Formation
Oncoids
bivalve
echinoderm
growth rate
Jurassic
lamination
limestone
microorganism
micropaleontology
morphology
oncolite
paleoecology
paleoenvironment
sedimentation rate
Argentina
Mendoza
South America
Bivalvia
Echinodermata
Echinoida
Foraminifera
Mollusca
Nubeculariidae
Serpulidae
description Microbial oncoids have been found in the Oxfordian limestones of the La Manga Formation in the La Vaina section at Potimalal River, Mendoza province. The oncoids ocurr either in packstone or floatstone-rudstone or are scattered in the wackestones. They are mostly elliptical, ameboidal and subordinately spherical in shape. Different types of oncoids were recognized, according to their features of envelopes: (1) micritic laminations, (2) grumose laminations, and (3) organism-bearing laminations. Molluscs and echinoid fragments, peloids, and intraclasts acted as oncoid nuclei. Laminae follow the shape of nuclei, especially in the inner zone of the cortices. However, in the outer zones the laminae contain encrusting organisms dominated by nubeculariids and serpulids. Some oncoids, especially the ameboidal or elliptical forms, are characterized by multiple nuclei, represented by small oncoids. The oncoids are associated with bivalves, echinoderms, forams, and serpulids. The fauna is indicative of calm, shallow conditions and the excellent preservation of echinoderms suggests minimal transport prior to burial. Growth histories are in evidence. The oncoids grew in a shallow, low energy, slightly to moderate agitated subtidal normal sea water environment. The limited rolling growth oncoids was probably accompanished by intermittent currents that reoriented the oncoids parallel to stratification. The discontinuous organisms-bearing laminations reflect periods of non-agitation and litification, which facilitated the growth of encrusting organisms on static oncoid particles during a period of low sedimentation rate. Deposition of the oncoid-bearing limestones took place during shallowing of the carbonate interval and associated with emersion, subaerial exposition and paleokarst as consequence of sea level fluctuations.
author Palma, Ricardo Manuel
Bressan, Graciela Susana
Kietzmann, Diego Alejandro
author_facet Palma, Ricardo Manuel
Bressan, Graciela Susana
Kietzmann, Diego Alejandro
author_sort Palma, Ricardo Manuel
title Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza
title_short Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza
title_full Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza
title_fullStr Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza
title_full_unstemmed Osagids-types oncoids from La Manga Formation and their paleoecological significance, La Vaina Creek, Mendoza
title_sort osagids-types oncoids from la manga formation and their paleoecological significance, la vaina creek, mendoza
publishDate 2007
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v62_n1_p116_Palma
http://hdl.handle.net/20.500.12110/paper_00044822_v62_n1_p116_Palma
work_keys_str_mv AT palmaricardomanuel osagidstypesoncoidsfromlamangaformationandtheirpaleoecologicalsignificancelavainacreekmendoza
AT bressangracielasusana osagidstypesoncoidsfromlamangaformationandtheirpaleoecologicalsignificancelavainacreekmendoza
AT kietzmanndiegoalejandro osagidstypesoncoidsfromlamangaformationandtheirpaleoecologicalsignificancelavainacreekmendoza
_version_ 1768546751348736000

Ejemplares similares