Taphonomy, sedimentology and chronology of a fossiliferous outcrop from the continental Pleistocene of Uruguay

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Main Author: Andrea Corona
Format: Artículo científico
Language:en
Published: Universidad Nacional Autónoma de México 2012
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author Andrea Corona
author_facet Andrea Corona
contents Taphonomy, sedimentology and chronology of a fossiliferous outcrop from the continental Pleistocene of Uruguay Andrea Corona Daniel Perea Pablo Toriño César Goso Ciencias de la Tierra bonebed Uruguay taphonomy Quaternary Libertad Formation The La Paz local fauna (34º44' S, 56º17' W, elevation 31 m) is a fossiliferous assemblage with abundant remains of typical southern South American Pleistocene mammals. The assemblage consists of a bonebed, containing a high concentration of skeletal remains, most of them completely disarticulated and fragmented, although very well preserved, and is unique in Uruguay as most remains have been found as single isolated finds until now. The goals of this study are to determine the sedimentary and taphonomic processes that produced this regionally unique concentration of bones and determine the age of the deposit. The bone fragments studied are not in their original anatomical position and consist of mostly, very fractured specimens accumulated in a multidominant bonebed. The number of identified specimens (NISP) is 130. Within the recovered sample, 50% of the studied specimens showed no signs of weathering; 70% showed some kind of fracture or breakage, many of the specimens (40%) parallel to the major axis; and a small number of specimens showed signs of abrasion (5%). Based on the sample there does not appear to have been selection (either by form or by size) by transport. The dominantly massive deposit lacks sedimentary structures, has poor sorting and a high degree of angularity of the largest pebbles suggesting that the final deposition of the remains resulted from a mudflow and were not channeled deposited. The taphonomic features observed on the bones are also compatible with this depositional process. The sediments in which the bonebed is located are attributed to the Libertad Formation, currently assigned to the lower-middle Pleistocene by other workers. We discuss the validity of the two available radiocarbon ages in the context of many failed essays. The mammals of the La Paz local fauna and the presence of particular clay mineral allow us to infer, in the context of this deposit, an arid to semi-arid environment. 2012 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57224696016 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.2 Vol.29
format Artículo científico
id redalyc_57224696016
institution Redalyc
language en
publishDate 2012
publisher Universidad Nacional Autónoma de México
spellingShingle Taphonomy, sedimentology and chronology of a fossiliferous outcrop from the continental Pleistocene of Uruguay
Andrea Corona
Ciencias de la Tierra
bonebed
Uruguay
taphonomy
Quaternary
Libertad Formation
Taphonomy, sedimentology and chronology of a fossiliferous outcrop from the continental Pleistocene of Uruguay Andrea Corona Daniel Perea Pablo Toriño César Goso Ciencias de la Tierra bonebed Uruguay taphonomy Quaternary Libertad Formation The La Paz local fauna (34º44' S, 56º17' W, elevation 31 m) is a fossiliferous assemblage with abundant remains of typical southern South American Pleistocene mammals. The assemblage consists of a bonebed, containing a high concentration of skeletal remains, most of them completely disarticulated and fragmented, although very well preserved, and is unique in Uruguay as most remains have been found as single isolated finds until now. The goals of this study are to determine the sedimentary and taphonomic processes that produced this regionally unique concentration of bones and determine the age of the deposit. The bone fragments studied are not in their original anatomical position and consist of mostly, very fractured specimens accumulated in a multidominant bonebed. The number of identified specimens (NISP) is 130. Within the recovered sample, 50% of the studied specimens showed no signs of weathering; 70% showed some kind of fracture or breakage, many of the specimens (40%) parallel to the major axis; and a small number of specimens showed signs of abrasion (5%). Based on the sample there does not appear to have been selection (either by form or by size) by transport. The dominantly massive deposit lacks sedimentary structures, has poor sorting and a high degree of angularity of the largest pebbles suggesting that the final deposition of the remains resulted from a mudflow and were not channeled deposited. The taphonomic features observed on the bones are also compatible with this depositional process. The sediments in which the bonebed is located are attributed to the Libertad Formation, currently assigned to the lower-middle Pleistocene by other workers. We discuss the validity of the two available radiocarbon ages in the context of many failed essays. The mammals of the La Paz local fauna and the presence of particular clay mineral allow us to infer, in the context of this deposit, an arid to semi-arid environment. 2012 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57224696016 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.2 Vol.29
title Taphonomy, sedimentology and chronology of a fossiliferous outcrop from the continental Pleistocene of Uruguay
topic Ciencias de la Tierra
bonebed
Uruguay
taphonomy
Quaternary
Libertad Formation
url https://www.redalyc.org/articulo.oa?id=57224696016