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dc.contributor.author
Gómez Peral, Lucia  
dc.contributor.author
Kaufman, Alan J.  
dc.contributor.author
Arrouy, Maria Julia  
dc.contributor.author
Richiano, Sebastián Miguel  
dc.contributor.author
Sial, Alcides N.  
dc.contributor.author
Poire, Daniel Gustavo  
dc.contributor.author
Ferreira, Valderez P.  
dc.date.available
2019-08-09T21:35:48Z  
dc.date.issued
2018-09  
dc.identifier.citation
Gómez Peral, Lucia; Kaufman, Alan J.; Arrouy, Maria Julia; Richiano, Sebastián Miguel; Sial, Alcides N.; et al.; Preglacial palaeoenvironmental evolution of the Ediacaran Loma Negra Formation, far southwestern Gondwana, Argentina; Elsevier Science; Precambrian Research; 315; 9-2018; 120-137  
dc.identifier.issn
0301-9268  
dc.identifier.uri
http://hdl.handle.net/11336/81363  
dc.description.abstract
The Ediacaran Loma Negra Formation may be deposited in a platform environment related to the Clymene Ocean. This unit is exposed in the Olavarría and Barker areas within the Tandilia Basin, and composed entirely of lime mudstones (∼40 m thick). The age of the Loma Negra Formation (LNF), the uppermost unit of the Sierras Bayas Group, has been debated, but it should be older than 560 Ma (age of the overlying succession) and younger than 600 Ma (age of the underlying iron-rich mudstone of the Colombo Formation). This extended carbonate platform (>100 km) is divided into two sedimentary facies: one related to the basal section, in which lime mud originated by suspension fall-out in an open-marine ramp (reddish or greenish limestones), and the other facies represented by black to dark grey limestones from the middle and upper sections. The LNF limestones studied, obtained from five sections near the Olavarría and Barker areas, reveal constant curves of positive δ13C values (∼+2 to +4%), similar to those recorded in other middle-Ediacaran marine proxies worldwide. Our sedimentological and geochemical study of the LNF sections shows extraordinarily consistent carbon and oxygen isotope trends that may be useful for detailed intrabasinal correlations. Samples of the LNF fabric-retentive micrite preserve an unusually narrow range of oxygen isotope compositions, which is consistent with potential climatic variation, considering the multi-proxies retained. A subsequent decrease in carbonate primary productivity and an increase in siliciclastic supply are associated with the negative δ13C trend in the overlying unit, at the base of the La Providencia Group. This negative excursion in δ13C from +2.8 to −3.6% is also regarded as a response to the cooling and sea-level fall probably linked to the Gaskiers glaciation. Furthermore, such data are consistent with late-Ediacaran carbonates from other Neoproterozoic successions. Strontium isotope ratios in limestones (0.7060–0.7070) should reflect the near-primary strontium isotope composition of the original seawater, particularly regarding the strontium content (∼300 ppm) and the Rb/Sr ratios (≤0.001) of primary micrite, consistent with a seawater origin. Strontium isotope data reaches 0.7082 with an Rb/Sr ratio of 0.001–0.006.  
dc.format
application/pdf  
dc.language.iso
eng  
dc.publisher
Elsevier Science  
dc.rights
info:eu-repo/semantics/openAccess  
dc.rights.uri
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/  
dc.subject
Chemostratigraphy  
dc.subject
Clymene Ocean  
dc.subject
Pre-Gaskiers Glaciation  
dc.subject.classification
Geología  
dc.subject.classification
Ciencias de la Tierra y relacionadas con el Medio Ambiente  
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS  
dc.title
Preglacial palaeoenvironmental evolution of the Ediacaran Loma Negra Formation, far southwestern Gondwana, Argentina  
dc.type
info:eu-repo/semantics/article  
dc.type
info:ar-repo/semantics/artículo  
dc.type
info:eu-repo/semantics/publishedVersion  
dc.date.updated
2019-07-24T17:42:11Z  
dc.journal.volume
315  
dc.journal.pagination
120-137  
dc.journal.pais
Países Bajos  
dc.journal.ciudad
Amsterdam  
dc.description.fil
Fil: Gómez Peral, Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina  
dc.description.fil
Fil: Kaufman, Alan J.. University of Maryland; Estados Unidos  
dc.description.fil
Fil: Arrouy, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina  
dc.description.fil
Fil: Richiano, Sebastián Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina. Universidad Federal Rural Pernambuco; Brasil  
dc.description.fil
Fil: Sial, Alcides N.. Universidad Federal Rural Pernambuco; Brasil  
dc.description.fil
Fil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina  
dc.description.fil
Fil: Ferreira, Valderez P.. Universidad Federal Rural Pernambuco; Brasil  
dc.journal.title
Precambrian Research  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0301926817306691  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.precamres.2018.07.005