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dc.contributor.author
Gómez Peral, Lucia
dc.contributor.author
Kaufman, Alan J.
dc.contributor.author
Poire, Daniel Gustavo
dc.date.available
2018-01-12T19:23:48Z
dc.date.issued
2014-07
dc.identifier.citation
Kaufman, Alan J.; Poire, Daniel Gustavo; Gómez Peral, Lucia; Paleoenvironmental implications of two phosphogenic events in Neoproterozoic sedimentary successions of the Tandilia System, Argentina; Elsevier Science; Precambrian Research; 252; 7-2014; 88-106
dc.identifier.issn
0301-9268
dc.identifier.uri
http://hdl.handle.net/11336/33125
dc.description.abstract
Two phosphogenic events of potential economic importance (preserving P2O5 abundances up to 25 and 35%, respectively) are recognized in the Neoproterozoic Tandilia System. The older of the two lies atop a quartz-arkosic facies association of the Villa Mónica Formation. The age of this unit remains controversial, but has previously been considered as Tonian to Cryogenian based on stromatolite assemblages and carbon isotope trends; strontium isotope abundances of <0.7071 currently support an earliest Cryogenian age for the formation. The younger phosphate level lies at the base of the Cerro Negro Formation above a widespread karstic surface in a succession containing Cloudina, so is most-likely to be Ediacaran in age. In both cases, the phosphatic concretionary levels are related to relative sea-level fall and exposure that may be related to glacial eustacy. In order to reconstruct the paleoenvironment associated with the formation of these concretionary phosphates, we combined field observations with thin-section petrography, XRD, SEM and geochemical analyses. Total rare-earth element (REE) contents range from 311 to 1010 ppm in concretions from the Villa Mónica Formation and from 290 to 1471 ppm those from the Cerro Negro Formation. Villa Mónica concretions reveal no anomalies in Ce abundance, but clearly positive Eu anomalies (ranging from 1 to 1.4). These results suggest reduced conditions in the marine depositional environment. In contrast, Eu anomalies are not recorded in Cerro Negro concretions, while negative Ce anomalies, ranging from −0.14 to −0.18, are noted. These results are consistent with oxic seawater conditions in mixed platform facies. This study suggests that depositional conditions where phosphate was concentrated in the Neoproterozoic Tandilla System were markedly different
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-sa/2.5/ar/
dc.subject
Phosphate Concretions
dc.subject
Ree
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Sierras Bayas Group
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Neoproterozoic
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Río de La Plata Craton
dc.subject.classification
Meteorología y Ciencias Atmosféricas
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Ciencias de la Tierra y relacionadas con el Medio Ambiente
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS
dc.title
Paleoenvironmental implications of two phosphogenic events in Neoproterozoic sedimentary successions of the Tandilia System, 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
2018-01-12T16:16:59Z
dc.journal.volume
252
dc.journal.pagination
88-106
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: 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.journal.title
Precambrian Research
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.precamres.2014.07.009
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0301926814002563
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