New age constraints for the Salamanca Formation and lower Río Chico Group in the western San Jorge Basin, Patagonia, Argentina: Implications for Cretaceous-Paleogene extinction recovery and land mammal age correlations

dc.contributor.authorClyde, William C.
dc.contributor.authorWilf, Peter
dc.contributor.authorIglesias, Ari
dc.contributor.authorSlingerland, Rudy L.
dc.contributor.authorBarnum, Timothy
dc.contributor.authorBijl, Peter K.
dc.contributor.authorBralower, Timothy J.
dc.contributor.authorBrinkhuis, Henk
dc.contributor.authorComer, Emily E.
dc.contributor.authorHuber, Brian T.
dc.contributor.authorIbañez-Mejia, Mauricio
dc.contributor.authorJicha, Brian R.
dc.contributor.authorKrause, J. M.
dc.contributor.authorSchueth, Jonathan D.
dc.contributor.authorSinger, Bradley S.
dc.contributor.authorRaigemborn, María Sol
dc.contributor.authorSchmitz, Mark D.
dc.contributor.authorSluijs, Appy
dc.contributor.authorZamaloa, María del Carmen
dc.date.accessioned2015-04-20T15:15:33Z
dc.date.available2015-04-20T15:15:33Z
dc.date.issued2014
dc.description.abstractThe Salamanca Formation of the San Jorge Basin (Patagonia, Argentina) preserves critical records of Southern Hemisphere Paleocene biotas, but its age remains poorly resolved, with estimates ranging from Late Cretaceous to middle Paleocene. We report a multi-disciplinary geochronologic study of the Salamanca Formation and overlying Río Chico Group in the western part of the basin. New constraints include (1) an 40Ar/39Ar age determination of 67.31 ± 0.55 Ma from a basalt flow underlying the Salamanca Formation, (2) micropaleontological results indicating an early Danian age for the base of the Salamanca Formation, (3) laser ablation HR-MC-ICP-MS (laser ablation high resolution-multi collector-inductively coupled plasma-mass spectrometry) U-Pb ages and a high-resolution TIMS (thermal ionization mass spectrometry) age of 61.984 ± 0.041(0.074)0.100] Ma for zircons from volcanic ash beds in the Peñas Coloradas Formation (Río Chico Group), and (4) paleomagnetic results indicating that the Salamanca Formation in this area is entirely of normal polarity, with reversals occurring in the Río Chico Group. Placing these new age constraints in the context of a sequence stratigraphic model for the basin, we correlate the Salamanca Formation in the study area to Chrons C29n and C28n, with the Banco Negro Inferior (BNI), a mature widespread fossiliferous paleosol unit at the top of the Salamanca Formation, corresponding to the top of Chron C28n. The diverse paleobotanical assemblages from this area are here assigned to C28n (64.67–63.49 Ma), ∼2–3 million years older than previously thought, adding to growing evidence for rapid Southern Hemisphere floral recovery after the Cretaceous-Paleogene extinction. Important Peligran and "Carodnia" zone vertebrate fossil assemblages from coastal BNI and Peñas Coloradas exposures are likely older than previously thought and correlate to the early Torrejonian and early Tiffanian North American Land Mammal Ages, respectively.
dc.format.extent289–306
dc.identifier0016-7606
dc.identifier.citationClyde, William C., Wilf, Peter, Iglesias, Ari, Slingerland, Rudy L., Barnum, Timothy, Bijl, Peter K., Bralower, Timothy J., Brinkhuis, Henk, Comer, Emily E., Huber, Brian T., Ibañez-Mejia, Mauricio, Jicha, Brian R., Krause, J. M., Schueth, Jonathan D., Singer, Bradley S., Raigemborn, María Sol, Schmitz, Mark D., Sluijs, Appy, and Zamaloa, María del Carmen. 2014. "New age constraints for the Salamanca Formation and lower Río Chico Group in the western San Jorge Basin, Patagonia, Argentina: Implications for Cretaceous-Paleogene extinction recovery and land mammal age correlations." <em>Geological Society of America Bulletin</em>, 126, (3/4) 289–306. <a href="https://doi.org/10.1130/B30915.1">https://doi.org/10.1130/B30915.1</a>.
dc.identifier.issn0016-7606
dc.identifier.urihttp://hdl.handle.net/10088/25354
dc.publisherThe Geological Society of America
dc.relation.ispartofGeological Society of America Bulletin 126 (3/4)
dc.titleNew age constraints for the Salamanca Formation and lower Río Chico Group in the western San Jorge Basin, Patagonia, Argentina: Implications for Cretaceous-Paleogene extinction recovery and land mammal age correlations
dc.typearticle
sro.description.unitNH-Paleobiology
sro.description.unitNMNH
sro.identifier.doi10.1130/B30915.1
sro.identifier.itemID118568
sro.identifier.refworksID36344

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