OSWALDO BAFFA
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Artigo IPEN-doc 20128 Electron spin resonance dating of megafauna from Lagoa dos Porcos, Piaui, Brazil2014 - KINOSHITA, ANGELA; MAYER, ELVER; MENDES, VINICIUS R.; FIGUEIREDO, ANA M.G.; BAFFA, OSWALDOExcavations performed at Lagoa dos Porcos site revealed a vast amount of extinct mammal fossil remains, becoming one of the richest palaeontological occurrences in the Serra da Capivara National Park region, a UNESCO World Heritage. Although anatomic and taxonomic aspects of extinct Quaternary mammals are relatively well known, chronologic information for deposits is rare. In this context, electron spin resonance (ESR) dating of megafauna samples provides important information for establishing a chronological background. This work presents the ESR dating of two teeth, one of Gomphotheriidae and other of Toxodontinae. Dose – response curves of each sample were constructed using spectra acquired with a JEOL FA-200 X-Band spectrometer resulting in equivalent dose (De) of 220+40 Gy and 39+2 Gy for Toxodontinae and Gomphotheriidae tooth, respectively. The conversion of De in age was made using ROSY ESR dating software resulting in 26+4 and 22+3 ka. These results place Lagoa dos Porcos fossil assemblage within the Late Pleistocene. These dates overlap with a period of abrupt increase in rainfall in northeast Brazil, and it is possible that this environmental change is related to the formation of this deposit.Artigo IPEN-doc 19041 The northernmost record of catagonus stenocephalus (Lund in Reinhardt, 1880) palaeobiogeographical significance2013 - AVILLA, LEONARDO S.; MULLER, LISIANE; GASPARINI, GERMAN M.; SOIBELZON, LEOPOLDO; ABSOLON, BRUNO; PEGO, FREDERICO B.; SILVA, RAFAEL C.; KINOSHITA, ANGELA; FIGUEIREDO, ANA M.G.; BAFFA, OSWALDODuring fieldwork carried out in January 2009 at Aurora do Tocantins (Tocantins State, northern Brazil), we recovered a fragmentary right maxilla (UNIRIO-PM 1006) of Catagonus stenocephalus from a sedimentary deposit of presumed late Pleistocene age in a karstic cave. This paper aims to: (1) provide the first record of C. stenocephalus in the northern region of Brazil (and consequently, also the northernmost one); (2) update the geographic distribution of C. stenocephalus; (3) present a date for the specimen; and (4) discuss the palaeoenvironmental and palaeobiogeographical implications of the finding. The species C. stenocephalus (Lund) is known from the Bonaerian (middle Pleistocene) and Lujanian (late Pleistocene to earliest Holocene) ages in Argentina, Uruguay, Brazil and Bolivia. The new record presented here extends the geographical distribution of C. stenocephalus more than 1000 km north from the former northernmost record (caves of Lagoa Santa region). Peccaries of the genus Catagonus have several morphological features associated with cursorial habits in relatively open and dry environments. The new distributional range of C. stenocephalus is coincident with the Chacoan subregion, characterized by dry climates and open areas. As the studied material comes from the top of the carbonate layer, this may suggest that the deposition of the C. stenocephalus remains described here is synchronous with the onset of a wetter climate phase. This argumentis also in accordancewith the datation results, around 20 ky BP, just after the last glacialmaximum. This increasingly wet climate, which may also be related to the climatic changes that occurred during the late Pleistocene/early Holocene, could be a factor in the extinction of C. stenocephalus in South America.Artigo IPEN-doc 13458 Electron spin resonance-native signal in thermally treated dental tissue2003 - BACHMANN, LUCIANO; SANTOS, ADEVAILTON B. dos; BAFFA, OSWALDO; ZEZELL, DENISE M.Artigo IPEN-doc 13213 Electron spin resonance dating of human teeth from Toca da Santa shelter of Sao Raimundo Nonato, Piaui, Brazil2008 - KINOSHITA, A.; FIGUEIREDO, A.M.G.; FELICE, G.D.; LAGE, M.C.S.M.; GUIDON, N.; BAFFA, O.Artigo IPEN-doc 11623 ESR dating of an acient goat tooth from Nuoro, Sardinia, Italy2006 - BAFFA, O.; KINOSHITA, A.; FIGUEIREDO, A.M.G.; BRUNETTI, A.; GINESU, S.Artigo IPEN-doc 10394 ESR dating at K and X band of northeastern Brazilian megafauna2005 - KINOSHITA, A.; FRANCA, A.M.; ALMEIDA, J.A.C.; FIGUEIREDO, A.M.G.; NICOLUCCI, P.; GRAEFF, C.F.O.; BAFFA, O.Artigo IPEN-doc 10180 Study of paramagnetic and luminescence centers of microcline feldspar2005 - TATUMI, S.H.; KINOSHITA, A.; FUKUMOTO, M.E.; COURROL, L.C.; KASSAB, L.R.P.; BAFFA, O.; MUNITA, C.S.Artigo IPEN-doc 10257 Chemical origin of the native ESR signals in thermally treated enamel and dentin2004 - BACHMANN, L.; BAFFA, O.; GOMES, A.S.L.; ZEZELL, D.M.Artigo IPEN-doc 12303 Thermal degradation of dentin collagen evaluated with ESR, infrared and optical spectroscopy2007 - BACHMANN, L.; BAFFA, O.; ZEZELL, D.M.Artigo IPEN-doc 13214 ESR dating of teeth from northeastern brazilian megafauna2008 - KINOSHITA, ANGELA; BARRETO, ALCINA; ALVES, ROSENBERG; FIGUEIREDO, ANA M.; SARKIS, JORGE E. de S.; DIAS, MARCELO L.; BAFFA, OSWALDO