Paleometry: molecular and elemental characterization of the sloth catonyx cuvieri (mammalia, xenarthra, mylodontidae) from the pleistocene-holocene of Paraguay

Abstract

In this work we present the results of the first paleometry studies using X-ray fluorescence (XRF) techniques, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and Raman spectroscopy, applied to the characterization of a specimen of Catonyx cuvieri (Lund 1839) extracted from the caves of Cerro Riso in the district of San Lázaro, Department of Concepción, Paraguay. The specimen is deposited in the Laboratorio de Paleontología collection of the Facultad de Ciencias Exactas y Naturales (FACEN), Universidad Nacional de Asunción (UNA), Paraguay. A total of 10 bone samples corresponding mostly to fragments of ribs were subjected to non-destructive analysis. These were selected because they did not suffer alterations in their surface as product of the processes of preservation (bonding, consolidation) to which this type of remains are usually subjected for their preservation in collections. The chemical characterization was performed by means of Fourier Transform Infrared (FTIR) and Raman spectroscopy with 785nm laser excitation source, identifying the functional groups (PO4)-3 and the presence of organic groups assigned to Amide I and II respectively. The elementary identification was performed by X-ray fluorescence spectrometry (XRF) with Silver target (Ag) and SDD detector of the majority elements. In addition to an analysis by Xray photoelectron spectroscopy (XPS)with dual source of Aluminum (Al,) for light elements and the determination of the proportion of Ca / P in the bone samples through the analysis of Ca 2p and P 1s. The C 1s to corroborate the presence of organic material in the analyzed samples. Differences of the data obtained with the XRF and XPS will be established, being a central point of discussion the difference in the ratio of Ca / P obtained in both techniques. The results obtained were compared with hydroxyapatite (main mineral material in bones) synthesized in the laboratory, showing differences in the (PO4) -3 P v3 bands due to the presence of amorphous and / or crystalline calcium phosphate material in the samples. The main objective of this work is to know the processes, molecular and structural changes caused by the incorporation of elements in the structures of bio-apatites in the processes of diagenesis.