Made available in DSpace on 2015-03-13T17:08:28Z (GMT). No. of bitstreams: 1 MiriamTSM_DISSERT.pdf: 746109 bytes, checksum: 9993efc70026d11b86a511c7cf5aa9bc (MD5) Previous issue date: 2007-05-04 / Nd ISOTOPES IN THE PROVENANCE OF TERRIGENOUS AND CARBONATE ROCKS AND SEDIMENTS OF THE POTIGUAR BASIN, NORTHEASTERN BRAZIL. Mesozoic and Cenozoic rocks from the Potiguar Basin, including terrigenous and carbonate sediments have been investigated to identify their isotopic signature and source areas. Additionally, this study aims to determine the provenance of terrigenous and carbonate sediments on the Brazilian Continental shelf adjacent to Potiguar Basin. The Sm-Nd isotopic signatures of the rocks yielded model ages (TDM) in the range of 2,19- 2,88 Ga, indicating archean to paleoproterozoic sources from the basement. The terrigenous sediments yielded model ages (TDM) in the range of 2,31-2,26 Ga, from 17,5 to 0 cm depth. Despite the small number of samples, limited variations of provenance ages indicates the homogenization of the sediments, probably due to the strong influence of the basement, as the main source of sediments to the shelf. The Sm-Nd isotopic signatures of the carbonate sediments yielded model ages (TDM) in the range of 2,09-2,61 Ga, indicating archean to paleoproterozoic sources from the basement. The results also indicate that the shelf sediments are mainly derived from the A?u River or other small rivers from the Setentrional Sector of Rio Grande do Norte State. The littoral drift doesn?t seem to contribute with sediments from the Oriental Sector since isotopic signatures from this sector were not detected. / An?lises isot?picas Sm-Nd em rochas mesoz?icas e cenoz?icas da Bacia Potiguar, incluindo sedimentos terr?genos e carbon?ticos que aportam do Rio Piranhas-A?u, foram realizadas objetivando a caracteriza??o de suas assinaturas isot?picas e identifica??o de suas ?reas fonte. As assinaturas isot?picas Sm-Nd das rochas apresentaram idades modelo (TDM) variando de 2,88 a 2,19 Ga, indicando fontes, principalmente, paleoproteroz?icas e arquenas do embasamento. Os sedimentos terr?genos plataformais apresentaram idades modelo (TDM) de 2,31 Ga e 2,26 Ga, coletados, respectivamente, nas profundidades de 10-17,5 cm e 0-5 cm. Apesar do n?mero pequeno de amostras, a pequena varia??o na idade indica homogeneiza??o dos sedimentos, talvez devido a forte influ?ncia do embasamento como fonte de material para a plataforma. As assinaturas isot?picas Sm-Nd dos sedimentos carbon?ticos plataformais apresentaram idades modelo (TDM) variando de 2,61 a 2,09 Ga, indicando fontes do embasamento arqueano a paleoproteroz?ico. Estes resultados indicam ainda que os sedimentos terr?genos presentes na plataforma em estudo s?o ou foram trazidos principalmente pelo rio A?u, ou outros rios menores da por??o setentrional do Rio Grande do Norte. A deriva litor?nea aparentemente n?o tem compet?ncia para arrastar sedimentos da por??o oriental para a setentrional, tendo em vista que os valores ?Nd registrados n?o s?o compat?veis com as rochas da por??o oriental.