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Universidade Federal Do Rio Grande Do Sul Instituto De Geociências Programa De Pós-graduação Em Geociências Evolução Paleoceanográfica E Estratigrafia Isotópica Com Foraminíferos Planctônicos No Quaternário Tardio Da
| Content Provider | Semantic Scholar |
|---|---|
| Author | Campos, B. D. |
| Copyright Year | 2013 |
| Abstract | Planktonic foraminifera is the most useful microfossil group for biostratigraphic studies, being considered the main carriers of paleoceanographic information and being applicable to the analysis of sedimentary basins. The main aim of this work is to propose a paleoceanographic reconstruction model in the Campos Basin, by analyzing 61 samples taken from the GL-77 core, collected at the lower continental slope, in the offshore part of the basin. The interval comprises the last two GlacialInterglacial cycles, corresponding to the planktonic foraminifera biozones W (partially), X, Y and Z. By means of analysis of the total fauna, datings in C and isotopic analyses of δO and δC in shells of planktonic foraminifera estimates of variations of paleoproductivity, paleosalinity and sea surface paleotemperature were obtained; an age model and, posteriorly, the sedimentation rates were calculated. The age model identified the Last Glacial Maximum (LGM) and estimated the ages of a few biostratigraphic events, such as YP.2 datum, the MIS 3/4 boundary (which coincides with the Y2/Y3 boundary), the Y1/Y2 boundary and the YP.4 datum. The sedimentation rates are strangely elevated in Biozone X (glacial period) where lower rates would be expected. In the Holocene there is an elevated sedimentation rate, associated to the influence of the Paraiba do Sul River delta, at the northern portion of the basin. The paleotemperatures oscillate seasonally in the glacial periods, when the amplitude between summer and winter is larger than the one registered in the interglacial periods. A correlation was observed between the paleotemperatures and the environmental conditions characterized by the warm and cold subzones in Biozone X. Based on the P/B ratio a limit of sequences can be identified next to the MIS 4/5 boundary. Paleosalinity is reduced in deglaciation periods. Paleoproductivity is reduced to 29 ka (MIS 2/3 boundary) by the LGM and increases near the Pleistocene/Holocene boundary. Finally, it was observed that the Pleistocene/Holocene transition occurs inside Biozone Y, and is not temporally related to the beginning of Biozone Z. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.lume.ufrgs.br/bitstream/handle/10183/94686/000915872.pdf?isAllowed=y&sequence=1 |
| Alternate Webpage(s) | http://www.ufrgs.br/prh-pb215/_arquivos/bc245245568ca6b4f6f1e104b9b32ece.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
