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| Pessenda,Luiz C.R.; Saia,Soraya E.M.G.; Gouveia,Susy E.M.; Ledru,Marie-Pierre; Sifeddine,Abdelfettah; Amaral,Paula G.C.; Bendassolli,José A.. |
| This study presents paleoenvironmental data based on pollen, elemental and isotopic compositions of organic matter (TOC, N, d13C and d15N) and 14C dating of 170 cm lake sediment record. Samplings have been made in Lagoa Grande at Parque Estadual Turístico do Alto Ribeira - PETAR, Southern São Paulo State, Southeastern Brazil. The variations in relative frequencies (in percentage) of arboreal pollen along the core range between 40 and 80%. The d13C values ranged from -23 to -30 and C/N of ~10 to 15, indicating the contribution of terrestrial C3 plants and algae in the sediment organic matter. The d15N results presented values from 3 to 4.5, also suggesting a mixture of algae and terrestrial C3 plants. The 14C dating indicates modern age for the shallow... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lacustrine sediment; C and N isotopes; Pollen; Atlantic Forest; Last millennium; Little Ice Age. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000300019 |
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| Sha, Longbin; Jiang, Hui; Seidenkrantz, Marit-solveig; Muscheler, Raimund; Zhang, Xu; Knudsen, Mads Faurschou; Olsen, Jesper; Knudsen, Karen Luise; Zhang, Weiguo. |
| Arctic sea ice represents an important component of the climate system, and the present reduction of sea ice in the Arctic is of major concern. Despite its importance, little is known about past changes in sea-ice cover and the underlying forcing mechanisms. Here, we use diatom assemblages from a marine sediment core collected from the West Greenland shelf to reconstruct changes in sea-ice cover over the last millennium. The proxy-based reconstruction demonstrates a generally strong link between changes in sea-ice cover and solar variability during the last millennium. Weaker (or stronger) solar forcing may result in the increase (or decrease) in sea-ice cover west of Greenland. In addition, model simulations show that variations in solar activity not only... |
| Tipo: Text |
Palavras-chave: Sea-ice variability; Solar activity; West Greenland; Last millennium. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53291/54134.pdf |
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