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Your search keyword '"Tatumi, Sonia H."' showing total 34 results
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34 results on '"Tatumi, Sonia H."'

4. Radiometric and stimulated luminescent characterization of Amazonian sediments from the Middle Rio Negro, Western Amazon

Author

Tatumi, Sonia H., Yee, Márcio, Soares, Emílio A.A., de Souza, Jefferson J., Grudzin, Emanuele D.O., Munita, Casimiro S., Ribeiro, Rogério B., de Farias Soares, Alvaro, Silva, Noemi Aguiar, Fernandes, Caroline P., Mathias, Matheus T., Rocca, René R., Nagabhushana, K.R., Lokesha, H.S., Rocha, Marcelo S., Lopez, Luis A.C., Venâncio, Diego W.P., and Costa, Solange dos S.

Published
2023
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23. Cover Image

Author

Rossetti, Dilce F., primary, Gribel, Rogério, additional, Tuomisto, Hanna, additional, Cordeiro, Carlos L.O., additional, and Tatumi, Sonia H., additional

Published
2018
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26. Upper Pleistocene deposits of the Comprida Island (São Paulo State) dated by thermoluminescence method

Author

SUGUIO KENITIRO, TATUMI SONIA H., KOWATA EMÍLIA A., MUNITA CASIMIRO S., and PAIVA ROSEMEIRE P.

Subjects
Pleistocene, São Paulo State, lcsh:Q, thermoluminescence ages, sea level, lcsh:Science
Abstract

The Cananéia (Upper Pleistocene) and the Comprida Island (Holocene) formations, outcropping in the Comprida island (SP) have been mapped using geomorphological and lithological criteria. Only one sample of the Cananéia Formation, collected in the homonymous island in front of the Comprida Island, was beyond the limit of the standard radiocarbon method. But since the publication of the geological map of the area in 1978, there has been some doubt on the real occurrence of Pleistocene deposits in southern extremity of Comprida Island. This paper deals with the results of thermoluminescence (TL) ages of eight samples from Comprida Island, which corroborate the Pleistocene age assumed during mapping surveys of these deposits. On the other hand, possible interpretations of the obtained ages, in relation to their depositional environments and related northern hemisphere Quaternary glaciations, are presented.

Published
2003

28. Late Quaternary megafans, fans and fluvio-aeolian interactions in the Bolivian Chaco, Tropical South America

Author

Latrubesse, Edgardo M, Stevaux, Jose C, Cremon, Edipo H, May, Jan-Hendrik, Tatumi, Sonia H, Hurtado, Martin A, Bezada, Maximiliano, Argollo, Jaime B, Latrubesse, Edgardo M, Stevaux, Jose C, Cremon, Edipo H, May, Jan-Hendrik, Tatumi, Sonia H, Hurtado, Martin A, Bezada, Maximiliano, and Argollo, Jaime B

Abstract

The Chaco is a huge plain and a main biogeographic biome of South America dominated by subtropical semideciduous vegetation that spreads on the Andes footslope onmore than 800,000 km2 through Bolivia, Argentina and Paraguay. The climate is tropicalwet–dry and the South American Summer Monsoon (SASM) leads to intensive convective rainfall during the summer season. Some of the world's largest river–fans such as the Parapeti and Grande rivers megafans developed in the Bolivian Chaco. Our research was based on morpho-sedimentary information and sustained by 25 OSL dating of fluvial and aeolian sediments. We demonstrate that these megafans are bigger than previously postulated by some authors.Morphostratigraphic analysis, geochronological data and regional correlations suggest that the Chaco megafans and large piedmont fans were generated and reached maximum development during the middle pleniglacial and early pleniglacial (ca. 60 to 28 ka) because of the presence of colder andmore seasonal conditions (dry–wet intense contrasting seasons) than those existing today in the Amazon and the Bolivian plains.We suggest that amainmechanism triggering themegafan developmentwas the presence of an intensemonsoonal effect on the Eastern flank of the Andes that enhanced rainfall by orographic excitation during MIS 3 and the early part ofMIS 2 that produced an increase in discharge and sediment supply. Concomitantly to fluvial processes the deflation of fluvial belts occurred and big sand dune fields developed by winds blowing out fromNorth to South following the same pattern the South American lower level jet follows presently. Maximumariditywas reached during MIS 2 with the deposition of loess deposits on the piedmont areas andmegafan surfaces, the continuous generation of aeolian dunes and a remarkable decrease in the fluvial activity. Cold air mass related to the polar advection (friagens or surazos) probably affected the area with more intensity and frequency. The Lateglacial was

Published
2012

34. Comparative study of TL and EPR properties of four solid solutions of garnets.

Author

Rocca, Rene R., Watanabe, Shigueo, Barbosa, Renata F., Cano, Nilo F., and Tatumi, Sonia H.

Abstract

In the present work four solid solutions of peralspite garnets indicated PP, PS, R and A have been investigated as to their TL properties. The glow curves of PP, PS, R and A irradiated by gamma rays with dose from 10 to 1000 Gy (2000 in A) presented peaks around 150, 200, 260 and 360-370 °C, but the response of these peaks to radiation doses varies from sample to sample. Also we present glow curves when samples were annealed at 500 °C for 30 min and irradiated to UV light. In other experiments samples irradiated to 1000 Gy were exposed to UV light; the TL intensity decreases under UV exposure. OSL measurements show a linear growth with radiation dose below 200 Gy. Almost straight line signal is obtained for EPR spectrum of natural PS sample. The change in the shape of EPR spectrum of PS sample annealed at high temperature in the range 800 to 1000 °C indicates that Fe2+ converts to Fe3+. This is confirmed by Molecular Absorption Spectroscopy measurements. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Published
2013
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