LUCAS SATIRO DO CARMO

LUCAS SATIRO DO CARMO

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Brazilian aeolian sediments dating using tl, osl and esr
2023 - CARMO, LUCAS S. do; WATANABE, SHIGUEO; DEWITT, REGINA
In this work, a dunefield known as Dama Branca (Brazil) has been dated using the following techniques: Optically Stimulated Luminescence (OSL), Thermoluminescence (TL) and Electronic Spin Resonance (ESR). They are part of what is called “trapped charge dating technique”. Sediments have been collected from several points to study age distribution throughout Dama Branca. These ages are related to events of sediment transportation and stabilization. For Dama Branca specifically, variables related to weather such as rainfall and wind power are suspected to be responsible for its formation. OSL results were obtained applying the SAR protocol. TL and ESR results were obtained using the Multiple Aliquot Additive Dose protocol (MAAD). With respect to ESR measurements, the Ti-Li center was chosen for dating since it can be completely bleached by sun light exposure , which makes it suitable for aeolian sediment dating. The Ti-Li center is strongly dependent upon preheat, its stability has been assessed and a preheat temperature of 180 °C was selected. OSL ages are within 0.05 kyears and 2.05 x kyears. TL ages agree with OSL ages for samples collected from the dune base, however there are discrepancies between OSL and TL ages for the DBM2BASE sample, suggesting that it underwent a quicker burial process. ESR results are satisfactory for two samples, 2DB10 and 2DB11 (they follow OSL and TL results). The ages were compared to a simplified morphological study. In recent works about the weather in the Cabo Frio region it has been seen that the studied areas were formed under influence of arid conditions and cold water, variables that control sediment transportation in the region. Keywords (max. 5): TL, ESR, OSL, quartz, sediments dating.
OSL-SAR dating of sediments from Brazilian aeolian system
2019 - CARMO, L.S. do; WATANABE, S.; DEWITT, R.
It has been reported that the formation and stabilization of coastal dune fields in Brazil have a dependence on the climatic changes, Relative Sea Level (RSL) variations, etc. In this work, a dune field known as “Dama Branca”, located in the city of Cabo Frio, Rio de Janeiro, has been studied to understand its mobility. Dating by trapped charge dating techniques as Optically Stimulated Luminescence (OSL) using the Single Aliquot Regenerative protocol (SAR), helps us to understand the formation and dynamics of aeolian systems in Brazil. Samples from two positions; DB and 2DB, were collected from different heights and points for dating. The results obtained by OSL-SAR showed that ages decrease as the height from the dune base increases and older samples are found in deeper horizontal positions. The ages from the base of the studied dunes indicated that its stabilization occurred during the recess of the sea level and that erosion caused by the wind action is revealing an old generation of this dune filed.
Dating aeolian sediments from Cabo Frio, Rio de Janeiro, using Ti-Li center electron spin resonance, thermoluminescence and optically stimulated luminescence
2019 - CARMO, LUCAS S. do; WATANABE, SHIGUEO; DEWITT, REGINA; SILVA, RAFAELA J.; FELIPE, LUIZ; CHUBACI, JOSÉ F.D.
In this work, optically stimulated luminescence (OSL), thermoluminescence (TL) and electron spin resonance (ESR) were used to date coastal aeolian sediments from a dunefield known as Dama Branca (White Lady) in Rio de Janeiro, Brazil. Sediments have been collected from seven different points to study sand transportation and stabilization. Results obtained by those different techniques were compared. The equivalent dose (De) measured by OSL, was obtained using the Single Aliquot Regenerative protocol (SAR), TL results have been corrected measuring residual TL and ESR measurements were carried out using Ti-Li center. The thermal stability of Ti-Li center was evaluated, samples were preheated to exclude the Ti-Li center thermally sensitive component. The gamma-ray spectroscopy was used to measure Uranium, Thorium and Potassium concentrations in the soil, the values were analyzed with the Dose Rate and Age Calculator (DRAC) to generate the Annual Dose Rate (Dr). A morphological analysis showed that the dunefield has been moving influenced by semi-arid conditions and upwelling close to the coast. Ages from 0.05 to 2.22 thousand of years were found.
Dating aeolian sediments using ESR Ti-Li center in quartz, TL and OSL-SAR
2018 - CARMO, L.S. do; WATANABE, S.; SILVA, R.J.; CHUBACI, J.F.D.
OSL-SAR dating of sediments from brazilian aeolian system: Dama Branca, Rio De Janeiro, morphodynamic study
2017 - CARMO, LUCAS S. do; WATANABE, SHIGUEO; DEWITT, REGINA
It has been reported that the formation and stabilization of coastal dune fields in Brazil have a dependence on the climate changes and Relative Sea Level (RSL) variations. A few topics regarding the morphodynamics of coastal aeolian systems in Brazil can be the RSL variations in the Holocene and weather conditions. In this work, a dune field known as “Dama Branca”, located in the town of Cabo Frio, Rio de Janeiro, has been studied to understand its formation and stabilization. Dating by trapped charge dating techniques as Optically Stimulated Luminescence (OSL) using the Single Aliquot Regenerative protocol (SAR), help us to understand the formation and dynamics of aeolian systems in Brazil. Samples from a dune were collected from different heights and points for dating. The results obtained by OSL-SAR showed that ages decrease as the height from the dune base increase and older samples are found in deeper horizontal positions. The ages for the base of the studied dunes indicated that its stabilization occurred during the recess of the sea level.
High-dose dosimetry using natural silicate minerals
2015 - CARMO, LUCAS S.; WATANABE, SHIGUEO; MENDES, LETICIA; BARBOSA, RENATA F.; RAO, GUNDU; LUCAS, NATASHA; SATO, KARINA
High-dose dosimetry of beta rays using blue beryl dosimeters
2015 - CARMO, LUCAS S. do; WATANABE, SHIGUEO; BITTENCOURT, JOSE F.