Datação das formações Rio Claro e Piraçununga por termoluminescência

Ferreira, Sandra Regina; Chang, Maria Rita Caetano

doi:10.1590/s0370-44672008000200004

Cited by 6 publications

(4 citation statements)

References 3 publications

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“…The accumulated doses were determined by the total regeneration method (SAR protocol), where a portion of the sample is exposed to solar radiation for 16 h and another portion is irradiated with a 60 Co source using several pre-defined doses (Gy) (TL/OSL Automated Systems reader, model 1100, Daybreak Nuclear Instruments INC, equipped with a OSL Hoya U-340 filter), for the design of the calibration curve. The annual doses were calculated using a Canberra Inspector Portable Spectroscopy Workstation (NaI-Tl) that measured 40 K, 232 Th, 238 U and 235 U concentrations (Ferreira and Caetano-Chang, 2008;Tatumi et al, 2003).…”

Section: Laboratory Analysesmentioning

confidence: 99%

Paleoenvironmental reconstruction of the Lower Mogi Guaçu River Basin (São Paulo State — Brazil), morphopedosedimentary records and fluvial processes

Celarino

Souza

Ladeira

et al. 2013

CATENA

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Section: Laboratory Analysesmentioning

confidence: 99%

Paleoenvironmental reconstruction of the Lower Mogi Guaçu River Basin (São Paulo State — Brazil), morphopedosedimentary records and fluvial processes

Celarino

Souza

Ladeira

et al. 2013

CATENA

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“…The study site is located at São Paulo State University in the city of Rio Claro, Brazil (Figure ). The site is part of the Rio Claro Aquifer, which has been studied and monitored extensively since 2000 (e.g., Ferreira and Caetano‐Chang ; Neto et al ; Gonçalves and Chang ). The Rio Claro Aquifer is a shallow unconfined aquifer composed of Cenozoic sedimentary rocks of the Rio Claro Formation overlaying the Permian aquitard of the Corumbataí Formation.…”

Section: Study Sitementioning

confidence: 99%

Quasi‐Saturated Layer: Implications for Estimating Recharge and Groundwater Modeling

et al. 2019

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This study presents an extension of the concept of ''quasi-saturation'' to a quasi-saturated layer, defined as the uppermost dynamic portion of the saturated zone subject to water table fluctuations. Entrapped air here may cause substantial reductions in the hydraulic conductivity (K ) and fillable pore water. Air entrapment is caused by a rising water table, usually as a result of groundwater recharge. The most significant effects of entrapped air are recharge overestimation based on methods that use specific yield (S y ), such as the water table fluctuation method (WTF), and reductions in K values. These effects impact estimation of fluid flow velocities and contaminant migration rates in groundwater. In order to quantify actual groundwater recharge rates and the effects of entrapped air, numerical simulations with the FEFLOW (Version 7.0) groundwater flow model were carried out using a quasi-saturated layer for a pilot area in Rio Claro, Brazil. The calculated recharge rate represented 16% of the average precipitation over an 8-year period, approximately half of estimates using the WTF method. Air entrapment amounted to a fillable porosity of 0.07, significant lower that the value of 0.17 obtained experimentally for S y . Numerical results showed that the entrapped air volume in the quasi-saturated layer can be very significant (0.58 of the air fraction) and hence can significantly affect estimates of groundwater recharge and groundwater flow rates near the water table. Article impact statement: Quasi-saturation due to air entrapment near the water table has major effects on estimated recharge rates and modeling groundwater.

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“…Other lakes of similar shape, but smaller in size, are found in the area, and they all appear to be strongly correlated to the Rio Claro formation. This formation presents unconsolidated sandy deposits formed by a meandering fluvial system (Zaine ) whose age is considered to be Tertiary by some authors (Fúlfaro & Suguio ; Melo ; Zaine ) or Quaternary by others (Ab´Saber, ; Ferreira & Chang ; Penteado, ). The Rio Claro formation ranges 7–40 m in thickness, always appearing at the top of hills.…”

Section: Archaeological Geological and Geomorphological Contextsmentioning

confidence: 99%

The “Lagoa do Camargo 1” Paleoindian site: some implications for tropical geomorphology, pedology, and paleoenvironments in southeastern Brazil

et al. 2017

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Lagoa do Camargo 1, a Paleoindian archaeological site located in southeast Brazil dated between 10.5 and 8.3 ka, was studied using a variety of analyses: artifact and charcoal frequencies, soil morphology and micromorphology, magnetic analysis, optically stimulated luminescence, and radiocarbon dating. Our results show that the sandy tropical Oxisol present at the site was accumulated by episodic erosion and accumulation of materials along the slope, by means of diffuse runoff (sheet wash), and that bioturbation, albeit present, played a minor role in the soil formation. From a geoarchaeological point of view, the site poses an important problem, which is the presence of a deeply buried archaeological site almost at the top of a plateau. Our conclusions are relevant for understanding the genesis of sandy Oxisols that cover a large portion of southeast Brazil, where charcoal fragments are abundant, and whose genesis is considered by some authors to be strongly related to pedoturbation.

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Datação das formações Rio Claro e Piraçununga por termoluminescência

Cited by 6 publications

References 3 publications

Paleoenvironmental reconstruction of the Lower Mogi Guaçu River Basin (São Paulo State — Brazil), morphopedosedimentary records and fluvial processes

Paleoenvironmental reconstruction of the Lower Mogi Guaçu River Basin (São Paulo State — Brazil), morphopedosedimentary records and fluvial processes

Quasi‐Saturated Layer: Implications for Estimating Recharge and Groundwater Modeling

The “Lagoa do Camargo 1” Paleoindian site: some implications for tropical geomorphology, pedology, and paleoenvironments in southeastern Brazil

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