000			02449nam a22002417a 4500
003			ZW-GwMSU
005			20221219132758.0
008			221219b |||||||| |||| 00| 0 eng d
040			_aMSU _cMSU _erda
100			_aBonotto, Daniel Marcos _eauthor
245			_aA comparative study of aquifer systems occurring at the Paraná sedimentary basin, Brazil: U-isotopes contribution _ccreated by Daniel Marcos Bonotto
264			_aSao Paulo: _bSpringer, _c2013.
336			_2rdacontent _atext _btxt
337			_2rdamedia _aunmediated _bn
338			_2rdacarrier _avolume _bnc
440			_vVolume , number ,
520			_aThe radioactivity due to 238U and 234U in three aquifer systems occurring within the Paraná sedimentary basin, South America, has been investigated. Uranium is much less dissolved from fractured igneous rocks than from the porous sedimentary rocks as indicated by the U-mobility coefficients between 7.6 × 10−6 and 1.2 × 10−3 g cm−3. These values are also compatible with the U preference ratios relative to Na, K, Ca, Mg and SiO2, which showed that U is never preferentially mobilized in the liquid phase during the flow occurring in cracks, fissures, fractures and faults of the igneous basaltic rocks. Experimental dissolution of diabase grains on a time-scale laboratory has demonstrated that the U dissolution appeared to be a two-stage process characterized by linear and second-order kinetics. The U dissolution rate was 8 × 10−16 mol m−2 s−1 that is within the range of 4 × 10−16–3 × 10−14 mol m−2 s−1 estimated for other rock types. The 234U/238U activity ratio of dissolved U in solutions was higher than unity, a typical result expected during the water–rock interactions when preferential 234U-leach from the rock surfaces takes place. Some U-isotopes data allowed estimating 320 ka for the groundwater residence time in a sector of a transect in São Paulo State. A modeling has been also realized considering all U-isotopes data obtained in Bauru (35 samples), Serra Geral (16 samples) and Guarani (29 samples) aquifers. The results indicated that the Bauru aquifer waters may result from the admixture of waters from Guarani (1.5 %) and Serra Geral (98.5 %) aquifers.
650			_a Groundwater
650			_a Uranium isotopes
650			_aParaná sedimentary basin
856			_uhttps://doi.org/10.1007/s12665-012-1838-1
942			_2lcc _cJA
999			_c160818 _d160818