• Economic and Environmental Geology
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• v.28 no.4
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• pp.351-367
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• 1995

The elemental geochemistry and oxygen isotopes of illite/smectite (I/S) have been studied in relationship to the mineralogical trend in the Reindeer D-27 well, Beaufort-Mackenzie Basin. The increase in concentrations of $K_2O$, Rb and rare earth elements (REE), the decrease in concentrations of tetrahedral elements such as Mg, Ti, Sc, Zn and Zr, and the increase in concentrations of tetrahedral elements such as Be and V can be related to I/S compositions that vary systematically with depth. Layer formulae of S- and I-layers are estimated as $[Al_{1.57}Fe_{.19}Mg_{.31}Ti_{.07}][Si_{3.84}Al_{.16}]O_{10}(OH)_2$ and $[Al_{1.84}Mg_{.16}][Si_{3.33}Al_{.67}]O_{10}(OH)_2$, respectively. The mobilization of REE appears to occur during illitization. The increase in concentrations of REE, especially La and Ce, with depth is probably linked to incorporation of ions with high valency (e.g. $V^{5+}$) in tetrahedral sites. The excess valency due to V is partly counter-balanced by ions with low valency (e.g. $Be^{2+}$) and, in turn, the local valency deficiency caused by $Be^{2+}$ could be compensated by high-charge interlayer cations such as REE (＋3). ${\delta}^{18}O$ values of I/S range from 2.91 to 15.72‰ (SMOW), and increase with depth, contrasting to trends observed in the Gulf Coast and elsewhere. The increase in ${\delta}^{18}O$ of I/S results from the rapid increase in ${\delta}^{18}O$ of pore water that overcomes the decrease in temperature-dependent fractionation values with increasing burial depth (${\delta}^{18}O_{pore\;water}>-d{\Delta}/_{I/S-water};\;d{\delta}^{18}O_{I/S}>0$). Calculated ${\delta}^{18}O$ values of pore water in equilibrium with I/S suggest that the original water was probably meteoric water. The stratification of pore water is postulated from the presence of an isotopically light interval, about 450m thick. The depth range of the isotopically light zone overlaps, but does not coincide with the interval of lowered I-content and $K_2O$ concentrations, suggesting that oxygens may have been exchanged independently of mineralogical and geochemical reactions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.958-964
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• 2004

This study examined the effects of maternal calcium intake levels on mineral metabolism during pregnancy and lactation. Five week-old female Sprague-Dawley rats were fed normal Ca (NCa, 0.5%) and low Ca (LCa, 0.15%) diets for 5 weeks during preconception. The low Ca intake group was divided into three groups and fed low Ca (0.15%), normal Ca (0.5%) and high Ca (1.5%) diets for 6 weeks during pregnancy and lactation. All of the rats were mated with normal male rats. The control group was consistently fed a normal Ca diet for 11 weeks. Pups were adjusted to 10 per dam. After weaning, dams and their weaned rats were sacrificed. We measured total protein, albumin, alkaline phosphatase and mineral content in serum and weight, length, breaking force, ash and mineral content in bone and kidney. There was no significant difference in weight gain and food intake among the groups. Serum total protein and albumin were in the normal range but slightly decreased with a low Ca diet during preconception. Calcium supplementation above normal level increased bone weight, Ca content and breaking force in femur of maternal and their weaned rats. However, high maternal Ca intake significantly decreased Mg and Fe contents in maternal serum and bone and Mg and Zn contents in serum of weaned rats. Also, it induced Ca, P and Mg deposit in maternal kidney. Our experimental results suggest that Ca deficiency during preconception may deteriorate bone status of mother and their offsprings. Moreover, high Ca supplementation during pregnancy and lactation may lead to disturb mineral metabolism in bone and other tissues.