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631.
Hydrogeochemistry of Roccamonfina volcano (Southern Italy) 总被引:1,自引:1,他引:0
Emilio Cuoco Giuseppe Verrengia Stefano De Francesco Dario Tedesco 《Environmental Earth Sciences》2010,61(3):525-538
This is the first hydro-geochemical investigation carried out on the Roccamonfina Volcanic Complex groundwaters. The chemistry
of Roccamonfina waters is defined by water–rock and water–rock–gas interactions. In fact, interactions between rocks of the
first eruptive high-K formations and circulating groundwaters are recognized by high K concentrations. On the other hand,
inverse concentration of calcium versus alkali metals is related to two different rock interactions occurring in different
areas of the volcano: (a) within the caldera where groundwaters flow within latite and pyroclastic formations releasing calcium,
and (b) similarly at the base of the volcano where groundwaters flowing from surrounding carbonates got strongly enriched
in Ca. These geochemical processes are also associated with K (SE of caldera) and Mg/Ca (in sites located at the NE base of
the volcano) decrease. Completely different dynamics occurs at Riardo groundwaters (SE). Here waters are the result of a mix
between the Roccamonfina deep aquifer and the carbonate aquifer of the Riardo plain. Rich-CO2 emissions make these waters strongly mineralized. Minor elements show a similar geochemical behavior of major ions and are
crucial defining interactions processes. The evolution of Roccamonfina groundwaters is also evident along the simultaneous
enrichment of Ba, Sr, and Ca. Ba increase is the result of deep local carbonate alteration enhanced by CO2 emissions and, the lower Sr/Ca ratio, from 10 to 2 (ppb/ppm), is also due to the same process. In the light of our results
the Roccamonfina aquifer can be schematically divided into two main reservoirs: (a) a superficial aquifer which basically
follows the volcanic structure morphology and tectonics and (b) a deeper reservoir, originating within the oldest Roccamonfina
volcano ultra potassic lavas and then flowing into the carbonate aquifers of the neighboring plain. Eventually, the chemistry
of the Roccamonfina aquifer does not show any specific and visible pollution, contrary to what happens in the volcano surrounding
plains. In fact, only 14% of the samples we collected (206) show a NO3 content >30 mg/l. These sites are all located at the base of the volcano, near the plain. 相似文献
632.
The thermal behaviour and the structural properties of three important industrial phyllosilicates, such as kaolinite, talc and Ca-rich montmorillonite, have been examined after mechanical treatment in a specifically built planetary ball mill working in vacuum (P = 0.13 Pa) at room temperature (25 °C). It is found that, on increasing the grinding time, the temperature of the dehydroxylation reaction decreases linearly as a result of a decrease of the crystallite size and structural order. To be noted that the mechanical treatment in our milling conditions did not induce significant amorphization. The temperature at which there is the maximum of dehydroxylation and the weight losses of the intralayer OH are linearly related to the increase of the FWHM of the 001 basal plane. These results are useful for predicting the thermal behaviour of layer silicates to be subjected to mechanical processing in industrial application. 相似文献
633.