Search results for "Gold deposit"
showing 2 items of 2 documents
Direct dating of gold by radiogenic helium: Testing the method on gold from Diamantina, Minas Gerais, Brazil
2013
New analytical developments have made radiogenic helium ( 4 He) applicable to archeological gold artifacts for age determinations. Here we report the application of the U/Th– 4 He method to the direct dating of gold from the historically important gold deposit in Diamantina, Minas Gerais, Brazil. The U/Th– 4 He age of 515 ± 55 Ma for the Diamantina gold is corroborated by a new U/Pb age of 524 ± 16 Ma for rutile recovered from auriferous pockets. These ages tie the Diamantina gold mineralization to the Brasiliano orogenic event, in the context of the Gondwana amalgamation. Our results indicate that U/Th– 4 He dating of gold is possible, opening new perspectives for the dating of gold deposi…
Nanostructuring thin Au films on transparent conductive oxide substrates
2013
Fabrication processes of Au nanostructures on indium-tin-oxide (ITO) surface by simple, versatile, and low-cost bottom-up methodologies are investigated in this work. A first methodology exploits the patterning effects induced by nanosecond laser irradiations on thin Au films deposited on ITO surface. We show that after the laser irradiations, the Au film break-up into nanoclusters whose mean size and surface density are tunable by the laser fluence. A second methodology exploits, instead, the patterning effects of standard furnace thermal processes on the Au film deposited on the ITO. We observe, in this case, a peculiar shape evolution from pre-formed nanoclusters during the Au deposition…