Geochemistry in Argentina: from pioneers to the present

Abstract

La Trucha is a granitic, second-order catchment (2 km2) located in the highest ranges (1400 m elevation) of the Sierra de Comechingones, in central Argentina (31°54? 07?S, 64°45?28?W; 31°53?11?, 64°44?16?W). The main geochemical characteristics were studied between March 2005 and February 2006, placing special attention on seasonal and spatial variability as well as on weathering-induced carbon consumption. The catchment is representative of hundreds of first- and second-order streams that constitute the upper drainage basins of the fluvial system that dissects the Achala Batholith, which is basically subjected to a weathering-limited denudation regime. Water chemistry is typical of a stream draining F-rich granite, with anions following the HCO3- > F- > Cl- > SO42- sequence of molar abundance, and cations following Na+ > Ca2+ > Mg2+ > K+.