Chemical weathering rates and reactions in the Lake Fryxell Basin, Taylor Valley: Comparison to temperate river basins

Much has been written recently about the influence of climate on chemical denudation rates. Some authors have argued that climate has little impact on chemical weathering unless coupled with high rates of physical weathering. Others have stated that physical erosion rates do not have a critical influence on chemical weathering but climate does. We present a comparison of chemical weathering rates, as determined by H4SiO4 and HCO3- fluxes in streams and rivers, between warm-temperate systems in Alabama and desert-polar systems in Taylor Valley. Chemical weathering rates, as represented as H4SiO4 fluxes in Alabama, range from 55x10(3) moles km(-2) yr(-1) for the Cahaba River basin to 29x10(3) mol km(-2) yr(-1) for the Tallapoosa River Basin. These values are slightly lower than the world average of 64x10(3) km(-2) yr(-1) calculated by Ming-hui er al. (1982). Our preliminary calculations indicate that chemical weathering rates in the Antarctic streams are equal to or greater than the Alabama rivers with rates ranging from 4 to 193x10(3) moles km(-2) yr(-1). These high chemical weathering rates suggest that temperature itself may not play the principal role in determining weathering rates. Geochemical modelling suggests a number of potential reactions occur within the stream reaches in Taylor Valley, Antarctica.