A comparative study was conducted of a tufa mound precipitating from a cold-water spring near Santa Rosa, New Mexico, relative to two non-precipitating control springs within 8 km. Using geochemical methods, the waters from the three springs were compared and contrasted. Results showed all three springs were fed by groundwater of the same composition. The waters from all three springs were shown to be super saturated with respect to calcite. The primary control of the precipitation may be either physico-chemical or biogenetic. To determine the current precipitation rate, artificial substrates consisting of calcite slides, glass slides, stainless steel wool, and copper wool were placed on the spring mound in the area of active precipitation. Copper serves as a nucleation site for physico-chemical precipitation of calcite crystals. Biogenetic precipitation rates on copper will be lower since copper inhibits microbial action. Preliminary results show less precipitation on the copper indicating a biologic component of the precipitation.

 

Katrina received a B.A. in Physics from Lake Forest College in 1997. She came to Socorro for graduate school and received a M.S. in Physics from New Mexico Tech in 2000. She is currently working on her PhD in hydrology, studying the topic of karstic groundwater.