GEOCHEMISTRY OF WATER AND TRAVERTINE AT HONEY CREEK, A SPRING-FED STREAM IN THE ARBUCKLE MOUNTAINS OF SOUTHCENTRAL OKLAHOMA

Two distinct forms of travertine have been found to occur at Honey Creek, a spring-fed stream in the Arbuckle Mountains of Southcentral Oklahoma. Laminated precipitates occur in faster moving portions of the creek. Encrustations and dendritic deposits are found in slower moving portions of the stream and bear a close association with organic material occurring near their surface. Rapid travertine precipitation rates and progressive CO₂ degassing of spring-water as it flows along Honey Creek provides a natural laboratory in which to model the evolution of water in spring systems and explore the use of Ca isotope partitioning and trace element distributions as environmental proxies in the terrestrial realm. Measurements of these parameters will be conducted on water and precipitates formed on substrates left out in quarterly intervals during the course of a year at two sites along a transect of Honey Creek. Additional water samples along the transect will be analyzed for major ion concentrations in order to model the seasonal evolution of water in the system and determine whether any trend in the travertine signal occurs due to changes in environmental conditions and/or microbial activity.

The results from preliminary geochemical analyses of water along the transect as well as two naturally occurring travertine samples from both experimental precipitate sites will be presented. The major ion concentrations of water will be used to determine the saturation state of carbonate minerals in the water along the transect. Solid samples will be thin-sectioned and examined in order to identify layering which could be indicative of seasonal precipitation. SEM images of the sections will be used to display morphological differences between samples and layers and EDX will be used to identify any variation in their compositions. Powder from whole samples and discrete layers will be analyzed using XRD and WD-XRF in order to determine their mineralogy and trace element concentration.