AN INITIAL ARCHAEOLOGICAL AND SOIL SURVEY OF LITTLE SPRING CREEK AND THE INFLUENCE OF GROUNDWATER SAPPING ON HEADWARD EROSION AT GREAT SAND DUNES NATIONAL PARK, COLORADO, USA

The Great Sand Dunes National Park and Preserve (GRSA) is located in the San Luis Valley of southern Colorado approximately thirty-seven miles northeast of Alamosa. The park hosts the tallest dune in North America and a complex aeolian system consisting four major components: sabkha, sand sheet, dune field, and sand ramp. A complete drainage system with headwaters originating above the dune field and a terminus located in the sabkha is a unique feature of GRSA. Because of non-consumptive ground and surface water rights associated with the park and the importance of water in this desert environment, the National Park Service is interested in understanding the hydrological processes affecting the dune field and meeting its obligation to protect the natural water levels necessary to maintain cultural, physical, and biological processes of the park.

Critical GRSA resources are gaining streams that emerge from the sand sheet and appear to be groundwater sapping systems with well exposed soil horizons. Upon reconnaissance of Little Spring Creek (LSC), it appears that there is strong evidence of a paleosol exposed along the banks of the creek. Few soil studies have been conducted along LSC with most of the research accomplished by the author. Research has been conducted on a buried soil horizon on Big Spring Creek, a similar creek three miles north of LSC by geomorphologist Rich Madole in 2001. He concluded that the ages discovered during radiocarbon dating are 1340 ± 500,000 and 340 ± 40 years, respectively. With the assistance of radiocarbon dating, ages of the paleosol will be determined along Little Spring Creek, as well as determine if the horizon is an ancient lake bed or an ancient landscape. The significance of discovering a correlation between buried soil horizons of two geographically separated areas may permit extrapolation of data and lead to future archaeological sites. Correlated data from Rich Madole is synergistic and will contribute greatly to understanding the geologic puzzle that is the San Luis Valley.