NON-DESTRUCTIVE CAVE SEDIMENT MAPPING TO DETERMINE SURFACE AND SUBSURFACE EROSIONAL AND DEPOSITIONAL HISTORY

Most cave sediment studies have focused on data obtained from sediment cores or sections of speleothems. Paleomagnetic data and isotope analyses have been used to determine paleoclimate and long-term depositional history, but these techniques are expensive and not widely available to all researchers. In wilderness areas, national parks, and other areas managed for resource preservation, coring, trenching, and speleothem removal may be prohibited, requiring alternative techniques.

Using this methodology, cave sediments are classified by composition and texture and then drawn on detailed maps of cave geomorphology. The wide availability of bedrock and surficial geology maps, may be used to determine cave sediment provenance. Evaluating the type and distribution of cave sediments allows some interpretation of the geologic history of an area. Surface-derived cave sediments preserve a record of surface erosion and transport. Sediments derived from in situ cave processes such as speleothem development and weathering may indicate periods of limited surface erosion or abandonment of caves as sediment conduits. Surface geologic maps and interpretation of cave sedimentary deposits allow the researcher to make important conclusions about landscape evolution.

This method was used to develop a sedimentary history for the caves of the Lime Creek Karst, an alpine area in Colorado. Detailed classification and mapping of cave sediments were accomplished with very little cave disturbance. Correlation between surface glacial materials and cave sediments allowed some interpretation of how glacial processes affected cave development and sedimentation.

This non-destructive, low-cost technique is widely applicable to areas where land management restrictions, project budget, and project scope limits the applicability of other methods. The type and distribution of cave sediments provide insights into the geologic history of an area where other evidence has been removed or is unclear.