HUMANS AS GEOLOGICAL AGENTS AND THE QUESTION OF SCALE

Humans are important geological agents over recent and historic time s cales, but whether human agency is significant in the context of longe r-term geologic evolution is unresolved, Are anthropic impacts ''noise '' in the grand trend of Earth's evolution or a fundamental change in the geologic environment? Four approaches to this problem are outlined , based on principles for determining whether or under what circumstan ces geologic processes or phenomena should be considered interdependen t or independent. The approaches are illustrated with field problems c oncerned with Holocene Impacts of human agency on geomorphic processes in the coastal plain of North Carolina. Whether humans represent shor t-term perturbations or more fundamental long-term changes in geologic systems depends on the problem, geologic system, and time scale of in terest; on the durations and frequencies of human impacts; on the sens itivity and relaxation times of the geologic components; and on the re lative rates of the human-influenced and relevant non-human geologic p rocesses, These principles can be incorporated into quantitative tools to address scale issues with respect to human agency in specific geol ogic systems.