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Temporal cycles of karst denudation in northwest Georgia, U.S.A.
Author(s) -
Kiefer Rudi H.
Publication year - 1994
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290190303
Subject(s) - denudation , karst , spring (device) , hydrology (agriculture) , geology , streams , seasonality , weathering , environmental science , geomorphology , ecology , mechanical engineering , paleontology , geotechnical engineering , biology , computer science , engineering , tectonics , computer network
Time patterns of karst denudation in northwest Georgia (U.S.A.) were investigated at three spring sites for 12 months and at five stream sites for 10 years. Rainfall was evenly distributed and showed no significant seasonality. At the springs, as well as the streams, water hardness was largely controlled by discharge. At the springs, soil pCO 2 and water pH were strongly correlated ( r + ‐0·69 to ‐0·83). Solute transport in spring waters was highly seasonal, with two conduit flow springs removing more limestone in the winter, and the diffuse flow spring removing more during the growing season. At the stream sites, most denudation occurred during the winter and spring seasons, and least during the summer. Fourier analysis showed that variations in denudation occur on deterministic (long‐wave) as well as stochastic (shortwave) time scales. As contributing variables, discharge varied in short‐wave and long‐wave cycles, whereas soil pCO 2 showed only a long‐wave cycle. The 12 month deterministic cycles were the most important, with changes in discharge taking precedence over soil pCO 2 . Time series regression explains up to 69 per cent of changes in denudation through rain and soil pCO 2 . Time cycles in available water are the key controlling factor of denudation, and amounts of available soil CO 2 may not be as important in the temporal patterns of karst downwearing as has been believed previously.