A QUANTITATIVE APPROACH TO LINKING DRAINAGE AREA AND DISTRIBUTIVE-FLUVIAL-SYSTEM AREA IN MODERN AND ANCIENT ENDORHEIC BASINS

摘要

Regression relationships are derived relating the areal extent of large distributive fluvial systems (DFSs) (> 30 km in length) formed in endorheic basins to contributing drainage area. The resulting correlation coefficients vary between 79 and 98. Derived correlation values are strikingly similar when stratified by climate, large-scale tectonic regime, and basin context. Regression-equation exponent values range from 0.41 to 0.75, indicating a strong positive relationship between drainage area and DFS area, while coefficients account for the influence of external parameters on the derived relationships. Analysis of the dataset using planform morphology and drainage-basin slope as additional variables reveals that regressions for braided bifurcating DFS produce a highly significant relationship. The relationship suggests that drainage-basin relief influences sediment supply to the sedimentary basin in terms of volume or caliber, which in turn affects the depositional gradient of the DFS surface and resultant channel planform. An evaluation of the predictive capability of the regression equations reveals that the relationships derived from braided bifurcating DFSs perform best, with 80 of the predicted values falling within +/- 25 of the measured DFS area value, with a third of the predicted values within +/- 10 of the measured DFS area value.