ISSN: 0214-1744 Revista DRAINAGE PATTERNS IN AN APPALACHIAN FOLD MOUNTAIN BELT: FLINDERS RANGES, & SOUTH AUSTRALIA C. R. Twidale & J. A. Bourne School of Earth and Environmental Sciences, Geology and Geophysics, University of Adelaide, Adelaide, South Australia, 5005 E-mail:
[email protected] Abstract: The streams and rivers draining the Flinders Ranges are largely concordant with structure but all major ele- ments and many other channels include sectors that cut across local structure in anomalous or transverse streams. These anomalous sectors can plausibly be explained in various ways: by capture involving headward erosion, or stream and valley impression made possible by the deep erosion of folds, or by underprinting. The possibility of referral is broached, as is the significance of catchment characteristics in relation to piracy. The impression mechanism raises the possibility that some transverse sectors are of great antiquity. But the origin of many structurally discordant elements remains ambiguous, for they are susceptible of explanation by more than one process or mechanism. Key words: Ridge and Valley topography, transverse drainage, fluvial piracy, impression, underprinting, referral, South Australia. Resumen: La red de drenaje desarrollada en las Flinders Ranges (Australia) es en su mayor parte concordante con la estructura geológica subyacente. No obstante, incluye importantes tramos fluviales que atraviesan la estructura geoló- gica subyacente dando lugar a drenajes transversals anómalos. Estas zonas anómalas pueden ser plausiblemente expli- cadas en cada caso por varios procesos tales como, capturas por erosión remontante, procesos de superposición de canales o valles fluviales debido a la profunda erosión de los mismos o por superimposición (underprinting).