Evolution of drainage patterns on Cape York Peninsula, northeast Queensland

Abstract

Drainage patterns along passive continental margins are often hypothesised to be the result of drainage disruption following highland uplift and downwarping of the highland flank. Several studies of stream catchments throughout southeast Australia have demonstrated that the opposite tends to be the case in this region because the field evidence favours stream and continental drainage-divide stability. While significant advances have been made towards understanding this phenomenon in the southeastern corner of the continent, little is known of the evolution of streams and highlands in northeast Australia. Our study examines palaeochannels and fluvial sedimentary units close to the continental drainage divide in six stream catchments along the length of Cape York Peninsula. The results show that four of the catchments (Barron-Mitchell and Stewart-Holroyd) have experienced continental divide and drainage stability, whereas the Pascoe-Wenlock system appears to have experienced westward migration of the continental drainage divide and diversion of the Pascoe River. River diversion here is likely to be a result of the raising of base-level and flooding of stream channels during the Cretaceous marine transgression and subsequent stream incision by the Pascoe River along structural weaknesses in the underlying strata, following cessation of marine conditions.