Many palaeochannels are arranged on old drainage patterns which are distinct from the current drainage system of a catchment. For example, palaeochannels may relate to a system of rivers and creeks which drained east-west and the current drainage direction is north-south.
Palaeochannels can be most easily identified as broad erosional channels into a basement which underlies a system of depositional sequences which may contain several episodes of deposition and represent meandering peneplains.
Thereafter, a palaeochannel may form part of the regolith of a region and, although it is unconsolidated or partly consolidated, is currently part of the erosional surface.
Palaeochannels can also be identified according to their age. For example, there are deposits of Tertiary lignites situated in Tertiary river systems which are preserved on top of Archaean basement in the Yilgarn Craton of Western Australia. These river systems have laid in place for ~15 to 50 million years and would be considered palaeochannels.
For longer preservation, palaeochannels must have the source of river flows removed, either via a river changing course, climate change strangling inflows into the catchment, or perhaps faulting or tectonic movements altering the dynamics of a river system and/or its flow direction.
Palaeochannels are not necessarily permanent; it is possible for them to become eroded via reactivation of erosional activity or reactivation of the original river system.
Deep Yellow Limited (ASX:DYL) Identifies Significant Uranium Mineralisation In Basement Rocks Beneath The Tubas-Tumas Palaeochannel In Namibia
Dec 13, 2010; Deep Yellow Limited (ASX:DYL) (PINK:DYLLF) is pleased to announce that follow-up infill drilling at Tumas Zone 3 of the...