Geoscience Reference
In-Depth Information
Table 3.5
Examples of morphological evidence of former more humid conditions in drylands.
Landforms
Indicative
Location
References
Rivers
Gravel-bed channels
remnants left in bas
relief by erosion of
surrounding soft
sediments
Wetter climates/greater channel flow
Oman
Maizels (1987)
Underfit modern
channels
Greater flow
Argentina
Baker (1978)
Dry valley networks
Higher rainfall and channel flow or
higher groundwater tables and
spring sapping
Kalahari, Botswana
Nash, Thomas and Shaw (1994)
Valleys crossed by dunes
Wet-arid climate changes
Southeastern Sahara
Pachur and Kropelin (1987)
Lakes
Strandlines
Higher former lake levels
Kalahari
Burrough and Thomas (2009)
Slopes and hillsides
Fossil screes
Colder, possibly moister conditions
Libya
McBurney and Hey (1955)
Cave and speleothem
development
Greater local rainfall
Kalahari, Mexico,
Somali
Brook, Burney and Cowart
(1990)
Alluvial fan aggradation
Increased effective precipitation
California
Harvey and Wells (1994)
Deep-weathering
profiles
Wetter climates
Niger
Williams, Abell and Sparkes
(1987)
Figure 3.6
Williams Point, Lake Eyre, central Australia. Sediments on the basin margin reveal deposits that have accumulated
as shoreline features during periods of more persistant lake occupancy of the basin.
