Sedimentology and genesis of slope deposits at sonskyn, Eastern Cape Drakensberg, South Africa

• Published in: Permafrost and Periglacial Processes
• Main Authors: Hanvey, Patricia M., Lewis, Colin A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1991
• Subjects: Permafrost and Periglacial Processes
• Online Access: http://dx.doi.org/10.1002/ppp.3430020107; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.3430020107; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.3430020107

Abstract The morphology and sedimentology of slope deposits exposed in a road cutting at Sonskyn are examined. The deposits have a lobate morphology and extend outwards from the lower reaches of a basin hollow at an altitude of approximately 2000 m a.s.l. The general stratigraphy shows an upward sequence from shattered bedrock and isolated pockets of colluvium, through stratified angular sediments which in turn are truncated by a series of channelized bouldery deposits. The concentration of colluvium towards the base of the sequence, together with the subjacent shattered bedrock, suggest cold‐climatic conditions, a scarcity of vegetation cover and slopewash processes. The transition up‐sequence to more clastic stratified sediments is indicative of freeze‐thaw cycles accompanied by slopewash during the melting phases. This has been attributed to the seasonal ablation of a snow patch. The overlying channelized bouldery deposits are attributed to solifluction processes related to the final dissolution of the snow patch. Palaeolithic artefacts found within the stratified sediments were used in southern Africa between 140000 and 40000 years BP . This indicates that the slope deposits at Sonskyn were laid down within the last 140000 years.