Elephant Tracks: A Biogenic Cause of Potholes in Pleistocene South African Coastal Rocks

• Published in: Journal of coastal research Vol. 37; no. 1; pp. 59 - 74
• Main Authors: Helm, Charles W., Cawthra, Hayley C., De Vynck, Jan C., Dixon, Mark, Stear, Willo
• Format: Journal Article
• Language: English
• Published: Fort Lauderdale Coastal Education and Research Foundation 01.01.2021; Allen Press Publishing; Allen Press Inc
• Subjects: aeolianites; Algae; Beaches; Cape south coast; Capes (landforms); coastal geomorphology; Coastal inlets; Coastal research; Coasts; Corridors; Elephants; Foreshore; foreshore deposits; Geology; intertidal zone; Isotopes; Littoral environments; Outcrops; Pleistocene; Precursors; Rivers; Rock; Rocks; Sand & gravel; Sediments; tracksites; Vertebrates
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/JCOASTRES-D-20-00064.1

Helm, C.W.; Cawthra, H.C.; De Vynck, J.C.; Dixon, M., and Stear, W., 2021. Elephant tracks: A biogenic cause of potholes in Pleistocene South African coastal rocks. Journal of Coastal Research, 37(1), 59–74. Coconut Creek (Florida), ISSN 0749-0208. The Cape south coast of South Africa contains extensive outcrops of Pleistocene aeolianite and cemented foreshore deposits. More than 250 vertebrate tracksites have been identified in these deposits, including 35 elephant tracksites. In places, where large palaeosurfaces are occasionally exposed, numerous potholes are evident on the remains of what is most likely a palaeo-coastline. Features suggestive of elephant tracks are apparent on such surfaces and in overlying layers. In order to develop, potholes require a disturbance or depression in the surface to act as a “pothole-precursor” on which erosive forces can act. While elephant tracks or similar biogenic origins for potholes have not previously been described, such an explanation appears plausible for at least some pothole features in areas known to have harboured elephants or other large vertebrate trackmakers when these surfaces were composed of unconsolidated sand. Four sites on the Cape south coast are examined and described. Evidence for use of beaches as travel corridors for elephants is described, and candidate Pleistocene trackmaker species are considered. The age of these palaeo-surfaces is considered to range from Marine Isotope Stage 11 to Marine Isotope Stage 5. It is concluded that depressions formed by elephant tracks should be considered as a precursor for the formation of potholes on suitable Pleistocene surfaces in littoral zones.