Luminescence dating a tool to interrogate multi-scale coastal landscape response, Cape south coast, South Africa.

The South African coast is a key region for Neogene and Pleistocene sea level studies (Hearty et al. 2020). Along the Western and Eastern Cape Provinces, thick sequences of cemented coastal deposits (dunes and near-shore deposits) form an archive of climatic and landscape change, as well as preserving numerous trace fossils (Helm et al., 2020) and evidence of human occupation (Helm et al., 2018). This project will interrogate these coastal sedimentary archives at two scales:

1. The long-term timing of onshore dune and shoreline emplacement broadly equates to high interglacial sea-levels (Bateman et al., 2011), with coastal dune formation on the continental shelf during low-stands (Cawthra et al 2018). However, variability in the peri-coastal stratigraphic record is imparted by the interplay of (inherited) sediment supply and offshore topography (Carr et al., 2019) and we predict more complex scenarios exist, particularly in areas with a narrower coastal shelf.

This is exciting as it offers scope to drill into far broader questions of diverse coastal landscape evolution(s) via, high-density geochronological sampling closely accompanied by targeted geophysical surveying.

2. Today parts of the coastline are rapidly eroding due to sea level rise and relatively soft Pleistocene coastal sediments. This occurs in the face of burgeoning coastal development.

This project will investigate the potential of luminescence rock surface dating methods to estimate the timing and rates coastal cliff erosion and to test the potential to date the displacement of large blocks from cliffs and shore platforms; the latter include potential storm surge and tsunami deposits (e.g. Brill et al., 2021). The potential of surface exposure luminescence dating methods is still being realised, but this approach - in a region rich in quartz with suitable luminescence properties - may offer entirely new insights into shorter-term coastal landscape change, and contribute to better-defining regional coastal hazards.

This project will primarily employ luminescence dating methods, in conjunction with other surveying techniques, to interrogate coastal landscape processes over multiple spatial-temporal scales. The student will focus on the development of the new luminescence dating chronologies at Leicester, in collaboration with researchers from the Council for Geoscience, South Africa.