16th November 2023: Talk by Dr. Peter Turner, The Late Triassic – Early Jurassic evaporites of the Berkine Basin

The Late Triassic – Early Jurassic evaporites of the Berkine Basin will be described. Time series analysis of gamma logs shows that astronomical forcing played a key role in their deposition. Long eccentricity cycles (~405kyr, ~50m) reflect lacustrine expansion and contraction, whereas precessional cycles (~20kyr, ~3m) reflect desiccation and halite deposition. These Saharan Platform basins bear much in common with other western Mediterranean evaporite basins. Many show the same overall pattern of sedimentation with increased sulphate deposition near the Tr-J boundary, possibly linked to the CAMP. In late Triassic times they formed a contiguous low-lying zone flanked by cratonic highlands. This zone spanned the Gondwana-Laurussia boundary immediately prior to the break-up of Pangea and Greater Adria formed the barrier between the basins and developing Neotethys to the east.