In the South Atlantic, at Sites 519 to 523, the dissolution of calcareous oozes ended in the formation of red clays rich in iron and manganese. The early authigenesis of manganese oxides and clays is described in Miocene marly calcareous oozes. The mineralogical and geochemical influences of basaltic basement weathering are shown by the occurrence of palagonite, authigenic clays, and oxides in the basal sediments. The development of red clay facies can be inhibited by local topographic and paleoceanographic changes, as at Site 520.

Supplement to: Karpoff, Anne Marie (1984): Miocene red clays of the South Atlantic: Dissolution facies of calcareous oozes at Deep Sea Drilling Project Sites 519 to 523, Leg 73. In: Hsü, KJ; LaBrecque, JL; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 73, 515-535