We examined the relative abundance of various components in the coarse fraction (> 150 µm) from a selected portion of the DSDP Site 480 piston core. The components consist mainly of diatoms, radiolarians, benthic and planktonic foraminifers with minor amounts of sponge spicules, terrigenous material, volcanic glass(?), dehydrated gypsum crystals, and spines of unknown biological origin. The examination shows that the siliceous organisms abound in the laminated sediments and that the calcareous organisms are more abundant in the nonlaminated sediments. Seasonal upwelling is responsible for the deposition of laminated sediments. The upwelling creates a strong oxygen-minimum zone, restricting the occurrence of burrowing benthic organisms and benthic foraminifers.

Supplement to: Crawford, Steve; Schrader, Hans-Jürgen (1982): Microfossil distribution in coarse-fraction (>150 µm) analysis of Deep Sea Drilling Project Site 480, Central Gulf of California: Preliminary results. In: Curray, J.R.; Moore, D.G.; et al., Initial Reports of the Deep Sea Drilling Project, 64, Initial Reports of the Deep Sea Drilling Project, 64, U.S. Government Printing Office, 64, 1245-1249