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Canopus Guyot: Hole U1372A

Drilling at Canopus Guyot recovered three cores containing pelagic sediment. This sediment was soupy in nature, requiring the core liner to be perforated and stood on end to allow excess water to drain before curation. This treatment may have allowed movement of nannofossils through the length of the core and resulted in a degree of homogenization of the assemblages. In general, the pelagic cap recovered from Hole U1372A contains nannofossil assemblages of Neogene age.

Sediment from Cores 330-U1372A-1R through 5R were examined for calcareous nannofossil content. In general, two samples were examined in each section (Table T1). All nannofossil samples examined exhibit very good to good preservation. Core 1R is only 10 cm long and is thought to have been recovered at the mudline. Small Gephyrocapsa spp. dominate the assemblage. The presence of Pseudoemiliania lacunosa indicates a Pleistocene age, assigned to Zone CN14.

Thirteen samples were examined from Core 330-U1372A-2R. Small gephyrocapsids compose the majority of the assemblage. P. lacunosa is present throughout Core 2R, and this species, together with the absence of discoasters, indicates Zones CN13–CN14 (early Pleistocene).

Sample 330-U1372A-3R-1, 0–1 cm, contains the first observed discoasters, including Discoaster brouweri, Discoaster tamalis, and Discoaster variabilis. These co-occur with Sphenolithus abies and Reticulofenestra pseudoumbilicus. The last appearance datum (LAD) of the latter taxon marks the top of Zone CN11. This assemblage persists through the base of Core 3R, which is assigned to Zone CN11 (Pliocene).

Samples from the matrix of the volcanic breccia/conglomerates in Cores 330-U1372A-4R and 5R were barren or composed of very rare, long-ranging specimens that were not age diagnostic.