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doi:10.2204/iodp.proc.303306.202.2009

Materials and methods

Four holes were drilled at Site U1304 to a total depth of 264 mcd. All cores were recovered using the advanced piston corer (APC). Recovery was excellent in Holes U1304A and U1304B but decreased in Holes U1304C and U1304D. The sediments at Site U1304 are predominantly interbedded nannofossil oozes and diatom oozes, with less common intervals of clay and silty clay, which also contain abundant nannofossils and/or diatoms.

For this study, we collected 298 samples with a resolution of 10 cm from the uppermost 30.08 mcd of Holes U1304A and U1304B. An automated coccolith recognition system called Système de Reconnaissance Automatique de Coccolithes (SYRACO) (Beaufort and Dollfus, 2004) was used in this study. A total of 14 coccolith species were recognized using this system. These species are Calcidiscus leptoporus, Coccolithus pelagicus, Emiliania huxleyi, Florisphaera elongata, Florisphaera profunda, Helicosphaera carteri, Gephyrocapsa ericsonii, Gephyrocapsa muellerae, Gephyrocapsa oceanica, Scapholithus fossilis, Syracosphaera spp., Syracosphaera pulchra, Umbilicosphaera sibogae, and Umbellosphaera tenuis. Smear slides were prepared and viewed with an optical microscope (Leica DM6000B) with an automatic stage. A computer connected to the microscope controls motion and focus on the smear slides. A 50× lens and a digital camera (Spot Insight 1420) permit grabbing the frames in which the coccoliths are recognizable and taking images of them. In this study, 40 frames were grabbed for each sample. The output images were analyzed by SYRACO to obtain the relative abundance of coccoliths.

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