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doi:10.2204/iodp.proc.338.205.2016

Materials and methods

The samples used for this research were collected from Holes C0002K and C0002L at an average interval of 3.5 m (1–3 samples per core). We treated 79 samples in the present study. The stratigraphy of the studied interval correlates to lithologic Unit II of previous drilling at Site C0002. Unit II is mainly composed of dark olive-gray silty claystone with subordinate sandstone, sandy siltstone, and volcanic ash (see the “Site C0002” chapter [Strasser et al., 2014c]). We generally followed the analytical techniques described in the “Methods” chapter (Strasser et al., 2014b). Sediment samples of 10–40 g dry weight were disaggregated using the sodium tetraphenylborate method (Hanken, 1979). After the samples had been macerated, each was wet-sieved through a 63 μm screen. Dried samples were then divided by a sample splitter into suitable volumes yielding ~200 planktonic foraminiferal specimens. Planktonic foraminiferal specimens larger than 125 μm were picked under a binocular microscope. We then conducted additional observations for all washed residues to detect index species. Species detected by the additional observation were recorded as “+” in occurrence table (Table T1). Scanning electron microphotographs of important species were obtained with a JCM-5000 instrument (JEOL Co. Ltd., Japan).

Preservation of each sample was recorded using the following criteria:

• P = poor (dissolution of surface structure and fragmentation are observed; more than a half of the individuals cannot be identified at the species level).
• M = moderate (dissolution and fragmentation are commonly evident; some individuals are hard to identify).
• G = good (no dissolution; fragmentation of individuals has slightly occurred).

Taxonomic names and biochronology in this study generally follow the usage of Wade et al. (2011). Moreover, we distinguished the two morphotypes of Globorotalia inflata (i.e., transitional and modern forms by the number of chambers [Hayashi et al., 2003]). The modern form differs from the transitional form in having three chambers in its last whorl, in contrast to the four chambers of the transitional form.

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