MATERIALS AND METHODS

Initially, four sites were sampled: Hole 1018A (36°59.300´N, 123°16.653´; 2478 meters below seafloor [mbsf]), Hole 1020C (41°0.051´N, 126°26.063´W; 3038 mbsf), Hole 1021B (39°5.248´N, 127°46.985´W; 4212 mbsf), and Hole 1022C (40°4.842´N, 125°20.558´W; 1926 mbsf) (Fig. 1; Table 1). Sample spacing ranged from one sample per core in Holes 1018A and 1021B to three samples per core in Holes 1020B and 1022C. Standard marine pollen-processing procedures, including the addition of measured quantities of an exotic tracer to determine pollen concentration (pollen grains/gram dry weight sediment [gdws]), were preceded and succeeded by sieving through 7-µm nylon monofilament screening (Heusser and Stock, 1984). Pollen types representing 35 taxa were identified to the lowest taxonomic level possible; for example, specific identification of Tsuga (T. heterophylla and T. mertensiana) and familial identification of grasses (Gramineae), chenopods (Chenopodiaceae), and composites (Compositae). Excluding the papillate thick-exined grains of S. sempervirens (coastal redwood) and inaperturate pollen of other genera in the Taxodiaceae, Cupressaceae, and Taxaceae (Juniperus, Torreya, Cupressus, Libocedrus, Chamaecyparis, and Thuja), taxa that cannot be satisfactorily separated using light microscopy are here referred to as juniper-cypress. Other groups of pollen and spores include herbs (Gramineae, Cyperaceae, and Compositae), chaparral (sclerophylous shrubs such as Ceanothus, Adenostoma, Rhus, and other members of Anacardiaceae, Rhamnaceae, and Rosaceae), and ferns (Polypodiaceae). For this initial survey, 100 pollen grains were identified in each of 327 samples from Sites 1018, 1020, and 1022. (Data files are available from the ODP Data Librarian.) Because pollen concentrations in samples from ODP Hole 1021B were extremely low (ranging from 100 to 1000 gdws), pollen data from this hole are not discussed in this report. Pollen percentages are based on the total number of pollen grains identified in each sample. Percentages of fern spores (and other pteridophytes such as Lycopodium spp. and Selaginella selaginoides) are calculated on the total number of pollen grain and spores identified in each sample.