We made biostratigraphic assignments to core-catcher samples in Holes 1110A, 1110B, 1111A, 1112A, and 1112B using calcareous nannofossils and planktonic foraminifers (Fig. F20). Estimates of paleobathymetry for these samples were made using benthic foraminiferal assemblages.
Sample 180-1110A-1H-CC contains abundant, well-preserved nannofossils. Few and well-preserved nannofossils occur in Sample 180-1110A-2H-CC. Samples 180-1110B-1H-CC and 2X-CC contain abundant, well-preserved nannofossils. Core 180-1110B-3X has no sediments.
There was no recovery of sediment in Cores 180-1111A-1R, 5R, 9R, 17R, and 18R. Samples 180-1111A-2R-CC to 4R-CC contain abundant, well-preserved nannofossils. Nannofossils in Samples 180-1111A-6R-CC and 7R-CC are common and well preserved. Nannofossils in Samples 180-1111A-8R-CC to 16R-CC are common to abundant, with preservation ranging from poor to good (mostly moderate). Reworking (and some possible contamination from higher in the hole) is common throughout the samples.
Cores 180-1112A-3R to 6R, 11R to 14R, and 180-1113A-1R to 3R have no sediments. Samples 180-1112A-9R-CC and 10R-CC and 180-1112B-3R-CC through 6R-CC are barren of nannofossils. Samples 180-1112A-1R-CC and 2R-CC yield abundant and well-preserved nannofossils. Samples 180-1112A-7R-CC and 8R-CC contain rare and poorly preserved nannofossils.
Cores 180-1110A-1H and 180-1110B-1H to 2X are placed in nannofossil Zone NN21, based on the presence of Emiliania huxleyi. Sample 180-1110A-2H-CC contains no Pseudoemiliania lacunosa and rare E. huxleyi, indicating Zone NN21-20.
Emiliania huxleyi is present in Samples 180-1111A-2R-CC and 3R-CC, indicating Zone NN21. Sample 180-1111A-4R-CC contains E. huxleyi, but also Pseudoemiliania lacunosa, which is probably reworked. The sample is assigned to Zones NN21-NN20 because of the mixed assemblage. We assign Samples 180-1111A-6R-CC to 16R-CC to Subzone NN19F, based on the presence of Pseudoemiliania lacunosa and Gephyrocapsa omega.
Core 180-1112A-1R is in the nannofossil Zone NN21, based on the common occurrence of Emiliania huxleyi. Sample 180-1112A-2R-CC contains rare E. huxleyi, indicating Zone NN21-NN20. We found five and one specimens of Gephyrocapsa oceanica in Samples 180-1112A-7R-CC and 8R-CC, respectively, which indicates Subzone NN19B or younger.
Sample 180-1110A-1H-CC, 11-14 cm, is a volcanic ash layer that contains only very small planktonic foraminifers of non-age-diagnostic species. Sample 180-1110A-1H-1, 91-93 cm, which contained well-preserved planktonic foraminifers, including Bolliella calida and Bolliella adamsi, was assigned to Zone N23. Sample 180-1110A-2H-CC was size sorted toward the large-size foraminifers and contained abundant phyllite grains. It contains Globorotalia truncatulinoides and may belong to either Zone N22 or N23. Samples 180-1110B-1H-CC and 2X-CC contained abundant, well-preserved planktonic foraminifers. These samples were assigned to Zone N23, given the presence of Bolliella adamsi and B. calida, which marks the base of the zone.
Planktonic foraminifers were abundant and had moderate to good preservation in the core catchers of Samples 180-1111A-2R, 3R, 7R, 11R to 15R, and the bottom of Core 16R, as well as in Samples 180-1111A-13R-1, 91-93 cm, and 15R-1, 51-53 cm. Specimens were common and had moderate preservation in Sample 180-1111A-8R-CC. Specimens were few to rare and poorly preserved in Samples 180-1111A-4R-CC, 6R-CC, and 10R-CC. There was no recovery of sediments in Cores 1R, 5R, 9R, 17R, and 18R.
Samples 180-1111A-2R-CC and 3R-CC are assigned Zone N23, based on the presence of Bolliella adamsi and B. calida. Sample 180-1111A-6R-CC contained only a few planktonic foraminifers, among them Globorotalia truncatulinoides and pink G. ruber (which was present from Samples 180-1111A-6R-CC through 14R-CC). This sample might fall in either Zone N23 or N22. Samples 180-1111A-7R-CC and 10R-CC through 16R-CC contained Globorotalia truncatulinoides without G. tosaensis, and Pulleniatina was dextrally coiled, indicating the upper part of Zone N22 (<0.65 Ma). A single occurrence of Globorotalia tosaensis in Sample 180-1111A-8R-CC was considered to be reworked.
Planktonic foraminifers were abundant and well preserved in Samples 180-1112A-1R-CC and 2R-CC. Core-catcher samples in Hole 1112B were barren of foraminifers. Samples 180-1112A-1R-CC and 2R-CC are assigned to Zone N23. Both samples contained Bolliella calida, marker for the zone. In addition, Sample 180-1112A-2R-CC contained pink specimens of Globigerinoides ruber, indicating an age no younger than 120 ka.
A lower bathyal (2000-4000 m) assemblage of benthic foraminifers is present in Samples 180-1110A-2H-CC, 180-1110B-1H-CC, and 2X-CC, consistent with the present water depth of the site of ~3200 m. The diverse assemblage consists of such species as Bolivinellina seminuda, Chilostomella oolina, Fontbotia wuellerstorfi, Gavelinopsis praegeri, Globocassidulina moluccensis, G. subglobosa, Melonis affinis, Oridorsalis umbonatus, Parrelloides bradyi, Pseudoparrella exigua, Quinqueloculina venusta, and Triloculina tricarinata auct.
The benthic foraminiferal assemblages of Hole 1111A were consistent with the lower bathyal depth of the site (~3200 m) and contained such species as Favocassidulina favus, Fontbotia wuellerstorfi, Hoeglundina elegans, Oridorsalis umbonatus, Parrelloides bradyi, Pullenia bulloides, and Uvigerina bradyana. Only occasional specimens of shallow-water origin were incorporated into these assemblages. However, in Sample 180-1111A-13R-1, 0-1 cm (a winnowed, coarse sand that was sampled in a temperature probe), specimens of large shallow-water benthic species outnumbered the in situ assemblage of large benthic specimens. These reefal inhabitants included Amphistegina bicirculata, A. lessonii, A. radiata, Calcarina spengleri, Gypsina vesicularis, Heterostegina depressa, Marginopora vertebralis, Planorbulinella larvata, and Schlumbergerella floresiana, along with various alcyonarian spicules, bryozoans, calcareous algae, echinoid plates and spines, mollusks, and otoliths.
A surface sample (Sample 180-1112A-1R-1, 0-1 cm) at Site 1112, which is located at a water depth of 3047 m, contained an assemblage of small benthic specimens, including the species Fijinonion schwageri, Melonis affinis, M. pompilioides, Pullenia bulloides, P. quinqueloba, Quinqueloculina venusta, and Saccammina sp. In Samples 180-1112A-1R-CC and 2R-CC, the lower bathyal (>2000 m) assemblage of benthic foraminifers included the species Favocassidulina favus, Fijinonion schwageri, and Fontbotia wuellerstorfi.