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doi:10.2204/iodp.proc.340.111.2013

Paleontology and biostratigraphy

Core catcher samples at Site U1401 contain calcareous nannofossils and planktonic foraminifers of generally low abundance and were often found to be barren. Because of the coarse nature of much of the material collected, very few core catcher samples were adequate for biostratigraphic analysis. However, planktonic foraminiferal and nannofossil content was sufficient to indicate a late Pleistocene age (Fig. F3) for Holes U1401B–U1401D.

Calcareous nannofossils

From the four holes drilled at Site U1401, only four core catcher samples (340-U1401B-1H-CC, 340-U1401C-1H-CC and 3H-CC, and 340-U1401D-1H-CC) were appropriate for calcareous nannofossil analysis. Nannofossil samples were found to be abundant to barren and nannofossil preservation was good to moderate in samples within Holes U1401B–U1401D because of the coarse nature of materials collected. In Hole U1401A, an additional sample was taken from the working half of the core (Sample 340-U1401A-1H-5W, 52–53 cm). This sample contains late Pleistocene species such as Emiliania huxleyi and Gephyrocapsa sp., dating this sample as younger than 0.08 Ma, Zone CN15. Core catcher samples in Holes U1401B–U1401D contain similar assemblages (except for Sample 340-U1401C-3H-CC, which was barren), with a notable occurrence of small forms of E. huxleyi present in all samples. Consequently, these samples were also assigned to Zone CN15.

Planktonic foraminifers

Three of the eleven core catchers collected from Hole U1401A, one of the three core catchers collected from Hole U1401B, two of the three core catchers collected from Hole U1401C, and the single core catcher collected from Hole U1401D were analyzed for planktonic foraminiferal content. The remaining core catchers were not suitable for analysis because of the extremely coarse nature of the material collected. The abundance of planktonic foraminifers was generally very low. In Hole U1401A, only one sample (340-U1401A-2H-CC) contained specimens, unfortunately at an extremely low abundance (four specimens). One sample from Hole U1401B (Sample 340-U1401B-1H-CC) contained a low abundance (rare) of planktonic foraminifers, but because of the lack of datum species, the sample was inadequate to determine an age for the sediment. All samples analyzed from Hole U1401C were entirely barren of planktonic foraminifers. The single sample from Hole U1401D (Sample 340-U1401D-1H-CC) was found to contain abundant, well-preserved foraminifers, pteropods, and heteropods. The most abundant species of planktonic foraminifers included Globigerinoides ruber (pink and white) and Globigerinoides sacculifer. Neogloboquadrina dutertrei and Globigerinita glutinata were also common in the sample. One datum species, Globigerinella calida (bottom occurrence at 0.22 Ma), was found in Sample 340-U1401D-1H-CC, assigning this sediment to the late Pleistocene.

Benthic foraminifers

No benthic foraminifers were found at this location.

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