For Bolboforma investigations, core catcher (CC) samples from Holes 982A and 982B and splits of the "paleo" samples taken on board by the scientific party were used. Approximately 15-20 g of dry sediment (10 cm3) per sample was analyzed. Twenty-six CC samples were studied for Hole 982A, from 8.14 to 245.77 meters below seafloor (mbsf) (Samples 162-982A-1H-CC through 26H-CC). Three hundred one samples were studied for Hole 982B, from 6.64 to ~605 mbsf (Samples 162-982B-2H-1, 114-116 cm, through 65X-CC). A re-examination of 71 samples from DSDP Hole 116 from Cores 1 through 28 (72.03 to 842.04 mbsf) is also given.
The preparation method used to obtain Bolboforma specimens was the same as that used for foraminifers. Soft sediments were soaked in water; slightly indurated sediments were soaked in diluted H2O2, then washed through a 63-µm mesh sieve. The samples were dried, and the Bolboforma specimens were picked under the binocular microscope. Additional isolated small specimens were observed under the electronic microscope to clarify specific characteristics. The abundance shown in the range charts is based on semiquantitative estimates as follows: A = abundant: >50 specimens; C = common: 25-50 specimens; R = rare: 2-24 specimens; T = tracers: one specimen; and B = barren of Bolboforma. The preservation of the specimens is good throughout the sequences in all holes, but most specimens are completely filled and heavily coated by calcareous nannoplankton. The list of samples and the ranges of Bolboforma species are given in Table 1, Table 2, Table 3, Table 4, and Table 5. The zone fossil columns are shaded in gray. The well-defined zonal boundaries are shown as full lines, and the tentative boundaries are given as dashed lines.
The specimens and the samples described and investigated have been deposited in the Natural History Museum of Basel, Switzerland.