The red clays of Site 1216 (Subunit 1A; Fig. F3) are barren of calcareous microfossils. Biostratigraphic control was provided by shipboard analysis of sporadic occurrences of silicious microfossils in the lower part of Hole 1216A (Fig. F4). The assemblages encountered indicate an early Eocene-middle Eocene age for these sediments. The fossil content of the upper part of the sequence is limited to ichthyoliths and occasional concentrations of agglutinated benthic foraminifers. The single core recovered from Hole 1216B (Core 199-1216B-1H) contained only ichthyoliths.
Radiolarians were found in Samples 199-1216A-6H-1, 40-42 cm, through 11H-CC (Table T2). However, they are never common, preservation is generally poor, and only in Core 199-1216A-6H are they moderately well preserved. It was difficult to disaggregate the clay component of the samples, and in most cases, NaOH was used in addition to the usual cleaning process (Sanfilippo et al., 1985). Zonal designations are somewhat tentative because the absence of certain species may be a reflection of poor preservation rather than true faunal composition.
Sample 199-1216A-6H-1, 40-42 cm, and slurry from Section 6H-3 contain Eusyringium lagena and an early form of Eusyringium fistuligerum, thus placing the samples in middle Eocene Zone RP13 (Sanfilippo and Nigrini, 1998). The last occurrence of Thyrsocyrtis hirsuta appears to be in Sample 199-1216A-7H-1, 47-49 cm, suggesting that this sample belongs to either Zone RP12 or RP11. The next relatively reliable datum is the first occurrence of Dictyoprora mongolfieri in Sample 199-1216A-9H-CC, which requires that all samples between Cores 199-1216A-9H and 7H lie within Zone RP11. The presence of Buryella clinata in Sample 199-1216A-11X-CC, together with the absence of Thyrsocyrtis rhizodon, places that sample in uppermost Zone RP9 or lowermost RP10. These zones straddle the lower/middle Eocene boundary.
Benthic foraminiferal assemblages at Site 1216 are composed of agglutinated forms only. Calcareous benthic foraminifers were not found in any of the samples examined. The taxa identified are long ranging (Cretaceous-Holocene) and cosmopolitan and, therefore, of little stratigraphic utility. Species diversity of foraminiferal assemblages is low, and species identification is problematic because of poor preservation and fragmentation of the delicate tests during sample preparation. The distribution of benthic foraminifers is reported in Table T3.
Samples 199-1216A-1H-CC through 3H-CC and 10H-CC through 11X-CC are barren of benthic foraminifers. Samples 199-1216A-4H-CC and 5H-CC are dominated by agglutinated forms. The assemblages are mainly characterized by Amodiscus sp., Bathysiphon sp., Trochamminoides proteus, and Glomospira gordialis. Miliammina sp. is also frequently present. These taxa indicate bathyal to abyssal paleodepths. Sample 199-1216A-6H-3, 104-106 cm, contains poorly preserved and fragmented benthic foraminifers. Assemblages from Samples 199-1216A-7H-CC and 8H-CC are less diverse than those from Samples 4H-CC and 5H-CC, but the dominant taxa are the same as in previous samples, indicating similar paleodepths. Benthic foraminifers are not found in Sample 199-1216B-1H-CC.