Distribution of trace fossils and ichnofabric indices in ODP holes of Leg 119

Trace fossils and ichnofabric were examined from cores of Late Cretaceous to Quaternary age recovered from the Kerguelen Plateau, Indian Ocean. Nearly all of the strata are completely bioturbated, with ichnofabric index 6 most commonly recorded. Preserved discrete trace fossils include Chondrites, Planolites, Zoophycos, and Thalassinoides. A continuous Cretaceous/Tertiary boundary section preserved at ODP Site 738 occurs within a 15-cm-thick interval of laminated sediments. The lack of bioturbation indicates the disappearance of bioturbating organisms from the seafloor, possibly as a result of the same factors that caused the mass extinction or changes in other environmental conditions - most probably, bottom-water oxygen concentrations.

Interstitial-water chemistry of ODP Leg 119 sites

Ocean Drilling Program inorganic geochemistry procedures routinely overlook more than 99% of the sediment column. Present and past biogeochemical reactions alter the sediment record; however, most of these reaction zones are bypassed by the normal methods where samples are collected every 30 m. A new approach to increase resolution was introduced during Leg 119. Ten milliliters of sediment provided interstitial-water samples for ammonia, silica, sulfate, magnesium, and calcium analyses. The new method introduced some systematic differences in concentrations, as well as some decrease in precision. A number of advantages, however, may warrant using the method in some instances. In cases where routine interstitial-water data showed anomalous results, core sections were retrieved from the storage facility and resampled. The new high-resolution procedure was used to provide water samples in cases were water contents were low and routine squeezing could not recover pore water.

Silicoflagellates of ODP Leg 119 samples

The occurrence of Quaternary and Oligocene silicoflagellates at two Ocean Drilling Program (ODP) Leg 119 Holes (736A and 744A) on the Kerguelen Plateau in the Southern Ocean was investigated to compare species distributions to Northern Hemisphere floras. This abstract gives the data determined (Tables 1 and 2) for 24 samples and few preliminary remarks. Quaternary assemblages of Hole 736A are noteworthy for the absences of key North Pacific zonal guide species such as Bachmannocena quadrangula, Dictyocha aculeata, Dictyocha subarctios, and Distephanus octangulatus (Bukry and Monechi, 1985). Other species such as Distephanus floridus, Distephanus speculum elongatus, and Mesocena octagona show limited ranges in Hole 736A and may help to subdivide the Quaternary locally. The late Oligocene assemblages of Hole 744A contain widely distributed species of Distephanus and Naviculopsis, which permit correlation to lower latitude assemblages. They also contain the high-latitude acme of Distephanus raupii which was first noted at Deep Sea Drilling Project (DSDP) Hole 278 (56°3.42'S, 160°04.29'E, water depth 3689 m) by Perch-Nielsen (1975) and Bukry (1975). Study of Hole 744A assemblages suggests that D. raupii developed from pentagonal Dictyocha deflandrei deflandrei. A final note on the Hole 744A assemblages is the brief late Oligocene acme (25%) of Dictyocha sp. aff. D. spinosa in Sample 119-744A-13H-4, 65-67 cm, which provides a direct correlation to the acme (16%) in DSDP Sample 29-278-31R-CC (Perch-Nielsen, 1975) in the Southern Ocean. Most of the taxonomy used in the tables is documented in earlier publications of the DSDP Initial Reports (see Bukry in Volumes 16, 35, 37, 40, 44, 49, 54, 67, 68, 69, 81, and 95). Also, see Loeblich et al. (1968) and Perch-Nielsen (1985) for extensive taxonomy and illustrations.