Relative abundance of pennate diatoms Thalassionema spp. and Thalassiothrix spp. im Upper Miocene-Lower Pliocene bulk sediment at ODP Hole 145-886B, North Pacific (Table 1) ...

• Main Authors: Dickens, Gerald Roy, Barron, John A
• Format: Dataset
• Language: English
• Published: PANGAEA 1997
• Subjects: DEPTH, sediment/rock; Sample code/label; Thalassionema spp.; Thalassiothrix spp.; Drilling/drill rig; DSDP/ODP/IODP sample designation; Leg145; Joides Resolution; Ocean Drilling Program ODP; Subarctic
• Online Access: https://dx.doi.org/10.1594/pangaea.679779; https://doi.pangaea.de/10.1594/PANGAEA.679779

Rapidly deposited Thalassionema-Thalassiothrti pennate diatom oozes previously have been described in Upper Miocene-Lower Pliocene sediment beneath the frontal boundary of the eastern equatorial Pacific. Here we document a new occurrence of Thalassionema-Thalassiothrix ooze in Upper Miocene-Lower Pliocene sediment beneath the frontal boundary of the subarctic North Pacific. The ooze is a 6 m interval of siliceous sediment at Ocean Drilling Program (ODP) sites 885/886 that was rapidly deposited between approximately 5.0 and 5.9 Ma. Bulk sediment in this interval may contain greater than 85% pennate diatom tests. There are also abundant laminae and pockets that are composed entirely of Thalassionema and Thalassiothrix diatoms. The presence of a rapidly deposited ooze dominated by pennate diatoms indicates unusual past conditions in the overlying surface waters. Time coincident deposition of such oozes at two distinct frontal boundary locations of the Pacific suggests that the unusual surface water conditions ... : depth is composite depth (mcd) ...