Miocene to Holocene diatom biostratigraphy of ODP Leg 105 sites

The diatom assemblage at Site 645 contains rare stratigraphic indicators. Fragmentation of frustules and the occurrence of species characteristic of high-latitude shelf, upper-slope environments suggest current transportation from the shelf.

The diatom abundance and preservation at Site 646 probably reflect climatic changes and are also affected by dissolution, but it is not possible to detect the dominant factor. Therefore, the stratigraphic ranges of the primary and secondary biostratigraphic indicators are often unreliable.