ALBERT

Description: Leg 81 of the DSDP drilled four sites in a small area on the southwest flank of the Rockall Plateau. The biostratigraphy of the cores is based on six groups of microfossils: calcareous nannofossils, diatoms, dinoflagellates, planktonic foraminifers, radiolarians, and silicoflagellates. A good magnetostratigraphic record covering the interval from the top of the Brunhes to the Gauss/Gilbert boundary was obtained from one of the sites. Since magnetostratigraphy was not available for the older part of the section, it was not possible to estimate whether biostratigraphic indications in sediments older than 3.4 m.y. are diachronous or synchronous from low to high latitudes. The biostratigraphic resolution is generally low for any single group, but higher resolution can be attained by using all available microfossil groups. A composite list of biostratigraphic events (mainly Neogene) is presented.

Description: Protoperidiniacean dinoflagellate cysts were identified in 19 of 28 samples from two sites on the Antarctic Peninsula continental rise. Cysts are most common in the lower Pliocene and upper Miocene and include species of Brigantedinium, Lejeunecysta, and Selenopemphix. Autotrophic gonyaulacacean dinoflagellate cysts are very rare in the samples. The dominance of taxa derived from assumed heterotrophic dinoflagellate motile forms may indicate high nutrient content in the surface waters, which sustained a considerable diatom population.

Description: Fjords are glacially over-deepened semi-enclosed marine basins, typically with entrance sills separating their deep waters from the adjacent coastal waters which restrict water circulation and thus oxygen renewal. The location of fjords is principally controlled by the occurrence of ice sheets, either modern or ancestral. Fjords are therefore geomorphological features that represent the transition from the terrestrial to the marine environment and, as such, have the potential to preserve evidence of environmental change. Typically, most fjords have been glaciated a number of times and some high-latitude fjords still possess a resident glacier. In most cases, glacial erosion through successive glacial/interglacial cycles has ensured the removal of sediment sequences within the fjord. Hence the stratigraphic record in fjords largely preserves a glacial-deglacial cycle of deposition over the last 18 ka or so. Sheltered water and high sedimentation rates have the potential to make fjords ideal depositional environments for preserving continuous records of climate and environmental change with high temporal resolution. In addition to acting as high-resolution environmental archives, fjords can also be thought of as mini-ocean sedimentary basin laboratories. Fjords remain an understudied and often neglected sedimentary realm. With predictions of warming climates, changing ocean circulation and rising sea levels, this volume is a timely look at these environmentally sensitive coastlines. Supplementary materialThe Glossary is available at: http://www.geolsoc.org.uk/SUP18440.

Description: The potential of using dinoflagellate cysts as proxies for palaeoceanographic conditions and as monitors of the dynamic marine environment of climatically sensitive Arctic fjords was investigated with sediment traps. Dinoflagellate cysts were analysed from three separate deployments in two high Arctic fjords in the Svalbard archipelago. Two deployments in Kongsfjorden on the west coast of Svalbard occurred during 2002 and 2006-2007 and a deployment in Rijpfjorden on the NE coast occurred during 2006-2007. The cyst production displayed peaks of abundance in the spring and late summer with distinct differences in cyst occurrence in different fjords and in different years. The recorded and identified cyst species were consistent both with the hydrography of the fjords and with changes in cyst composition that are comparable to the seasonal shifts in water mass characteristics. The presence of the heterotrophic species Protoperidinium conicum in Kongsfjorden during 2002 is of note and may reflect the availability of a particular food source possibly associated with the strong influx of Atlantic Water. Cysts recovered from Kongsfjorden during 2006-2007 were dominated by Islandinium minutum, an indicator of cold, polar to subpolar conditions. The temperature and salinity characteristics of the ambient hydrography in this period indicated less influence by Atlantic Water than in 2002, and the cyst production was consistent with regional cyst distribution patterns. In Rijpfjorden, cyst assemblages were dominated by Pentapharsodinium dalei, consistent with the fjord being dominated by full Arctic conditions during the mooring deployment and the possible occurrence of stratified water with high productivity during the spring phytoplankton bloom.