Occurence of foraminifera and other microfossils in sediment core CRP-2/2A (Table 1)

Sparse to moderately abundant foraminiferal assemblages from Oligocene and Lower Miocene sediments in the CRP-2/2A drillhole contain C.27 genera and 42 species of calcareous benthic foraminifera. No planktic or agglutinated taxa were observed. On the basis of their faunal characteristics, four Foraminiferal Units are defined in drillhole succession: Foraminiferal Unit I (26.91-193.95 mbsf), mostly sparse assemblages with Elphidium magellanicum and Cribroelphidium sp.; Foraminiferal Unit II (193.95-342.42 mbsf), mostly moderately abundant assemblages with Cassidulinoides aequilatera and Eponides bradyi; Foraminiferal Unit III (342.42-486.19 mbsf), moderately abundant to sparse assemblages characterised by Cassidulinoides chapmani and Stainforthia sp.; and Foraminiferal Unit IV, Improverished (486.19-624.15, total depth, mbsf), with mostly barren residues, but with large Milioliidae recorded in situ at various horizons in the drill core. Foraminiferal Units I-IV lack taxa allowing correlation to standard zonal schemes. Inspection of faunal records from CIROS-1 and DSDP 270 indicates that, although the faunas show an overall similarity, CRP-2/2A Foraminiferal Units I-IV are not identifiable at these sites. The units are therefore most likely to reflect local environmental changes, and probably will prove useful for local correlation, but their lateral extent is undetermined. All four assemblages apparently represent various glacially-influenced shelf environments, and appear to reflect a long term deepening trend from Units IV to II, from perhaps inner to mid or outer-shelf depths, followed by a return to shallower, inner shelf, conditios for Unit I.

Prominent deformation features and interpretation of sediment core CRP-2/2A (Table 1)

Sediment deformation features in CRP-2/2A were described during normal logging procedures and from core-scan images. In this paper the origin of soft-sediment folding, contorted bedding, microfaulting, clastic dykes, shear zones and intraformational breccias is discussed. The features have a stratigraphic distribution related to major unconformities and sequence boundaries. Hypotheses for the origins of sediment deformation include hydrofracturing, subglacial shearing, slumping, and gas hydrate formation. Shear zones, microfaults, clastic dykes and contorted bedding within rapidly deposited sediments, suggest that slumping in an ice-distal environment occurred in the early Oligocene. A till wedge beneath a diamictite at 364 mbsf the mid-Oligocene section represents the oldest evidence of grounded ice in CRP-2/2A. Shear zones with a subglacial origin in the early late Oligocene and early Miocene sections of the core are evidence of further grounding events. The interpretation of sediment deformation in CRP-2/2A is compared to other Antarctic stratigraphic records and global eustatic change between the late Eocenel/early Oligocene and the middle Miocene.

Planktic foraminifer-based sea-surface temperature reconstruction for sediment cores JM97-948/2A and MD95-2011 from the Vøring Plateau, eastern Norwegian Sea

The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclimate archives from the Northern Hemisphere. Reconstructed summer temperature anomalies from across northern Europe show a clear maximum around 6000 years before present (6 ka). For the marine realm, Holocene trends in sea-surface temperature reconstructions for the North Atlantic and Norwegian Sea do not exhibit a consistent pattern of early to mid- Holocene warmth. Sea-surface temperature records based on alkenones and diatoms generally show the existence of a warm early to mid-Holocene optimum. In contrast, several foraminifer and radiolarian based temperature records from the North Atlantic and Norwegian Sea show a cool mid- Holocene anomaly and a trend towards warmer temperatures in the late Holocene. In this paper, we revisit the foraminifer record from the Vøring Plateau in the Norwegian Sea. We also compare this record with published foraminifer based temperature reconstructions from the North Atlantic and with modelled (CCSM3) upper ocean temperatures. Model results indicate that while the seasonal summer warming of the seasurface was stronger during the mid-Holocene, sub-surface depths experienced a cooling. This hydrographic setting can explain the discrepancies between the Holocene trends exhibited by phytoplankton and zooplankton based temperature proxy records.