Middle Campanian-lowermost Maastrichtian nannofossils and foraminifers of the northwestern Australian margin

The middle-late Campanian was marked by an increase in the bioprovinciality of calcareous microfossil assemblages into distinct Tethyan, Transitional, and Austral Provinces that persisted to the end of the Maastrichtian. The northwestern Australian margin belonged to the Transitional Province and the absence of key Tethyan marker species such as Radotruncana calcarata and Gansserina gansseri has led petroleum companies operating in the area to use the locally developed KCCM integrated calcareous microfossil zonation scheme. The KCCM zonation is a composite scheme comprising calcareous nannofossil (KCN), planktonic foraminiferal (KPF) and benthonic foraminiferal (KBF) zones. This paper presents the definitions and revisions of Zones KCCM8-19, from the highest occurrence (HO) of Aspidolithus parcus constrictus to the lowest occurrence (LO) of Ceratolithoides aculeus, and builds on our previous early-late Maastrichtian study. The presence of a middle-upper Campanian disconformity is confirmed by microfossil evidence from the Vulcan Sub-basin, Exmouth and Wombat plateaus, and the Southern Carnarvon Platform. In the Vulcan Sub-basin and on the Exmouth Plateau (ODP Hole 762C) the hiatus extends from slightly above the LO of common Rugoglobigerina rugosa to above the LO of Quadrum gothicum. On the Wombat Plateau (ODP Hole 761B) it spans from above the LO of Heterohelix semicostata to above the LO of Quadrum gothicum; and in the Southern Carnarvon Platform the disconformity has its longest duration from above the HO of Heterohelix semicostata to above the LO of Quadrum sissinghii. A significant revision of the events which define Zones KCCM18 and 19 was necessary owing to the observation that the LO of Ceratolithoides aculeus occurs below the HOs of Archaeoglobigerina cretacea and Stensioeina granulata incondita and the LO of common Rugoglobigerina rugosa. In the original zonation these events were considered to be coincident.

Sedimentological investigations of a sediment core profile from the continental slope of the South Orkney Islands

Sediment patterns such as texture, composition, and facies from three selected areas of the Antarctic continental margin of the Weddell Sea are discussed in relation to environmental variations of the Quaternary hydrosphere and kryosphere. Advance and retreat of ice shelves as well as oscillations in sea ice coverage are reflected by particular sediment facies. The distribution of ice-rafted detritus tracks the Antarctic Coastal Current, and the Weddell Sea Bottom water contour current can be recognized by its distinctive winnowing and erosion pattern. Distribution and abundance of biogenic sediment components are mainly controlled by duration of sea ice coverage reflecting the long-term climatic evolution.

Compilation of results of the STRATAGEM project as ISO-image of the final CD-ROM

The study of the Neogene (Miocene to Holocene) stratigraphic record on the glaciated Atlantic margin of NW Europe has, to date, largely been undertaken on an ad-hoc basis. Whereas a systematic approach to understanding the stratigraphic development of Palaeogene and older strata has been undertaken in areas such as the North Sea, West of Shetland and Norway, the problem of establishing a Neogene framework has been only partly addressed by academia and the oil industry. In most cases where a Neogene stratigraphy has been constructed, this has been largely in response to problem solving and risk assessment in a restricted area. Nevertheless, in the past few years it has become increasingly apparent that there is a common history in the Neogene development of the passive Atlantic margin of NW Europe, between mid-Norway and SW Ireland. The inspection and interpretation of an extensive geophysical and geological database has identified several regionally significant and correlatable unconformities along this continental margin. Thus, a regional approach to the stratigraphical development of the Neogene succession on the glaciated European Atlantic margin is undertaken in this volume.

Marine ice-rafted debris records and age determinations along the northern Eurasian margin

Ice-rafted debris (IRD) (>2 mm), input in eight sediment cores along the Eurasian continental margin (Arctic Ocean), have been studied over the last two glacial/interglacial cycles. Together with the revised chronologies and new micropaleontological data of two cores from the northern Barents Sea (PS2138) and northeastern Kara Sea (PS2741) spanning Marine Isotope Stages (MIS) 6 to 1, the IRD data give new insights into the glacial history of northern Eurasian ice-sheets over the last 150 ka. The chronologies of the cores are based on stable isotope records, AMS 14C datings, paleomagnetic and biostratigraphic data. Extensive episodes of northern Barents Sea ice-sheet growth, probably to the shelf edge, occurred during the late Weichselian (MIS 2) and the Saalian (MIS 6). Major IRD discharge at the MIS 4/3-transition hints to another severe glaciation, probably onto the outer shelf, during MIS 4. IRD-based instabilities of the marine-based ice margin along the northern Barents Sea between MIS 4 and 2 are similar in timing with North Atlantic Heinrich events and Nordic Seas IRD events, suggesting similar atmospheric cooling over a broad region or linkage of ice-sheet fluctuations through small sea-level events. In the relatively low-precipitation areas of eastern Eurasia, IRD peak values during Termination II and MIS 4/3-transition suggest a Kara Sea ice-sheet advance onto the outer shelf, probably to the shelf edge, during glacial MIS 6 and 4. This suggests that during the initial cooling following the interglacials MIS 5, and possibly MIS 7, the combined effect of sustained inflow of Atlantic water into the Arctic Ocean and penetration of moisture-bearing cyclones into easterly direction supported major ice build-up during Saalian (MIS 6) and Mid-Weichselian (MIS 4) glaciation. IRD peak values in MIS 5 indicate at least two advances of the Severnaya Semlya ice-sheet to the coast line during the Early Weichselian. In contrast, a distinct Kara Sea ice advance during the Late Weichselian (MIS 2) is not documented by the IRD records along the northeastern Kara Sea margin.