Species of the diatom taxa <i>Aulacodiscus</i> and <i>Trinacria</i> with biostratigraphic utility in Palaeogene and Neogene North Sea sediments

Species of Aulacodiscus and Trinacria, two important marine diatom genera with biostratigraphic utility in offshore North Sea exploration and onshore correlation, are identified, described and emended and the North Sea microfaunal zonation scheme is revised accordingly. Occurring mainly as pyritised diatom moulds or steinkerns, detailed scanning electron microscope (SEM) analysis of several specimens, formerly in open nomenclature, has allowed the correct taxonomic identification of pyritised morphologies found to belong to the genus Aulacodiscus, including A. allorgei, A. heterostictus, A. insignis, A. singilewskyanus, A. subexcavatus and A. suspectus. The important marker species Trinacria regina is emended. SEM studies, using specimens preserved in pyrite and original silica, have shed further light on the varying forms and frustule morphology of Trinacria regina so that valves and frustules formerly thought to represent separate species are now found to be grouped within this taxon; SEM studies have shown that many of these variations represent different valves within a chain, whilst others may signify ecophenotypic variants. Emendments are therefore made to clarify the taxonomic status of different variants within T. regina, important in the Palaeocene–Eocene boundary interval onshore and offshore such as the Sele and Balder formations and the Fur Formation diatomite of Jutland, Denmark. Species of taxa formerly in open nomenclature are now assigned to Aulacodiscus insignis, which are important offshore markers in offshore late Oligocene to early Miocene sediments in northwest Europe.</p

Cold spells in the Nordic Seas during the early Eocene Greenhouse

Abstract The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth’s history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of &lt;300 m. Such near-freezing temperatures have not previously been reconstructed from proxy data for anywhere on the early Eocene Earth, and these data therefore suggest that regionalised cool episodes punctuated the background warmth of the early Eocene, likely linked to eruptive phases of the North Atlantic Igneous Province.</jats:p

Analysis and interpretation of Holocene sedimentary sequences in the Humber Estuary

The interpretation of the Holocene evolution of the Humber Estuary has been made possible only through integrated multidisciplinary studies involving inter alia: drilling, to obtain sedimentary records of the Holocene Estuary fill; multi-element, carbon-nitrogen-sulphur and stable carbon isotope geochemistry; heavy and clay mineralogy; palaeomagnetism; radio-carbon dating; and pollen, diatom and foraminiferal studies. Eight chemostratigraphic suites and 14 palaeo-environments have been recognized. Sediment types, environments of deposition and provenance change in response to rising sea-level, showing a range from freshwater fluvial deposition of locally derived terrestrial sediment to intertidal and subtidal deposition of sediments from marine sources. The methods used are illustrated with reference to sediment cores from inner and outer estuary locations. The results show that Holocene environmental characterization is most secure when a number of different, but complementary, techniques are used. The integration of radiocarbon dates with palaeomagnetic and geochemical data improves the understanding of the presence and significance of time breaks, which is crucial to constraining sedimentation rates and material budgets

European Conference on Silicon Carbide and Related Materials

http://www.ecscrm2006.org/ Wide-band gap semiconductors such as SiC and GaN have become the materials of choice for future developments in high power and temperature environments. In recent years, exciting new products using SiC in particular have come to the market and the future looks bright for these materials. The European Conference on Silicon Carbide and Related Materials is well-established as Europe's leading conference on this topic . Submitted abstracts are invited in all subject areas related to Silicon Carbide and Related Materials. In particular, abstracts are welcomed on the following topics: Materials Growth (Bulk and Epitaxy) Materials Characterization and Theory Device Processing Device Optimization/Performanc