A 200,000-yr interval of extreme global warming marked the start of the Eocene epoch about 55 million years ago. Negative carbon- and oxygen-isotope excursions in marine and terrestrial sediments show that this event was linked to a massive and rapid (approximately 10,000 yr) input of isotopically depleted carbon. It has been suggested previously that extensive melting of gas hydrates buried in marine sediments may represent the carbon source and has caused the global climate change. Large-scale hydrate melting, however, requires a hitherto unknown triggering mechanism. Here we present evidence for the presence of thousands of hydrothermal vent complexes identified on seismic reflection profiles from the Vøring and Møre basins in the Norwegian Sea. We propose that intrusion of voluminous mantle-derived melts in carbon-rich sedimentary strata in the northeast Atlantic may have caused an explosive release of methane--transported to the ocean or atmosphere through the vent complexes--close to the Palaeocene/Eocene boundary. Similar volcanic and metamorphic processes may explain climate events associated with other large igneous provinces such as the Siberian Traps (approximately 250 million years ago) and the Karoo Igneous Province (approximately 183 million years ago).

Avoluminous magmatic complexw asemplaced int he Vøringa ndM øreb asins duringP aleocene/Eocenec ontinentalr iftinga ndb reak-up int he NE Atlantic.Thisintrusivee vent hashad asignificant impactondeformation,source-rock maturation andfluid flow inthe basins. Intrusivecomplexesandassociated hydrothermalv ent complexeshaveb eenm apped on aregional2 Dseismic dataset( c .1500 00 km) andon one large 3Dsurvey. The extent ofthe sill complexisatleast 800 00 km 2 ,withanestimated totalvolumeof0.9 to 2.8 £ 10 4 km 3 .The sheetintrusions aresaucer-shaped inu ndeformed basins egments. The widthso fthe saucers becomelargerw ithi ncreasinge mplacement depth.Morevaried intrusion geometriesaref oundi n structured basinsegments. Some734hydrothermalvent complexeshavebeenidentified,although itisestimated that2-3000 vent complexesarepresent int he basins. The vent complexesarelocated abovesills andwere formed asad irectconsequence ofthe intrusivee vent byexplosivee ruption ofg ases,liquidsandsediments, formingup to 11 kmwide craters atthe seafloor. The largest vent complexesarefoundinbasinsegments with deeps ills (3-9kmp alaeodepth). Moundsandseismic seepanomaliesl ocated abovethe hydrothermalv ent complexess uggest thatt he vent complexeshaveb eenr e-used for verticalfluid migration longa ftert heir formation. The intrusivee vent mainly tookplace just prior to,or during, the initialp haseofmassiveb reak-up volcanism (55.0-55.8Ma). Thereisalso evidence for aminor UpperPaleocenevolcanic event documented by the presence of20 vent complexest erminatingi nt he UpperPaleocenesequence andthe localp resence of extrusivevolcanic rockswithinthe Paleocenesequence.Volcanic processesanddeposits mayhaveastrongimpactonthe structureandgeodynamic development ofcontinentalmargins and associated sedimentary basins. The identification ofvolcanic deposits andthe evaluation oftheirimpacto nt he marginhistory are, thus,two important aspects ofpetroleum exploration of continentalrifted margins. Significant attention has,overt he past decade, beendevoted to studieso fe xtrusiveprocessesand deposits on volcanic rifted margins (e.g.Eldholm etal .1 989; Menzies etal. 2002; White etal .2 003). However,petroleum explorationists will commonly encounterintrusivec omplexes beforetheyencounterextrusivevolcanic rocksw hent heym ove from shallow-watert odeep-waterareas. Deep-waterexplorationists,therefore, need to know how to recognize, interpretand risk-evaluatei ntrusivec omplexes.The frontierVøringa ndM øreb asins off mid-Norwayare classicalexampleso fi ntruded volcanic basins located on arifted volcanic margin( e.g.Skogseid etal .1 992; Skogly 1998;Berndt etal .2 000; Brekke 2000; Gernigon etal .2 003). The volcanic activity inthesebasins wasassociated withLatePaleocenerifting andc ontinentalbreak-up int he NE Atlantic.Similarintrusive basinprovincesarelocated alongthe entireEuropeanNE Atlantic margin(e.g.Gibb &Kanaris-Sotiriou 1988;Bell &Butcher2002; Smallwood&Maresh2002) andonshoreincentral-east Greenland (e.g.Larsen&M arcussen1 992; Price etal .1 997).Sill comp...

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Intensive ¢sh production worldwide has increased the risk of infectious diseases. However, before any infection can be established, pathogens must penetrate the primary barrier. In ¢sh, the three major routes of infection are the skin, gills and gastrointestinal (GI) tract. The GI tract is essentially a muscular tube lined by a mucous membrane of columnar epithelial cells that exhibit a regional variation in structure and function. In the last two decades, our understanding of the endocytosis and translocation of bacteria across this mucosa, and the sorts of cell damage caused by pathogenic bacteria, has increased. Electron microscopy has made a valuable contribution to this knowledge. In the ¢sh-farming industry, severe economic losses are caused by furunculosis (agent, Aeromonas salmonicida spp. salmonicida) and vibriosis [agent, Vibrio (Listonella) anguillarum]. This article provides an overview of the GI tract of ¢sh from an electron microscopical perspective focusing on cellular damage (speci¢c attack on tight junctions and desmosomes) caused by pathogenic bacteria, and interactions between the 'good' intestinal bacteria [e.g. lactic acid bacteria (LAB)] and pathogens. Using di¡erent in vitro methods, several studies have demonstrated that co-incubation of Atlantic salmon (Salmo salar L.) foregut (proximal intestine) with LAB and pathogens can have bene¢cial e¡ects, the cell damage caused by the pathogens being prevented, to some extent, by the LAB. However, there is uncertainty over whether or not similar e¡ects are observed in other species such as Atlantic cod (Gadus morhua L.). When discussing cellular damage in the GI tract of ¢sh caused by pathogenic bacteria, several important questions arise including: (1) Do di¡erent pathogenic bacteria use di¡erent mechanisms to infect the gut? (2) Does the gradual development of the GI tract from larva to adult a¡ect infection? (3) Are there di¡erent infection patterns between di¡erent ¢sh species? The present article addresses these and other questions. Ã Intestinal sac.wAs only 13 autochthonous bacterial strains were isolated one can not draw a general conclusion.zUssing chamber.PC, pyloric cacea; FG, foregut; MG, midgut; HG, hindgut; HGC, hindgut chamber; NI, not investigated.Lactic acid bacteria vs. pathogens in the gastrointestinal tract of ¢sh E RingÖ et al.

The Geological Survey of Norway (NGU) has produced new aeromagnetic and gravity maps from Norway and adjacent areas, compiled from ground, airborne and satellite data. Petrophysical measurements on core samples, hand specimens and on in situ bedrock exposures are essential for the interpretation of these maps. Onshore, the most prominent gravity and magnetic anomalies are attributed to lower crustal rocks that have been brought closer to the surface. The asymmetry of the gravity anomalies along the Lapland Granulite Belt and Kongsberg–Bamble Complex, combined with the steep gradient, points to the overthrusted high-density granulites as being the main source of the observed anomalies. The Kongsberg–Bamble anomaly can be traced southwards through the Kattegat to southern Sweden. This concept of gravity field modelling can also be applied to the Mid-Norwegian continental shelf and could partially explain the observed high-density rocks occurring below the Møre and Vøring basins and in the Lofoten area. Extrapolations of Late-Caledonian detachment structures occurring on the mainland can be traced on aeromagnetic and gravimetric images towards the NW across the continental margin. Subcropping Late Palaeozoic to Cenozoic sedimentary units along the mid-Norwegian coast produce a conspicuous magnetic anomaly pattern. The asymmetry of the low-amplitude anomalies, with a steep gradient and a negative anomaly to the east and a gentler gradient to the west, relates the anomalies to gently westward dipping strata. Recent aeromagnetic surveys in the Barents Sea have revealed negative magnetic anomalies associated with shallow salt diapirs. Buried Quaternary channels partly filled with gravel and boulders of crystalline rocks generate magnetic anomalies in the North Sea. The new maps also show that the opening of the Norwegian–Greenland Sea occurred along stable continental margins without offsets across minor fracture zones, or involving jumps in the spreading axis. A triple junction formed at 48 Ma between the Lofoten and Norway Basins.