Metallic mineral deposits in the Nordic countries

The Nordic countries, including Greenland, have a long tradition in mining. Documented mining dates back to the 8th century AD. Today this region is the most important metallic mining district of the European Union. Metals are produced from active mines in all countries except Iceland and related industries are thriving in all countries.
Important ore deposit types include： volcanogenic massive sulphide deposits （Cu, Zn, Pb, Au, Ag）, orogenic gold deposits （Au）, layered intrusions （Ni, PGE, Ti±V）, intrusive hosted Cu-Au, apatite-Fe deposits, Cr- and anorthosite hosted Ti deposits. Besides these well- documented deposits, new kinds of deposits are being explored, e.g., iron oxide-copper-gold （IOCG）, shale-hosted Ni-Zn-Cu and different types of uranium deposits.     

Transport measurements from in-service undersea telephone cables

The motion of the ocean through the Earth's magnetic field creates a cross-stream voltage proportional to the transport of the stream. These motion-induced voltages have been observed for more than ten years by the use of an abandoned cable spanning the Florida Current. In-service undersea telephone cables, including fiber optic cables with branch lines, can also be used to determine the motion-induced voltages between the cable sea-Earth grounds because the repeaters in these cables are powered by a nearly constant electric current, the return path for this current is through the ocean via the sea-Earth grounds, and the power voltage and current are readily measured at the cable station or stations. Ocean voltages between West Palm Beach, FL, and Eight Mile Rock, Grand Bahama Island, observed since 1985 by use of an in-service cable yield monthly estimates of the Florida Current transport with an r.m.s. accuracy of 1.1 Sv when compared with the monthly voltage-derived transports between Jupiter, FL, and Settlement Point, Grand Bahama Island, observed by the use of an abandoned cable. This corresponds to an accuracy of 3% of the mean transport of 32.3 Sv     

Molecules in Circumstellar Envelopes of Carbon Stars

We have searched for line emission from various transitions of a number of molecules, including CO, HCN, CN, CS and SiO, as well as some of their isotopic variants, towards a sample of 68 bright carbon stars. Part of the data has already been published in Olofsson et al. (1993a,b). The aim of the project is to obtain a better understanding of the carbon star phenomenon and the processes involved. In particular, we would like to obtain reliable mass loss rates and molecular abundances for these objects. This requires careful and detailed modelling, which is currently underway. Our hope is that the study of these bright carbon stars will serve as a guide to the study of higher mass loss rate objects. Some preliminary observational results are presented here. This revised version was published online in September 2006 with corrections to the Cover Date.     

Early and Middle Valdaian glaciations, ice-dammed lakes and periglacial interstadials in northwest Russia: new evidence from the Pyoza River area

The Pyoza River area in the Arkhangelsk district exposes sedimentary sequences suitable for study of the interaction between consecutive Valdaian ice sheets in Northern Russia. Lithostratigraphic investigations combined with luminescence dating have revealed new evidence on the Late Pleistocene history of the area. Overlying glacigenic deposits of the Moscowian (Saalian) glaciation marine deposits previously confined to three separate transgression phases have all been connected to the Mikulinian (Eemian) interglacial. Early Valdaian (E. Weichselian) proglacial, lacustrine and fluvial deposits indicate glaciation to the east or north and consequently glacier damming and meltwater run-off in the Pyoza area around 90–110 ka BP. Interstadial conditions with forest-steppe tundra vegetation and lacustrine and fluvial deposition prevailed at the end of the Early Valdaian around 75–95 ka BP. A terrestrial-based glaciation from easterly uplands reached the Pyoza area at the Early to Middle Valdaian transition around 65–75 ka BP and deposited glaciofluvial strata and subglacial till (Yolkino Till). During deglaciation, laterally extensive glaciolacustrine sediments were deposited in ice-dammed lakes in the early Middle Valdaian around 55–75 ka BP. The Barents–Kara Sea ice sheet deposited the Viryuga Till on the lower Pyoza from northerly directions. The ice sheet formed the Pyoza marginal moraines, which can be correlated with the Markhida moraines further east, and proglacial lacustrine deposition persisted in the area during the first part of the Middle Valdaian. Glacio-isostatic uplift caused erosion followed by pedogenesis and the formation of a deflation horizon in the Middle Valdaian. Widely dispersed periglacial river plains were formed during the Late Valdaian around 10–20 ka BP. Thus, the evidence of a terrestrial-based ice sheet from easterly uplands in the Pyoza area suggests that local piedmont glaciers situated in highlands such as the Timan Ridge or the Urals could have developed into larger, regionally confined ice sheets. Two phases of ice damming and development of proglacial lakes occurred during the Early and Middle Valdaian. The region did not experience glaciation during the Late Valdaian.     

Rhyodacite magma storage conditions prior to the 3430 yBP caldera-forming eruption of Aniakchak volcano, Alaska

This study presents a pre-eruptive magma storage model for the rhyodacite and andesite magmas erupted during the 3430 yBP caldera-forming eruption of Aniakchak volcano, Alaska, derived from phase equilibria experiments and petrological data. The compositions of Fe–Ti oxide pairs from the early erupted Plinian rhyodacite pumice yield core temperatures of 871–900°C, with rims up to ∼942°C, and fO₂ from −10.6 to −11.8 log units. Melt inclusions entrapped in plagioclase phenocrysts have H₂O contents between 3 and 5 wt%, estimated by FTIR and electron microprobe volatiles by difference methods, with no detectable CO₂. Assuming water saturation, this corresponds to entrapment pressures between ∼65 and 150 MPa. Phase equilibria results reproduce the natural phase assemblages at of 95–150 MPa at 870–880°C, assuming water saturation. A mismatch in experimental versus natural glass SiO₂ and Al₂O₃, and MELTS models for H₂O-undersaturated conditions indicate that the rhyodacite may not have been H₂O saturated. MELTS models with and P _total of 125–150 MPa at 870–880°C reproduce the natural groundmass glass Al₂O₃ composition best, indicating the magma may have been slightly H₂O undersaturated. Those pressures correspond to storage at 4.5–5.4 km depth in the crust. MELTS models and VBD estimates from melt inclusions in titanomagnetite grains from the andesite indicate pre-eruptive conditions of ∼1,000°C and > 110 MPa, corresponding to a minimum residence depth of ∼4.1 km assuming water saturation or greater if the magma was H₂O undersaturated. Previous geochemical studies indicate separate histories of the two magmas, though they retain some evidence that they are ultimately related through fractional crystallization processes. Analogous to the 1912 Novarupta magmas, the rhyodacite and andesite presumably originated within the same crystal mush zone beneath the edifice, yet were separated laterally and underwent different degrees of crustal assimilation. The andesite must have resided in close proximity, with ascent occurring in response to movement of the rhyodacite, and resulting in extensive syn-eruptive mingling.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Deep saltwater in Chalk of North-West Europe: origin, interface characteristics and development over geological time

High-concentration saltwaters occur in many places in the regional Chalk aquifers of North-West Europe; to investigate deep occurrences, profiles of interstitial porewater chemistry have been studied from three 250–450m deep cores drilled in the eastern parts of Zealand, Denmark. At the studied location, saline water in the Chalk resides at depths from 40 to 80m and salinity increases with depth. Concentrations of chloride up to ca. 30,000ppm have been observed at depths of 400m. Measured vertical hydraulic heads in open boreholes suggest that advective groundwater flow is now restricted in deeper parts of the Chalk formation and diffusive transport is thus the predominant transport mechanism. Laboratory-measured porosity and effective diffusion coefficients were used as input to a numerical 1D diffusion model of the interface between freshwater in an upper, fractured aquifer and modified connate formation water below. The model satisfactorily simulated the observed chloride and δ¹⁸O profiles. The diffusive refreshening of the Chalk formation has been going on for about 0.9 million years. The connate water in the Chalk of parts of the sedimentary basin seems to have been modified by transport of saltwater from underlying Mesozoic and Paleozoic sediments during compaction, which presumably ceased around 4 million years ago.