Sedimentology and geomorphology of drumlins in western Allgäu, South Germany

Form, lithological composition, geomorphological situation and internal structure of three different drumlins belonging to the Pleistocene Rhine and Iller glacial systems in South Germany are described: one consisting almost completely of subglacial till, another consisting of ice-marginal deposits with an incomplete mantle of till, the third consisting of delta deposits. It is concluded that no precise limits should be drawn between accumulation and erosion drumlins.     

Cloud condensation nuclei measurements at Mace Head, Ireland, over the period 1994–2002

Analyses of cloud condensation nuclei (CCN) number concentrations (cm^− 3) measured at the Mace Head Atmospheric Research Station, near Carna, County Galway, Ireland, using a DH Associates Model M1 static thermal diffusion cloud chamber over the period from March 1994 to September 2002 are presented in this work. Air masses are defined as being ‘marine’ if they originate from a wind direction of 180–300° and ‘continental’ air masses are defined as originating from a wind direction of 45–135°. Air masses without such filtering were classified as ‘undefined’ air masses. Air masses were found to be dominated by marine sector air, re-affirming Mace Head as a baseline atmospheric research station. CCN levels for specific air masses at Mace Head were found to be comparable with earlier studies both at Mace Head and elsewhere. Monthly averaged clean marine (wind direction of 180–300° and black carbon absorption coefficient < 1.425 Mm^− 1) CCN and marine CCN varied between 15–247 cm^− 3 and 54–670 cm^− 3, respectively. As expected, significant increases in number concentration were found in continentally sourced CCN over that of marine CCN and were found to follow a log-normal distribution significantly tighter than that of clean marine air masses. No significant trend was found for CCN over the 9-year period. While polluted continental air masses showed a slight increase in CCN concentrations over the winter months, most likely due to increased fuel usage and a lower mixed boundary layer, the dominance of marine sector air arriving at Mace Head, which generally consists of background CCN concentrations, reduced seasonal differences for polluted air. Marine air showed a distinct seasonal pattern, with elevated values occurring over the spring and summer seasons. This is thought to be due to enhanced biogenic aerosol production as a result of phytoplankton bloom activity in the North Atlantic.     

New Chilean iron meteorites: Medium octahedrites from Northern Chile are unique

Abstract— We report data on three new iron meteorites from Northern Chile and propose names. All are unnamed iron meteorites from the meteorite collection at the Universidad de La Serena. For two, the provenance is unknown; for the third, the presumed discovery site is in the countryside east of Iquique. The three meteorites have been analyzed by instrumental neutron activation analysis (INAA) and their structures examined with a binocular microscope. La Serena is a complete 663 g iron, a new member of group IIICD; it is not paired with any other iron. Elqui has a mass of 260 g; two faces are fractures, possibly produced by human actions, but fusion crust appears to be present on some of the remaining surface. It is a hexahedrite and a member of group IIAB, but its composition differs from that of all other Chilean hexahedrites. The third iron, Pozo Almonte, is a medium octahedrite member of group IIIAB, one of the most common meteorite groups. To find out whether it is paired, we assembled a full set of IIIAB iron meteorites from Northern Chile. Our compositional data show that Pozo Almonte is not paired with any other IIIAB iron, and that there are no pairings within the full set with the possible exception of Joel's Iron and Sierra Sandon, which differ only in their contents of Ir, 0.39 and 0.34 μg/g, respectively. However, Buchwald's (1975) structural observations rule out this possible pairing. We find appreciable differences in Cu, As and Au between the previously paired IIIAB irons Chañaral and Ilimaës and conclude that these should not be paired.     

Dense-media separation as a more efficient pollen extraction method for use with organic sediment/deposit samples: comparison with the conventional method

Dense-media separation, frequently adopted as a standard pollen extraction method for use with minerogenic sediment samples, was adapted for use with organic-rich sediment and peat samples. A total of 15 organic-rich sediment samples, obtained from sites in Corsica and the Southern European Alps, was treated using both dense-media separation and the conventional preparation method in order to compare the relative efficiencies of the two methods. The dense-media separation method consistently achieved a remarkably higher purity of extracted pollen grains. This was especially true for the Corsican peat samples, the dense-media separations being quite pure, whereas the classical method produced samples that were so severely polluted with organic fragments that it was impossible to carry out a satisfactory pollen analysis. The percentage values of each taxon were generally similar using both methods, showing that the two methods are compatible for pollen analytical studies. Total pollen concentrations were generally higher with the dense-media separation method (especially for gyttja samples). In conclusion, dense-media separation is an efficient method for pollen extraction from organic as well as from minerogenic sediments and deposits.     

Mass Spectrometric Isotope Dilution Determination of Cadmium in Geochemical Reference Samples

Twenty seven geochemical reference samples have been analysed for cadmium using the stable isotope dilution technique. These include four USGS, one NBS, five CRPG, eleven ANRT and six NIMROC samples. Each sample has been analysed at least in duplicate.
The four USGS samples have previously been measured in this laboratory by Rosman and De Laeter, but the present results are believed to be more accurate than the earlier data. Our results for the other twenty three samples are much lower than most of the published data. There is also evidence of cadmium inhomogeneities in some of the samples.     

Structural identification using linear models and earthquake records

The problem of determining linear models of structures from seismic response data is investigated using ideas from the theory of system identification. The approach is to determine the optimal estimates of the model parameters by minimizing a selected measure-of-fit between the responses of the structure and the model. Because earthquake records are normally available from only a small number of locations in a structure, and because of noise in the records, it is necessary in practice to estimate parameters of the dominant modes in the records, rather than the stiffness and damping matrices of the linear model. A new algorithm is developed to determine the optimal estimates of the modal parameters. After tests with simulated data, the method is applied to a multi-storey building using records from the 1971 San Fernando earthquake in California. New information is obtained concerning the properties of the lower modes of the building and the time-varying character of the equivalent linear parameters.     

Mass Spectrometric Isotope Dilution Analyses Of Barium in Geochemical Reference Samples

Twenty-four geochemical reference samples have been analysed far barium using the stable isotope dilution technique. These include five CRPG, ten ANRT, six Nimroc and two CCRMP samples together with the Tonalite from Tanzania, Duplicate analyses have been made in each case and our values for barium are believed to be accurate to approximately 3 %. In general, our results are in good agreement with the published data except for Nimroc samples where our data are consistently lower than the presently accepted values. No evidence of sample inhomogeneities was observed in the present work.