The pre-weichselian glaciations of North-West Europe

In North-West Europe no evidence has been found for glaciations older than the Elsterian. The Elsterian seems to consist of at least two separate ice advances with a minor interval in between. During the Elsterian in the area south of the Baltic Sea over 400 m deep channels were cut into the underlying substratum by a combination of glacial erosion and meltwater activity. The channels were active until the Late Elsterian and were subsequently filled with meltwater deposits and glaciolacustrine silt and clay. During the Saalian no comparative channels were being formed. Three different ice advances can be distinguished within the Saalian, the stratigraphical correlation of which is to be discussed. No convincing evidence was found for any interglacial within the Saalian sequence. There are good reasons to assume that the ice advances were only separated from each other by minor ice-free intervals.     

THE USE OF CITATION INDICES IN COMPARING GEOGRAPHY PROGRAMS: AN EXPLORATORY STUDY*

Citation information is discussed as a means for ranking the research and publication visibility of eleven graduate programs in geography. It is suggested that the ranks produced by this objective method correspond better to the peer-based ranks of the 1982 NRC survey of graduate programs than those derived from publication counts. Citation information also provides a means of evaluating the differences between programs' inter- and intradisciplinary visibility.     

Methods to determine the angular resolution of the HEGRA extended air shower scintillator array

A precise knowledge of the angular resolution of scintillator arrays used to observe extended air showers (EAS) is of key importance in the search for VHE/UHE γ point sources. Four independent methods have been used to determine the mean resolution for which a value of ΔΘ₆₃ of 0.8°(1.0°) at a proton threshold of 50 (40) TeV has been found for the HEGRA EAS-array.     

Leptonic jets from young stellar objects?

Various explanations of the bipolar-flow phenomenon in star-forming regions are compared and confronted with the observed facts. It is concluded that stellar-wind interpretations are inconsistent with the constraints. The exotic property of young stellar objects may be their extreme spin which implies strong magnetic fields and vacuum discharges above thee ^± pair-formation threshold (of 10¹² eV). Pair-plasma jets are thought to be centrifugally driven by young stars during their first 10^4±1 years of rapid rotation.     

The effect of low temperature on Antarctic endolithic green algae

Laboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50 degrees C. 14CO2 incorporation after freezing to -20 degrees C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface.     

Risk perception and decision-making: do farmers consider risks from climate change?

This paper provides one of the first empirical studies that examine the impact of climate change adaptation practices on technical efficiency (TE) among smallholder farmers in Nepal. An adaptation index is used to explore the impact of farmers’ adaptation on TE using the stochastic frontier analysis framework. Data for six districts of Nepal representing all three agro-ecological regions (terai, hill, and mountain) were collected from a focus group discussion, a stakeholder workshop and a household survey. The survey shows that about 91% of the farming households have adopted at least one practice to minimize the adverse impacts of climate change. Empirical results reveal that adaptation is an important factor explaining efficiency differentials among farming households. Those adopting a greater number of adaptation practices on a larger scale are, on average, found to be 13% more technically efficient than those adopting fewer practices on smaller scale. The empirical results also show that average TE is only 0.72, indicating that there are opportunities for farming households in Nepal to further improve productive efficiency, on average by 28%. Other important factors that explain variations in the productive efficiency across farming households include farmer’s education level, irrigation facilities, market access, and social capital such as farmer’s participations in relevant agricultural organizations and clubs. This study provides empirical evidence to policy makers that small scale adjustments made by farmers in response to climate change impacts are effective in improving farmers’ efficiency in agriculture production. This indicates a need for farmers’ involvement in climate change adaptation planning.     

Regional search, selection and geological characterization of a large anticlinal structure, as a candidate site for CO2-storage in northern Germany

This paper reports on the regional screening, selection and geological characterisation of a potential on-shore CO₂ storage site (saline aquifer) in north-eastern Germany. The main objective of this study was to identify and investigate a candidate storage site, capable to accommodate the total amount of approximately 400 million tons of CO₂. Such a volume is produced by a modern, lignite-fired power plant within its operation lifetime of approximately 40 years. Within north-eastern Germany, several saline aquifers of Triassic, Jurassic and Cretaceous age have been evaluated with respect to their regional occurrence, storage potential and basic reservoir properties. Subsequent to a ranking, considering different criteria, the anticlinal structure Schweinrich holding suitable saline aquifers of the uppermost Triassic and lowest Jurassic has been selected from a number of identified candidate sites. According to results of the geological site characterisation, including structural geological investigations and 3D reservoir modelling, the structure Schweinrich seems to be a suitable site for industrial large scale CO₂ storage. Further data acquisition (new wells and 3D seismics) and research (more detailed and comprehensive modelling) is needed in order to prove the structural integrity of the storage site and assure long-term safety.     

Detailed hydraulic head profiles as essential data for defining hydrogeologic units in layered fractured sedimentary rock

This paper describes a study in southern Wisconsin where vertical hydraulic head profiles measured in exceptional detail provided the key data for defining hydrogeologic units (HGUs) in a layered sequence of sandstone, siltstone, shale, and dolostone. The most important data were obtained from corehole MP-6 which was cored 131 m into bedrock and instrumented using a Westbay^® multilevel system with 36 depth discrete monitoring intervals. The resulting head profile is consistant over time and shows eight distinct inflections in hydraulic head. Several of the inflections occur between adjacent permeable units and are likely due to poor vertical connectivity of fracture sets rather than distinct lower permeability layers or aquitards in the conventional sense. No other type of data was capable of identifying the position of such distinct hydrogeologic features. These zones of abrupt head loss provide the primary dataset for delineation of eleven HGUs at MP-6 and are supported by less detailed head profiles at other locations. Although the detailed head profiles are essential, core logs and geophysical logs from other boreholes are nessessary to fully establish the lateral continuity of the HGUs.     

Hydrothermal gold mineralization at the Hira Buddini gold mine,India: constraints on fluid evolution and fluid sources from boron isotopic compositions of tourmaline

We determined the boron isotope and chemical compositions of tourmaline from the Hira Buddini gold deposit within the Archean Hutti-Maski greenstone belt in southern India to investigate the evolution of the hydrothermal system and to constrain its fluid sources. Tourmaline is a minor but widespread constituent in the inner and distal alteration zones of metabasaltic and metadacite host rocks associated with the hydrothermal gold mineralization. The Hira Buddini tourmaline belongs to the dravite–schorl series with variations in Al, Fe/(Fe+Mg), Ca, Ti, and Cr contents that can be related to their host lithology. The total range of δ¹¹B values determined is extreme, from −13.3‰ to +9.0‰, but 95% of the values are between −4 and +9‰. The boron isotope compositions of metabasalt-hosted tourmaline show a bimodal distribution with peak δ¹¹B values at about −2‰ and +6‰. The wide range and bimodal distribution of boron isotope ratios in tourmaline require an origin from at least two isotopically distinct fluid sources, which entered the hydrothermal system separately and were subsequently mixed. The estimated δ¹¹B values of the hydrothermal fluids, based on the peak tourmaline compositions and a mineralization temperature of 550°C, are around +1 and +10‰. The isotopically lighter of the two fluids is consistent with boron released by metamorphic devolatilization reactions from the greenstone lithologies, whereas the ¹¹B-rich fluid is attributed to degassing of I-type granitic magmas that intruded the greenstone sequence, providing heat and fluids to the hydrothermal system. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.