Reply to the Discussion by Dillenburg et al. on “Evidence for a transgressive barrier within a regressive strandplain system: implications for complex response to environmental change” by Hein et al. (2013), Sedimentology 60, 469–502     

Christopher J. Hein  Duncan M. Fitzgerald  Antonio H. Da F. Klein  Marcio B. Albernaz  Joao Thadeu de Menezes  William J. Cleary 《Sedimentology》2014,61(7):2213-2217

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Metallic mineral deposits in the Nordic countries     

Paer Weihed Pasi Eilu Rune B. Larsen Henrik Stendal Mikko Tontti 《《幕》》2008,31(1):125-132

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.  相似文献   

The effect of different sweep lengths on the length composition of bottom-sampling trawl catches   总被引：4，自引：4，他引：0  

Engas  Arill; Godo  Olav Rune 《ICES Journal of Marine Science》1989,45(3):263-268

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Effect of enhanced water exchange on ecosystem functions in backwaters of an urban floodplain     

Elisabeth Bondar-Kunze  Stefan Preiner  Friedrich Schiemer  Gabriele Weigelhofer  Thomas Hein 《Aquatic Sciences - Research Across Boundaries》2009,71(4):437-447

This study evaluated the effects of a controlled surface water connectivity scheme on several backwaters in an urban floodplain within the city limits of Vienna, the Upper Lobau. A phosphorus budget and ecosystem metabolism measurements were used to assess the reaction of two trophically distinct floodplain backwater sections on changed connectivity conditions. The surface water connection led to a reduction of the retention times in the backwater system. The water column nutrient concentrations in the individual backwater sections approached those of the source water body. The significance of these effects, however, depends on the historical and current trophic situation of the respective water bodies. Generally, the surface water connectivity introduced particulate phosphorus export up to 30% increase over the influent loading and dissolved phosphorus up to 14% increase over the influent loading. However, in sections with submersed macrophyte development, which provided enhanced filtering capacities for particulate matter, sediment and phosphorus accumulation rates were increased. At the same time, water transparency increased resulting in a positive feedback supporting further macrophyte development. Based on these findings, the evaluation of restoration measures in urban floodplains needs to consider the spatial and temporal dynamics of nutrients and ecosystem processes such as gross primary production and community respiration to predict long-term development.  相似文献   

Laboratory Observation and Micromechanics-Based Modelling of Sandstone on Different Scales     

Liming Li  Idar Larsen  Rune M. Holt 《Rock Mechanics and Rock Engineering》2015,48(4):1407-1422

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Eemian landscape response to climatic shifts and evidence for northerly Neanderthal occupation at a palaeolake margin in northern Germany     

Michael Hein  Brigitte Urban  David Colin Tanner  Anton Hermann Buness  Mario Tucci  Philipp Hoelzmann  Sabine Dietel  Marie Kaniecki  Jonathan Schultz  Thomas Kasper  Hans von Suchodoletz  Antje Schwalb  Marcel Weiss  Tobias Lauer 《地球表面变化过程与地形》2021,46(14):2884-2901

The prevailing view suggests that the Eemian interglacial on the European Plain was characterized by largely negligible geomorphic activity beyond the coastal areas. However, systematic geomorphological studies are sparse. Here we present a detailed reconstruction of Eemian to Early Weichselian landscape evolution in the vicinity of a small fingerlake on the northern margin of the Salzwedel Palaeolake in Lower Saxony (Germany). We apply a combination of seismics, sediment coring, pollen analysis and luminescence dating on a complex sequence of colluvial, paludal and lacustrine sediments. Results suggest two pronounced phases of geomorphic activity, directly before the onset and at the end of the Eemian period, with an intermediate period of pronounced landscape stability. The dynamic phases were largely driven by incomplete vegetation cover, but likely accentuated by fluvial incision in the neighbouring Elbe Valley. Furthermore, we discovered Neanderthal occupation at the lakeshore during Eemian pollen zone (PZ) E IV, which is chronologically in line with other known Eemian sites of central Europe. Our highly-resolved spatio-temporal data substantially contribute to the understanding of climate-induced geomorphic processes throughout and directly after the last interglacial period. It helps unraveling the landscape dynamics between the coastal areas to the north and the loess belt to the south.  相似文献   

Coupled trace element mobilisation and strain softening in quartz during retrograde fluid infiltration in dry granulite protoliths   总被引：1，自引：0，他引：1  

Bjørn Eske Sørensen  Rune B. Larsen 《Contributions to Mineralogy and Petrology》2009,157(2):147-161

This study focuses on the retrograde rheological and chemical evolution of quartz and the behaviour of quartzites during retrograde metamorphism following dry high grade metamorphism at 750°C, 7 kbar. SEM-CL and LA-HR-ICP-MS are applied to document quartz texture and chemistry, respectively. Four generations of quartz were distinguished by SEM-CL; Qz1, Qz2, Qz3 and Qz4. Qz1, brecciated and partly dissolved old grains, is enriched in B, Al and Ti when compared with the other types. Qz2, formed during brecciation and partial dissolution of Qz1, has low Al contents (<50 ppm) but, due to rutile inclusions, variable Ti contents when occurring in amphibolite (210–10 ppm) but more consistent values when occurring in quartzites (peak value 32 ppm). Qz3, dark grey luminescent quartz forming fluid migration channels (fluid pathways), has Ti < 5 ppm and Al contents below 10 ppm and B < 1 ppm. Qz4, comprises are group of quartz later than Qz3 filling micron thick cracks and pods with very low luminescent quartz, i.e. darker than Qz3. The textural and chemical evolution of quartz in our study is explained by two major influxes of aqueous fluids during regional uplift and retrogression. They facilitated rehydration and recrystallisation in the otherwise dry high grade quartzites. The first introduction of aqueous fluids was associated with brecciation of the high grade quartz (Qz1) and dissolution/precipitation of quartz (Qz2). Ti in quartz geothermometry (Wark and Watson, Contrib Mineral Petrol 152(6):637–652) gives 626°C in agreement with the retrograde PT-path deduced from phase diagrams. Later fluid influx associated with scapolitisation of amphibolite caused localised recrystallisation (Qz3) and alteration of biotite to muscovite along mm-wide fluid migration channels. During subsequent deformation, Qz3 deformed plastically and recovered by subgrain rotation recrystallisation (SGR), resulting in a reduction of grain size, whereas Qz1 quartz formed micro faults. Qz2 was plastic but did not experience SGR to the same degree as Qz3 quartz. Increased plasticity and recovery rates most likely relate to an increased H₂O fugacity and the depletion in trace elements of the quartz lattice by promoting strain softening processes dislocation climb and recovery. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

The local impacts of climate change in the Ferlo, Western Sahel     

Lars Hein  Marc J. Metzger  Rik Leemans 《Climatic change》2009,93(3-4):465-483

Recent increases in the accuracy of climate models have enhanced the possibilities for analyzing the impacts of climate change on society. This paper explores how the local, economic impacts of climate change can be modeled for a specific eco-region, the Western Sahel. The people in the Sahel are highly dependent on their natural resource base, and these resources are highly vulnerable to climate change, in particular to changes in rainfall. Climate models project substantial changes in rainfall in the Sahel in the coming 50 years, with most models predicting a reduction in rainfall. To connect climate change to changes in ecosystem productivity and local income, we construct an ecological–economic model that incorporates rangeland dynamics, grazing and livestock prices. The model shows that decreased rainfall in the Sahel will considerably reduce local incomes, in particular if combined with increases in rainfall variability. Adaptation to these climate change projections is possible if reductions in rainfall are followed by destocking to reach efficient grazing levels. However, while such a strategy is optimal from the perspective of society, the stocking rate is determined by individual pastoralists that face few incentives to destock.  相似文献   

Migration, remittances and regional development in Southern Morocco   总被引：1，自引：0，他引：1  

Hein de Haas 《Geoforum》2006,37(4):565-580

Although Morocco has evolved into one of the world’s leading emigration countries, the systematic study of the developmental impact of migration in migrant-sending regions in Morocco and the Maghreb has been relatively neglected after a temporary surge of pessimistic studies in the 1970s. Empirical work from this region has therefore been largely absent from the lively theoretical debate on migration and development. This study attempts to re-establish this link through qualitative research and a survey among 507 non-migrant, internal and international migrant households in the Moroccan Todgha oasis. The study shows that international migration and remittances have significantly contributed to economic development, improved standards of living and enabled the partial emancipation of subaltern ethnic groups. International migrant households invest more than others in housing, agriculture and other enterprises. Risk spreading and income stabilisation rather than increasing incomes seem to be the prime rationale behind internal migration, although internal migration tends to facilitate the education and international migration of younger household members. Remittance expenditure and investments have stimulated the diversifying and urbanising regional economy and have triggered a counter-flow of “reverse” internal migration. However, several structural constraints prevent the high development potential of migration from being fully realised.  相似文献   

Discrete Element Modeling of Stress and Strain Evolution Within and Outside a Depleting Reservoir   总被引：1，自引：0，他引：1  

Haitham T. I. Alassi  Liming Li  Rune M. Holt 《Pure and Applied Geophysics》2006,163(5-6):1131-1151

Stress changes within and around a depleting petroleum reservoir can lead to reservoir compaction and surface subsidence, affect drilling and productivity of oil wells, and influence seismic waves used for monitoring of reservoir performance. Currently modeling efforts are split into more or less coupled geomechanical (normally linearly elastic), fluid flow, and geophysical simulations. There is evidence (from e.g. induced seismicity) that faults may be triggered or generated as a result of reservoir depletion. The numerical technique that most adequately incorporates fracture formation is the DEM (Discrete Element Method). This paper demonstrates the feasibility of the DEM (here PFC; Particle Flow Code) to handle this problem. Using an element size of 20 m, 2-D and 3-D simulations have been performed of stress and strain evolution within and around a depleting reservoir. Within limits of elasticity, the simulations largely reproduce analytical predictions; the accuracy is however limited by the element size. When the elastic limit is exceeded, faulting is predicted, particularly near the edge of the reservoir. Simulations have also been performed to study the activation of a pre-existing fault near a depleting reservoir.  相似文献