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121.
R.?BastEmail author E.?E.?Scherer K.?Mezger H.?Austrheim T.?Ludwig H.?R.?Marschall A.?Putnis K.?L?wen 《Contributions to Mineralogy and Petrology》2014,168(4):1069
The Bamble sector of southern Norway comprises metagabbros and metasediments that were metasomatically altered to various extents during a late stage of the Sveconorwegian orogeny (~1.06 Ga). The infiltration of highly saline brines along veins led to penetrative scapolitization and albitization on a regional scale and the local deposition of Fe–Ti oxides. Typical secondary mineral assemblages include either scapolite + apatite + amphibole + phlogopite + tourmaline, or albite + epidote + calcite + chlorite + white mica, indicating that the fluids introduced large amounts of Na, Cl, Mg, Ca, K, P, and B to the system. Metasomatic tourmalines associated with different alteration stages as identified by variations in major-element composition and initial 87Sr/86Sr were analyzed for B isotopic compositions to constrain possible sources and the evolution of the hydrothermal fluid(s). Measured δ11B values range from ?5 to +27 ‰ relative to SRM-951, suggesting marine evaporites interlayered with various amounts of continental detritus and pelagic clay as a possible B source reservoir. The influence of a seawater-derived component is clearly indicated by the heavy B isotope signature of tourmaline related to Al–Mg-rich metapelites. In contrast, negative δ11B values can be explained by the influence of pneumatolytic fluids associated with granitic pegmatites. On a regional scale (i.e., several km), δ11B values in tourmaline vary widely, whereas variations within a single outcrop (tens of m) are typically small and can be ascribed to different generations of tourmaline related to several fluid pulses. 相似文献
122.
123.
Lihe Yin Yangxiao Zhou Jinting Huang Jochen Wenninger Guangcai Hou Eryong Zhang Xiaoyong Wang Jiaqiu Dong Jun Zhang Stefan Uhlenbrook 《Environmental Earth Sciences》2014,71(12):4997-5006
Sap flow (SF)of a willow tree, meteorological variables, soil water content, and water table depth were measured during the growing period from mid-April to October, 2011 in the semi-arid Hailiutu River catchment, Northwest China. The measurements of SF showed diurnal fluctuations in sunny days and seasonal changes from 1.65 l/h in mid-April to 33 l/h in July. At hourly scale, SF is significantly correlated with net radiation, followed by air temperature, relative humidity, and wind speed. At daily scale, air temperature affects the dynamics of SF significantly. Daily SF correlates positively with net radiation and negatively with relative humidity. There is no correlation observed between daily SF and wind speed. The measurements of SF do not indicate water stress although the experimental period is dry. Correlation analysis shows that SF is strongly correlated with soil moisture and water table depth, indicating the willow tree uses both soil water and groundwater for transpiration. 相似文献
124.
Robert Wood Doug Johnson Simon Osborne Meinrat O. Andreae Brain Bandy Timothy S. Bates Colin O'Dowd Paul Glantz Kevin Noone Patricia K. Quinn Jochen Rudolph Karsten Suhre 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):401-422
Aircraft measurements are presented of the Lagrangian evolution of a marine boundary layer over a 30‐h period during the ACE‐2 field campaign. At the start of the observational period, a 500‐m deep polluted marine internal boundary layer (MIBL) was overlain by the remnants of a polluted continental boundary layer extending to around 2 km below a clean, dry free troposphere. The MIBL grew rapidly to a thickness of 900–1000 m in response to increasing sea surface temperatures. No significant aerosol spectral evolution was observed in the boundary layer. Low concentrations of SO2 were observed in the MIBL suggesting that the air mass contained relatively aged aerosol. Aerosol spectra show a broad mode with a modal diameter of around 0.1μm. The polluted layer between the MIBL and the unpolluted free troposphere was only weakly and intermittently turbulent which prevented significant entrainment of clean air into the polluted layer from aloft. The polluted layer depth was thus controlled mainly by subsidence which as a result becomes shallower, decreasing from over 2000 m to around 1200 m during the observational period. The aerosol characteristics of the polluted layer were similar to those in the MIBL and so although the MIBL entrained considerable amounts of air from above the MIBL the aerosol characteristics underwent no significant change. This has important implications for the rate at which a polluted continental air mass is converted to a clean marine one. The dataset should prove useful in the validation of the modelling of continental pollution outbreaks. 相似文献
125.
Jochen Heidt Immo Appenzeller Armin Gabasch Klaus Jäger Stella Seitz The FDF-Team 《Astrophysics and Space Science》2003,284(2):385-388
The FORS Deep Field project is a multi-colour, multi-object spectroscopical investigation of a ∼ 7′ × ′' region near the south
galactic pole based mostly on observations carried out with the FORS instruments attached to the VLT telescopes. It includes
the QSO Q 0103-260 (z = 3.36). The goal of this study is to improve our understanding of the formation and evolution of galaxies
in the young Universe. In this contribution, the photometric observations are presented. In particular, a combined B and I
selected UBgRIJKs photometric catalog of 8753 objects in the FDF is presented and its content is briefly described. The formal
50% completeness limits for point sources, derived from the coadded images, are 25.64, 27.69, 26.86, 26.68, 26.37, 23.60 and
21.57in U, B, g, R, I, J and Ks, respectively.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
126.
Analysis of water flow pathways from hillslopes to streams is essential for the optimal protection of water resources as well as for ecohydrological studies. This study addresses runoff generation processes at a hillslope and near‐stream shallow groundwater system in the Black Forest Mountains, southwestern Germany. The changing spatial and temporal flow patterns during differing hydrological situations were examined using a combined hydraulic and hydrochemical approach. Groundwater levels at 10 wells, discharge at a near‐stream saturated area, and several natural tracers (deuterium, dissolved silica, and major anions and cations) were observed at different locations during high and low flows. The importance of the groundwater component during flood formation was clearly demonstrated: its contribution was about 80% during a double peak flood event at the saturated area. In addition, a rapid change of the shallow groundwater levels was observed along two transects of groundwater wells in the floodplain. This led to an enhanced groundwater discharge into the saturated area located at the end of one study transect. The amount of groundwater additionally activated during the event was about 30% of total discharge recorded at the outlet of the saturated area. Two alternative hypotheses are discussed to explain this phenomenon: the establishment of locally confined conditions and the development of a pressure wave (hypothesis A), or the significant change of the three‐dimensional groundwater flow lines that caused a large increase of the groundwater catchment at the saturated area during the investigated event (hypothesis B). Even if the exact flow paths and mechanisms could not be clearly identified, the importance of rapid responding hillslope groundwater was undoubtedly demonstrated by a combination of tracer and hydrometric methods. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
127.
Jochen Knies Hans-Peter Kleiber Jens Matthiessen Claudia Müller Norbert Nowaczyk 《Global and Planetary Change》2001,31(1-4)
Ice-rafted debris (IRD) (>2 mm), input in eight sediment cores along the Eurasian continental margin (Arctic Ocean), have been studied over the last two glacial/interglacial cycles. Together with the revised chronologies and new micropaleontological data of two cores from the northern Barents Sea (PS2138) and northeastern Kara Sea (PS2741) spanning Marine Isotope Stages (MIS) 6 to 1, the IRD data give new insights into the glacial history of northern Eurasian ice-sheets over the last 150 ka. The chronologies of the cores are based on stable isotope records, AMS 14C datings, paleomagnetic and biostratigraphic data.Extensive episodes of northern Barents Sea ice-sheet growth, probably to the shelf edge, occurred during the late Weichselian (MIS 2) and the Saalian (MIS 6). Major IRD discharge at the MIS 4/3-transition hints to another severe glaciation, probably onto the outer shelf, during MIS 4. IRD-based instabilities of the marine-based ice margin along the northern Barents Sea between MIS 4 and 2 are similar in timing with North Atlantic Heinrich events and Nordic Seas IRD events, suggesting similar atmospheric cooling over a broad region or linkage of ice-sheet fluctuations through small sea-level events.In the relatively low-precipitation areas of eastern Eurasia, IRD peak values during Termination II and MIS 4/3-transition suggest a Kara Sea ice-sheet advance onto the outer shelf, probably to the shelf edge, during glacial MIS 6 and 4. This suggests that during the initial cooling following the interglacials MIS 5, and possibly MIS 7, the combined effect of sustained inflow of Atlantic water into the Arctic Ocean and penetration of moisture-bearing cyclones into easterly direction supported major ice build-up during Saalian (MIS 6) and Mid-Weichselian (MIS 4) glaciation. IRD peak values in MIS 5 indicate at least two advances of the Severnaya Semlya ice-sheet to the coast line during the Early Weichselian. In contrast, a distinct Kara Sea ice advance during the Late Weichselian (MIS 2) is not documented by the IRD records along the northeastern Kara Sea margin. 相似文献
128.
Peter John Marcotullio Andrea Sarzynski Jochen Albrecht Niels Schulz Jake Garcia 《Climatic change》2013,121(4):621-634
The purpose of this paper is to describe global urban greenhouse gas emissions by region and sector, examine the distribution of emissions through the urban-to-rural gradient, and identify covariates of emission levels for our baseline year, 2000. We use multiple existing spatial databases to identify urban extent, greenhouse gas emissions (CO2, N2O, CH4 and SF6) and covariates of emissions in a “top-down” analysis. The results indicate that urban activities are significant sources of total greenhouse gas emissions (36.8 and 48.6 % of total). The urban energy sector accounts for between 41.5 and 66.3 % of total energy emissions. Significant differences exist in the urban share of greenhouse gas emissions between developed and developing countries as well as among source sectors for geographic regions. The 50 largest urban emitting areas account for 38.8 % of all urban greenhouse gas emissions. We find that greenhouse gas emissions are significantly associated with population size, density, growth rates, and per capita income. Finally, comparison of our results to “bottom-up” estimates suggest that this research’s data and techniques are best used at the regional and global scales. 相似文献
129.
130.