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排序方式: 共有68条查询结果,搜索用时 250 毫秒
61.
Carbonaceous dolomites and shales of the 1.64 billion years (Ga) old Barney Creek Formation (BCF), McArthur Basin, northern Australia contain the oldest, clearly indigenous biomarkers. We describe three new series of regularly branched aryl isoprenoids with base ions at m/z 119, 161 and 175. The m/z 119 compounds were identified as a complete series of C15–C40 oligoprenyl-perhydro-ar-curcumenes (oligoprenyl-curcumanes). Their likely biogenic precursors are oligoprenyl-β-curcumenes that occur in a wide range of bacterial phyla. 相似文献
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63.
Various land–atmosphere coupling mechanisms exist that may lead to large-scale impacts on climate and hydrology. Some of them are still less understood and not adequately represented in state-of-the-art climate modelling. But, as the current generation of climate models enables consideration and implementation of important coupling processes, the present study provides perspectives for the modelling of relevant climate–hydrology interactions. On a more short-term perspective, these comprise anthropogenic land use and especially irrigation, which has been shown that it may even affect remote regions. On a long-term perspective, the coupling of hydrology to carbon cycle and vegetation becomes important, specifically the dynamics of permafrost and wetlands. Here, we present a review of current knowledge combined with some exemplary studies from a large-scale point of view. Therefore, we focus on climate–hydrology interactions that are relevant on scales utilized in the current or forthcoming global and regional climate modelling exercises. 相似文献
64.
Werner Ehrmann Gerhard Schmiedl Yvonne Hamann Tanja Kuhnt 《International Journal of Earth Sciences》2007,96(4):769-780
Extensive published data sets and some new data on the clay mineral composition of surface sediments in the Aegean Sea, northeastern
Mediterranean Sea, have been compiled in order to map the distribution patterns of clay mineral assemblages and to decipher
source areas and transport paths. We distinguished six provinces, a Northwest Aegean Province, a Marmara-Dardanelles Province,
a West Turkey Province, a Southeast Aegean Province, a Kithira Province and a Central Aegean Province. The clay mineral assemblages
in the coastal and shelf areas carry the signature of the riverine sediment discharge from southeast Europe and Turkey, respectively.
The southern Aegean Sea is probably influenced by the River Nile discharge and transport of clay minerals by surface currents.
The clay minerals in the central Aegean Sea form a mixed assemblage comprising components of the other assemblages. A dispersion
and dilution of clay minerals by surface currents is obvious. 相似文献
65.
Désirée Hilbring Tanja Titzschkau Alfons Buchmann Gottfried Bonn Friedemann Wenzel Eberhard Hohnecker 《Natural Hazards》2014,70(3):1795-1825
This paper analyzes the potential of earthquake early-warning systems for transport lines. The interdisciplinary work focuses on rapidly producing an alert map during an ongoing earthquake as well as providing a damage map immediately after the strong-motion phase that visualizes potential damages to the railway infrastructure. In order to meet these application requirements, a service-oriented architecture based on geospatial standards is specified. This ensures the portability of the system architecture to different geographic regions as well as a potential transfer to other natural disasters and infrastructure systems. The first part of the paper describes the standard-based services of the system architecture together with design principles that are useful for the realization of early-warning systems. In the second part of the paper, an online demonstrator for the exemplary test area in the federal state of Baden-Württemberg, Germany, is presented. The system architecture of the demonstrator includes an earthquake early-warning methodology based on artificial neural networks and an infrastructure-specific damage assessment. The third part of the paper analyzes the potential of implementing low-cost sensors in the track, which would provide a dense network directly at the railway infrastructure. 相似文献
66.
Todorović Bratislav Ž. Stojiljković Dragan T. Pantić Tanja Petrović Matović Branko Djordjević Marija Prekajski Petrović Sanja M. Stojiljković Milena S. Stevanović Miloš M. 《Natural Resources Research》2019,28(4):1259-1267
Natural Resources Research - There are no available data about direct burkeite formation on the geothermal waters pipelines in Europe. Data about accompanying minerals of burkeite are also scarce.... 相似文献
67.
In offshore waters of the German North Sea multiple stakeholder activity is increasing in both type and intensity. Newcomers such as wind farms make for additional claims and exclude, due to current legal constraints, other sectors, such as traditional fisheries. In this context, integrating marine aquaculture with designated wind farm areas might provide chances to combine two industries in the frame of a multiple-use concept. This paper takes up concerns and possible management framework requirements as expressed through interviews with the wind farm industry and the mussel harvesting sector when inquiring about such a multiple-use setting. The article closes with a discussion on two co-management strategies that might be appropriate for governing potential interacting wind farm–mariculture activities. 相似文献
68.
Early Archean spherule layers from the Barberton Greenstone Belt,South Africa: Mineralogy and geochemistry of the spherule beds in the CT3 drill core
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Seda Ozdemir Toni Schulz Christian Koeberl Wolf Uwe Reimold Tanja Mohr‐Westheide Desiree Hoehnel Ralf Thomas Schmitt 《Meteoritics & planetary science》2017,52(12):2586-2631
Little is known about the Hadean and the Archean impact record on Earth. In the CT3 drill core from the Fig Tree Group of the northern Barberton Greenstone Belt, 17 spherule layer intersections occur, which, provide an outstanding new opportunity to gain insights into meteorite bombardment of the early Earth. CT3 spherules, as primary features, mostly exhibit textural patterns similar to those of the other Barberton spherule layers, but locally mineralogical and chemical compositional differences are observed, likely as a result of various degrees of alteration. The observed mineralogy of the spherule layers is of secondary origin and comprises K‐feldspar, phyllosilicates, carbonates, sulfides, and oxides, with the exception of secondary Ni‐Cr spinel that is of primary origin. Our petrographic investigations suggest alteration by K‐metasomatism, sericitization, silicification, and carbonatization. Siderophile element contents of bulk samples show significant enrichments in Ni (up to 2 wt%) and Ir (up to ~3 ppm), similar to previously studied Archean spherule layers. These values are indicative of the presence of a meteoritic component. On the other hand, lithophile and chalcophile element abundances indicate hydrothermal overprint on the CT3 samples; this may also have influenced the redistribution of the meteoritic component(s). Last, we group the CT3 spherule layers, which occur in three intervals (A, B, and C), according to their petrographic and geochemical features, which indicate evidence for at least three distinct impact events before tectonic overprint that affected the original deposits. 相似文献