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771.
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Marin Ivanov Kardjilov Sigurdur Reynir Gíslason Gudrún Gísladttir 《Journal of Geochemical Exploration》2006,88(1-3):292
The overall objective of this study is to define and interpret the annual dissolved inorganic carbon (DIC) flux in selected river catchments in North Eastern Iceland. The flux stems primarily from chemical weathering of basalt. The DIC flux out of the catchments is compared with the spatial distribution of the various vegetation communities and their gross primary production (GPP), net primary production (NPP) and net ecosystem exchange (NEE). There is no correlation between the DIC flux and the GPP, but one between DIC and NPP. The DIC flux is highly dependent on the NEE, which in turn is governed by the area extent of wetlands in these catchments. A variation by a factor 5 of the NEE results in a variation by a factor 2.8 in the river dissolved inorganic flux. 相似文献
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B. V. Ivanov V. I. Gorelchik V. N. Andreev A. M. Maksimov V. V. Stepanov A. M. Chirkov 《Bulletin of Volcanology》1981,44(1):1-10
A new Klyuchevskoy volcano eruptive cycle encompasses terminal (March 30, 1972 to August 23, 1974) and lateral (August 23, 1974 to December, 1974) eruption stages. The terminal eruption stage resulted in lava flows and parasitic cones that formed on the south-western flank of the volcano. Eruption products are moderately alkalic high-alumina olivine-bearing andesite-basalts. The terminal eruption stage was accompanied by volcanic earthquakes and volcanic tremor. The lateral eruption was accompanied by explosive earthquakes. Volcanic tremor was the most useful prognostic sign indicating the onset of the lateral eruption. Eruptive mechanisms are discussed. 相似文献
776.
The paper describes a new sensor for the spatial registration and measurement of particle parameters in near and deep space. The following modern materials are applied in the sensor structure: a PVDF piezoactive film and lightweight heat-shielding high-temperature aerogel. The results from studying the aerogel morphology as well as its thermal conductivity depending on the air temperature are presented. The thermal conductivity of a SiO2-aerogel is compared with one of foreign aerogels and air. Its elemental quantitative chemical composition is determined. 相似文献
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V. N. Smirnov K. S. Ivanov Yu. L. Ronkin V. A. Koroteev P. A. Serov A. Gerdes 《Doklady Earth Sciences》2017,474(1):516-519
According to isotopic analysis of rocks of the Reft gabbro–diorite–tonalite complex (Middle Urals), gabbro and related diorite and dikes and vein-shaped bodies of plagiogranitoids, crosscutting gabbro, are similar to the depleted mantle substance in εNd(T) = 8.6–9.7 and εHf(T) = 15.9–17.9. Their model Hf ages are correlated with the time of crystallization. Here, the tonalites and quartz diorites constituting most of the Reft massif are characterized by lower values: εNd(T) = 3.7–6.0, εHf(T) = 11.1–12.7, and T DM values significantly exceeding the age datings. This is evidence that Neoproterozoic crustal rocks were a source of parental magma for these rocks. The primary 87Sr/86Sr ratio in rocks of both groups is highly variable (0.70348–0.70495). The data obtained allow us to reach the conclusion that the Reft gabbro–diorite–tonalite complex was formed as a result of nearly synchronous processes occurring in the crust and the mantle within a limited area. 相似文献
780.
Geoinformational analysis shows that the fraction of lands that are optimal for farming of the main crops in Russia is about 10% of the available land at best (for summer wheat, buckwheat). For the majority of other crop cultures, this value is a few percent at most. The available resources are used very incompletely. The index of completeness of land resource potential use is no more than 10% for the majority of crops. Only in the case of soy are the available resources almost completely involved, whereas available land resources of winter wheat, grain maize, and sunflowers are used at 20–30%. 相似文献