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681.
The water characteristics of the Gucheng Lake, such as eutrophication, health and spatial distribution, were investigated.
On the basis of the trophic state index (TSI) and entropy weight, a synthesized trophic state index (STSI) model was established
to assess lake eutrophication condition through calculating STSI, choosing TP, TN, COD, BOD and NH3-N as trophic variables. The STSI ranged from 50.58 to 62.44, which showed that the water has been between eutrophic and supereutrophic.
A histogram was applied to health risk assessment which was analyzed from carcinogenic substances (Cr+6, As and Cd) and non-carcinogenic substances (hydroxybenzene, Pb, Hg, CN− and NH3), and the results showed that the former was much greater than the latter for effect. The total risk for each resident caused
by all pollutants ranged from 5.18E-05 to 8.34E-05, which is far higher than the standard, recommended by Sweden Bureau of
Environment Protection and Holland Ministry of Building and Environment Protection (1.0E-05). Cluster analysis was used to
detect similarities and dissimilarities among the seven sampling sites and explain the observed clustering in terms of affected
conditions. Twenty-one variables were used to divide seven sampling sites into three groups, namely, north lake, south lake
and lake center. 相似文献
682.
I. S. Krassivskaya E. V. Sharkov N. S. Bortnikov A. V. Chistyakov N. V. Trubkin T. I. Golovanova 《Petrology》2010,18(3):263-277
Altered variolites described for the first time in the axial zone of the Mid-Atlantic Ridge are represented by rounded globules
of andesite (icelandite) composition with light trachyandesite rim embedded in a picrobasaltic matrix. The globules were transferred
with picrobasaltic melt and then floated to the surface of lava flow, while formation of leucocratic rims was presumably related
to thermodiffusion (Soret effect) in a cooling heterogeneous melt. This heterogeneous melt was formed by penetration of ascending
column of picrobasaltic magma in already existing small intracructsal magmatic chamber filled with residual icelanditetype
andesite melt and involvement of the latter into a general upward movement. The rapid ascent of the melts in the oceanic spreading
zones by means of turbulent flowing caused dispersion of the extragenous melt into small drops in a jet of picrobasaltic magma,
without their interaction. Variolites were formed during cooling of such heterogeneous lava flow. No signs of liquid immiscibility
were found in the studied variolites. 相似文献
683.
684.
This paper reports REE data on resin-asphaltene components of oil from six oil-gas-bearing provinces and on bitumoids from
inferred oil-source rocks (domanikites and bazhenites). It was shown that, regardless of geological-tectonic structure of
the regions, oil composition, depth of reservoirs, and host lithologies, oil exhibits significant REE fractionation, and,
unlike bitumoids, positive Eu anomaly. The (Eu/Sm)n ratio increases from asphaltenes to resins and further to oils. Based on REE distribution in oil, source rocks, and bitumoids,
it was concluded that deep-seated fluids were one of the possible sources that defined the trace element composition of oil. 相似文献
685.
686.
Studies on the water and suspended matter concentration dynamics were performed for the summer and autumn periods in Kruglaya
Bay, Chupa Inlet (Karelian Coast, the White Sea). The tidal cycle appeared as the major factor defining the water salinity,
temperature, and suspended matter concentration. The water temperature and suspended matter concentration increased during
low tide, and the opposite pattern was observed for water salinity; all the processes were true for both surface and bottom
water layers. Therefore, we conclude that major bulk of the allochtonous suspended matter is carried into the sea by the ebb
stream. 相似文献
687.
688.
689.
A. A. Sorokin I. V. Buchko A. B. Kotov S. D. Velikoslavinsky 《Russian Journal of Pacific Geology》2010,4(5):418-428
The Baladek Massif represents a tectonic block located at the boundary between the SE framing of the North Asian craton and
the fold structures of the Galam terrane of the Mongol-Okhotsk fold belt. According to the existing concepts, the rocks of
this massif are regarded as Precambrian complexes of the aforementioned craton. This paper reports the results of studying
the fragment of the Baladek Massif in the Gerbikan River basin. New geochemical data obtained on the gabbros, gabbroanorthosites,
and ultramafic rocks testify to their similarity with typical ophiolite complexes. An underlying complex of metamorphic ultrabasic
rocks, a layered complex of pyroxenites and “cumulate” gabbros, gabbroanorthosites, and a complex of isotropic gabbros were
distinguished within this fragment. It is highly possible that the basic volcanic rocks and jaspers of the Silurian-Lower
Devonian sequences of the Galam segment of the Mongol-Okhotsk fold belt also belong to the inferred ophiolite complex. 相似文献
690.
I. Yu. Melekestseva V. A. Kotlyarov P. V. Khvorov V. N. Ivanov V. E. Beltenev I. G. Dobretsova 《Geology of Ore Deposits》2010,52(8):800-810
The porous fine-grained to microcrystalline copper-zinc ore of the Semenov-2 hydrothermal field, a site in the Semenov hydrothermal
cluster discovered in 2007 (13°31′N, MAR), is anomalously enriched in Au (22–188 ppm) and Ag (127–1787 ppm). Chalcopyrite,
isocubanite, würtzite, and opal are major minerals; sphalerite, marcasite, pyrite, and covellite are auxiliary; and galena,
pyrrhotite, native gold, silver telluride, barite, and aragonite are sporadic. Gold containing 0.31 to 23.07 wt % Ag occurs
as up to 9-μm-sized subhedral, dendritelike, and elongated grains mostly hosted in opal and less frequently in sphalerite
and in pores within isocubanite-chalcopyrite aggregate. An elongated grain (2 × 4 μm in size) of the Ag-Te phase was found
in a pore. So far only basalts have been dredged from the Semenov-2 field, but anomalous gold and silver concentrations suggest
the influence of ultramafic rocks; the latter were found 1.5 km westward, in the Semenov-1 hydrothermal field. Mineral assemblage
and morphology of gold particles indicate its primary origin in contrast to the hydrothermal fields hosted in basalts, where
gold is a product of remobilization. Zonal gold grains, found on oceanic floor for the first time, are characterized by low
Ag content in the cores and high Ag content in the outer rims, reflecting variation in formation conditions. 相似文献