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Zircons from the porphyry-like quartz-diorite boss of the Pebble Cu-Au-Mo deposit (southwest Alaska) have been examined. By
their appearance and internal structure (cathode luminescence and electron probing), the zircons have been subdivided into
four genetic groups: (1) xenogenic detrital (mainly rounded); (2) magmatogene (protolith crystal in the center and growth
zone at the edge); (3) hydrothermally altered (with new-formed regeneration edges in growth zones); (4) metamict-altered (unconsolidated
center of the crystal and sectoring in growth zones). Based on SHRIMP U-Pb dating for the principal heterogeneous elements
in every group, the following stages of ore formation have been identified for the Pebble deposit: (a) crystallization of
quartz diorite-porphyry bosses (95–92 Ma, the concordant age is 94.7 ± 1.5 Ma); (b) late magmatic metasomatic alterations
with copper-molybdenum mineralization (92–85 Ma, the concordant age is 90.15 ± 0.78 Ma); (c) postmagmatic argillization with
epithermal gold-sulfide mineralization (82–80 Ma, the concordant age is 82.9 ± 2.7 Ma). 相似文献
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Samolyubov B. I. Zamarashkin A. L. Shil'nev A. V. Kremenetskii V. V. Silaev A. V. 《Water Resources》2001,28(2):123-128
The results of comprehensive hydrophysical studies of gradient and density-induced gravitational currents with thermal stratification in valley reservoirs are considered. The lengthwise and vertical development of currents as well as their evolution is considered. Local swells are detected in the near-bed nepheloid layer and clouds of suspended materials are found to be ejected from the density-induced current near abrupt changes in the bed relief. The near-bed density-induced current is found to strongly interact with the drift current in the presence of inner wave and variable-direction wind. The measured vertical profiles of velocity in the sections along the axis of the current and the longitudinal distributions of the average flow velocity and suspended material concentration are found to agree with model calculations. 相似文献
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A. G. Zatsepin N. N. Golenko A. O. Korzh V. V. Kremenetskii V. T. Paka S. G. Poyarkov P. A. Stunzhas 《Oceanology》2007,47(3):301-312
An analysis of the data of measurements of the fine structure and microstructure fluctuations of hydrophysical fields in the upper 200-m layer of the Black Sea carried out using CTD profilers and a Baklan free falling microstructure and turbulence profiler revealed the existence of a positive correlation between the intensity of the fine structure and microstructure fluctuations and the dynamics of the currents. On the other hand, the level of the fine structure and microstructure fluctuations reflects the rate of the vertical turbulent exchange. It was shown that, in the case of the absence of the Black Sea Rim Current (BSRC) jet or clearly manifested mesoscale eddy structures, the vertical turbulent exchange in the pycnocline is weak, while, in the opposite case, it is stronger. The results obtained support the supposition that the interbasin dynamics play an important role in the maintenance of the rate of small-scale mixing in the pycnocline and halocline and provide the vertical transport of dissolved oxygen from the cold intermediate layer into the deeper layers of the sea. 相似文献
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A. G. Zatsepin A. O. Korzh V. V. Kremenetskii A. G. Ostrovskii S. G. Poyarkov D. M. Solov’ev 《Oceanology》2008,48(4):466-475
Results of the studies of the spatiotemporal variability in the hydrophysical and hydrodynamical structure of the shelf area and its dependence on the water dynamics of the deep-water zone of the Black Sea off Gelendzhik are presented and discussed. The field materials were collected in early October of 2006 with the use of traditional and new measurement techniques. A combined analysis of on-line satellite oceanological information, data of onboard surveys, and data time series of the vertical profiling of the hydrophysical characteristics at a moored buoy station was performed. 相似文献
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A. V. Dubinin T. P. Demidova V. V. Kremenetskii N. M. Kokryatskaya M. N. Rimskaya-Korsakova E. V. Yakushev 《Oceanology》2012,52(2):181-190
The report presents the results of the studies of the reduced sulfur species in the water of the anoxic zone of the Black
Sea. The content of hydrogen sulfide was determined by means of spectrophotometry using dilution with oxygen-free distilled
water. The detection limit of the H2S amounted to 0.3 μM with the method’s precision below 3%. The accuracy of the spectrophotometric determination was verified
by iodometry after the fixation of the hydrogen sulfide in zinc acetate under the distillation with argon from the acidified
seawater sample. 相似文献
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