Laws of formation and criteria for predicting nickel content in weathering crusts of east Kazakhstan

The article considers from the theoretical point of new global tectonics the geological conditions of formation, peculiar features of material composition, and criteria for predicting deposits of nickeliferous weathering crusts of east Kazakhstan. According to geotectonic zoning, this territory includes geological structures of the Big Altai (BA), which is part of the central Asian mobile belt. The ore-controlling role is assigned to the area of global interaction of the Kazakhstan and Siberian paleocontinents during the stage of the Hercynian collision (Ñ₁-Ñ₃) followed by the formation of the Zaisan suture zone, the structure of which is represented by the Charsky-Gornostaevsky ophiolite belt (suture stitch). During the Hercynian cycle of tectogenesis, main gold fields of the regions appeared in the Zaisan suture (gold-quartz, gold-sulphide, gold-listvenite, etc.) in a collision situation, controlled by a system of deep faults of the crust and mantle type. In similar tectonic environment, large stockwork gold deposits were formed in Rudny Altai, north Kazakhstan, and other regions. During the Cimmerian cycle, the residual weathering crust deposits of Au, Ti-Zr, Ni-Co were formed in the region of continental rifting. The article emphasizes the spatial association of silicate cobalt-nickel deposits to the outputs of serpentinized ultrabasites of the Charsky-Gornostaevsky belt and provides a characteristic of the geological structure and material composition of nickel content in ores of the Belogorskoye and Gornostaevskoye standard deposits. Expansion of prospects depends on the possibility of growth of reserves of cobalt and nickel ores on the flanks and deep horizons of the known ore fields and search for buried deposits in prospective areas determined by geological and geophysical studies.     

Sensitivity of the Humboldt Current system to global warming: a downscaling experiment of the IPSL-CM4 model

The impact of climate warming on the seasonal variability of the Humboldt Current system ocean dynamics is investigated. The IPSL-CM4 large scale ocean circulation resulting from two contrasted climate scenarios, the so-called Preindustrial and quadrupling CO₂, are downscaled using an eddy-resolving regional ocean circulation model. The intense surface heating by the atmosphere in the quadrupling CO₂ scenario leads to a strong increase of the surface density stratification, a thinner coastal jet, an enhanced Peru–Chile undercurrent, and an intensification of nearshore turbulence. Upwelling rates respond quasi-linearly to the change in wind stress associated with anthropogenic forcing, and show a moderate decrease in summer off Peru and a strong increase off Chile. Results from sensitivity experiments show that a 50% wind stress increase does not compensate for the surface warming resulting from heat flux forcing and that the associated mesoscale turbulence increase is a robust feature.     

Analysis of investments in technology development and resource conservation

A methodology is presented for the economic analysis of investments in research, technology development and water resources conservation. The role of technology development and resource conservation is directly related to the availability of resources. Mathematically speaking, we are dealing with a problem in which part of the control variables are investments on technologies related to the manufacturing of diverse products. The methodology enables the decision maker to distribute efficiently restricted amounts of capital and resources to the different manufacturing systems so as to achieve the most profitable combination of production levels.Using the so called ‘technology function’, the solution procedure consists of a combination of decomposition and dynamic programming. Two specific technology functions are considered as examples and it is shown how analytical consideration can be incorporated in the solution procedure so as to reduce computational requirements.Possible extensions of the problem are also discussed.     

Observable blueshifts near compact objects

We show that observable blueshifted radiation can emanate from material freely falling toward compact objects. Using a fully relativistic treatment and considering possible blocking of photon trajectories by a neutron star or black hole, we demonstrate that blueshifts are observable.Supported in part by the National Science Foundation.     

A variant of the Hori-Lie series method

If the undisturbed Hamiltonian F₀ is a function of the momenta only, then a variant of the Hori-Lie series perturbation method achieves a solution to any order with a single canonical transformation, without the use of the pseudo-time.     

Volcanism of the Kerguelen Plateau (Indian Ocean): Composition,Evolution, and Sources

Petrographic and geochemical study of basalts in the Kerguelen Plateau basement revealed changes in the composition and character of volcanism during the development of this tectonovolcanic structure. The Kerguelen Plateau is one of the largest intraplate rises in the World Ocean. It started to form about 120 Ma ago. The age of basalts and overlying sediments shows that the plateau formation succeeded in the northwestern direction. Basalts of the Kerguelen Plateau basement are products of tholeiitic melts in terms of geochemistry, but differ from the mid-oceanic ridge basalt (MORB). They are enriched in incompatible trace elements and rare earth elements (REE) relative to MORB, and the degree of enrichment varies in basalts from different segments of the plateau. The composition of basalts does not directly depend on their age. Specific features of the plateau magmatism are commonly explained in terms of a long-living deep magma plume, which variously interacted with a depleted upper mantle source at different stages of the plateau formation. However, taking into account block morphology and deep structure of the plateau, one can suggest that the plateau volcanism was initiated by a large fault. As the volcanism prograded to the northwest, the depth of fault penetration into the mantle changed. The composition of basalts in the plateau basement was also governed by the formation depth of primary melts.     

Opening geometry of the Kurile Basin (Okhotsk Sea) as inferred from structural data

Abstract   The Kurile Basin in the Okhotsk Sea, northwestern Pacific, is a back-arc basin located behind the Kurile Island Arc. It is underlain by oceanic crust and its origin has been attributed to back-arc spreading. Two models for the opening of the Kurile Basin exist, for which the spreading axis is oriented northeast–southwest and northwest–southeast, respectively. New data are presented here on the morphostructure of the slope of the northern Kurile Basin and of the central Kurile Basin which support a strike of the spreading axis in the latter direction. Bathymetric as well as single-channel and multichannel seismic reflection data demonstrate the existence of dominant northwest-striking normal faults on the northern slope of the Kurile Basin. In the central Kurile Basin a basement rise striking north-northwest–south-southeast (here named the Sakura Rise) was mapped. The rise morphology has the distinct imprint of a rift structure with symmetrical volcanic edifices on the rise axis and faulted blocks that tilt in opposite directions on the flanks. These data suggest that the Kurile Basin opened in a northeast–southwest direction. In the generally accepted plate tectonic reconstructions, northwest–southeast spreading associated with dextral strike–slip along the north–south-striking shear zone of Sakhalin and Hokkaido islands has been assumed. In the present model, spreading in the Kurile Basin was presumably connected with dextral displacement along a northeast-striking shear zone on the southern segment of the Okhotsk Sea.