Tok-Algoma magmatic complex of the Selenga-Stanovoi Superterrain in the Central Asian fold belt: Age and tectonic setting

According to the results of U-Pb geochronological investigations, the hornblende subalkali diorite rocks making up the Tok-Algoma Complex in the eastern part of the Selenga-Stanovoi Superterrain of the Central Asian fold belt were formed in the Middle Jurassic rather than in the Middle Archean as was suggested previously. Thus, the age of the regional amphibolite facies metamorphism manifested itself in the Ust??-Gilyui rock sequence of the Stanovoi Complex and that superimposed on granitoids of the Tok-Algoma Complex is Mesozoic rather than Early Precambrian. The geochemical features of the Tok-Algoma granitoids are indicative of the fact that they were formed in the geodynamic setting of the active continental margin or a mature island arc. Hence, it is possible to suggest that the subduction processes along the southern boundary between the Selenga-Stanovoi Superterrain and the Mongolian-Okhotsk ocean basin in the Middle Jurassic resulted in the formation of a magmatic belt of over 500 km in length.     

Metabasalts of the Bryanta sequence of the Stanovoi complex of the Dzhugdzhur-Stanovoi superterrane, Central Asian fold belt: Age and geodynamic environment of formation

In this paper, we report U-Pb geochronological, Sm-Nd isotopic, and geochemical data for the basic schists of the Bryanta sequence of the Stanovoi complex of the Dzhugdzhur-Stanovoi superterrane of the Central Asian fold belt. It was shown that the protolith of the schists was composed of island-arc subalkali basalts, which crystallized at 1933 ± 4 Ma; the age of the earliest metamorphic processes is approximately 1890?C1910 Ma. This metamorphic event could be related to the collision of the Aldan and Stanovoi continental plates or accretion-collision processes at the boundary of the Ilikan and Kupurin lithotectonic zones during the formation of the latter.     

Harmony of the Local System

An analytical representation and observational verification of a new harmonic scheme for the local system are presented. In it massive shell structures (spurs) play a dominant role, in combination with belts of stars, gas and dust. The geometry of the triaxial local system is closely coupled to the ecliptic coordinate system. Each axis has its own equator and its own discrete, periodic system of meridians. The largest axis, z, is normal to the S plane passing through the cores of four spurs (I-IV). Six meridians intersect along this axis, including the Gould belt (GB), the Vaucouleurs-Dolidze (V-D) belt, and the G plane, which is perpendicular to the ecliptic E at the solstice points. Four meridians, including E and S, intersect along the middle axis x, which coincides with the equinoctial line. The z axis is inclined by H"45° to E and by H"21° to the galactic plane. The overall number of nonrepeating principal planes in the local system is nine. Counts of stars brighter than V=9^m confirms that they are concentrated along all the principal planes. As a symmetry plane, the meridian perpendicular to the Gould belt ( GB) divides the system of spurs into two groups: (I, IV, Dor) and (II, III, Eri). Each encompasses a grid of 5 halves of the z meridians and isolates a group and the spurs within the group. At the same time, as bridges the x meridians and their equator G couple the cores of some of the spurs with the shells of others both within their own and in opposite groups. The convergence of the meridians (belts) to the X, Y, and Z poles couples all the details with the local system as a whole. The symmetry of the local system with its discrete elements resembles a crystal.     

On Wind Profiles over Developing Wind Wave in the Water-Air Interface

The results of studying the vertical profile of wind velocity and the vortex-formation mechanism in the atmospheric layer immediately adjacent to the water surface under the condition of developing wind wave are considered. Materials of field and laboratory experiments are used.__________Translated from Vodnye Resursy, Vol. 32, No. 3, 2005, pp. 295–300.Original Russian Text Copyright © 2005 by Anisimova, Pokazeev, Soboleva, A. Speranskaya, O. Speranskaya.     

Wind-wave generation and the wind velocity structure in the air above a wavy water surface

Research results are presented, under natural and laboratory conditions, concerning the process of wind-wave generation. The complementary problem, the effect of waves on the structure of the wind field above them, is also studied.