Shkol’noe gold deposit, the Russian Northeast

The Shkol’noe deposit is localized in a small granitoid stock, the root portion of which is traced using geophysical data to a depth of 5–8 km. The high-grade gold ore (33 gpt Au) is enriched in silver and principally differs in ore composition from the previously studied mesothermal gold-quartz and epithermal gold-silver deposits in the Russian Northeast. The main reserves of the Shkol’noe deposit concentrate in bonanzas (20% of the total volume of orebodies). The internal deformation is related to the rearrangement of matter in freibergite; exsolution structures in fahlore and native gold are related to postmineral metamorphism. It is suggested that the ore of the Shkol’noe deposit occupies a transitional position between porphyrytype and epithermal levels of ore deposition.     

Native gold from the Plavica epithermal deposit, Republic of Macedonia

Mineralogical-geochemical studies have shown that gold from the Plavica high sulfidation epithermal deposit (Republic of Macedonia) contains an admixture of Fe and Cu, that the morphology of gold indicates the proximity of the primary source, and that the chemical composition of gold is independent of its morphology. The composition of gold and its morphology are the direct searching criteria, indicating the genetic type of mineralization. Pan sampling and the subsequent study of the typomorphism of gold may serve as an effective method for searching for epithermal high sulfidation deposits. Pan sampling allows us to distinguish and study in detail the chemical composition and morphology of native gold from deposits of this type.     

Possibility of investigation of the microstreams and associations by the radiotomographic method

This article contains the tomographic problem's solution of the radiants distribution study by the meteor radar data. It was received the distribution of meteors velocities for the parts of celestial sphere with angular dimensions 10° × 10° and 1° × 1°. Was shown that the angular dimensions of most of radiants are equal 1° – 3° and larger part of the sporadic background looks like a totality of microstreams.