International Geology Review

Litvinovskiy, V.A.

doi: 10.1080/00206816809474882pmid: N/A

Potentially favorable environments for the development of alkalic rocks, as products of infiltrational magmatic replacements of carbonates in upper part of the section, are indicated by analysis of processes in endo- and exo-contacts of a granitic intrusion, in zones of deep fractures, where the rocks were subjected to fragmentation and mylonitization. The phenomenon is contingent upon an enrichment of volatile and alkalic substances in the tops of the granitic intrusion and a development of advancing magmatic solutions in front of the intrusion. -- IGR Staff.

Paffengol'ts, K.N.; Ter-Mesropyan, G.T.

doi: 10.1080/00206816809474883pmid: N/A

The Aragats upland is underlain by faulted schists of upper-Proterozoic and lower Paleozoic age. These are overlain by Upper Cretaceous volcanic rocks and limestones and those, in turn, by Eocene volcano-sedimentary rocks. A thick series of volcanic rocks whose , age has been in question overlies all those mentioned above. The present paper describes this series in great detail, characterizes it chemically, and gives new evidence on its age. On the basis of new finds of fossils in these rocks, and because they are cut by lower Miocene intrusive bodies, it is concluded that the volcanics in question are Oligocene. -- E. Ingersoll.

Trifonov, V.G.

doi: 10.1080/00206816809474884pmid: N/A

The upper Paleozoic (predominantly Carboniferous) history of volcanic activity in the geosyncline is compiled from the lithology and sequence of the intrusives, the ancient topography (typically volcanic forms), and the attitude of the extrusive rock. The geosyncline was essentially a graben; therefore, extrusion occurred through a fissure channel complex along the southwestern and southern margins of the geosyncline. The lithologic sequence in the Upper Carboniferous was andesite-dacite-liparite. All three types are represented by tuffs, breccias, and lavas.

Dmitriyev, L.M.

doi: 10.1080/00206816809474885pmid: N/A

The tectonic setting of the “polymetal mineralization” of the northeast part of the Russian Platform and adjacent mobile zones is outlined in considerable detail; that is, the relation is given between the mineralization and such tectonic features as basins, folded zones, cross-folds, faults, and fracture zones. Relation to type of country rock is also discussed; the deposits are mostly in folded Paleozoic rocks. Ore bodies are more common in the carbonate rocks than in the associated clay and sand rocks. Favored locations are where the main fold axes are intersected by cross structures (cross-folds, faults, fractures). -- E. Ingerson.

Vlasov, G.M.; Petrachenko, Ye.D.

doi: 10.1080/00206816809474886pmid: N/A

More than 30 sulfur deposits of various sizes are now known in Kamchatka and the Kuril Islands. They are associated with volcanic rocks and the series extends into the Japanese Islands along the volcanic arc. Some ten years ago the Russian geologists concluded that the larger volcanic sulfur deposits are of metasomatic origin. A few years later Japanese geologists decided that some of their large sulfur deposits are probably also metasornatic. These deposits occur in the older (Miocene-Pliocene) arc of volcanoes. In the younger outer arc, sulfur occurs as crater-lacustrine deposits that are smaller near surface accumulations. The metasomatic deposits occur characteristically in agglomerates capped by impervious tuffs. This is taken as evidence for their origin, as is the fact that the sulfur cuts across agglomerate layering and the larger ones are thicker than any of the individual agglomerate layers. Also, the sulfur grades downward into S-pyrite accumulations, then Hg-As, Sb, Au-Ag, Pb-Zn, and Cu-Mo, in that order, which is characteristic of hydrothermal metasomatic deposits. Sulfur oxidizes rapidly at the surface, so that best deposits are those that have remained sealed. Some are as much as 200–300 m below the surface, so geophysical methods (mostly electrical and magnetic) are used to localize the large deposits before drilling. Porous zones in the agglomerate, silicified with quartz and opal, are good indicators of the proximity of sulfur. -- E. Ingerson.

Petersil'ye, I.A.; Andreyeva, Ye. D.; Sveshnikova, Ye.V.

doi: 10.1080/00206816809474887pmid: N/A

Parts of certain alkalic intrusive massifs contain up to 63 cc methane per kilogram of rock, with smaller amounts of heavier hydrocarbon gases, bitumen, hydrogen, carbon monoxide and carbon dioxide. The authors argue that the hydrocarbons cannot have come from assimilated limestone, because the igneous rocks contain much more of these gases than do the enclosing limestones. Likewise, the hydrocarbons cannot have been introduced by late solutions because they are much lower in hydrothermal and metasomatic fades than in primary minerals of the high temperature intrusive facies. Hydrocarbons are not stable at magmatic temperatures; the authors conclude that these must have formed in the presence of natural catalysts during slow cooling below 500°C, in accordance with industrial synthesis of hydrocarbons. The C12/C13 ratio of the bitumens is in the range for ordinary petroleum, suggesting that they formed at relatively low temperature, but the carbon of the gaseous hydrocarbons is lighter, which may indicate that they formed at somewhat higher temperatures. -- E. Ingerson.

Burenkov, E.K.; Kuzina, K.I.

doi: 10.1080/00206816809474888pmid: N/A

Two areas with different geologic and geographic conditions were selected as examples for geobotanical prospecting for boron. Field methods are described and it is pointed out that geobotanical studies, for effective results, should precede prospecting. Plants may be direct or indirect indicators. Direct ones are high in the element sought and, in general, their habitat is prospective. Indirect indicators are associated with rocks that are, in turn, associated with the element sought. Reliability and validity indexes are defined and applied to plant analyses for boron in the two areas studied. It is concluded that geobotanical prospecting is relatively inexpensive and that by means of reliable indicator plants it is possible to designate areas warranting further exploration. -- E. Ingerson.

Sirotin, K.M.

doi: 10.1080/00206816809474889pmid: N/A

Pegmatites of several areas are described. It is contended that their properties and relationships support Fersman's idea that pegmatites are magmatic rather than hydrothermal or metasomatic. The principal arguments are as follows: 1) contacts of the pegmatite material are sharp where it occurs in the original bides or in xenolithic fragments; 2) later K-Na metasomatism affects pegmatites and enclosing granite the same way; 3) a pegmatite body contains the same minerals, including, accessories, whether the country rock is granite, diabase or limestone; 4) graphic texture occurs in some of the dikes; 5) there is strong differentiation in thick dikes; less, in thin ones (branches); 6) method of incorporation of xenoliths in pegmatites suggests viscous melt, not aqueous solution; 7) Xenoliths in pegmatite are'only slightly altered, if at all. -- E. Ingerson.

Pinneker, Ye.V.; Lomonosov, I.S.

doi: 10.1080/00206816809474890pmid: N/A

The brines, found throughout the world, occupy the interior parts of intermontane basins at depths between 400 and 3000 m. They exhibit the entire range of concentration, through twophase salt water systems, and are found in rocks representing every interval of geologic time Brines with high calcium chloride concentrations are restricted to those cross-sections which include abundant sulfates.

Murzayev, P.M.

doi: 10.1080/00206816809474891pmid: N/A

Although not indicated by the title this article is a review of a monograph by Sokolova and Karavayko on “Physiology and Geochemical activity of Thio-bacteria” and a comparison of that study with the findings of other authors. The emphasis is on two species, - Thiobacillas thioparus and Thiobacillus thiooxiclans. Part one of the monograph deals with morphology, preparation of cultures, physiological experiments and systematics; Part two, with experimental techniques, geochemical activity of the bacteria in various environments, and microbiological production of sulfur. The two varieties of bacteria are treated in considerable detail as to their ecology and the types of sulfur-bearing compounds that each can transform most readily. -- E. Ingerson.