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Yavnel, A. A.; Dyakonova, M. I.
doi: 10.1080/00206816009473564pmid: N/A
At present, investigations on the chemical composition of meteoritic matter are being made in two directions: 1) the determination of the main constituents of meteorites of different classes. (A generalization of these data led to the classification of meteorites depending on their chemical composition); 2) the determination of all the element contents including small admixtures in meteoritic matter according to their phases: metallic, silicate, and also in accessory minerals. A review of all data on the composition of meteorites ensures the systematic study of their mineral content, structure and other properties and makes possible a closer approach to the solution of their origin. As a result of a critical review of existing general investigations and separate data concerning the contents of the basic constituents of meteorites, the composition of each subclass divided into families according to groups is given in the tables. Changes in the composition of_meteorites of each group while passing from one subclass to another are clearly seen in the tables, and this allows an opinion to be formed on the laminated planetary bodies from which the meteorites were formed. The contents of all the chemical elements found in meteoritic matter are given in tables. The results of recently published works have been taken into account, and old data have been reconsidered. -- from English supplement to Meteoritika. from English supplement to Meteoritika.
doi: 10.1080/00206816009473565pmid: N/A
A newly compiled geobotanical map of the U.S.S.R. scale 1:4,000,000 is described. Two hundred and ten categories of vegetation are mapped, classified under 15 major groups. The relation of the mapped vegetation units to climate, soil, ground condition (permafrost), watersheds, and major geomorphic features is emphasized. -- M. Russell.
doi: 10.1080/00206816009473566pmid: N/A
Feldspar group minerals reacting with water at depth determine, by their reaction with environment, the character of newly formed minerals. Although plagioclase is the most abundant member of this group experimental data are very limited on the nature of its reactions under high pressure and temperature conditions. The author experimented on acid plagioclase with analytical data and physical constants corresponding to those of oligoclase. The reaction between oligoclase and water was studied under various pressures and temperatures, using a diffusion autoclave (previously described by the author [1]). Silicon, sodium, and aluminum in significant amounts went into solution; and, smaller amounts of calcium and potassium were observed. With increased temperature, larger amounts of material constituting oligoclase went into solution: The maximum occurred at 350 to 400° C; and, a marked decrease, at 500 to 600° C. Quantitative ratios of material in the condensate were found to correspond to albite indices. Increased pressure does not alter this behavior, there is only increased passage of separate components of the mineral into solution. At 350°, newly formed material was not observed microscopically; at higher temperatures, kaolinite and chalcedony appeared at sucessively higher temperatures. Experimentation by Morey and Chen on albite indicate that transfer of the albite component of oligoclase into solution is predominant. By comparison of its stability with that of two other minerals, albite is the most reactive with water. At 350° Centigrade and under pressure of 350 kilograms per square centimeter, the transfer into solution (in milligrams per liter) is for albite, 318; for microcline, 268; and, for oligoclase, 220. Labradorite was studied under analogous conditions; in that the transfer of labradorite predominates over that of the anorthite molecule, its behavior corresponds to albite. It was found that basic plagioclase shows less stability than is evident from microscopic examination of plagioclase in rocks. Data from these and previous experiments indicate possible types of solutions that can form within intragranular spaces in rocks by reaction between acid plagioclase and water. It is evident from the data that leaching of the albite component predominates by variation in composition of the solution throughout a wide range of temperature and pressure conditions. --D. D.Fisher
doi: 10.1080/00206816009473567pmid: N/A
Investigations of widely distributed negative magnetic anomaties in the Maymecha-Kotuy region (72° N. Latitude, 102° E. Longitude), showed that remanent magnetization is present in the rocks; and, that they could be subdivided into magnetically stable and unstable categories. Studies were based on 1,600 oriented rock samples. Paleomagnetic data derived from mean directions of magnetization were used to calculate the North Polar coordinates for the time of formation for the various rocks; these data can be compared to mean values of North Polar coordinates determined for various periods. Mean values for the North Polar coordinates derived from remanent magnetization data on basic and ultrabasic rocks of the Maymecha-Kotuy region, correspond to those of Permian-Carboniferous time. No paleomagnetic age correlation was possible for magnetically unstable rocks. Results disagree with paleontological data, which indicates these rocks to have formed in late Permian to Early Triassic times; however, they are found to agree with data derived by the argon method. A correction of 20° mean value of dip in meymechites, was incorporated into the calculations with the result that the corresponding polar coordinates were 44° N. Latitude, 148° E. Longitude; and, in agreement with findings for all other rocks. Thus, meymechites probably were formed as a horizontal layer and, later, uplifted by younger intrusion of dunite-peridotite magma; and, that they are probably of effusive origin. It is believed that this method can be used eventually for more extensive determination of age correlation for various rocks and massifs. --D. D. Fisher.
doi: 10.1080/00206816009473568pmid: N/A
Practically all oil and gas accumulations throughout the world are associated with some extensive productive series which consist of highly permeable rocks containing oil and gas pools, interbedded with shales and marls containing dispersed organic matter. All of the important recent discoveries between the Volga and the Urals were based on the observed association of oil and gas pools with certain lithologic-stratigraphic complexes of the Devonian, Carboniferous, and part of the Permian; although accumulation is related to many diverse Structural zones. Here, the productive series is the source rock as well, for the pelites contain dispersed organic matter including bitumen whose composition is related to the oils. Where accumulations occur in sediments deposited under oxidizing conditions, factors are sought which favor migration from possible source rocks along faults, unconformities, or surfaces of facies change. For example, in Azerbaidjan and Turkmenistan large oil and gas accumulations in Pliocene continental beds occur along structural zones that allowed migration from underlying, principally Paleogene and Miocene, deposits. As shales compact, their organic constituents gradually change; the coaly part from a ligniferous to a carboniferous stage and, ultimately, to graphite. The mobile bituminous substances formed by dissociation of organic matter and disproportioning of hydrogen, change from asphaltines and resins to oils and then to methane in the subcapillary pores of pelites, where they are in a dispersed, loosely bound state. Compaction causes slow removal of the loosely bound water and molecular migration with differentiation of the bituminous substances. After differentiation, the more mobile hydrocarbons are carried by the water into reservoir rocks. The bituminous substances move from small to large pores also by capillary forces. Migration in subcapillary pores apparently ceases when rocks become lithified and are no longer plastic. In the super-capillary pores and fissures of reservoir rock, free migration takes place as both molecular migration and movement in larger masses. Water circulates in reservoir beds from elevated areas of the outcrop toward lower discharge areas. When the hydrocarbon-bearing water moves into different environments of temperature and pressure, the hydrocarbons may come out of solution, rise to the top of the carrier-beds, and unite into oil and gas pools if traps are available. The location of oil and gas reflects the present equilibrium of fluids with the structural pattern and hydrogeological environment. --D. C. Van Siclen.
doi: 10.1080/00206816009473569pmid: N/A
Industrial development of the Angara region has necessitated geological exploration for available resources. The Angara River flows north from Lake Baikal, intersecting the mountains surrounding it; passes through the 'Irkutsk Amphitheater, ' part of the central Siberian platform; and, near Bratsk, flows across a diabase intrusion, forming the Bratsk rapids (approximately 300 kilometers long). The Angara river basin is underlain by crystalline basement (the Siberian craton) composed of schists, gneisses, marble, and Archean and Proterozoic granites. These rocks dip sharply from the Sayan and Baikal ranges, where they outcrop, toward the Irkutsk Amphitheater, where they reach 3000 meters depth. The craton is covered by sediments ranging in age from Cambrian to Quaternary. Lower Cambrian rocks over 2500 meters thick are overlain by Middle Cambrian strata which are generally eroded. In the Irkutsk coal basin, north of Lake Baikal, Mesozoic rocks 600 meters thick are covered unconformably by Tertiary sediments. Quaternary deposits are known to occur; the Angara River terraces are probably pre-Quaternary. Regional tectonics involved fracturing within the Irkutsk Amphitheature and in the surrounding mountains. Geophysical survey and drilling revealed a wide horizontal protrusion (the 'Angara swell') in the Siberian craton; this protrusion divides the Irkutsk Amphitheater in the Pre-Baikal and Pre-Sayan depressions. Overlying Cambrian sediments are folded in conformity with these basement-complex dislocations. Jurassic deposits, generally horizontal, are disturbed only near the younger uplifts of Sayan and Baikal. The southwestern part of a large trap-rock intrusion crosses the Irkutsk Amphitheater; concordant intrusions, e. g. sills, entered lower Paleozoic sediments along with dikes, during late Permian and, principally, Triassic times. Mineral deposits are rich and varied: Precambrian rocks contain magnetic iron ore (of the Krivoy Rog type); talc; magnesite; pure crystalline limestone; and, possibly, phosphates. Paleozoic rocks contain large marine and lacustrine salt deposits, gypsum, phosphatized shell rock, and, possibly, oil: as well as carbonaceous rocks with lead and zinc minerals. Hydrogen-sulfide -saturated and saline mineral waters as well as subsurface water with high potassium content occur in Cambrian rocks. Siberian trap rocks are rich in magnesium and iron; magnesium-magnetite ores occur in volcanic necks as large veins of pure ore, associated with tuffs and aureoles. Trap rock (diabase) may be used in the new stone-melting industry. Jurassic deposits include saprolitic-bog and humus coals as well as extensive fire-clay and high-quality kaolin deposits. Cambrian fossils include trilobite and brachiopod remains, reefs, and molluscs; fish, insects, ostracods, and numerous fossil plant traces, are representative of the Mesozoic. The Angara River terraces, 25 to 30 meters thick, contain mammal remains, brackish-water molluscs, and, from the Middle Paleolithic, Azilian and Solutrean artifacts. -- D. D. Fisher
doi: 10.1080/00206816009473570pmid: N/A
In order to meet a planned increase in annual oil-production to 240 million tons and gas to 150 billion cubic meters, oil and gas exploration in the U. S. S. R. must be greatly expanded. The former Minister of the Oil Industry is criticized for neglecting this phase. Finds and Prospects in Central Asia, Kazakhstan, the northern Pre-Caucasus, Siberia, and the Far East are reviewed. M. Russell
doi: 10.1080/00206816009473571pmid: N/A
The coastline of the Chinese People's Republic, more than 12, 000 kilometers long, is becoming increasingly important as an industrial site and as a potential source of raw materials. The author participated in the organization of research on coastal dynamics and morphology in several areas. During investigation of silt deposition in the port of Hsin-kang a collection of data on movement of saturated turbid suspensions under natural conditions, has been obtained for the first time. Other areas under investigation include: Liaotung and Shantung peninsulas, Hang-chou Bay and the Yangtze river mouth, Lei-chou-wan Tao peninsula (Kwangtung province), and Hainan Island. A sea-coast studies laboratory was organized recently in the Oceanographic Institute at Tsingtao; research programs are developing at Peiping University, Shanghai Teacher's Institute, and at Sun Yat-sen University in Canton. Perhaps the most difficult problem encountered was lack of data from previous studies or from hydrological observations. Present studies indicate that the seacoasts composed of silt develop uniquely; evidently their stability is determined by changing equilibrium between deposition of silty material into the ocean from river mouth9 and the amount of material stirred up and removed from the coastal zone by wave action. A low gradient (1:2, 000) is characteristic of the great Chinese plain, the drainage belt, and the shoals. Mountainous coastal areas are of the ria type; fringed by an archipelago of small islands. Along embayed, or incurved, areas of the coastline, sandy material tends to accumulate; heavy-mineral accumulations are to be found in these areas. Additional joint Soviet-Chinese coastal-zone studies are proposed under sponsorship of the Chinese People's Republic Academy of Sciences; a planned study on latitudinal zonality in coastal processes will involve comparison of data for the Pacific Ocean coastline from the Bering Strait to the tropics. D. D. Fisher
doi: 10.1080/00206816009473572pmid: N/A
The status of geology in China is summarized. The number of geologists is now several thousand and many more are in training at newly established universities. A general statement of the structural and stratigraphic components of China relates the principal ore deposits to igneous and tectonic activity. Recent geologic studies of note by Chinese geologists include new geologic mapping, oil and coal investigations, discoveries in paleontology and paleobotany, regional and theoretical studies in tectonics, petrography, geophysics and geochemistry. New discoveries of iron and copper have been made, and increased production of coal, oil, mineral fertilizers, and construction materials accomplished. M. Russell
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