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Consideration is given to the nature of mafic–ultramafic bodies in the southeastern part of the Aldan-Stanovoi Shield using the Kun-Manie ore field as an example. These bodies played an important role in the formation of the Kun-Manie sulfide copper–nickel deposit as conduits of sulfide-bearing magmas. A detailed mineralogical and geochemical study with interval sampling was carried out on core samples from the drilling of two intrusive bodies, Treugolnik and Iken, using drill holes 21 and 25. The drill–core data present evidence for their origin from a single parent magma. The Treugolnik and Iken minor intrusions were emplaced in magmatic chambers at different depths during the cotectic crystallization of dark minerals from the primary picrite (Treugolnik body) and intermediate picrobasalt (Iken body) magmas. A comparative study of petrogeochemical and mineralogical data suggests that the Treugolnik intrusion formed as a closed system with magma emplaced in a single, relatively rapid injection and crystallized without losses; the Iken sill formed as an open system as a result of magma emplacement in several pulses with time intervals between injections. These magma bodies, together with the host metamorphic rocks, were involved in tectonic deformations after they crystallized.

The article discusses the problem of large-scale contamination of the Shufan volcanic plateaus basalts (Primorye) by selective melts from xenoliths. Silicic and alkaline liquids, selectively extracted from xenoliths, mix in a limited way with basaltic melts forming bands of granophyre that give lavas a taxitic structure. The article describes the unique compositions of buchites that were chemically modified by the diffusion interaction with basaltic magma and selectively molten politic xenoliths. Their mineral associations are represented by a high ferriferous cordierite (sekaninaite), ultra-ferriferous hercynite, (Al, Zr) Fe-armalcolite, Zr-ilmenite, mullite, sillimanite, high-lanthanum monazite, and barium-phosphate-aluminosilicate phase. The chemical and mineral compositions of buchites reflect the accumulation of refractory elements (Al, Fe, Ti, Zr, Ni, Cr) in the restite material of xenoliths. It is followed by the formation of ultra-alumina, ultra-ferruginous, initially immiscible metal-silicate composition. Low Pb isotopic ratios in Shufan basalts suggest a selective contamination by an ancient cratonic basements material. A consecutive increase of the isotopic ratios is observed the basalts contaminated by the upper crustal material, which is also shown by buchites isotopic composition.

The problems of large-scale contamination of the Shufan volcanic plateau (Primorye) basalts with selective melts from xenoliths are discussed. Silico-alkaline liquids that are selectively extracted from xenoliths mix only to a limited extent with the basalt melt, and form granophyre bands that give lavas a taxitic texture. The unique compositions of buchites (pelitic xenoliths chemically modified with a diffusion interaction with basaltic magma and selectively molten politic xenoliths) are characterized. The mineral associations of buchites are represented by highly ferriferous cordierite (sekaninaite), ultra-ferriferous hercynite, (Al, Zr) Fe-armalcolite, Zr-ilmenite, mullite, sillimanite, high-lanthanum monazite, and a barium–phosphate–aluminosilicate phase. The features of the chemical and mineral composition of buchites reflect the accumulation of refractory elements (Al, Fe, Ti, Zr, Ni, and Cr) in the restitic material of xenoliths, followed by the formation of ultra-aluminous, ultra-ferriferous, and initially immiscible metal-silicate composition. Low Pb isotopic ratios in the Shufan basalts indicate selective contamination with material of the ancient cratonic basement. A steady increase in these values is observed for basalts contaminated with the upper crustal material, which also reflects the isotopic composition of buchites.

Composition and typomorphic features have been studied for rare earths-bearing minerals from the central part of the Malmyzhskoe gold-copper-porphyry deposit. This deposit is located in the Russian Far East, approximately 220 km northeast from Khabarovsk city. The deposit porphyry clusters occur as diorite and granodiorite stocks of Cretaceous age intruding the hornfels-altered siltstone and sandstone sedimentary sequences. The rare earth mineralization in ores and altered host rocks is represented by anhydrous phosphates (monazite, xenotime, REE -bearing apatite), silicates (allanite, huttonite), fluorocarbonates (synchysite) and oxides (davidite). These minerals occur there as individuals, but also they shows reactionary relations between them and ore minerals in altered rocks. It means that rare earth minerals in the central part of the Malmyzhskoe deposit participated actively in metasomatic processes, and likely they have a hydrothermal origin.

The mineral and chemical compositions of the layered subvolcanic ultrabasic rocks formed through fluid–silicate (liquid) separation of the ultrabasic magma into high-potassium and low-potassium fractions are characterized by the example of the layered picritic sill from the Late Cretaceous ultrabasic volcanic complex of Eastern Kamchatka. It is determined that the main potassium concentrator in the picrites from the high-potassium layers is a residual volcanic glass containing up to 8–9 wt % K2O, which is unique for ultrabasic melts.

В статье приведены новые данные об акцессорных минералах в пеплах, образовавшихся при фреатическом извержении вулкана Корякский в 2008—2009 гг. Охарактеризованы формы выделения, состав и свойства гранатов, корунда и дельталюмита, муассанита, сульфидов таллия, самородных металлических и углеродных фаз, включая алмаз, а также предположительно абиогенных конденсированных органических соединений. Особенностью корякских алмазов является очень мелкий размер и кубический габитус, что может свидетельствовать об их кристаллизации из газовой фазы в условиях значительных пересыщений по углероду. Обнаружения в пеплах на Корякском вулкане разнообразных по форме и цвету частиц и нитей конденсированных органических соединений подтверждает ранее сделанный вывод о систематическом неорганическом синтезе на современных вулканах достаточно высокоорганизованных предбиологических форм органического вещества.

The Kirganik copper–porphyry deposit is situated in the central part of the Sredinnyi Mountain Range of Kamchatka and is confined to fields of development of potassic orthoclase metasomatite and hypabyssal intrusions of shonkinite. Platinum group metals (PGMs), such as merenskyite, kotulskite, keithconnite, and temagamite, were discovered in the chalcopyrite–bornite and chalcopyrite–bornite–chalcosine ore of the deposit for the first time.

The characteristics of formation of the opal mineralization in the host rock within Mutnovskaya volcanic zone were studied. The type of metasomatic rock alteration and its consecutive order were established. The results of study allowed identifying the mineral inclusions in opals, which was linked to the metalliferousness of the Mutnovsky hydrothermal system. Probable mechanism of opals formation within the North Mutnovskaya zone is considered, and its characteristics are compared to those from the opal field Raduzhnoye, Primorye.

Quantitative X-ray fluorescence determination of major rock-forming oxides (Na 2 O, MgO, Al 2 O 3 , SiO 2 , P 2 O 5 , K 2 O, CaO, TiO 2 , MnO and Fe 2 O 3 ) and some microelements (Sr and Zr) was performed in the samples of 143 cm-long sediment core of Lake Baunt (Buryat Republic) by the wavelength-dispersive X-ray fluorescence analysis on the S8 Tiger spectrometer. Calibration curves were obtained by measuring the certified reference materials of the sedimentary rocks. Both analyzed and reference samples were prepared as glass beads by fusion of 110 mg of sample with1.1 g of lithium metaborate. We have used 110 mg mass to ensure the formation of beads with appropriate 10 to 12 mm size across to be measured by the spectrometer with8 mm mask. Rh Kα Compton line was used as a background standard for Sr and Zr determination. The repeatability did not exceed the allowable standard deviation for a wide range of concentrations. Results of major rock-forming oxides determination were compared with the data of spectrophotometry and flame photometry techniques, results of Sr and Zr determination were compared with the data of synchrotron radiation excited X-ray fluorescence technique. All results of the X-ray fluorescence analysis were accepted as satisfactory. Quantitative analysis of each centimeter of Lake Baunt sediment core allowed building first reconstructions of the local environment during the last 7000 years with unique resolution of about 100 years. Keywords: wavelength-dispersive X-ray fluorescence analysis, synchrotron radiation induced X-ray fluorescence analysis, sediments, paleoclimate (Russian) DOI: http://dx.doi.org/10.15826/analitika.2017.21.1.003 A.A. Amosova, V.M. Chubarov,E.V. Kaneva, Iu.N. Markova Vinogradov Institute of Geochemistry, Siberian Branch of Russian Academy of Sciences, ul. Favorsky , 1A, Irkutsk , 664033, Russian Federation

For the first time, the particles of organic polymers have been found in the products of modern volcanism in Kamchatka. They are probably of abiotic origin, which makes it possible to interpret the results of studies from the perspective of volcanic-atmospheric-oceanic hypothesis about the origin of life on the Earth by A. I. Oparin–J. Haldane.

The problem of the geochemical classification of granitoid magmatism in the zone of interaction of oceanic and continental plates is considered in this paper by the example of Mesozoic granitoids of the Krutogorova and Kol’ intrusive complexes of the Sredinny Range, Kamchatka. Based on new geological, petrological, and geochemical data (including the Sr, Nd, and Pb isotope systematics of rocks), it was shown that the protoliths of the granitoids were volcanic-terrigenous sequences accumulated within a Cretaceous marginal basin in the eastern Asian continent. The granitoids crystallized at ∼80 Ma (SHRIMP U-Pb age) under the conditions of the andalusite-sillimanite depth facies corresponding to a pressure of approximately 2 kbar and induced contact metamorphism in the host sequences, which are made up of sediments with sheetlike bodies of mafic and ultramafic volcanics (Kikhchik Group and its metamorphic analogues of the Kolpakova, Kamchatka, and Malki groups). The lower age boundary of sedimentation of the host sequences and the time of basic volcanism coincide with the beginning of the formation of the Okhotsk-Chukotka volcanic belt. Such a correlation is not accidental and reflects a genetic connection between the processes of magmatic activation in the continental-margin sedimentary basin and the formation of the continental margin volcanic belt in eastern Asia. The development of basic volcanism in the sedimentary basin accompanied by the ascent of deep fluids resulted in the entrainment of crustal materials into magmatic processes and the formation of crustal magma chambers, the activity of which was manifested by the eruption of intermediate and silicic lavas and emplacement of shallow granitoid intrusions of considerable areal extent. These intrusions induced contact metamorphism in the enclosing volcanosedimentary complexes. The subsequent Eocene (60-50 Ma) collision processes related to the obduction of the oceanic segment of the crust of the transitional zone onto the Asian continental margin resulted in the tectonic piling of the rocks of Central Kamchatka and strong crustal thickening, which was favorable for its metamorphic alteration reaching the kyanite-sillimanite depth level of the amphibolite facies under the influence of a thermal front and deep fluids affecting lower crustal zones. The Eocene regional metamorphism caused not only metamorphic transformations, migmatization, and granitization in the sequences of the Sredinny Range, which underwent only contact hornfels formation during the first stage, but also metamorphism, migmatization, and extensive foliation in the igneous rocks of the Kol’ and Krutogorova complexes, which were transformed into gneissic metagranites.

Metabasites (amphibolites, garnet amphibolites, and basic crystalline schists) compose numerous sheeted bodies (often highly boudined) from a few to 100 meters thick in the plagiogneisses and migmatites of the Kolpakov Group. Chemically, they are reconstructed as basalts and picrites that were metamorphosed, as host terrigenous rocks, under the kyanite-sillimanite subfacies of the amphibolite facies (t = 620–650°C, P s = 5.9–6.9 kbar). Metabasites are dominated by amphibolites and basic crystalline schists distributed throughout the entire section of the Kolpakov Group, whereas garnet amphibolites are more typical of the upper parts of the group, where they are intercalated with amphibolites, basic crystalline schists, plagiogneisses, and quartzites. Metaultrabasites (plagioclase-free amphibolites) occur much more rarely as small boudins up to few meters in size. According to U-Pb SHRIMP zircon dating, the plagiogneiss protolith age corresponds to the end of the Early-Late Cretaceous (90–100 Ma), which is similar in age to the weakly metamorphosed terrigenous deposits of the Kikhchik Group of the Sredinny Range. This allows us to consider the terrigenous rocks of these groups as isofacial sedimentary rocks. The same age (Early-Late Cretaceous boundary) was taken for protoliths of metabasites forming interbeds among metaterrigenous deposits of the Kolpakov Group. The interval of 100−90 Ma coincides with the beginning of the formation of the Okhotsk-Chukotka volcanogenic marginal-continental belt in East Asia. It is shown that the Kolpakov Group possesses the geochemical features of tholeiitic basalts of different geodynamic settings and comprises both typically island arc (low-Ti) and oceanic (moderate to high-Ti) tholeiites associated with ultrabasic volcanic rocks—picrites. Such a chemical peculiarity of basic rocks is typical of the marginal-continental extension zones (pull-apart basin) that were initiated on the sialic crust. It is obvious that similar geodynamic setting of the basite magmatism existed for the Sredinny Range of Kamchatka. The ascent of the mantle matter beneath the extension zone of the continental crust of the sedimentary basin and its intersection by faults that formed simultaneously with the Okhotsk-Chukotka volcanogenic belt served as the beginning of the basite volcanism in the sedimentary basin. They provided an intense fluid effect and a temperature increase in the crust with subsequent granitization and metamorphism of volcanogenic-terrigenous deposits and, finally, the development of the modern structure of the Sredinny Kamchatka Massif. The intense Late Cretaceous basite volcanism and associated granitoid magmatism in Kamchatka were presumably caused by the ascent of mantle plumes bearing hydrogen fluids.

The metavolcanic rocks of the Kvakhona Formation exposed on the western slopes of the Sredinnyi Range metamorphic massif are represented by two sequences. The lower sequence occupying the most part of the exposed formation is dominated by porphyric and aphyric clinopyroxene-plagioclase metabasalts and their tuffs with subordinate metapicritic basalts, metaandesites and their tuffs, and metadacites. The latter form isolated bodies in the northern part of the Kvakhona exposures. The upper sequence is composed of metaandesites, metabasalts, and their tuffs intercalated with terrigenous rocks (siltstones, sandstones, and carbonate graywacke) and metadacite bodies. The rocks were subjected to intense metamorphism under the greenschist facies conditions (t = 250–420°C, P s around 1 kbar) with the replacement of clinopyroxene phenocrysts (or their clasts in the tuff varieties) by actinolite, chlorite, and epidote, while plagioclase phenocrysts are replaced by albite, muscovite, chlorite, and epidote. In the metabasalts enriched in ore minerals, clinopyroxene is replaced by very thin veinlets and the finest grains (about 20–30 μm) of Ca-Na and Na amphiboles (winchite, ferrowinchite, glaucophane, and ferroglaucophane). The groundmass of the rocks (or tuff cement) consists of variable combinations of titanite, magnetite, chlorite, epidote, silpnomelane, and albite. The metabasalts of the formation belong to the high-Fe and often high-Ti rocks, which makes them similar to the tholeiitic basalts of mid-ocean ridges or rifting zones. The metaandesites and metadacites also preserved an elevated Fe content and belong to calc-alkaline series rocks typical of island arcs and active continental margins. It is suggested that the primary rocks of the Kvakhona Formation were formed within volcanic centers on the floor of a vast Cretaceous epicontinental marginal basin, which accumulated thick sequences of terrigenous rocks. The detrital material for these rocks was supplied from the northeastern Asian continent. The geological and geochemical data testify to the similarity of the Kvakhona metavolcanic rocks and the greenstone altered volcanic rocks of the Pensantain Range of Western Kamchatka, which are dated by the U-Pb SHRIMP method at 90–100 Ma. The protolith of the metavolcanic rocks of the Kvakhona Formation was presumably formed within the same age interval.

The Dukuk intrusive massif is considered as petrotype of the Ni-bearing gabbro-norite-cortlandite complex of Kamchatka. This paper advances a new concept of the structure of the Dukuk Massif and relations between its gabbroid and ultrabasic rocks. The study of the trace element distribution sheds light on the origin of the parental melt of the norite-cortlandite complex and on the prospects for the discovery of economic sulfide mineralization in it. New U-Pb data on the Dukuk intrusion specified the age of this massif and the entire complex.

Chances for estimating the FeO/Fe2O 3 tot ratio in rocks by the K and L series of X-ray fluorescence spectra are studied. The errors in the determination of FeO/Fe2O 3 tot by the intensity ratio of the Kβ2,5/Kβ1,3 and Lβ/Lα1,2 lines are compared. The relative standard deviation of determining FeO using a set of 49 standard samples of eruptive rocks varies in the range 5–16%, depending on the ratio FeO/Fe2O 3 tot and the concentration of FeO. The better precision is attainable for a ratio above 0.45 at a FeO concentration in the range 5–15%. For samples of andesites and basalts, the relative standard deviation is better than 4%, for rocks of the granite family it is 23% at FeO concentrations below 3%. For samples of metamorphic and sedimentary rocks, the error of FeO determination is higher than that for the eruptive ones. For samples with the ratio FeO/Fe/Fe2O 3 tot < 0.25, the deviation may exceed 30 rel %. In contrast to chemical analysis, the X-ray fluorescence method appears advantageous in time and cost of sample preparation and can be used for routine analysis in geochemical research.

This study was performed to search for the possibility of assessing the FeO/Fe2O3tot ratio in rocks using K- and L-series of the X-ray fluorescence (XRF) spectrum. The uncertainty in the determination of the FeO/Fe2O3tot ratio was compared from the obtained ratios of Kβ2, 5-/Kβ1, 3- and Lβ-/Lα1, 2-line intensities. The measurements were implemented by a conventional XRF spectrometer, S4 Pioneer. The assessment of the uncertainty in FeO/Fe2O3tot determination in mineral powder fractions proved that the Kβ2, 5/Kβ1, 3 ratio of lines could be selected as the analytical signal. A relative standard deviation of FeO content in the collection of 48 reference materials of igneous rocks varies within the range of 5–16%, depending on the range of the FeO/Fe2O3tot ratio and the FeO content. The best accuracy was attained for FeO/Fe2O3tot >0.45 with FeO contents varying within 5–15%. In the andesite and basalt samples, the relative standard deviation was 0.25, the XRF determination of FeO content can be performed at an accuracy comparable with that of wet chemical analysis. The XRF method is preferred because it is fast and convenient for sample preparation. It could be used as an analytical technique in routine geochemical investigations. Copyright © 2009 John Wiley & Sons, Ltd.

It is shown that formation of high-temperature granulite-like rocks in the contact aureole of the Yurchik gabbronorite intrusion of the Ganal Ridge in East Kamchatka was caused by contact metamorphism, metasomatism, and local melting of the primary sedimentary-volcanogenic rocks of the Vakhtalkinskaya Sequence of the Ganal Group. The temperature in the inner part of the aureole reached 700–800°C and caused transformation of basic rocks into two-pyroxene-plagioclase, clinopyroxene-amphibole-plagioclase, and amphibole-plagioclase rocks, while sedimentary rocks were replaced by garnet-biotite and garnet-cordierite-biotite hornfelses. Locally, basic volcanic hornfelses were subjected to metasomatic alteration with the formation of bodies of biotite-orthopyroxene-plagioclase metasomatites. In the zones of the most intense fluid filtration, the metasomatites experienced local magmatic replacement resulting in the formation of biotite-orthopyroxene-plagioclase ± garnet migmatite veinlets and patches. Bodies of garnet enderbites were formed after sedimentary interlayers at temperatures of 700–800°C and a lithostatic pressure of 3.2–4.8 kbar. The comparison of the chemical composition of the Vakhtalkinskaya basic volcanics and the products of their transformation indicates that, in terms of chemistry, the metasomatic alterations and magmatic replacement correspond to siliceous-alkaline metasomatism (granitization) causing a subsequent and uneven influx of Si, Al, Na, K, Rb, Ba, Zr, Nb, and Cl and removal of Fe, Mg, Mn, Ca, and some trace elements (Cr, Co, Ti, Y, and S). The processes of metamorphism and metasomatism were presumably provoked by highly mineralized mantle fluids that were filtered through magmatic channels that served as pathways for gabbroid magma.

Geological-petrological data were first obtained on the Early Miocene basaltoids and spinel-fassaite carbonatite tuffs of the Ambinsky volcanic structure in southwestern Primorye. The geological study of Ambinsky volcano allowed the reconstruction of stratigraphic sections across lava and pyroclastic basaltic rocks and stratified carbonatite tuffs. The chemical compositions of rocks and mineral phenocrysts from basalts and carbonatite tuffs are reported. The basaltoids are classed with undifferentiated moderately alkaline within-plate basalts. Evidence of carbonate-silicate immiscibility was found in the basaltoids and carbonatite tuffs. It was suggested that the formation of the carbonatite melt associated with simultaneous basification and abundant crystallization of spinel, fassaite, as well as oversaturation of the silicate system in Ca was caused by limestone assimilation, subsequent transformation of the melt, and liquid immiscibility. Thermal decomposition of carbonates with dissolution of released CaO in magma and accumulation of CO2 in a closed magmatic chamber gave rise to the autoclave gas effect and, correspondingly, heavy explosive eruptions atypical of such volcanic rocks. The genesis of carbonatite tuffs of Ambinsky volcano can serve as a model example of exsolution of carbonate melt in the moderately alkaline nonagpaitic basaltic system.

This paper reports specific mineralogical and geochemical characteristics of deposits from the local depressions of the Derugin Basin. They were formed in an environment with periodic changes from oxic to anoxic conditions and show evidence for the presence of hydrogen sulfide in bottom waters. The deposits of this type can be considered as a modern model for ancient ore-bearing black shale associations. Compared with typical metalliferous black shale sequences, which are characterized by high contents of organic matter, the sediments described here are depleted in the elements of the organophilic association (Mo, Ni, Cu, Zn, V, and U) but have higher Mn contents.

The geology and mineralogy of host metamorphic rocks, the mineralogy of sulfide ores, and the distribution of PGE mineralization were studied in detail for the Kvinum-1 and Kvinum-2 copper-nickel occurrences of the Kvinum ore field, which are the most promising targets for the copper-nickel-PGE mineralization of the Sredinny Range of Kamchatka. It was established that stringer-disseminated and massive copper-nickel ores are localized in amphibole peridotites, cortlandites, and form ore bodies varying from tens of centimeters to 5–20 m thick among the layered cortlandite-gabbroid massifs. The massive sulfide ores were found only at the bottom of cortlandite bodies and upsection grade into stringer-disseminated and disseminated ores. Pyrrhotite, chalcopyrite, and pentlandite are the major ore minerals with a sharply subordinate amount of pyrite, sphalerite, galena, arsenopyrite, and lollingite. Besides pentlandite, the Ni-bearing minerals include sulforasenides (gersdorffite), arsenides (nickeline), and tellurides (melonite) of nickel. It was found that PGE mineralization represented by antimonides (sudburyite) and tellurobismuthides (michenerite) of Pd with sharply subordinate platinum arsenide (sperrylite) is confined to the apical parts of massive sulfide zones and the transition zone to the stringer-disseminated ores. Ore intervals enriched in arsenides and tellurides of Ni, Pd, and Bi contain high-purity gold. In the central parts of the orebodies, the contents of PGE and native gold are insignificant. It is suggested that the contents of major sulfide minerals and the productivity of PGE mineralization in the cortlandites are defined by combined differentiation and sulfurization of ultramafic derivatives under the effect of fluids, which are accumulated at the crystallization front and cause layering of parental magmas with different sulfur contents. The fluid-assisted layering of mafic-ultramafic massifs resulted in the contrasting distribution of PGM in response to uneven distribution of sulfur (as well as As, Te, and Bi) during liquid immiscibility. The productivity of PGE mineralization significantly increases with increasing contents of S, As, Te, and Bi (elements to which Pt and, especially, Pd have high affinity) in fluids.

Under existing conditions at depths on the order of hundreds of meters, gravitational force is comparable with the strength of rocks, and with an increase in depth it becomes controlling. In this paper, a two-layer model is considered in which the upper layer is almost dry sand, a material where gravitational force is controlling. A study is done of mechanisms for deformation and breakdown of the upper layer of a two-layer model in which gravitational force is controlling with uniform tension or compression for the lower layer. A diagram of the experimental device is shown. Both uniaxial and biaxial deformation were studied. Diagrams show the formation of different fissure families, and the dependence of average distance between neighboring fault planes on sand layer thickness is presented.

Some varieties of magnetite with relatively high content of SiO2 (about 5,4%) were found by the authors. Silica-bearing magnetite of the Korshunovskoye scarn deposit is enriched in Ca (up to 1.99% CaO), Al, Mg, Ti. In serpentinites of the Atlantic and Indian oceans Si-magnetite forms pseudomorphs on Cr-spinel and includes impurities of Mn (to 3.5% MnO), Cr, Mg and Al. Distinct quantitative correlations of silica and other trace elements are observed. The authors suggest possible models of cation distribution in Si-magnetites and suppose that emplacement of silica into the magnetite crystal structure is due to the presence of chlorine in mineral-forming solutions.

1. The method of producing Al-B composite materials must ensure little or no formation of AlB2 at the matrix-filament interface. 2. Use of a matrix of heat treated aluminum alloy and increasing the diameter of the boron filament makes it possible to double or triple the transverse strength of unidirectionally reinforced composites. 3. The increase of the transverse strength due to crisscross reinforcement leads to reduction of the strength in the principal direction of the filament.

The problem of similarity of explosions is related inseparably with the mechanism of energy expenditure during their development. By mechanism here, is understood the investigation of those courses of energy expenditure which are decisive. Three such courses can be shown for cratering (dumping) explosions, depending on the role of which the law of similarity will be changed. The energy in the case of cratering explosions is expended on fracturing the massif or deforming it. This course of energy expenditure is determined by the volume of the medium, within the limits of which its destruction or deformation takes place. The energy expenditure in this case should be proportional to the volume of rock shattered, i.e., E~V. For the explosion of a charge with weight Q, for which this course of energy expenditure takes away a certain part q~, the relation

1. In the manufacture of VKA-1 composite material the diffusion welding of the semifinished product is accompanied by the formation at the fiber/matrix interfaces of the AlB2 phase in the form of spherical inclusions at sites of Al2O3 film disintegration on the matrix foils. 2. To each diffusion welding temperature there corresponds a certain period of time during which no AlB2 phase is formed at the fiber/matrix interfaces. 3. A method of assessing the defectiveness of the surfaces of reinforcing fibers is described, which can be effectively employed for studying the reaction in the CM, particularly its early stages.

The results are presented of an experimental study, based on thermal, x-ray structural, metallographic, and x-ray spectral investigations, of the system nickel-boron. A new compound, NiB12, was found, and high melting points were determined for the compounds Ni4B3 (o), Ni4B3(m), and NiB. A new phase diagram has been constructed for the system nickelboron.

1. The fatigue strength of composite AD33-V, with a volume content of boron fibers of 50%, is directly proportional to the ultimate strength. The dependence of the endurance of the material on ultimate strength is expressed by a power law. 2. The relations and parameter values presented here can be used in strength calculations for structures and to determine the endurance of other composites with different characteristics and strength parameters after minimal empirical checking. 3. With large values of the exponents in (5), the expressions in the parentheses should be calculated with a high degree of accuracy in order to obtain reliable values of endurance.