MINERALOGY OF COASTAL DEPOSITS OF NORTH-WESTERN SEA OF JAPAN

Distribution of heavy, light and clay minerals in Late Pleistocene—Holocene deposits from different coastal environments (beaches, lagoons, dunes, relict lakes, ria bays and inlets, open inlets) was analysed. It was established that mineralogical composition of coastal deposits was a result of provenance and its hypergenous changes, transformation of material within transit zone, and accumulative conditions of inshore zone. Contents of stable minerals increase in deposits of the inlets confined to mouths of the small streams and in horizons of the sections, formed during regressive phases. Unstable minerals amount is higher in deposits of inlets, confined to mouths of the large river. The clay mineral fraction of shelf sediments consists mostly of illite. Authigenous pyrites dominate in deposits of ria bays, lagoons and relict lakes, formed during transgressive phases. Volcanic glass, found in deposits, is product of Holocene eruptions of Baegdusan (Baitushen) Volcano.     

Demographic processes of urbanisation in Delhi

"Metropolitanisation has been observed by experts as one of the main characteristics of Indian urbanisation. Rural to urban migration has been a major player in urban growth of metropolitan cities, particularly Delhi. Not only Delhi but its hinterland [are] urbanising fast as compared to the hinterlands of other major cities of India. There are several processes of urbanization viz. historical, physical, demographic and economic. In this paper the role of demographic processes in urban expansion of Delhi [is examined]."     

Simultaneous multifrequency observations of Markarian 421

The highly variable BL Lacertae object Mrk 421 has been observed simultaneously in the radio, optical ultraviolet, and X-ray bands over a period of 4 days in early 1984 December and once again in early 1985 January. Using the EXOSAT observatory, we found that dramatic changes occurred in the X-ray flux on a time scale of less than a mouth. During this time the 2-10 keV flux dropped by a factor of 8, whereas the 0.1-1 keV flux decreased by a factor of only 2. These changes were not reproduced at longer wavelengths during the period of simultaneous observations. However, a drop in the ultraviolet flux occurred some months later, which is consistent with the longer characteristic loss times for the lower energy electrons. Since the ultraviolet through radio flux is stable when the X-ray flux is changing, it is extremely unlikely that a simple synchrotron model can account for the full spectrum; in this model the whole spectrum is expected to rise uniformly and in phase as a result of the injection of energetic particles. A simple synchroton self-Compton model that is self-absorbed in the radio also requires an X-ray flux which is many orders of magnitude greater than is observed. However, this discrepancy may be explained by relativistic beaming of electrons with delta > approximately 40 or by a model in which the self-absorption turnover occurs in the optical, and the synchrotron break occurs in the X-rays. Shorter time scale (approximately 10,000 s) variability was also apparent in the 2-10 keV X-ray light curves, and we suggest that it may be a direct measure of the injection time scale. Although reasonable fits resulted when the X-ray data were compared with a simple power-law model with some absorption, a substantial improvement in chi 2 was obtained by adding a high-energy exponential cutoff. Use of this model produced a spectral index close to that typically found in the optical for BL Lacertae objects, in contrast to the high values usually inferred from X-ray spectra.     

Radiogenic heating of comets by 26Al and implications for their time of formation

The effect of radiogenic heating on the thermal evolution of spherical icy bodies with radii 1 km < R < 100 km was investigated. The radioisotopes considered were 26Al, 40K, 232Th, 235U, and 238U. Except for the 26Al abundance, which was varied, the other initial abundances were kept fixed, at values derived from those of chondritic meteorites and corresponding to a gas-to-dust ratio of 1. The initial models were homogeneous and isothermal (To = 10 K) amorphous ice spheres, in a circular orbit at 10(4) AU from the Sun. The main object of this study was to examine the conditions under which the transition temperature from amorphous into cubic ice (Ta = 137 K) would be reached. It was shown that the influence of the short-lived radionuclide 26Al dominates the effect of other radioactive species for bodies of radii up to approximately 50 km. Consequently, if we require comets to retain their ice in amorphous form, as suggested by observations, an upper limit of approximately 4 x 10(-9) is obtained for the initial 26Al abundance in comets, a factor of 100 lower than that of the inclusions in the Allende meteorite. A lower limit for the formation time of comets may thus be derived. The possibility of a coexistence of molten cometary cores and extended amorphous ice mantles is ruled out. Larger icy spheres (R > 100 km) reached Ta even in the absence of 26Al, due to the decay of the other radionuclides. As a result, a crystalline core formed whose relative size depended on the composition assumed. Thus the outermost icy satellites in the solar system, which might have been formed of ice in the amorphous state, have probably undergone crystallization and may have exhibited eruptive activity when the gas trapped in the amorphous ice was released (e.g., Miranda).     

Proton production in relativistic heavy ion collisions; comparison with a thermodynamical model

Experimental results concerning proton production in nuclear collisions, obtained at Saturne with the Diogene 4 pi facility, are compared with the predictions of a thermodynamical model, using collective velocity distributions combined with a statistical thermodynamics in local rest frames. Experimental differential cross sections for alpha + nucleus and Neon + nucleus central collisions at incident energies between 200 and 800 MeV per nucleon are well reproduced by the model, for an angular range 30-110 degrees in the laboratory system. Extracted values of the temperatures are compared with those given by other authors.     

Geomorphological processes and landforms of glacier forelands in the upper Aktru River basin(Gornyi Altai), Russia: evidence for rapid recent retreat and paraglacial adjustment

The glaciers in the Aktru River basin of Gornyi Altai, Russia currently represent some of the fastest receding glaciers in the world. Formation of the morainic complexes closest to the contemporary glaciers in the Aktru River basin took place during the 17^th-18^th centuries with recession commencing at the end of the 18 th century. Coupled with this glacial retreat, earth surface processes and vegetation succession are responding to shape the glacier forelands. This article presents the first geomorphological maps for the upper reaches of the Aktru River basin and focuses on the geomorphological landforms that occur in the rapidly changing glacier forelands. Geomorphological mapping is difficult in steep mountainous regions and, thus, mapping was completed using satellite imagery, field mapping and observations coupled with highresolution aerial photography obtained from Unmanned Aerial Vehicles(UAVs). Critical steps of the procedure used to process UAV imagery and difficulties encountered in this mountainous terrain are noted. The acquired spatial data enable the mapping and classification of small-scale transient geomorphological features such as talus, glacial and glaciofluvial landforms. Their dynamics provide insights into supraglacial and subglacial processes of the glaciers of the Aktru River basin and subsequent paraglacial adjustment. The presented highresolution spatial data, which can also be obtained at high temporal resolutions in the future, can act as a reference frame for geomorphologists and ecologists studying the temporal evolution of glacier forelands of the Aktru River basin during paraglacial adjustment and subsequent colonisation and stabilisation by biota.     

Model Forming of Mesoarchean Gridino Mafic Dyke Swarm during Subduction "Mid-Ocean Ridge – Continent"

正The high-pressure metamorphosed Gridino dyke swarm comprises a major group of Mesoarchean 2.87-2.82 Ga mafic dykes intruded within the Mesoarchean continental crust of the Kola craton(the Belomorian tectonic province     

油藏地层损害中的温敏现象

在将油气开采的实验室测量转换成油藏条件下的结果时，温度是一个很重要的但常被忽略的变量。本文给出了油藏地层损害随温度的变化关系，介绍了获取确定油藏潜在地层损害的各模型参数对温度的敏感性的方法。     

Tourmaline Composition of the K??lada? Au Deposit, U?ak, Turkey

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