Type Ia supernovae: Non-standard candles of the universe

We analyze the influence of the evolution of light absorption by gray dust in the host galaxies of type Ia supernovae (SN Ia) and the evolution of the mean combined mass of close-binary carbon-oxygen white dwarfs merging due to gravitational waves (SN Ia precursors) on the interpretation of Hubble diagrams for SN Ia. A significant increase in the mean SN Ia energy due to the higher combined masses of merging dwarfs should be observable at redshifts z > 2. The observed relation between the distance moduli and redshifts of SN Ia can be interpreted not only as evidence for accelerated expansion of the Universe, but also as indicating time variations of the gray-dust absorption of light from these supernovae in various types of host galaxies, observational selection effects, and the decreasing mean combined masses of merging degenerate dwarfs.     

Radiation of a neutrino mechanism for type II supernovae

We propose a new mechanism for type II supernova explosions. An important element of the model is large-scale convection that arises due to non-equilibrium neutronization of the matter in the central region of the proto-neutron star. Our analytical estimates and numerical simulations of the convection rate are in good mutual agreement. Large-scale convection leads to the rapid transport of neutrinos from the center of the star to the bounce shock formed during the pause in the collapse of the stellar matter in the proto-neutron star. The mean neutrino energy is 30–50 MeV. We analyze the dependence of the mean neutrino energy on the size of the convection cells—“bubbles.” Our computations of the interaction between the neutrinos and the shock show that the velocity of the shock along the rotational axis of the star exceeds the escape velocity. Thus, explosion of the envelope and a supernova with a very asymmetrical envelope structure become possible, leading to the formation of a neutron star.     

Merging of components in close binaries: Type Ia supernovae,massive white dwarfs,and Ap stars

The “Scenario Machine” (a computer code designed for studies of the evolution of close binaries) was used to carry out a population synthesis for a wide range of merging astrophysical objects: main-sequence stars with main-sequence stars; white dwarfs with white dwarfs, neutron stars, and black holes; neutron stars with neutron stars and black holes; and black holes with black holes. We calculate the rates of such events, and plot the mass distributions for merging white dwarfs and main-sequence stars. It is shown that Type Ia supernovae can be used as standard candles only after approximately one billion years of evolution of galaxies. In the course of this evolution, the average energy of Type Ia supernovae should decrease by roughly 10%; the maximum and minimum energies of Type Ia supernovae may differ by no less than by a factor of 1.5. This circumstance must be taken into account at estimating the parameters of the Universe expansion acceleration. According to theoretical estimates, the most massive—as a rule, magnetic—white dwarfs probably originate from mergers of white dwarfs of lower mass. At least some magnetic Ap and Bp stars may form in mergers of low-mass main-sequence stars (M ? 1.5 M _⊙) with convective envelopes.     

Thermal radio emission and absorption in HII regions in the vicinity of remnants of type II supernovae

Data on thermal radio emission and absorption in and near the directions towards supernova remnants are used to estimate the distribution of ionized gas surrounding remnants of type II supernovae. The amount of absorption and emission toward the supernova remnants are determined by two types of HII regions. The first are extended HII regions around the supernova remnants (Strömgren spheres), while the second are more compact and bright HII regions surrounding early-type stars. In the early stages of evolution of the supernova remnants (1000–3000 yrs), the amount of thermal absorption and emission is minimum, apparently indicating that only the supernova Strömgren zones contribute in these stages, while there is an absence of absorption or emission from the compact HII regions. Possible mechanisms for this scenario are discussed.     

Boundary conditions for simulations of the thermal outburst of a type Ia supernova

We present a technique to calculate the boundary conditions for simulations of the development of large-scale convective instability in the cores of rotating white-dwarf progenitors of type Ia supernovae. The hydrodynamical equations describing this situation are analyzed. We also study the impact of the boundary conditions on the development of the thermal outburst.     

Systematics of the spinel structure type

Systematic trends in the geometry of 149 oxide and 80 sulfide binary and ternary spinels have been examined from the standpoint of ionic radius and electronegativity. The mean ionic radii of the octahedral and tetrahedral cations, taken together, account for 96.9 and 90.5% of the variation in the unit cell parameter, a, of the oxides and sulfides, respectively, with the octahedral cation exerting by far the dominant influence in sulfides. The mean electronegativity of the octahedral cation exerts an additional, but small, influence on the cell edge of the sulfides. The equation a=(8/3√d)d _tet+(8/3)d _oct, where d _tet and d _oct are the tetrahedral and octahedral bond lengths obained from the sum of the ionic radii, accounts for 96.7 and 83.2% of the variation in a in the oxides and sulfides, respectively, again testifying to the applicability of the hard-sphere ionic model in the case of the spinel structure. Comparison of observed and calculated u values for 94 spinels indicates that up to 40% of the experimentally measured anion coordinates may be significantly in error. In addition to these compounds, u values are given for 52 spinels for which no data have previously been determined. Diagrams are presented for the rapid interpretation of the internal consistency of published data and the prediction of the structural parameters of hypothetical or partially studied spinels.     

Observations of five supernovae in 1995–1997

We present the results of photometric observations of the type Ia supernovae SN 1995al, 1996bo, 1996bk, the type Ib/c supernova SN 1997X, and the type II supernova SN 1996an. The photometric characteristics of SN 1995al are close to the average for type Ia supernovae. Our analysis has revealed possible peculiarities in the light-curve shape and deviations from the average photometric parameters for SN 1996bk and 1996bo. Sn 1996an probably belongs to type IIP. The light curve of SN 1997X resembles that of the type Ic supernova SN 1994I. Light-curve parameters and absolute magnitude estimates are presented.     

Dynamics of bubbles in supernovae and turbulent vortices

We consider the motion of a bubble in a central acceleration field created by gravity or a centrifugal force. In the former case, the bubble moves outwards from and, in the latter, towards the center. We have calculated the characteristic time needed for a bubble to leave or reach the center. The solution obtained provides insight into the processes of thermonuclear supernovae and combustion; in other words, into the interaction between a flame and a turbulent vortex. In the case of combustion, a light bubble of burnt material propagates towards the axis of a strong turbulent vortex faster than it drifts in the direction of rotation of the vortex. It is expected that the development of bubbles should prevent the formation of “pockets” at the flame front, similar to those predicted by a simplified model of turbulent combustion in a constant density flux. In the case of a thermonuclear supernova in a deflagration burning regime, it is shown that light products of burning rise from the center of the white dwarf substantially more rapidly than the thermonuclear flame front propagates. As a result, a flame cannot completely burn the central part of the star, and instead is pushed to the outer layers of the white dwarf. The effect of bubble motion (large-scale convection) makes spherically symmetric models for thermonuclear supernovae unrealistic, which is of prime importance for the supernova spectrum and energy. The motion of bubbles is even faster in the case of a rotating white dwarf; under certain conditions, the centrifugal force may dominate over the gravitational force. To test this theory, we have carried out numerical simulations of supernovae explosions for various sizes of the burned region in the core of the presupernova. We have derived a relation between the rate of large-scale convection and the size of the burned region, which is specified by the rate of the deflagration in the thermonuclear burning.     

The role of large-scale convection in supernovae explosions

We present the results of simulations of Type Ia and II supernovae explosions taking into account the rotation of the initial configuration. The main idea is development of a large-scale convective instability which affects strongly the geometry of the explosion. For Type Ia supernova a jet-like structure of the ejecta was obtained. An important point here is the possibility of continuing consecutive flares, produced when the fresh thermonuclear fuel is ignited in the central part of the star. This fuel is moved to the center by convective fluxes from the outer stellar layers. For Type II supernova a large-scale convection results in a non-equilibrium neutronization of the matter. Large bubbles, moving to the surface, contain high-energy neutrinos from the central region of the proto-neutron stellar core. The following ejection of these neutrinos to the stellar envelope gives enough energy support to the bounce shock, which finally destroys the envelope producing a non-spherical explosion.     

Observations of currents and density structure across a buoyant plume front

Observations of the Mobile Bay, Alabama, plume during a flood event in April 1991 reveal significant differences in the current field on either side of a front associated with the buoyant plume. During a strong southeasterly wind, turbid, low salinity water from Mobile Bay was pushed through an opening in the west side of the ebb-tidal delta and moved parallel to the coast. A stable front developed between the low salinity water of the buoyant plume (11‰) and the high salinity coastal water (>23‰) that was being forced landward by the prevailing winds. Despite the shallow water depth of 6 m, measurements of currents, temperature, and salinity show large shears and density gradients in both the vertical and the horizontal directions. At a station outside of the buoyant plume, currents at 0.5 m and 1.5 m below the surface were in the same direction as the wind. Inside the plume, however, currents at 0.5 m below the surface were parallel to the coast, 45°, off the direction of the wind and the magnitude was 45% larger than the magnitude of the surface currents outside the plume. Beneath the level of the plume, the currents were identical to the wind-driven currents in the ambient water south of the front. Our observations suggest that the wind-driven surface currents of the ambient water converged with the buoyant plume at the front and were subducted beneath the plume. The motion of the ambient coastal surface water was in the direction of the local wind stress, however, the motion of the plume had no northerly component of motion. The plume also did not show any flow toward the front, suggesting a balance between the northerly component of wind stress and the southerly component of buoyant spreading. In addition, the motion of the plume did not appear to affect the motion of the underlying ambient water, suggesting a lack of mixing between the two waters.     

广元地区龙门山前缘中低温对流型地热系统分析

通过广元地区龙门山前缘的遥感地质解译,野外地质考查以及结合前人地热水勘查成果,对其地热水的热源、水源、构造特征等综合分析认为,该区无附加热源,热源为深循环加热,水源以大气降水为主,具有深部循环的有利地质构造条件,为在正常的区域地温场背景条件下。出现在裂隙介质发育的深部碳酸盐岩地层之中的地下热水环流系统——中低温对流型地热系统,具有很好的勘探开发前景。     

冻融循环作用下富平黄土微观结构几何类型变化研究

冻融循环作用可通过影响寒区土体结构致使基础设施发生破坏,而导致工程失稳宏观现象的根源来自于冻融作用改变了土体的微观结构。为探索冻融作用下土体微观结构变化规律,将富平黄土作为研究对象,分别对其进行0、4、6、8、10、50、100次冻融循环下的电镜扫描观测试验,得到对应次数下的微观照片,对其从颗粒形态、连结方式、排列形式对孔隙的影响三方面进行分析,并且将微观照片中出现的颗粒接触方式以几何模型的方式进行归类,研究几何模型随冻融循环次数增加后的变化规律。结果表明：随着冻融循环次数的增加,土颗粒大小朝着均一性的方向发展,平均粒径呈先减小后增大趋势;颗粒的连结形式从面胶结为主逐渐演变为点接触为主最终再回归为面胶结为主;土体在0~6次冻融循环时孔隙率呈下降趋势,6~8次冻融循环时孔隙率快速上升,之后随着冻融循环次数的增加孔隙率逐渐减小;粒状粒子几何模型变化规律从棱边接触逐渐过渡为粒面接触,扁平状粒子几何模型变化规律从初始粒面接触为主逐渐演变为棱边接触为主,最终再演变为粒面接触。     

The structure type of Joaquinite

Summary The structure type of joaquinite has been derived from precession photographs (Mo radiation) of a polysynthetic twin. Space group: C 2/m; lattice constants:a=10.50Å,b=9.58Å;c=11.78Å;=109°32;cell content: Ba₄Fe₂RE₄Ti₄O₄[Si₄O₁₂]₄.The atomic arrangement was determined by Patterson-, Fourier-, and (F₀–F_c)-syntheses. The least squares refinement (with isotropic temperature factors) led toR=0.16. The authors are of the opinion that this relativeley highR-value is due to the poor quality of the crystal.The main structural feature are double layers of [Si₄O₁₂]-rings parallel to (001) which are connected by 10-coordinated Ba and octahedrally coordinated Ti. These double layers have pseudo-symmetry C mmm, with mirror planes perpendicular toa, b, andc ^*. They are stacked alongc ^* and translated –3/8a. The orthorhombic pseudo-symmetry allows also the translation +3/8a which is responsible for both the formation of twins and the frequent stacking disorder. The described double layers are connected by 7-coordinated RE and 4-coordinated Fe.The rôles of Fe, which has an occupancy of only 1/2, and of Na and OH. which are reported in published analyses, are discussed.

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Der Strukturtyp von Joaquinit

Zusammenfassung Der Strukturtyp von Joaquinit wurde aus Präzessionsaufnahmen (MoStrlg.) eines polysynthetischen Zwillings abgeleitet. Raumgruppe: C 2/m; Gitterkonstanten:a=10,50Å;b=9,58Å,c=11,78Å; =109°32, Zellinhalt: Ba₄Fe₂SE₄Ti₄O₄[Si₄O₁₂]₄.Die Atomanordnung wurde aus Patterson-, Fourier- und (F₀–F_c)-Synthesen abgeleitet. Die Verfeinerung mit der Methode der Kleinsten Quadrate führte (mit isotropen Temperaturfaktoren) aufR=0,16. Die Autoren sind der Ansicht, daß dieser relativ hoheR-Wert von der schlechten Qualität des Kristalles herrührt.Wesentliches Strukturmotiv sind Doppelschichten von [Si₄O₁₂]-Ringen parallel (001), die durch 10-koordiniertes Ba und oktaedrisch koordiniertes Ti verknüpft werden. Diese Doppelschichten haben die Pseudosymmetrie C mmm mit Symmetrieebenen senkrechta, b undc ^*. Sie werden nachc ^* gestapelt und um –3/8a translatiert. Die rhombische Pseudosymmetrie läßt andererseits die Translation +3a zu, was für die Zwilligsbildung und die häufige Stapelungsunordnung verantwortlich ist. Diese Doppelschichten werden weiter durch 7-koordinierte SE und 4-koordinertes Fe verknüpft.Die Rollen des Fe, welches eine Punktlage nur zur Hälfte besetzt, und des Na und OH, welche in publizierten Analysen angegeben werden, werden diskutiert.

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Mit 10 Abbildungen     

砂岩型铀矿床层间氧化带前锋区稀有元素富集机制

在深入研究砂岩型铀矿床层间氧化带各地球化学分带中铀及其伴生元素的分布规律时,发现一些单价态(不变价)元素也常常富集在层间氧化带前锋区,其典型代表是钪(Sc)、钇(Y)和稀土元素(REE)等。作者在综合分析前苏联众多砂岩型铀矿床各地球化学分带中各种元素大量测试数据的基础上,论述了层间氧化带前锋区Eh值和pH值的变化规律以及它们所导致的变价元素(U、Se、Mo和V)和不变价元素(Sc、Y和REE)的分布规律和富集机制。实际上,层间氧化带前锋区既是氧化-还原电位(Eh值)又是酸碱度(pH值)的急剧变化区,两者大致同步消长。层间氧化带前锋区有两类地球化学障:单纯的还原障和还原-碱性综合障。两种地球化学障的发育与强度取决于原始未氧化岩石中硫化物、有机质和碳酸盐的含量。     

Depositional setting and geometric structure of the Beypazari lignite deposits, Central Anatolia, Turkey

The Neogene Beypazari basin is one of the important coal districts of Central Anatolia with approximately 600 million short tons lignite reserves. The coal-bearing Neogene sediments occurring in the Beypazari basin are divided into seven formations, in ascending order; Çoraklar, Hirka, Akpinar, Çayirhan, Bozbelen and Kirmir Formations with Sariyar Limestone and Teke volcanics.The Çoraklar Formation consists of cross-bedded sandstones, channel-fill conglomerates, mudstones, carbonaceous shales and volcanoclastic pebblestones, which are fluvial in origin. The lower lignite seam occurs in the lower part of the Çoraklar Formation.The upper lignite seam occurs in the uppermost part of the Çoraklar Formation and is overlain by the Hirka Formation with a sharp contact. The Hirka Formation consists mainly of alternating shale, mudstone, bituminous shale, claystone, tuffite and silicified limestone, and they all are apparently of lacustrine origin.The lignite deposite occur in the Çayirhan and Koyunaǧili parts of the Beypazari Neogene basin. The Çayirhan coal field consists of lower and upper lignite seams, but the Koyunaǧili field contains only an upper lignite seam.The lower lignite seam, which does not crop out at the surface, indicates a fluvial origin of the lignite deposits, based on the lateral discontinuity and the lower sulphur content of the lower lignite seam, and the sedimentologic and stratigraphic features of the associated sediments. But the uniform stratigraphic and sedimentologic features, high sulphur content and wide-spread distribution of the upper lignite seam indicate that the upper lignites were deposited probably in a mud-flat facies of playa-lake environment. The lower and upper lignites are completely different in relation to the depositional environment, the geometry and degree of rank in lateral directions.The lateral spreading and geometry of the lower lignite deposits were controlled by channel, floodplain and well-drained marshes of a fluvial system. On the basis of recent drillings and field investigations, the lower lignite deposit has been demonstrated to be a linear spreading parallel to the axis of the channel fills and throughcross beds in clastic sediments of fluvial facies. Therefore, the lower lignite deposits trend along a northeastern direction and is not expected to be as widely spread as the upper lignites.     

Evolution of the first supernovae in protogalaxies: Dynamics of mixing of heavy elements

The paper considers the evolution of the supernova envelopes produced by Population III stars with masses ofM _* ?? 25?C200M _?? located in non-rotating protogalaxies with masses of M ?? 10⁷ M _?? at redshifts z = 12, with dark-matter density profiles in the form of modified isothermal spheres. The supernova explosion occurs in the ionization zone formed by a single parent star. The properties of the distribution of heavy elements (metals) produced by the parent star are investigated, as well as the efficiency with which they are mixed with the primordial gas in the supernova envelope. In supernovae with high energies (E ? 5 × 10⁵² erg), an appreciable fraction of the gas can be ejected from the protogalaxy, but nearly all the heavy elements remain in the protogalaxy. In explosions with lower energies (E ? 3 × 10⁵² erg), essentially no gas and heavy elements are lost from the protogalaxy: during the first one to threemillion years, the gas and heavy elements are actively carried from the central region of the protogalaxy (r ?? 0.1r _v , where r _v is the virial radius of the protogalaxy), but an appreciable fraction of the mass of metals subsequently returns when the hot cavity cools and the envelope collapses. Supernovae with high energies (E ? 5 × 10⁵² erg) are characterized by a very low efficiency of mixing of metals; their heavy elements are located in the small volume occupied by the disrupted envelope (in a volume comparable with that of the entire envelope), with most of the metals remaining inside the hot, rarified cavity of the envelope. At the same time, the efficiency of mixing of heavy elements in less energetic supernovae (E ? 3 × 10⁵² erg) is appreciably higher. This comes about due to the disruption of the hot cavity during the collapse of the supernova envelope. However, even in this case, a clear spatial separation of regions enriched and not enriched in metals is visible. During the collapse of the supernova envelope, the metallicity of the gas is appreciably higher in the central region ([Z] ?? ?1 to 0) than at the periphery ([Z] ?? ?2 to ?4) of the protogalaxy; most of the enriched gas has metallicities [Z] ?? ?3.5 to ?2.5. The masses of enriched fragments of the supernova envelope remain appreciably lower than the Jeans mass, except in regions at the center of the protogalaxy upon which the surrounding enriched gas is efficiently accreted. Consequently, the birth of stars with metallicities close to those characteristic of present-day Galactic stars is very probable in the central region of the protogalaxy.     

龙门山中段山前带构造楔的发现及其几何学、运动学特征:对青藏高原东南缘隆升动力学机制的约束

运用断层相关褶皱几何学原理,对龙门山中段山前的地震反射剖面进行解释。研究发现,龙门山中段山前带垂向上具有多套滑脱层。其中深层次滑脱层位于前震旦系基底深度约(19±2)km的地方,其上发育双重构造和叠加构造楔,构造楔是龙门山中段山前带重要的构造样式之一。工区A剖面深层构造楔模型以后展破裂式叠加形成,断层产生的滑移量达45.5 km;B剖面深层构造楔模型以前展破裂式叠加形成,断层产生的滑移量约16.6 km;构造楔的形成导致上部断裂和岩层隆升并褶皱变形,A、B剖面山前地层相对川西平原最大抬升量分别为8 km和3 km。构造楔沿龙门山中段山前带走向平面上呈带状分布,具有不同的规模和几何形态;分析其形成时间较晚,可能形成于喜马拉雅期。通过对深层叠加构造楔几何学和运动学的定量计算,其正演运动学模型与实际剖面解释相吻合。深层叠加构造楔的形成在龙门山中段前山带有着其相应的成因机制,在所能限定的空间范围内,其特殊的地理位置、构造特征与成因,可以为研究青藏高原东南缘隆升的动力机制提供一定的约束。     

Interannual variability in the structure of the Kuroshio front along the western boundary of the North Pacific Ocean associated with the 1982 ENSO event

The vertically averaged temperature (T_av) over the upper 200 m of ocean in the W boundary of the N Pacific is used to detect changes in the strenght and path of the Kuroshio Front along the W boundary from Luzon (18° N) to Honshu (34° N) during the period, 1979–1982. During this time period the Kuroshio Front experienced significant interannual changes associated, both with the disappearance of the Kuroshio Meander in late 1980 and with the development of the 1982 ENSO event in early 1982. When the Kuroshio Meander S of Honshu disappeared in the fall of 1980, lasting until the summer of 1981, the intensity of the Kuroshio Front increased, associated with warmer than normal temperatures all along the W boundary of the N Pacific from Luzon to Honshu. The amplitude of the Kuroshio Meander was also correlated with fluctuations in the path of the Kuroshio Front at the Tokara Strait (30° N) and the Bashi Strait (20° N), and with the amplitude of the East China Sea Meander. The East China Sea Meander occurs W of the Ryukyu Islands at 25° N, formed when the Kuroshio Current enters the East China Sea from the Philippine Sea NE of Taiwan Island. It had large amplitude in winter and smaller amplitude in spring and early summer, similar to that in the Kuroshio Meander when it was present during this period. It also had related interannual variability; i.e., when the Kuroshio Meander disappeared in fall of 1980, the East China Sea Meander was weak. These results and earlier ones dealing with the Kuroshio Front E of Japan (e.g., White and He) indicate that fluctuations in the amplitude of the Kuroshio Meander S of Honshu were associated with similar changes in the meandering character over the entire Kuroshio Current System during this four year period. During the 1982 ENSO event, the temperature in the region of the Kuroshio Front in the W boundary became colder than normal, while the Kuroshio Meander S of Honshu and the East China Sea Meander NE of Taiwan Island developed larger amplitudes. This is consistent with the results of White and He, who found during this same time period that the mesoscale meander pattern in the Kuroshio Extension intensifying during the 1982 ENSO period. During this time, the magnitude of the Kuroshio Front all along the W boundary and in the Kuroshio Extension region was weaker in comparison with the three years prior to the 1982 ENSO event.     

Evolution of the Cape Henry front

The evolution of a front that forms inshore of the main Chesapeake Bay plume, near Cape Henry, Virginia, United States, was observed during a period of downwelling-favorable winds in May 1999. A novel aspect of this study was the use of an underway, horizontally-oriented acoustic Doppler current profiler (ADCP) to map the front and to study its evolving shape. Measurements made during flood tide show the front forming about 2 km from shore and then advancing shoreward (at about 20 cm s⁻¹) over dense, inshore water. Measurements made while anchored 1 km from shore show the surface salinity increasing during ebb tide, then abruptly decreasing during flood tide as the front moves inshore. To account for this cycle of events, a conceptual model is proposed in which dense water upwells to the surface during ebb tide near Cape Henry, helping to set the stage for frontal formation on the flood. The cyclic recurrence of this Cape Henry front so close to the mouth of the bay may provide a mechanism for recirculating estuarine material that would otherwise be transported southward in the coastal buoyancy current.     

Development of block structure in the crust below the Pannonian basin

The analysis of geophysical and geological data on the structure of the pre-Miocene substratum of the Pannonian basin has revealed a block structure. The crust was divided by deep-seated faults of mainly NE-SW orientation. The deep-seated faults separate zones of continental crust (with granitoids), which were more intensely consolidated during the Hercynian, from strips with volcanic-sedimentary rocks of eugeosynclinal character (sub-oceanic crust). In geological development of the Pannonian basin crust during the last 330 million years, subsidence predominated over uplift and denudation. The great mobility of the crust ist related to its lesser thickness compared to the thick crust in the orogenic border and median massifs, e. g. of the Balkan region. The block structure is superimposed on the original belt structure and nucleus stage of continental crust formation. In the pre-Hercynian stage, tectonic division along E-W and N-S lines predominated. The long persistence and magmatic activity of deep-seated faults and their almost vertical dip do not support proposed models of partial subduction and closing of microoceans in the region of the Pannonian basin. Strips or blocks of suboceanic crust are considered to be relicts of more weakly sialized original thin oceanic crust. The Pannonian basin is not a typical ensialic basin. Tectonic development has distinctly changed the mantle diapir, which originated in the Late Cretaceous. Along the circumference of this diapir, shear zones originated in the crust, along which seismic activity has persisted to the present. The Pannonian megablock is a type of simatic median massif, preserving long-lasting subsidence mobility. The Pannonian mantle diapir is considered to be an autonomous deep structure in the sense ofvan Bemmelen (1972). We do not relate the ascent of the mantle diapir to subduction of lithospheric plates, which must have been the cause of folding of the Carpathians according toStegena et al. (1975).

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Zusammenfassung Die Analyse der geophysikalischen und geologischen Angaben über den Bau des vormiozänen Untergrundes des Pannonischen Becken enthüllte einen Blockbau. Die Erdkruste war durch Tiefenbrüche gegliedert, vorwiegend in NO-SW Richtung. Die Tiefenbrüche trennen Streifen der kontinentalen Kruste mit Granitoiden, epiherzynisch intensiver konsolidiert, von den Streifen mit vulkanisch-sedimentären Serien eugeosynklinalen Charakters (subozeanischer Krustentyp). In der geologischen Entwicklung der Kruste während der letzten 330 Mill. Jahren herrschte die Subsidenz über Hebungen und Denudationen vor. Die große Mobilität der Kruste wird mit ihrer geringeren Dicke verbunden zum Unterschied von der mächtigen Kruste im orogenen Raum und der medianen Massive, z. B. der Balkan-Region. Der Blockbau ist aufgelegt auf den ursprünglichen Zonenbau und das Nukleus-Stadium der kontinentalen Krustenbildung. In der vorherzynischen Etappe war die tektonische Gliederung nach den Linien W-O und N-S vorherrschend.Die lange Lebensdauer und magmatische Aktivität der Tiefenbrüche, ihre fast vertikale Neigung unterstützen die Modelle der Teil-Subduktionen und Schließung der Mikroozeane im Raume des Pannonischen Beckens nicht. Die Streifen-Blöcke der subozeanischen Kruste werden als Relikte der schwächer sialisierten ursprünglichen dünnen ozeanischen Kruste betrachtet. Das Pannonische Becken ist kein typisches ensialisches Becken.Die tektonische Entwicklung verändert deutlich den Manteldiapir, dessen Entstehung schon in die Oberkreide gestellt wird. Am Umfang dieses Diapirs sind in der Kruste Scherzonen entstanden, auf welchen die seismische Aktivität bis zur Gegenwart andauert. Der pannonische Megablock ist ein Typ eines simatischen medianen Massivs, welches eine langdauernde Subzidenzmobilität erhält. Der pannonische Manteldiapir wird als autonome Tiefstruktur im Sinnevan Bemmelens (1972) betrachtet.Wir setzen den Aufstieg des Manteldiapirs nicht mit der Subduktion der lithosphärischen Platten in Verbindung, welche nachStegena et al. (1975) die Ursache der Faltung der Karpaten sein sollte.

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Résumé L'analyse des données géologiques et géophysiques sur la constitution du soubassement prémiocène du bassin pannonique a fait découvrir l'existence d'une structure en bloc. La croûte a été compartimentée par des failles profondes de direction NE-SW. Ces cassures profondes séparent des bandes de croûte continentale avec granitoïdes, bien consolidée par l'orogenèse epihercynienne, de bandes à séries volcano-sédimentaires à caractère eugéosynclin (type sub-océanique). Au cours du développement géologique de la croûte pendant ces dernières 330 M/A, c'est la subsidence qui a prédominé sur les soulèvements et al dénudation. La grande mobilité de la croûte est liée à sa faible épaisseur, différant en cela de la croûte épaisse du domaine orogénique et des massifs médians (p. e. la région balcanique). La structure en blocs est superposée à la structure zonaire primitive d'une part, et au stade de «nucleus» de la croûte continentale d'autre part. Dans l'étape anté-hercynienne, la subdivision prédominante se faisait conformément aux direction W-E et N-S.La longévité et l'activité magmatique des cassures profondes, leur position quasiverticale, sont en contradiction avec les modèles de subduction partielle et de fermeture de microocéans dans la région du bassin pannonique. Les bandesblocs de l'écorce subocéanique sont considérées comme des relictes faiblement sialisés de l'écorce océanique originellement peu épaisse. Le bassin pannonique n'est pas un bassin typiquement ensialique.Le développement tectonique modifia de toute évidence le diapir du manteau qui prend déjà naissance au Crétacé supérieur. Dans le pourtour de ce diapir, des zones de cisaillement sont apparues dans l'écorce, qui ont été et sont restées jusqu'à ce jour le siège d'une activité seismique. Le megabloc pannonique est un type de massif médian simatique à mobilité subsidente de longue durée. Le diapir pannonique est considéré comme une structure autonome et profonde dans le sens devan Bemmelen (1972). L'ascension du diapir du manteau n'est pas, d'après nous, liée à la subduction de plaques lithosphériques, laquelle, d'aprèsStegena et al. (1975) devrait être responsable de l'orogenèse des Carpathes.

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