Diagnostics of the Internal Structure of Stars using the Differential Response Technique

We address the problem of the diagnosing the deep interior structure of stars using acoustic p-modes, and investigate the diagnostic capabilities of two complementary approaches both based on the differential response technique (Vorontsov, 1998): (a) direct calibration using a grid of evolutionary stellar models, and (b) linear and non-linear (with consecutive linearisations) inversion of low-degree frequencies. We apply this analysis to the frequencies of a model of an old 0.8M star, and to the solar frequencies obtained from BiSON measurements, using a 2-D grid of reference models of different mass and age. We explore the convergence and stability of the asteroseismic inversion, performed with the adaptive regularisation technique of Strakhov and Vorontsov (2001).     

Cretaceous radiolarian fauna from the Kiselyovsky subterrane, the youngest accretionary complex of the Russian continental far east: Paleotectonic and paleogeographic implications

Abstract The Kiselyovsky subterrane is the northeastern section of the Kiselyovsko-Manominsky terrane, a distinguishable tectonic unit in the north of the Sikhote-Alin Range. The terrane has been treated as part of the accretionary wedge belonging to the Khingan-Okhotsk active continental margin, but its structure and stratigraphy have been poorly understood. This paper presents new data on the subterrane structure, lithology and radiolarian biostratigraphy. The following lithostratigraphic units are established in the terrane: a ribbon chert unit, a siliceous mudstone unit and a elastics unit. Abundant Valanginian to late Hauterivian-early Barremian radiolarian assemblages are obtained from the upper part of the chert unit in addition to the known Jurassic radiolarians. The radiolarian age of the lower part of the siliceous mudstone unit (red siliceous mudstone) is determined as early Hauterivian-early Aptian. The unit's upper part (greenish-gray siliceous mudstone and dark-gray silicified mudstone) and the clastics unit contain Albian-Cenomanian assemblages. The arrangement of the units is treated as a chert-elastics sequence, whose vertical lithologic variations indicate environmental changes from a remote ocean to a convergent margin, reflecting an oceanic plate motion towards a subduction zone. The subterrane structure is a stack of imbricated slabs composed of various lithostratigraphic units, and is complicated by folding. The structure's origin is related to subduction-accretion, which occurred in the Albian-Cenomanian. The data presented provide a unique basis for accretionary wedge terranes correlation in the circum-Japan Sea Region, and the Kiselyovsky subterrane is correlated in this study with the synchronous parts of the East Sakhalin, Hidaka and Shimanto terranes. The Albian-Cenomanian radiolarian assemblages were deposited in the Boreal realm, while Valanginian ones are Tethyan; this indicates a long oceanic plate travelling to the north. The former assemblages contain an admixture of older species, redeposited by bottom traction currents and turbidite flows in trench environments.     

沉积盆地学说的发展及主要的含油气盆地分类

从科学史观出发，介绍了含油气盆地概念及其学说的发展。展示主要的盆地分类方案，论述含油气盆地分类研究在盆的含油气性评价中所具有的重要意义。指出盆地分类研究的发展方向和未来分类方案所应具有的特点。     

西伯利亚克拉通寒武纪沉积史:碳酸盐台地和盆地的演化

西伯利亚克拉通或古西伯利亚台地，其面积４００００００ｋｍ２以上，是亚洲北部最主要的大陆地块之一。它以寒武系分布区域极为广泛、层序非常完整为特色。寒武系构成了遍及全区的下沉积盖层和出露在大的正向构造内。寒武纪时，研究区是重要的碳酸盐沉积区，有碳酸盐－硅质碎屑的混合沉积、蒸发盐、礁和深水盆地的碳酸盐沉积。半个多世纪来，区内进行了各种大型的旨在找烃的地质调查及有关的寒武系层理、古地理和古构造的重建，以及沉积环境的重塑。但关于沉积物内部构造的研究工作一直主要是根据传统地层学的“连续地层柱”概念。有些工作者认为，古深度和地貌史或排列的各式各样的恢复不强调瞬时。只有最近１０—１５年，地下调查配合成因地层学和盆地分析概念的发展，使得有可能将生物群演化、沉积体边界的形状和类型以及它们的成因和对各种因素（诸如以上所述各种及相对海平面变化之类）的影响综合为统一的系统。这种区域继承观点的研究方法在６０年代后期由Ｇｒａｃｈｅｖｓｋｙ（１９６９）提出，然后由Ｓａｖｉｓｔｋｙ（１９７９）和Ａｓｔａｓｈｋｉｕ（１９８４）详尽阐述，其目的是重建西伯利亚克拉通盆地充填和发展中的动力学     

Relict back-arc basins of Eurasia and their hydrocarbon potentials

Abstract Large petroliferous basins in the continental interior are characterized by very thick sedimentary sequences. It is suggested that these are not intracratonic basins, but areas underlain by oceanic crust. These include the Western Siberian, Pre-Caspian, South Caspian, North and South Kara Basins of the Commonwealth of Independent States, and Tarim, junggar and Qaidam Basins of China. The relict ocean basins are distinguished by their basement topography, by their magnetic signatures and by their elevated Moho. Their sedimentary history is distinguished by an abrupt subsidence, followed by isostastic subsidence under sedimentary load. Two circumstances have contributed to the genesis of giant hydrocarbon deposits in these basins: (1) the geochemical environment in those basins was at one time oxygen-deficient as they evolved from the open marine, through restricted marine to become inland alluvial basins; and (2) the sedimentary in-fill provide thick reservoir beds. Oil has accumulated in older structures, folds, faults, unconformities etc. on the margin of the basins, trapping early migrated hydrocarbons.     

On the classical expansion of the perturbing function in individual orbital elements

Starting from the classical expansion of the perturbing function in the three‐body problem, the transformation to individual orbital elements is performed in principle up to any degree in small parameters. Some corrections to the results presented in the well‐known article by Yuasa on secular perturbations of asteroids are given. Consequences for the expansion of the indirect part of the perturbing function are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Salt tectonics driven by differential sediment loading: stability analysis and finite-element experiments

At many continental margins, differential sediment loading on an underlying salt layer drives salt deformation and has a significant impact on the structural evolution of the basin. We use 2‐D finite‐element modelling to investigate systems in which a linear viscous salt layer underlies a frictional‐plastic overburden of laterally varying thickness. In these systems, differential pressure induces the flow of viscous salt, and the overburden experiences updip deviatoric tension and downdip compression. A thin‐sheet analytical stability criterion for the system is derived and is used to predict conditions under which the sedimentary overburden will be unstable and fail, and to estimate the initial velocities of the system. The analytical predictions are in acceptable agreement with initial velocity patterns of the numerical models. In addition to initial stability analyses, the numerical model is used to investigate the subsequent finite deformation. As the systems evolve, overburden extension and salt diapirism occur in the landward section and contractional structures develop in the seaward section. The system evolution depends on the relative widths of the salt basin and the length scale of the overburden thickness variation. In narrow salt basins, overburden deformation is localised and characterised by high strain rates, which cause the system to reach a gravitational equilibrium and salt movement to cease earlier than for wide salt basins. Sedimentation enhances salt evacuation by maintaining a differential pressure in the salt. Continued sedimentary filling of landward extensional basins suppresses landward salt diapirism. Sediment progradation leads to seaward propagation of the landward extensional structures and depocentres. At slow sediment progradation rates, the viscous flow can be faster than the sediment progradation, leading to efficient salt evacuation and salt weld formation beneath the landward section. Fast sediment progradation suppresses the viscous flow, leaving salt pillows beneath the prograding wedge.     

Sicilian serpentinite xenoliths containing abiotic organics with nanodiamond clusters as key model for prebiotic processes

Rock fragments from the deepest parts of a buried hydrothermal system belonging to the Mesozoic Tethys Ocean entered as xenoliths in a Miocenic diatreme,hence brought to the surface,in the Hyblean Plateau(Sicily).Some xenoliths consist of strongly serpentinized ultramafic rocks bearing blebs of abiotic organic matter,where clusters of amorphous carbon nanoparticles,including nanodiamonds,are immersed.Such an occurrence conjures up established hypotheses that diamond surfaces are suitable catalytic platforms stimulating the assemblage of complex bio-organic molecules relevant to the emergence of life on Earth.The appearance of bio-organic molecules under primitive Earth conditions is one of the major unsolved questions on the origin of life.Here we report new micro-Raman spectra on blebs of abiotic organic matter from a selected xenolith.Diamond bands were related to hydrogenated nanocrystalline diamonds,with size of nearly 1-1.6 nm,formed from organics at low pressures and temperatures.In particular,diamond surfaces can give rise to crystalline interfacial water layers that may have played a fundamental role in the early biosphere evolution as a good medium for rapidly transporting positive charges in the form of hydrated protons.Nowadays,proton gradients in alkaline hydrothermal vents along oceanic ridges are generally viewed as key pre-biotic factors.In general,serpentinites span the entire geological record,including prebiotic times.These hydrous ultramafic rocks often display evidence of abiotic carbon species,both organic and inorganic,including nanodiamonds,being also capable to give rise to chemiosmotic processes and proton gradients necessary to the organisms,such as the"Last Universal Common Ancestor"(LUCA),in the prebiotic Earth.