Estimating Travel Times of Coronal Mass Ejections to 1 AU Using Multi-spacecraft Coronagraph Data

We study the relationship between the speeds of coronal mass ejections (CMEs) obtained close to the Sun and in the interplanetary medium during the low solar-activity period from 2008 to 2010. We use a multi-spacecraft forward-modeling technique to fit a flux-rope-like model to white-light coronagraph images from the STEREO and SOHO spacecraft to estimate the geometrical configuration, propagation in three-dimensions (3D), and the radial speeds of the observed CMEs. The 3D speeds obtained in this way are used in existing CME travel-time prediction models. The results are compared to the actual CME transit times from the Sun to STEREO, ACE, and Wind spacecraft as well as to the transit times calculated using projected CME speeds. CME 3D speeds give slightly better predictions than projected CME speeds, but a large scatter is observed between the predicted and observed travel times, even when 3D speeds are used. We estimate the possible sources of errors and find a weak tendency for large interplanetary CMEs (ICMEs) with high magnetic fields to arrive faster than predicted and small, low-magnetic-field ICMEs to arrive later than predicted. The observed CME transit times from the Sun to 1?AU show a particularly good correlation with the upstream solar-wind speed. Similar trends have not been observed in previous studies using data sets near solar maximum. We suggest that near solar minimum a relatively narrow range of CME initial speeds, sizes, and magnetic-field magnitudes led to a situation where aerodynamic drag between CMEs and ambient solar wind was the primary cause of variations in CME arrival times from the Sun to 1?AU.     

Bauxite provinces of the world

Phanerozoic bauxite provinces are contoured and characterized. The relations to large tectonic units—ancient and young platforms, island arcs and foldbelts, active continental margins, etc.—are chosen as the major criterion for the recognition of bauxite provinces; 19 provinces of different age and conditions of bauxite deposition are described. Single- and multistage as well as single- and multilevel provinces are distinguished depending on the type of tectonic and geomorphic structure. The most productive bauxite provinces are located in the present-day tropical zone within ancient Gondwanan platforms. Three-level provinces with Cretaceous bauxite at the highest and oldest (post-Gondwanan) surface and Cenozoic deposits at lower and younger planation surfaces are predominant. The most complex, two- and three-stage and multilevel provinces are related to ancient fold regions. The single-level provinces are localized in young island arcs and oceanic islands. The prevalent genetic types of bauxite deposits—lateritic, sedimentary, and karst—are shown in the map of bauxite provinces.     

Isotope (δ<Superscript>13</Superscript>C and δ<Superscript>18</Superscript>O) and genetic features of manganese carbonates of the Mazul deposit (Krasnoyarsk region)

New isotope and mineral data on manganese carbonates of the Mazul deposit (Krasnoyarsk region) in combination with morphology of ore bodies suggest that the ores were formed in several stages with the involvement of meteoric solutions through infiltration and, possibly, exfiltration mechanisms. Based on the geological–geochemical data, manganese carbonates of the Mazul deposit may be ascribed to a new genetic subtype of the catagenesis (epigenesis) zone.     

The influence of a finite conductivity on the spectrum of solar <Emphasis Type="Italic">p</Emphasis>-modes

We consider the influence of a finite conductivity on the spectrum of solar p-modes (by taking into account their absorption at cusp resonance levels) in a plane two-layer model that consists of an upper isothermal layer with a uniform horizontal magnetic field and a lower adiabatic layer with a linear increase in temperature with depth. We show that an allowance for the finite, but high conductivity of the medium is required only to calculate the eigenfrequencies of the p-modes for which the resonance levels are located almost at the interface between the layers.     

Global Asymmetry of the Sun Observed in the Extreme Ultraviolet Radiation

We report on observations of the solar luminosity variations in the Fexii line (195 Å) over the period 1996–1999, which corresponds to the minimum and rising phase of the current 23rd solar cycle. The relatively or rather high temporal cadence and spatial resolution of the Extreme-ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO) allowed a nearly continuous measurement of intensity of different structures on the Sun. We find that a significant contribution to the longitudinal asymmetry, and thus to the 27-day variability of the solar EUV radiation, is produced by the numerous intermediate brightness elements that are globally distributed over large areas (up to about of the whole surface of the Sun). When activity is low, this component even becomes dominant over the contribution from localized active regions and bright points. This suggests that weak magnetic field areas outside active regions constitute an important factor through which solar activity modulates the solar EUV luminosity.     

Model for the development of rhythmically banded wollastonite-hedenbergite skarns at the Dal’negorsk deposit,southern Russian Far East

Skarns at the Dal’negorsk boron deposit belong to the infiltration type. In their outer contact zone (bounded by limestone and consisting of wollastonite + hedenbergite), rhythmically banded textures developed, with alternating wollastonite and hedenbergite bands. The petrological study and modeling of the process that produced them led us to propose a mechanism for the genesis of such textures. They are thought to form as a consequence of a dissipative structure in the infiltrating solution and its interaction with the rock. The dissipative structure itself resulted from the instability of the equilibrium state of the skarn-solution system and the development of pervasive spatial oscillations in the redox potential of the solution. The progressive development of the banded texture was associated with a change in the dissipative structure because of the existence of feedback (mutual influence) between the structure of the solution and the texture of the rock. The rhythms generated thereby are of several orders (as follows from their thicknesses and the distances between them), which is an indication of a large-scale invariance of the developing texture. The simulation of the process involved the analysis of a system of kinetic equations, the stability of the equilibrium, and the conditions of the stability of spatial oscillations in the concentrations of major components in the solution. A necessary condition of the stability of the dissipative structure is a low velocity of fluid filtration, which should be no higher than a critical value, with the latter controlled by kinetic parameters of the system. The proposed model can be modified and adapted for rhythmically banded skarns of other composition and for banded hydrothermal mineralized veins with the aim of constraining the petrogenetic conditions and elucidating the role of banded textures as precipitators of ore and minor components of the solution.     

Structure and Formation Conditions of the Bazhenovo Horizon in the Pal’yanovo Area,West Siberia

Comprehensive studies of cores from 7 boreholes drilled in the Pal’yanovo area provided insight into the Bazhenovo Horizon in southwestern Siberia represented by the lower subformation of the Tutleim Formation. The work presents a typification of organic-rich biogenic-terrigenous rocks. The Bazhenovo Horizon is divided into 11 lithotypes grouped into 5 large members. Members I?IV correspond to the lower subformation of the Tutleim Formation; member V, to the upper subformation. The identified members are traced explicitly over the Pal’yanovo area, making it possible to examine the whole vertical succession of the Tutleim Formation and reconstruct its evolution based on the proposed sedimentation model.     

Detection of Quasi-Periodic Pulsations in Solar EUV Time Series

Quasi-periodic pulsations (QPPs) are intrinsically connected to the mechanism of solar flares. They are regularly observed in the impulsive phase of flares since the 1970s. In the past years, the studies of QPPs regained interest with the advent of a new generation of soft X-ray/extreme ultraviolet radiometers that pave the way for statistical surveys. Since the amplitude of QPPs in these wavelengths is rather small, detecting them implies that the overall trend of the time series needs to be removed before applying any Fourier or wavelet transform. This detrending process is known to produce artificial detection of periods that must then be distinguished from real ones. In this paper, we propose a set of criteria to help identify real periods and discard artifacts. We apply these criteria to data taken by the Extreme Ultraviolet Variability Experiment (EVE)/ESP onboard the Solar Dynamics Observatory (SDO) and the Large Yield Radiometer (LYRA) onboard the PRoject for On-Board Autonomy 2 (PROBA2) to search for QPPs in flares stronger than M5.0 that occurred during Solar Cycle 24.     

Erratum to: Sedimentary Basins of the East Siberian Sea and the Chukchi Sea and the Adjacent Area of the Amerasia Basin: Seismic Stratigraphy and Stages of Geological History

Geotectonics - erratum     

Geochemistry of Rare and Rare-Earth Elements in Manganiferous Sediments of the Polar Urals and Pai-Khoi

Lithology and Mineral Resources - Data on the concentration of rare and rare-earth elements in the Devonian manganese-rich metasediments of the Polar Urals and Pai-Khoi Ridge are presented. It is...