Space Physics Interactive Data Resource—SPIDR

SPIDR (Space Physics Interactive Data Resource) is a standard data source for solar-terrestrial physics, functioning within the framework of the ICSU World Data Centers. It is a distributed database and application server network, built to select, visualize and model historical space weather data distributed across the Internet. SPIDR can work as a fully-functional web-application (portal) or as a grid of web-services, providing functions for other applications to access its data holdings.

A New Compound of the (K,Na)3Ca8Si6[Si4O12]3 Charoite Substrate

Doklady Earth Sciences - As a result of experimental studies on the interaction between a charoite substrate and host lamprophyres of microcline-arfvedsonitic composition, a new...     

The timing and extent of the eruption of the Siberian Traps large igneous province: Implications for the end-Permian environmental crisis

We present new high-precision ⁴⁰Ar/³⁹Ar ages on feldspar and biotite separates to establish the age, duration and extent of the larger Siberian Traps volcanic province. Samples include basalts and gabbros from Noril'sk, the Lower Tunguska area on the Siberian craton, the Taimyr Peninsula, the Kuznetsk Basin, Vorkuta in the Polar Urals, and from Chelyabinsk in the southern Urals. Most of the ages, except for those from Chelyabinsk, are indistinguishable from those found at Noril'sk. Cessation of activity at Noril'sk is constrained by a ⁴⁰Ar/³⁹Ar age of 250.3 ± 1.1 Ma for the uppermost Kumginsky Suite.The new ⁴⁰Ar/³⁹Ar data confirm that the bulk of Siberian volcanism occurred at 250 Ma during a period of less than 2 Ma, extending over an area of up to 5 million km². The resolution of the data allows us to confidently conclude that the main stage of volcanism either immediately predates, or is synchronous with, the end-Permian mass extinction, further strengthening an association between volcanism and the end-Permian crisis. A sanidine age of 249.25 ± 0.14 Ma from Bed 28 tuff at the global section and stratotype at Meishan, China, allows us to bracket the P–Tr boundary to 0.58 ± 0.21 myr, and enables a direct comparison between the ⁴⁰Ar/³⁹Ar age of the Traps and the Permo–Triassic boundary section.Younger ages (243 Ma) obtained for basalts from Chelyabinsk indicate that volcanism in at least the southern part of the province continued into the Triassic.     

Extreme Statistics of Storm Surges in the Baltic Sea

Statistical analysis of the extreme values of the Baltic Sea level has been performed for a series of observations for 15–125 years at 13 tide gauge stations. It is shown that the empirical relation between value of extreme sea level rises or ebbs (caused by storm events) and its return period in the Baltic Sea can be well approximated by the Gumbel probability distribution. The maximum values of extreme floods/ebbs of the 100-year recurrence were observed in the Gulf of Finland and the Gulf of Riga. The two longest data series, observed in Stockholm and Vyborg over 125 years, have shown a significant deviation from the Gumbel distribution for the rarest events. Statistical analysis of the hourly sea level data series reveals some asymmetry in the variability of the Baltic Sea level. The probability of rises proved higher than that of ebbs. As for the magnitude of the 100-year recurrence surge, it considerably exceeded the magnitude of ebbs almost everywhere. This asymmetry effect can be attributed to the influence of low atmospheric pressure during storms. A statistical study of extreme values has also been applied to sea level series for Narva over the period of 1994–2000, which were simulated by the ROMS numerical model. Comparisons of the “simulated” and “observed” extreme sea level distributions show that the model reproduces quite satisfactorily extreme floods of “moderate” magnitude; however, it underestimates sea level changes for the most powerful storm surges.     

Interstellar Scintillations of Polarization of Compact Sources

We present analysis of a high spatial resolution ( approximately 1&farcs;5) O vi lambda1032 spectroheliogram taken with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory. This image shows numerous narrow, looplike structures. The widths of the narrowest resolved features are at the spatial resolution of the SUMER spectrometer. In contrast to earlier Skylab observations, however, comparisons with a Michelson Doppler Imager magnetogram reveals that the majority of these looplike structures do not connect network magnetic fields. Instead, they extend from the supergranulation network into the cell-center regions where no magnetic fields are detected in these data. We conjecture that these fine structures are related to spicules and are highly dynamic.     

Geochemistry and petrogenesis of basalts from the West Siberian Basin: an extension of the Permo–Triassic Siberian Traps, Russia

New major and trace element data for the Permo–Triassic basalts from the West Siberian Basin (WSB) indicate that they are strikingly similar to the Nadezhdinsky suite of the Siberian Trap basalts. The WSB basalts exhibit low Ti/Zr (50) and low high-field-strength element abundances combined with other elemental characteristics (e.g., low Mg#, and negative Nb and Ti anomalies on mantle-normalised plots) typical of fractionated, crustally contaminated continental flood basalts (CFBs). The major and trace element data are consistent with a process of fractional crystallisation coupled with assimilation of incompatible-element-enriched lower crust. Relatively low rates of assimilation to fractional crystallisation (0.2) are required to generate the elemental distribution observed in the WSB basalts. The magmas parental to the basalts may have been derived from source regions similar to primitive mantle (OIB source) or to the Ontong Java Plateau source. Trace element modelling suggests that the majority of the analysed WSB basalts were derived by large degrees of partial melting at pressures less than 3 GPa, and therefore within the garnet-spinel transition zone or the spinel stability field.

It seems unlikely that large-scale melting in the WSB was induced through lithospheric extension alone, and additional heating, probably from a mantle plume, would have been required. We argue that the WSB basalts are chemically and therefore genetically related to the Siberian Traps basalts, especially the Nadezhdinsky suite found at Noril'sk. This suite immediately preceded the main pulse of volcanism that extruded lava over large areas of the Siberian Craton. Magma volume and timing constraints strongly suggest that a mantle plume was involved in the formation of the Earth's largest continental flood basalt province.     

Transport and Crystallization of Noble Platinum in Supercritical C–O–H Fluid

Experimental data is provided for the transport of platinum in a supercritical C–O–H fluid system. The transfer of platinum in space with its condensation on the surface of native carbon (diamond and amorphous carbon) in the form of micro- and nanocrystals, shapeless particles, and filamentous formations is established for the first time. The dominant participation of platinum in the formation of carbon micro- and nanotubes is demonstrated. The results are important in modeling the formation of noble metal deposits with deep fluid carbon systems.     

Numerical Modeling of Meteorological Sea Level Oscillations in the Black Sea

Oceanology - To study the features of short-period meteorological sea level oscillations, adaptation of the numerical Princeton Ocean Model (POM) to the Black Sea conditions was performed. The...     

Pole tide in the Baltic Sea

The pole tide, which is driven by the Chandler Wobble, has a period of about 14 months and typical amplitudes in the World Ocean of ～0.5 cm. However, in the Baltic Sea the pole tide is anomalously high. To examine this effect we used long-term hourly sea level records from 23 tide gauges and monthly records from 64 stations. The lengths of the series were up to 123 years for hourly records and 211 years for monthly records. High-resolution spectra revealed a cluster of neighboring peaks with periods from 410 to 440 days. The results of spectral analysis were applied to estimate the integral amplitudes of pole tides from all available tide gauges along the coast of the Baltic Sea. The height of the pole tide was found to gradually increase from the entrance (Danish Straits, 1.5–2 cm) to the northeast end of the sea. The largest amplitudes—up to 4.5–7 cm—were observed in the heads of the Gulf of Finland and the Gulf of Bothnia. Significant temporal fluctuations in amplitudes and periods of the pole tide were observed during the 19th and 20th centuries.     

Geochemical features of metabasite inclusions in gray gneisses of the Baidarik block (Central Mongolia)

The Baidarik block of the Dzavhan microcontinent (Central Asian Fold Belt) includes the Upper Archean Baidaragin gray-gneiss complex. Among gray plagiogneisses, there are metabasic bodies, which are probably relics of early volcanics. By composition, the metabasites are divided into three petrochemical groups, whose protoliths were tholeiitic basalts, Al-undepleted and Al-depleted basaltic komatiites. Only a few samples are similar in REE composition to these protoliths. We have found metabasites with crustal-contamination features. The unusual geochemical properties of the metabasites (LREE enrichment and Nb, Zr, and Ti depletion) are related to their metasomatism.