Harpacticoida taxocen diversity in the silty-sandy littoral zone of Kandalaksha Bay of the White Sea

The fauna composition, ecological groups, and life forms of Harpacticoids of soft littoral grounds from 15 sites off the Karelian coast in Kandalaksha Bay of the White Sea were studied. Six types of harpacticoid taxocens with different sets of dominating species are described. On silty sands with clear signs of desalination, the Stenchelia palustris taxocen is common; medium-grained sands are characterized by the Heterolaophonte minuta, Paraleptastacus kliei — Huntemannia jadensis, and Amphiascoides nanus — Scottopsyllus minor taxocens; while on coarse sands, the Ameira parvula and Ameira scotti — Mesochra lilljeborgi taxocens have developed. The diversity of the taxocens is partly explained by the differences in the grain-size composition and salinity at different sites. In addition, groups of various taxocens dwelling on the same type of the sediments were found in different minor bights of the coastline.     

Regional tectonic trends on the inner continental shelf off Konkan and Central West Coast of India

Satellite imagery and offshore magnetic data were analysed to correlate regional tectonic elements on the inner continental shelf off Konkan and the adjacent Deccan plateau. Three statistically important lineament trends—N-S, WNW-ESE and ENE-WSW—that prevail on land are correlatable well with the offshore trends. This positive correlation suggests simultaneous deformation. The major magnetic lineament observed off Jaigad Bay, west coast of India, may be the extension of onshore lineaments. The correlation of both the offshore and onshore trends indicates that the fracture pattern of the crystalline basement has also controlled the offshore structural pattern.     

Magnetic disturbance effects in the E region of the ionosphere

Detailed studies of the daytime E-region critical frequency at Aberystwyth (geomagnetic latitude +56°) show clear evidence for changes associated with both the axially-symmetric (Dst) and asymmetric (DS) components of the disturbance magnetic field. Comparison of the sensitivity of the E-region peak density to these two influences shows that the changes cannot entirely (if at all) be ascribed to the influence of electric currents in the region. It is suggested that a major role is played by dynamical influences associated with the neutral air “storm circulation” which distributes the energy fed into the auroral region to lower latitudes.     

Laboratory simulation of volatilisation from melts induced by micrometeoroid impacts

The laboratory simulation experiments on volatilization from the melts formed due to micrometeoroid impacts on the lunar surface were carried out. The simulation was performed using modulated laser pulses incident on rocks and minerals in vacuum; in so doing microcraters on the targets, glass particles, condensates were formed and gases solved in the bulk of the rock and mineral grains were released. It is shown that volatilization from only the crater glass layers is negligible, which fully confirms the theoretical predictions of Nussinov and Chernyak.The volatilizations from the drops formed by the micrometeoric impacts can be noticeable. For micron-sized drops, predominant among the others after the impact, the volatilization of Na, K and other volatiles can be up to 10 to 20%. For larger-sized (d10² m) drops the volatilization should lead to the appearance of the significant gradients of the element concentrations over the particle cross-section and as a result of their normalization it leads to the surface enrichment by some elements (Si and others).The mechanism of dust formation due to the surface rocks attack by volatilizing alkaline metals (Naughtonet al.) on the Moon probably is not effective. It is the consequence of such a fact that the condensate of the target materials evaporated due to other simultaneous micrometeoric impacts and had the same (as the target has) elemental composition is the very strong background for volatilizing and condensating alkaline elements.Preliminary conclusions about a possible correlation between the composition and the sizes of dust particles in the Solar system and in the Universe (at similar initial composition) have been drawn.