Distribution of Ixodes ricinus L., 1758 and Ixodes persulcatus Shulze, 1930 (Parasitoformes,Ixodidae) in Russia and adjacent countries in view of observable climate changes

Possible changes in the area inhabited by the ticks Ixodes ricinus and Ixodes persulcatus, the main transmitters of tick-borne encephalitis and Lyme disease in Russia, caused by temperature changes in 1976–2005 compared to 1946–1975 are discussed. It is shown that these changes could result in some areal expansion of these species. In the European part of Russia, I. ricinus expanded its areal boundaries to the east 100–300 km. I. persulcatus expanded its areal in the Asian part of Russia. Its boundary moved to the north and northeast 100–300 km. Areal expansion both of species has not been observed.     

Kyanite–sillimanite metamorphism of the Precambrian complexes,Transangarian region of the Yenisei Ridge

Four Precambrian metamorphic complexes in the vicinity of regional faults in the Transangarian region of the Yenisei Ridge were examined. Based on geothermobarometry and P-T path calculations, our geological and petrological studies showed that the Neoproterozoic medium-pressure metamorphism of the kyanite–sillimanite type overprinted regionally metamorphosed low-pressure andalusite-bearing rocks at about 850 Ma. A positive correlation between rock ages and P-T estimates for the kyanite-sillimanite metamorphism provide evidence of the regional structural and tectonic heterogeneity. The medium-pressure metamorphism was characterized by (1) the development of deformational structures and textures, and kyanite-bearing blastocataclasites (blastomylonites) with sillimanite, garnet, and staurolite after andalusite-bearing regional metamorphic rocks; (2) insignificant apparent thickness of the zone of medium-pressure zonal metamorphism (from 2.5 to 7 km), which was localized in the vicinity of the overthrusts; (3) a low metamorphic field gradient during metamorphism (from 1–7 to 12 °C/km); and (4) a gradual increase in lithostatic pressure towards the thrust faults. These specific features are typical of collisional metamorphism during overthrusting of continental blocks and are evidence for near-isothermal loading. This event was justified within the framework of the crustal tectonic thickening model via rapid overthrusting and subsequent rapid uplifting and erosion. The results obtained allowed us to consider medium-pressure kyanite-bearing metapelites as a product of collision metamorphism, formed either by unidirectional thrusting of rock blocks from Siberian craton onto the Yenisei Ridge in the zones of regional faults (Angara, Mayakon, and Chapa areas) or by opposite movements in the zone of splay faults of higher orders (Garevka area).     

Berriasian (Lower Cretaceous) brachiopods from the Crimea

Four successive assemblages of Berriasian brachiopods distinguished for the first time in the Crimea are correlated with concurrent subdivisions of the ammonoid scale. Berriasian brachiopods are represented by 44 species of 27 genera and 14 families, which are most complete in terms of taxonomic composition as compared to other concurrent brachiopod faunas known elsewhere. The assemblages are dominated by local species. As is proved, the Berriasian brachiopods studied are appropriate for age determination, subdivision and correlation of their host deposits. Their geographic distribution that has been analyzed elucidates connections of the Berriasian sea basins within the Mediterranean paleozoogeographic region.     

VLA observations of class I methanol masers in the region of low-mass star formation L1157

We present the results of VLA observations of a maser candidate in the low-mass star formation region L1157 in the 7₀-6₁ A ⁺ transition at 44 GHz. The line is emitted by a compact, undoubtedly maser source associated with clump B0a, which is seen in maps of L1157 in thermal lines of methanol and other molecules. A much weaker compact source is associated with clump B1a, which is brighter than B0a in thermal methanol lines. The newly detected masers may form in thin layers of turbulent post-shock gas. In this case, the maser emission may be beamed, so that only an observer located in or near the planes of the layers can observe strong masers. On the other hand, the maser lines are double with a “red” asymmetry, indicating that the masers may form in collapsing clumps. A detailed analysis of collapsing-cloud maser models and their applicability to the masers in L1157 will be developed in subsequent papers.     

A study on the interpretation of spontaneous potential and resistivity logs in layered aquifer sequence of Pondicherry Region,South India

Geophysical logs provide a strong mechanism for interpretation and determination of the depositional environments, facies and also help in interpretations of hydrogeologic units. Spontaneous potential (SP) and resistivity logs can be used as an indicator of textural parameters. Pondicherry region has a complicated geology and with formation of different ages. The boreholes (BH) of this region are examined for litholog, SP and resistivity from four different BH locations, viz, Ariyankuppam, Chinnaverampattinam, Thavalakuppam and Nallavadu. These locations were studied and interpreted by using the shapes of the curves to identify the depositional environments, and this was later compared with the vertical litholog profile. Comparing the variation of these logs, the lateral variation of sedimentary facies was also attempted. The average resistivity values of Ariyankuppam, Chinnaverampattinam, Thavalakuppam and Nallavadu are 42.4, 30.4, 50.4 and 28.3?Ωm, respectively. Majority of the resistivity values corresponds from fine- to medium-grained sand, clayey pebbles, fine to very coarse sand and clayey sand with lignite. Frequency of resistivity values in each BH were identified for determining the dominant representative grain size. The study has pointed out the lithological variation of the system laterally and vertically using geophysical well logs.     

A synthesis of the geologic evolution of Taiwan

The island arc of Taiwan is composed of Cenozoic geosynclinal sediments more than 10,000 m thick, lying on a pre-Tertiary metamorphic basement. Pleistocene to Miocene andesitic islands surround the main island and are related mostly to arc magmatism. The Penghu Island Group in the Taiwan Strait is covered with Pleistocene flood basalt. Neogene shallow marine clastic sediments are exposed mainly in the western foothills with Pleistocene andesitic extrusives at the northern tip and the northeastern offshore islands. A thick sequence of Paleogene to Miocene argillitic to slaty metaclastic rocks underlies the western Central Range and forms the immediate sedimentary cover on the pre-Tertiary metamorphic complex to the east, which represents an older Mesozoic arc-trench system. The Coastal Range in eastern Taiwan is a Neogene andesitic magmatic arc, including also a large variety of volcaniclastic and turbiditic sediments. Cenozoic Taiwan is the site of arc-continent collision where the Luzon arc on the Philippine Sea plate overrides the Chinese continental margin on the Eurasian plate. East and northeast of Taiwan, the polarity of subduction changes whereby the oceanic Philippine Sea plate is subducting beneath the Ryukyu arc system on the Eurasian plate. Continent-arc collision in Taiwan island is anomalous and may occur in a broad belt of deformation rather than along a well-defined plate boundary or subduction zone.     

Preliminary results of seismic hazard assessment in the Sannio-Matese area of Southern Italy

The seismic hazard in the Sannio-Matese area has been worked out by a modification of the McGuire (1976) computing programme, taking into account the influence of nine potential seismic source zones.The method uses truncated-quadratic intensity-frequency distribution and azimuth-dependent intensity attenuation derived from isoseismal maps for each of the seismogenetic sources. A new modification has been introduced to take into account different decay of the intensity in the near (to VIII degree) and far (from VIII degree) field.Different assumptions about maximum possible intensities and truncation of intensity-frequency laws are used to evaluate the effects of the uncertainties on the computed hazard at high intensities. Intensities associated with different level of annual probability are computed for five test sites in the considered area. Maps displaying the expected intensity for a mean return period of 500 years (pa 0.002) are presented and compared with observed intensities.Presented at the XXIst General Assembly of the European Seismological Commission, Symposium on Methods of Seismic Hazard Assessment in Europe, Sofia, 23–27 August 1988.     

Igneous carbonates in dolerites of Franz Joseph land

Doklady Earth Sciences - Carbonates showing the signs of crystallization from a melt were found in dolerites and basalts of lava covers and dikes of Alexandra Land, Heiss, and Newcomb islands....     

U-Pb dating of minerals in alteration halos of Superior Province massive sulfide deposits: syngenesis versus metamorphism

U-Pb geochronology of igneous zircon from rhyolitic host rocks to the Archean Kidd Creek, Geco and Winston Lake massive sulfide deposits, in the Superior Province of Ontario, shows that volcanism, which accompanied mineralization, occupied a narrow time span (2717±2 Ma, 2720±2 Ma and 2723±2 Ma, respectively). Precise ages of hydrothermal monazite, allanite and rutile from alteration zones surrounding the above deposits indicate that these minerals crystallized 40–70 million years after volcanism. Monazite from Kidd Creek mine is 2659±3 Ma old, in agreement with spatially associated 2664±25 Ma old rutile. Monazite from a biotite schist at Geoco mine gives a similar age of 2661±1 Ma. However, monazite from a sericite schist, which hosts the ore at Geco mine, is 2675±2 Ma old. Abraded large monazite grains from three units in the Winston Lake deposit are coeval with biotite crystallization and record an age of 2677±2 Ma, approximately the same as monazite in the sericite schist at Geco. Data points from allanite fractions from both the Winston Lake and Geco deposits fall on a Pb-Pb isochron that gives an age of 2672±5 Ma. Rutile from Winston Lake gives a younger age of 2651±6/-2 Ma and may date retrograde alteration of biotite to chlorite. The ca. 2676 Ma age of monazite from Winston Lake and in the sericite schist at Geco mine probably dates a regional metamorphic event that affected most of the southern Superior Province. The ca. 2660 Ma old monazite in the biotite schist at Geco mine and in the chlorite-sericite alteration at Kidd Creek may date later K-metasomatism caused by metamorphically derived fluids that were focussed along old fault structures. Such fluids were also responsible for local sulfide remobilization. Monazite and rutile are spatially associated with chlorite and sericite alterations at Kidd Creek. Their young ages indicate that these originally syngenetic mineral assemblages may have been significantly affected by regional metamorphism. Formation of monazite at all three deposits studied was a result of significant REE remobilization during metamorphism. The discrete character of syn-metamorphic hydrothermal activity in different units of the same deposit, as well as its synchroneity among different, widely separated deposits, requires a mechanism for episodic injection of heat and fluid into the crust on a regional scale. These activities are broadly coeval with, and probably related to, plutonism within adjacent metasedimentary subprovinces and middle to lower crustal metamorphism in the Superior Province.