Shear-zone deformation and bulk strain in granite-greenstone terrain of the Western Superior Province,Canada

The later Archaean history of the granite-greenstone terrain of the western Superior Province in Manitoba was marked by the development of numerous shear zones with varying orientation and sense of movement. Data are presented on the orientation, width and displacement of 15 shear zones in a 61,000 km² area east of Lake Winnipeg. By making simplifying assumptions, estimates are made of the orientation of the maximum compressive stress (N-S) and the bulk shortening strain caused by the shear zone displacements (39–45%).The estimates of shear zone displacement strain are compared with estimates of bulk strain obtained by analysing the granite-greenstone shape pattern over a large area of the western Superior Province, again making simplifying assumptions. As expected, the contribution of the more ductile greenstones to the bulk strain is proportionately greater. A value of around 40% is indicated for the bulk shortening strain.Estimates of mean shear strain obtained both from shear zone displacement/width measurements and from strain profiles show a wide range in values from around 10 in some narrow zones to around 1 in very wide zones.     

Evidence against the core/cover interpretation of the southern sector of the Menderes Massif,west Turkey

The Menderes Massif, in western Anatolia, has been described as a lithological succession comprising a basal ‘Precambrian gneissic core of sedimentary origin’ overlain in sequence by ‘Palaeozoic schist’ and ‘Mesozoic-Cenozoic marble’ forming the envelope. The boundary between core and schist envelope was interpreted as a major unconformity, the ‘Supra-Pan-African unconformity’. By contrast, our field observations and geochemical data show that around the southern side of Besparmak Mountain, north of Selimiye (Milas), the protoliths of highly deformed, mylonitized augen gneisses are granitoid rocks intrusive into the adjacent Palaeozoic metasedimentary schists. The field relationships indicate the age of intrusion to be younger than late Permian and there is no evidence for the existence of either an exposed Precambrian basement or the ‘Supra-Pan-African unconformity’ in this sector of the Menderes Massif.     

The low seismic activity of the Korean Peninsula surrounded by high earthquake countries

Although the Korean Peninsula is locatednear several great earthquake regions suchas NE China and SW Japan, it has neversuffered from catastrophic earthquakes forthe last 2000 years according to historicaland instrumental records. We investigatedthe low seismicity of Korea based on thehypothesis of the Baikal-Korea Plate (BKP)or Amurian Plate movement which isinitiated by the Baikal Rift Zone spreadingin a southeastward motion with acounter-clockwise rotation due to thecollision of the Indian Plate against theEurasian Plate. Many disastrous earthquakesof NE China, SW Japan and Sakhalin releaselarge amounts of seismic energy along theboundary of the Baikal-Korea Plate. It isnecessary to compute the released seismicenergy along the presumed boundary of theBaikal-Korea Plate compared to the KoreanPeninsula in order to estimate themicro-plate boundary. The total energyreleases (1900–1999) from the majordisastrous earthquakes (M6.0) alongthe Baikal-Korea plate are about10³–10⁴ times as much as theKorean Peninsula (M3.0). The focalmechanisms for the intra-continentalearthquakes near and/or along theBaikal-Korea Plate boundary of NE China, SW Japan, Sakhalin and Mongolia mostlyrepresent the horizontal motions of theright-lateral strike slip type, indicatingthat the Baikal-Korea Plate is acounter-clockwise and transcurrent motion. The relative displacement vectors of GPS(global positioning system) also indicatedthat the Baikal-Korea Plate movescounter-clockwise around the KoreanPeninsula. These factors may indicate thatthe Korean Peninsula is not located at thePlate boundary, but just within a margin ofthe Baikal-Korea Plate which movessoutheastward with a counter-clockwiserotation from the Baikal Rift Zone in NEAsia. Therefore there is no enoughaccumulated strain to generate largeearthquakes in the Korean Peninsula and itmakes the Korean Peninsula free fromseismic hazard of large catastrophicearthquakes.     

Retracking considerations in spaceborne GNSS-R altimetry

The European Space Agency Passive Reflectometry and Interferometry System In-orbit Demonstrator (IoD) aims to perform mesoscale altimetric observations by measuring the Global Navigation Satellite System (GNSS) opportunity signals reflected over the sea surface. Altimetry based on GNSS reflectometry (GNSS-R) is significantly affected by satellite motion, since it requires relatively long integration times to reduce noise. We present the impact of the satellite motion on the GNSS-R observables and the need to retrack the waveforms. By using a detailed GNSS-R space mission simulator, the change of delay difference between the direct and the reflected signals during the incoherent averaging of the waveform has been investigated. Their effects on the waveform shape and the altimetric performance are presented comparing the aligned and non-aligned waveforms. Results show that the performance of spaceborne GNSS-R altimeter is seriously degraded without a proper alignment of the waveform samples.     

The Asian Dust Aerosol Model 2 (ADAM2) with the use of Normalized Difference Vegetation Index (NDVI) obtained from the Spot4/vegetation data

The operational Asian Dust Aerosol Model (ADAM)1 in Korea Meteorological Administration has been modified to the ADAM2 model to be used as an operational forecasting model all year round not only in Korea but also in the whole Asian domain (70-160°E and 5-60°N) using the routinely available World Meteorological Organization (WMO) surface reporting data and the Spot/vegetation Normalized Difference Vegetation Index (NDVI) data for the period of 9 years from 1998 to 2006. The 3-hourly reporting WMO surface data in the Asian domain have been used to re-delineate the Asian dust source region and to determine the temporal variation of the threshold wind speed for the dust rise. The dust emission reduction factor due to vegetation in different surface soil-type regions (Gobi, sand, loess, and mixed soil) has been determined with the use of NDVI data. It is found that the threshold wind speed for the dust rise varies significantly with time (minimum in summer and maximum in winter) and surface soil types with the highest threshold wind speed of 8.0 m?s^?1 in the Gobi region and the lowest value of 6.0 m?s^?1 in the loess region. The statistical analysis of the spot/vegetation NDVI data enables to determine the emission reduction factor due to vegetation with the free NDVI value that is the NDVI value without the effect of vegetation and the upper limit value of NDVI for the dust rise in different soil-type regions. The modified ADAM2 model has been implemented to simulate two Asian dust events observed in Korea for the periods from 31 March to 2 April 2007 (a spring dust event) and from 29 to 31 December 2007 (a winter dust event) when the observed PM₁₀ concentration at some monitoring sites in the source region exceeds 9,000 μg m^?3. It is found that ADAM2 model successfully simulates the observed high dust concentrations of more than 8,000 μg m^?3 in the dust source region and 600 μg m^?3 in the downstream region of Korea. This suggests that ADAM2 has a great potential for the use of an operational Asian dust forecast model in the Asian domain.     

Environment and mass dependencies of galactic λ spin parameter: cosmological simulations and observed galaxies compared

We use a sample of galaxies from the Sloan Digital Sky Survey (SDSS) to search for correlations between the λ spin parameter and the environment and mass of galaxies. In order to calculate the total value of λ for each observed galaxy, we employed a simple model of the dynamical structure of the galaxies, which allows a rough estimate of the value of λ using only readily obtainable observables from the luminous galaxies. Use of a large volume-limited sample (upwards of 11 000) allows reliable inferences of mean values and dispersions of λ distributions. We find, in agreement with some N -body cosmological simulations, no significant dependence of λ on the environmental density of the galaxies. For the case of mass, our results show a marked correlation with λ, in the sense that low-mass galaxies present both higher mean values of λ and associated dispersions, than high-mass galaxies. These results provide interesting constrain on the mechanisms of galaxy formation and acquisition of angular momentum, a valuable test for cosmological models.     

Negative Impacts of Perkinsus olseni Infection in Manila Clam Ruditapes philippinarum Observed from Tidal Flats in Anmyeondo Island on the West Coast of Korea During Post-Spawning Period

Ocean Science Journal - The high load of protozoan parasites in marine bivalves often leads to mass mortalities of the hosts. On the west coast of Korea in the Yellow Sea, the protozoan parasite...