Multi-proxy Stratigraphy and Paleoceanographic Variations in Sediment from the Korea Plateau,East Sea (Japan Sea), Over the Last 500 kyr

Ocean Science Journal - High-resolution geochemical measurements were performed on core E09-08, which was taken from the top flat area of the Korea Plateau in the East Sea (Japan Sea). Based on...     

Lithological and structural prerequisites for localization of ore deposits in the Mesoproterozoic-Neoproterozoic Uchur-Maya depression (Siberian Platform)

A set of sketch maps has been compiled including a structural map for the Uchur-Maya depression, maps of the fractures based on the data derived from the digital elevation model processed using the modulus of the topographic gradient for discriminating the fault boundaries, and maps of the lineament distribution and the density of the elementary linear structures. On these sketch maps, the location of the ore deposits and the occurrences of various metals are plotted within the bounds of the Uchur-Maya depression with the defining structural and lithological factors that control the ore occurrences. The locations of the ore objects relative to the differently oriented faults and the lineament network based on the data of the digital elevation model’s processing and the density of the linear structures have been analyzed. The most important lithological factors that control the ore deposits are the pre-Mesoproterozoic structural-stratigraphic unconformity zones, the contact zones between the Mesoproterozoic formations with their contrasting physical and chemical properties, and the high-porosity (cavernous) dolomite member in the Yudomian Group of the Vendian.     

Reductive dechlorination of polychlorinated biphenyls (PCBs) by ultrasound-assisted chemical process (UACP)

The dechlorination of aqueous polychlorinated biphenyls (PCBs) using the ultrasound-assisted chemical process (UACP), which is a combination of ultrasonic irradiation and radical generations using di-tert-butyl peroxide as a radical initiator and ferrous ion as a catalyst at moderate temperature in alkaline 2-propanol, was demonstrated with a high reduction of PCBs. A commercial PCB-containing compound, Aroclor 1260, was also decomposed with the removal efficiency of 97 % achieved within 3 h of UACP. The gas chromatograph was used as a quantitative method to measure the decomposition rate of PCBs. The competitive elimination among the ortho (2-position), meta (3-position), and para (4-position) chlorine atoms of PCB was also identified.     

Comparing recent geopotential models in Andalusia (Southern Spain)

This work focuses on the comparison between satellite-only and combined Global Geopotential Models (GGMs) derived from the CHAMP and GRACE satellite missions with land gravity anomalies, geoid undulations provided by the gravimetric geoid ANDALUSGeoid2002 and GPS/levelling geoid undulations in Andalusia in order to find the GGM that best fits this area in order to be used in a further geoid computation. The results show that the EIGEN-CG01C model or the combined models GGM02C/EIGEN-CG01C and ITG-CHAMP01E/EIGEN-CG01C should be used.     

Static telescope aberration measurement using lucky imaging techniques

A procedure has been developed to compute static aberrations once the telescope PSF has been measured with the lucky imaging technique, using a nearby star close to the object of interest as the point source to probe the optical system. This PSF is iteratively turned into a phase map at the pupil using the Gerchberg?CSaxton algorithm and then converted to the appropriate actuation information for a deformable mirror having low actuator number but large stroke capability. The main advantage of this procedure is related with the capability of correcting static aberration at the specific pointing direction and without the need of a wavefront sensor.     

Cycling Changes in the Amplitudes of the 27-Day Variation of the Galactic Cosmic Ray Intensity

We study quasi-periodical changes in the amplitudes of the 27-day variation of the galactic cosmic ray (GCR) intensity, and the parameters of solar wind and solar activity. We have recently found quasi-periodicity of three to four Carrington rotation periods (3?–?4 CRP) in the amplitudes of the 27-day variation of the GCR intensity (Gil and Alania in J. Atmos. Solar-Terr. Phys. 73, 294, 2011). A similar recurrence is recognized in parameters of solar activity (sunspot number, solar radio flux) and solar wind (components of the interplanetary magnetic field, solar wind velocity). We believe that the 3?–?4 CRP periodicity, among other periodicities, observed in the amplitudes of the 27-day variation of the GCR intensity is caused by a specific cycling structure of the Sun’s magnetic field, which may originate from the turbulent nature of the solar dynamo.     

Fractures and Breakouts Analysis from Borehole Image Logs: Preliminary Results for Interpretation of Stress History and In Situ Stress State

Fractures and borehole breakouts from image data acquired from Logging-While-Drilling (LWD) were identified and analyzed using GMI Imager software. Conductive (e.g., dark-colored images) and resistive fractures (e.g., light-colored images) were identified on the images. Breakouts occurring along the borehole wall in the direction of the minimum horizontal stress were also investigated. For fracture analysis, we investigated dip and direction of fractures on the resistivity images acquired from two sites in the Ulleung Basin, East Sea. Dip angles at two sites are 42° and 62.5° on average, respectively. Dip direction shows preferred orientation northerly. From fracture analysis, the maximum horizontal stress direction may be the NW-SE direction. This pattern likely reflects regional stress regime of this area. We also analyzed borehole breakouts on the LWD image data (borehole radius and density data) acquired from Site U1378, IODP Exp. 334 off Costa Rica. We estimated present-day in situ stress orientation from borehole breakouts. Breakout orientation of slope sediments at Site U1378 indicates that maximum horizontal principal stress direction is oriented northwest-southeast. This direction is probably related to plate motion in this area. This study presents preliminary results in order to interpret not only stress history of the Ulleung Basin but also in situ stress state of continental slope off Costa Rica in near future.     

Impacts of land use on the hydrological response of tropical Andean catchments

Changes in land use and land cover are major drivers of hydrological alteration in the tropical Andes. However, quantifying their impacts is fraught with difficulties because of the extreme diversity in meteorological boundary conditions, which contrasts strongly with the lack of knowledge about local hydrological processes. Although local studies have reduced data scarcity in certain regions, the complexity of the tropical Andes poses a big challenge to regional hydrological prediction. This study analyses data generated from a participatory monitoring network of 25 headwater catchments covering three of the major Andean biomes (páramo, jalca and puna) and links their hydrological responses to main types of human interventions (cultivation, afforestation and grazing). A paired catchment setup was implemented to evaluate the impacts of change using a ‘trading space‐for‐time’ approach. Catchments were selected based on regional representativeness and contrasting land use types. Precipitation and discharge have been monitored and analysed at high temporal resolution for a time period between 1 and 5 years. The observed catchment responses clearly reflect the extraordinarily wide spectrum of hydrological processes of the tropical Andes. They range from perennially humid páramos in Ecuador and northern Peru with extremely large specific discharge and baseflows, to highly seasonal, flashy catchments in the drier punas of southern Peru and Bolivia. The impacts of land use are similarly diverse and their magnitudes are a function of catchment properties, original and replacement vegetation and management type. Cultivation and afforestation consistently affect the entire range of discharges, particularly low flows. The impacts of grazing are more variable but have the largest effect on the catchment hydrological regulation. Overall, anthropogenic interventions result in increased streamflow variability and significant reductions in catchment regulation capacity and water yield, irrespective of the hydrological properties of the original biome. Copyright © 2016 The Authors. Hydrological Processes. Published by John Wiley & Sons Ltd.     

Present-day stress-strain state in the upper crust of the Amurian lithosphere plate

Consideration is given to the issues of studying current geodynamic processes in the upper crust within the Amurian lithosphere plate. Present-day geodynamic processes in the lithospheric layer are shown to be located by different indicators that correspond to geological features of comparable scale and varying extension and are recognized by a set of investigative techniques. A variety of original data on vertical and horizontal motions of the surface is used to indicate the latest deformation processes. The best studied Trans-Baikal block was used as an example to analyse present-day geodynamics in the context of the tectonic flows conception. The present ideas concerning the stress-strained state of the upper part of the section within the Amurian plate have been refined based on non-uniformly scaled factors.