Differentiation of the Cuthbert Lake ultramafic dikes and related mafic dikes

In the Cuthbert Lake region of north-central Manitoba, northeasterly trending ultramafic-mafic dikes, part of the Molson dike swarm, show a range of composition from gabbro to olivine-hornblende pyroxenite to hornblende peridotite. The major dike which is ultramafic in composition is 60 m thick. Olivine and chromian spinel were the earliest cumulus phases formed in a subcrustal magma chamber before the emplacement of the dikes. Orthopyroxene and clinopyroxene were formed following emplacement at about 1120° C. Plagioclase and hornblende were the latest phases to crystallize from the intercumulus melt. Mineralogical and chemical variations across the major dike are interpreted to have resulted from flow differentiation of multiple injections of magma carrying suspended olivine crystals. Olivine phenocrysts changed their compositions from about Fo₈₇ to values ranging from Fo₈₀to Fo₇₃ as a function of the amount of intercumulus melt. The composition of this melt is estimated to have been basaltic. A mafic dike, about 10 m thick and occurring about 20 m away from the main ultramafic dike, is believed to have been formed from magmas that were tapped from an upper layer overlying the olivine-rich zone in a subcrustal magma chamber. Separation must have occurred when clinopyroxene and plagioclase appeared on the liquidus.Geological Survey of Canada Contribution 36486     

DDT,DDE, and PCB residues in fish,crustaceans and sediments from the eastern Mediterranean coast of Turkey

Residues of DDE, DDT and PCBs were determined in four different commercial bony fishes: grey mullet, red mullet, striped mullet and gold bandgoat fish, as well as in shrimps, limpets and sediments obtained from the eastern Mediterranean coast of Turkey. The PCB levels in living organisms and sediments were found to be very low, and in most cases below the detection limits. The DDE and DDT values were relatively high compared to PCBs and there was a linear correlation between the organochlorine residue concentrations and the extractable organic material of the analysed samples.     

Kinematics of landslide estimated by repeated GPS measurements in the Avcilar region of Istanbul, Turkey

The aim of this study is to analyze the spatial and temporal behavior of the landslide located in Avcilar region which is situated between Kucukcekmece and Buyukcekmece Lakes in the north-west of Marmara region, Turkey. A network consisting of 10 sites has been surveyed four times from November 2007 to May 2009 using Global Positioning System (GPS). The deformation analysis has been applied to determine the landslide movement parameters of the sites using GPS measurements of the four epochs. The reliable and high precision deformation rates are presented in terms of displacement vectors, velocity vectors and changes of accumulated strain. Landslides of the region are characterized from a regional GPS network. Each site has statistically different temporal behavior and significant relative motions and the region has irregular landslide movements.     

Evaluation of the GPS Precise Point Positioning technique during the 21 July 2017 Kos-Bodrum (East Aegean Sea) Mw 6.6 earthquake

Precise Point Positioning (PPP) algorithms have been widely used in the Global Positioning System (GPS)-based applications. A PPP technique with a single receiver provides effective solutions where accurate absolute positioning is required. This paper provides the performance assessment of GPS PPP for detecting the displacements caused by an earthquake. For this purpose, the earthquake that occurred on 21 July 2017 at Kos-Bodrum with the impact of Mw 6.6 was investigated by analyzing the data of the permanent GPS stations located around the related region with the PPP technique. The location distances of these GPS stations range from 10 to 89 km to the epicenter of this earthquake. GPS data provided from seven permanent stations from the Continuously Operating Reference Stations-Turkey (CORS-TR) and local Bodrum CORS networks were processed to determine the co-seismic displacements during the earthquake. The data of these stations for days of year (DOYs) 200, 201, 202, and 203 were analyzed with post-process static PPP and kinematic PPP methods. GIPSY-OASIS II v6.4 was used for processing the data and all of the solutions were performed in the ITRF2008 reference frame. Two strategies were followed on the post-process static solutions. In the first strategy, 4-day data with 24-h observations were separately analyzed day by day. In the second strategy, the 24-h data were divided into 3-h duration, which is the minimum duration for optimum PPP solutions, and then the analyses were performed. When the displacements between DOYs 200 and 203 are considered in the 24-h data analysis, significant displacements have been observed through northwest direction in the northern stations whereas MUG1 is excluded. Moreover, there is significant displacement through the southeast direction in the station DATC located in the south of the epicenter. When the 3-h solutions are examined, displacements, especially on n and e directions, are observed starting from the solutions, which include Mw 6.6 earthquake. According to the kinematic PPP solutions, the effects of the Mw 6.6 earthquake can be seen clearly in the stations DATC, ORTA, TRKB, and YALI. Considering all outcomes, the PPP technique with both static and kinematic solutions provides effective results for detecting the displacements during the earthquake.