Karen Black December 2, 2011 Geologic relationships of granitoid bodies in NW Turkey 1. Introduction Purpose This summer, I conducted fieldwork in NW Turkey and collected samples from granite plutons in order to better understand their tectonic evolution. I prepared for this work by collecting maps of my field area from Google Earth and Google Maps. These consisted mainly of road maps. I also used a paper geologic map. I would now like to create more useful and conclusive maps of my field area that can be used in my thesis. These maps will effectively display the geology of my field area as well as sample locations. I would also like to obtain DEMs of my field area to help interpret the relationship between faults and granite plutons in my field area. It will be very helpful to have all of this information stored in a usable GIS that I can manipulate as needed. I will also be able to create maps from the DEM that can be used to analyze that interaction between faults and the granite plutons in the region. Background Turkey is the amalgamation of numerous continental fragments that were sutured together by the opening and closing of Tethyan Oceans. Currently, Turkey is undergoing compressional tectonics in the east, strike-slip tectonics across the entire northern portion of the continent, and extensional tectonics in the west. As the African plate collides with the Eurasian plate, the Arabia platform collides with Anatolia in the west. A free lateral boundary in the west allows for strike-slip tectonics to occur and for Turkey to escape laterally southwestward via the North Anatolian Shear Zone. The retreat of the Hellenic Arc is believed to be caused by slab-roll back that results in extension in western Turkey.Northwest Turkey is a complex region that contains geologic evidence of the suturing of continental fragments followed by the current N-S extension and SW strike-slip movements. There are multiple granite bodies in this region that were exhumed during the current extensional regime. During my field season, I focused on collecting samples from three plutons including the Kozak, Eybek, and Kestanbolu. Objective The object of this project is to create a useable GIS that will be used to analyze the geologic relationships of granitoid bodies in northwest Turkey. Data will also be used to analyze the relationships of samples collected this past summer. The final products will be a geologic map of my field area, a road map with granite outcrops, contours and sample locations, and a hillshade and aspect map with granite outcrops and faults to help analyze the topography of the region. 2. Data Collection ASTER ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) Global DEM v.2 data was obtained from NASA (http://reverb.echo.nasa.gov/reverb/#utf8=%E2%9C%93&spatial_map=satellite&spatial_type=rectangle). This ASTER GDEM is a product of METI and NASA. ASTER data was sent to me via e-mail Mark Helper because a NASA account is needed to download data from this website. I needed two tiles to cover my field area and they are N39E026 and N39E027. This data is 30m resolution and is in a zipped folder that contains metadata and a GeoTiff.Geologic Map An online geologic map of Turkey with high resolution was hard to find. I scanned a paper version of a geologic map with my field area and saved it as a .jpeg that could be opened in ArcMap. Roads An online file containing an accurate and complete set of roads in Turkey was hard to find. During fieldwork, I found that Google Maps was very accurate with roads in my field area. Therefore, I used a screen shot of Google Maps for roads of my field area for this GIS. I was also able to find precise latitude and longitude coordinates for points on my screen shot that could be used to georeference my roads screen shot. Samples During field work, sample locations were recorded as waypoints on a handheld GPS unit. These latitudes and longitudes were exported as an excel file that could be imported into ArcMap. 3. ArcGIS Before any processing any data with ArcGIS, I first created a folder for my project on an external drive. This folder contained the two unzipped ASTER files, the scanned geologic map, screen shot of roads from Google Maps, and the excel table of my sample locations. I also, created a geodatabase for the geologic map I would be digitizing titled “NWTurkey”. Also, I created a folder titled ‘MyData’ to save anything I modified such as the ASTER files. I opened a black ArcMap document and connected it to this project folder I created. I initially set the data frame coordinate system to GCS_WGS1984 (Figure 3.1).4. ArcGIS Data Processing ASTER To process the ASTER data I dragged my two unzipped geotiff files from ArcCatalog into ArcMap. These files were automatically projected in my document. In order to see the elevation in documents I had to change the symbology of the layers (Figure 4.1). The symbology tab is located under properties when you right click on the ASTER layers in the Table of Contents (TOC). Symbology was changed to stretched with standard deviations of n=2. Figure 3.1. The spatial reference of the data frame was set to GCS_WGS1984.Because there are two ASTER datasets, the elevation scales are different for each file and there appears to be a line between the two sets (Figure 4.1). Therefore, I used to the Mosaic tool to create a new raster with the two datasets combined (Figure 4.2). The ‘mosaic to new raster’ tool is located in Arctoolbox under data management tools, then raster, and then raster dataset. Figure 4.1 Screen shot of ArcMap and 2 ASTER data. Notice the line in the middle separating the two files. Figure 4.2. Screen shot of ArcMap and one ASTER raster after using the mosaic toolGeologic Map I loaded the geologic map into my ArcMap document by dragging the scanned map I save as a .jpeg from ArcCatalog into my document. To georeference the map (Figure 4.3), I turned on the georeference toolbar and also opened the link table. I used the ‘add control points’ tool to add six points to intersecting latitude and longitude lines on the geologic map in my field area. I then changed the X Map and Y Map locations in the link table to the corresponding latitude and longitude points on the map. I rectified the image, saved it in the ‘My_Data’ folder, and opened the new georeferenced raster in ArcMap. In