DESCRIPTION OF THE DIGITAL DATABASE FOR Bedrock geologic and structural map through the western Candor Colles region of Mars USGS SCIENTIFIC INVESTIGATIONS MAP 3309 Reference: Okubo, C., 2014, Bedrock geologic and structural map through the western Candor Colles region of Mars, Scale 1:18,000, U.S. Geological Survey Scientific Investigations Map SIM 3309. URL: http://pubs.usgs.gov/sim/3309 INTRODUCTION Candor Colles are a population of low, conical hills along the southeast flank of Ceti Mensa, in west Candor Chasma, within the Valles Marineris system. The structure and geology of the layered deposits in the Candor Colles region corresponding to units Avfs, Avme and Hvl of (Witbeck and others, 1991) are reevaluated in this 1:18,000-scale map. The primary dataset used in mapping is a pair of stereo HiRISE observations PSP_001641_1735 and PSP_002063_1735. The 1 m/pixel orthorectified HiRISE images were most useful for identifying the mapped features (e.g., bedding, faults, unconformities), and the 0.25 m/pixel versions were used only to verify interpretations of meter-scale features such as bedforms and fault offsets that were initially made using the 1 m/pixel images. In this map, all units are allostratigraphic; that is, they are defined by unconformities at their upper and lower contacts. Allostratigraphy was selected because at HiRISE scale, bounding unconformities can be directly observed, are the most rominent stratigraphic divisions observed, and are mappable in a systematic way. While there are numerous unconformities in the mapped layered deposits, not all unconformities define unique geologic units. Instead, geologic units are identified primarily based on the most prominent regional unconformities observed within the map area and in adjacent areas. Secondarily, each geologic unit is further described based on characteristic surface expressions (albedo, erosional texture, bedforms). Each unit may contain numerous subordinate unconformities that do not define unit boundaries. The intent of this approach is to define broad units that are mappable at regional scales (i.e., these units could be sensibly included within a smaller-scale geologic map of west Candor Chasma in its entirety). This map is the first in a series of large-scale geologic maps in west Candor Chasma, and an important objective of this broader effort is to define units that can be correlated between maps. Further, only bedrock units were defined. Surficial materials such as eolian sand dunes were not mapped. All GIS data are in Mars Transverse Mercater using the Mars 2000 geographic coordinate system (GCS_Mars_2000_Sphere, 3396190.0 radius). Units are in meters. Center Longitude = -75.00 GEOLOGIC CONTENT (contents of "ESRI_FileGeodatabase" Folder, SIM3309_Geodatabase_18K.gdb) This ArcGIS geodatabase contains one feature dataset (WCandor7_MTM_clon70Sclat0) with the following features: Bedding_orientations - Point feature class, contains “Dip” and "Strike" fields for the orientations of measured stratigraphy. Has associated annotations in Bedding_orientationsAnno file. Domes - Point feature indicating the location of positive relief domical features. Fracture_orientations - Point feature class, contains “Dip” and "Strike" fields for the orientations of fractures and faults. Has associated annotations in Fracture_orientationsAnno file. Unconformity_orientations - oint feature class, contains “Dip” and "Strike" fields for the orientations of fractures and faults. Has associated annotations in Unconformity_orientationsAnno file. Contacts_unconformities - Line feature class, contacts and unconformities features. Contains a "Type" field denoting the type of contact or unconformity. Contours_100m - Line feature class containing 100 m contours created from the project's digital terrain model (DTM) Contours_20m - Line feature class containing 20 m contours created from the project's digital terrain model (DTM) Cross_sections - Line feature class containing the location of the cross section shown in Figure 6 on the printed and PDF map. Faults - Line feature class, contains a "Type" field denoting the type of fractures and faults. Folds - Line feature class, contains a "Type" field denoting different types of anticlines and synclines. Landslide_features - Line feature class, contains a "Type" field denoting different types scarps, cracks, and downslope directions. Fault zones - Polygon feature class, contains a "Type" with breccia zone around fault as the sole attribute. Geologic_units - Polygon feature class, contains a "Unit_Symbols" field with the unit abbreviations as denoted in the correlation and description of map units. Has associated annotations in Bedding_orientationsAnno file. WCandor7_Anno - Annotation feature class, contains the nomenclature for regional features, the names of the fault zones, and the symbology for the cross section. BASE MAP CONTENT High Resolution Imaging Science Experiment (HiRISE) image were used for the basemap. HiRISE is a camera on board the Mars Reconnaissance Orbiter (MRO). A digital terrain model (DEM/DTM) was generated from a pair of HiRISE images at the USGS in Flagstaff, AZ. References: * McEwen, A. S., et al. (2007), Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE), J. Geophys. Res., 112, E05S02, doi:10.1029/2005JE002605. * Kirk, R.L., et. al., 2008, Ultrahigh resolution topographic mapping of Mars with MRO HiRISE stereo images: Meter-scale slopes of candidate Phoenix landing sites, J. Geophys. Res., 113, E00A24, doi:10.1029/2007JE003000. * http://www.uahirise.org//dtm/about.php See Pamphlet for more information and references. DIGITAL DATABASE AND METADATA PACKAGE (SIM3292_database.zip) The geologic map files, basemaps, and supportive files are included in the database package, as described below: "SIM3309_CandorCollesGeologicGIS_18K" directory -------------------------------------------- Files Description --------------------------------------------------------------------- --------------------------------------------------------------------- SIM3309_README.txt This readme file. SIM3309_metadata.txt Text-format FGDC-style metadata for the database package SIM3309_metadata.xml XML-format FGDC-style metadata for the database package SIM3309_MarsGlobalGeologicGIS_20M_ArcMap10.2.mxd ArcGIS (version 10.2) project "Basemaps" basemap directory -------------------------------------------- "W_Candor_6-7S_284-2E" basemap sub directory dem_w_candor71.tif - HiRISE stereo-derived digital terrain model (DTM/DEM), 1 m/pix PSP_001641_1735_REDmos_dejittered_25cm_o.jp2, PSP_001641_1735_REDmos_dejittered_1m_o.jp2 - one half of a HiRISE stereo pair at full (25 cm/pix) and DEM (1 m/pix) resolutions. PSP_002063_1735_REDmos_dejittered_25cm_o.jp2, PSP_002063_1735_REDmos_dejittered_1m_o.jp2 - one half of a HiRISE stereo pair at full (25 cm/pix) and DEM (1 m/pix) resolutions. Vector directories -------------------------------------------- "SIM3309_Geodatabase_18K.gdb" - ArcMap 10.0 versioned geodatabase "SIM3309_Shapefiles" - This directory contains GIS shapefiles exported from the ArcGIS geodatabase described above using decimal degrees. As such, the names and descriptions for each shapefile are identical to the content of the included geodatabase. See above "GEOLOGIC CONTENT" for details. Users of the database package may wish to download the PDF version of the map for the Description of Map Units. The material described above is available on the World Wide Web at http:/pubs.usgs.gov/sim/3309 "SIM3309_LayersSymbologies" directory -------------------------------------------- Contains layer file to draw symbologies with the correct color and symbol for each of the vector files. ZIP FILES The files described above are packaged within a ZIP file. Utilities to uncompress ZIP files are available for most operating systems and may be found readily with a simple web search. DIGITAL DATABASE FORMAT The digital information compiled in this report used v 10, a commercial Geographic Information System produced by Esri, Redlands, California. OBTAINING HARD-COPY OF SIM 3309 USGS Information Services Box 25286 Denver Federal Center Denver, CO 80225-0046 (303) 202-4200 1-888-ASK-USGS Email: infoservices@usgs.gov