Identification_Information: Citation: Citation_Information: Originator: Ren A. Thompson Originator: Michael N. Machette Originator: Benjamin J. Drenth Publication_Date: 2007 Title: Preliminary Geologic Map of the Sanchez Reservoir Quadrangle and eastern part of the Garcia Quadrangle, Costilla County, Colorado Edition: version 1.0 Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: USGS Open-File Map Issue_Identification: OF 2007-1074 Publication_Information: Publication_Place: Denver, Colorado, U.S.A. Publisher: United States Geological Survey Online_Linkage: http://pubs.usgs.gov/of/2007/1074/ Description: Abstract: This geologic map is based entirely on new mapping by Thompson and Machette, whereas the geophysical data and interpretations were supplied by Drenth. The map area includes most of San Pedro Mesa, a basalt covered mesa that is uplifted as a horst between the Southern Sangre de Cristo fault zone (on the west) and the San Luis fault zone on the east. The map also includes most of the Sanchez graben, a deep structural basin that lies between the San Luis fault zone (on the west) and the Central Sangre de Cristo fault zone on the east. The oldest rocks in the map area are Proterozoic granites and Paleozoic sedimentary rocks, which are only exposed in a small hill on the west- central part of the mesa. The low hills that rise above San Pedro mesa are comprised of middle(?) Miocene volcanic rocks that are undated, but possibly correlative with mapped rocks to the east of Sanchez Reservoir. The bulk of the map area is comprised of the Servilleta Basalt, a regional series of flood basalts of Pliocene age. The west, north, and northeast margins of the mesa are covered by extensive landslide deposits that rest on poorly exposed sediment of the Santa Fe Group. Rare exposures of the sediment are comprised of siltstones, sandstones, and minor fluvial conglomerates. Most of the low ground surrounding the mesa is covered by surficial deposits of Quaternary age. The piedmont alluvium is subdivided into three Pleistocene units, and three Holocene units. The oldest Pleistocene gravel (unit Qao) forms an extensive coalesced alluvial fan and piedmont surface that is known as the Costilla Plains. This surface extends west from San Pedro Mesa to the Rio Grande. The primary geologic hazards in the map are are from earthquakes and landslides. There are three major fault zones in the area (as discussed above), and they all show evidence for late Pleistocene to possible Holocene movement. Two generations of landslides are mapped (younger and older), and both may have seismogenic origins. Purpose: This digital map can serve various purposes other than the primary one—new geologic mapping. The geology can be used in association with topography for land-use plannng, hazards analysis, and resource assessments. This map distinquishes rock units based on lithology (rock type and mineralogy), texture (size of particles or clasts), soil development (for surficial units), and age. Although only a few age determinations are available in the map area, additional dating of correlative units from adjacent areas provide support for our age calls. The ages of surficial units are based on common age-related properties, such as surface morphology, height relative to stream channels, and soil development. Using these criteria, experts can use this map to derive thematic maps that show the suitability of surficial or bedrock material for various uses by man, or to derive maps that show areas susceptible to certain hazards, such as faulting, surface deformation, landsliding and flooding. Supplemental_Information: Coverages included in this geospatial database: sanrgeo: polygon coverage of geologic units and faults sanrpts: age location point features Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2007 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: formal USGS SIM publication planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -105.5283333 East_Bounding_Coordinate: -105.3750000 North_Bounding_Coordinate: 37.1250000 South_Bounding_Coordinate: 37.0000000 Keywords: Theme: Theme_Keyword_Thesaurus: American Geological Institute Glossary of Geology Theme_Keyword: Geologic map Theme_Keyword: San Pedro Mesa Theme_Keyword: Sanchez Reservoir Theme_Keyword: Garcia Theme_Keyword: San Luis basin Theme_Keyword: Rio Grande Rift Theme_Keyword: Geologic map Theme_Keyword: Geologic history Theme_Keyword: Proterozoic rocks Theme_Keyword: Paleozoic rocks Theme_Keyword: Cenozoic rocks Theme_Keyword: Quaternary deposits Theme_Keyword: Sangre de Cristo fault zone Theme_Keyword: Landslides Theme_Keyword: Seismic hazards Theme_Keyword: Santa Fe Group Theme_Keyword: Servilleta basalt Place: Place_Keyword_Thesaurus: U.S. Board of Geographic Names (BGN) Geographic Names Information System (GNIS) Place_Keyword: USA Place_Keyword: United States of America Place_Keyword: Colorado Place_Keyword: Alamosa Place_Keyword: Sanchez Reservoir Place_Keyword: Costilla Plain Place_Keyword: Garcia Place_Keyword: San Pedro Mesa Access_Constraints: None Use_Constraints: None. Users of this geospatial database and geologic information derived there from should acknowledge the U.S. Geological Survey as the source of the data. Although software enables a user to display images at various scales, map data in this report should not be used at scales greater than 1:100,000. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Ren A. Thompson Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: MS 980, Box 25046 DFC City: Denver State_or_Province: CO Postal_Code: 80225-0046 Country: USA Contact_Voice_Telephone: 303-236-0929 Contact_Facsimile_Telephone: 303-236-0214 Contact_Electronic_Mail_Address: rathomps@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2007/1074/pdf/OF07-1074map.pdf Browse_Graphic_File_Description: graphic representation of map layout Browse_Graphic_File_Type: PDF Data_Set_Credit: The geologic mapping was conducted by Ren Thompson and Michael Machette. Theodore Brandt, U.S. Geological Survey, served as primary author of the GIS database. Scott Snyders, U.S. Geological Survey, assisted in GIS database attribution and revision. Paco Van Sistine, U.S. Geological Survey, converted illustration files to GIS format. Native_Data_Set_Environment: Windows_XP, Intel ARC/INFO version 9.2 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Data were entered and checked by the geologist that made the field observations and compilation. The attributes of this geospatial data set consist of text identifiers and numeric codes that indicate the identity of the geologic unit or type of geologic feature, and determine how each feature is colored or symbolized. To check the attribute accuracy, a color check plot was visually compared to the geologist's original compilation. Discrepancies between the digital geospatial data set and the original analog compilation were corrected as needed. Machine-created listings of unique attribute values were used to identify spelling errors or other inconsistencies, and corrections were made as needed. Logical_Consistency_Report: Map elements were visually checked for overshoots, undershoots, duplicate features, polygon closure, and other errors by the authors and by the GIS technician(s) who created the digital database. Automated (ArcInfo) routines were also used to check the databases for polygon label errors, line or point attribution errors, sliver polygons, dangling arcs, intersection errors, and projection information. Check plots of the map were reviewed by another geologist and cartographer for consistency with basic geologic principles and general conformity to USGS mapping standards. Completeness_Report: Data are preliminary. No features that could be accurately represented at a scale of 1:24,000 were eliminated or generalized. The smallest area represented is approximately 150 square meters. All geospatial database elements are attributed. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Most digitized positions on the map that depict distinct contacts between rock formations in the field are estimated to be within 20 m of the actual contact on the land in most instances. Boundaries (lines) between Quaternary units (for example, terrace gravels) that correspond closely to distinct edges of landforms (for example, river terraces) are of comparable accuracy. Boundaries (lines) between some Quaternary units, such as eolian deposits and broad alluvial aprons, are approximately located within an indefinite gradational zone between them. Horizontal positional accuracy is tested by visual comparison of hard copy test plots to source maps or comparing locations of data on a computer monitor to other data layers in the same geographic area. The database contains no elevation data. Accuracy of these digital data indirectly depends on accuracy of the base maps on which the original source geologic maps were compiled. These base maps were made by the U.S. Geological Survey, which routinely checks them for compliance with the National Map Accuracy Standards. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Lewis, R. S. Originator: Derkey, P. D. Title: Digital geologic map of part of the Thompson Falls 1:100,000 quadrangle, Idaho Publication_Date: 1999 Series_Information: Series_Name: U.S. Geological Survey Open File Report Issue_Identification: OFR 99-438 Source_Scale_Denominator: 100000 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1999 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Lewis and Derkey (1999) Source_Contribution: GIS database structure source Process_Step: Process_Description: The geology for the map was compiled by Ren Thompson and Michael Machette, U.S. Geological Survey. The geophysical data were analysed and compiled by Benjamin Drenth, U.S. Geological Survey. Process_Date: 2006 Process_Step: Process_Description: The geology map was drawn in Adobe Illustrator by Michael Machette, U.S. Geological Survey. Process_Date: 2006 Process_Step: Process_Description: The Abobe Illustrator files were converted to ArcInfo coverages by Paco Van Sistine, U.S. Geological Survey. Process_Date: 2007 Process_Step: Process_Description: The geologic database was initially attributed and revised using ArcInfo by Scott Snyders, U.S. Geological Survey. Process_Date: 2007 Process_Step: Process_Description: The geologic database was further attributed and revised using ArcInfo by Theodore Brandt, U.S. Geological Survey. Brandt prepared the scan of the geo-registered base map and served as author of the GIS database. Process_Date: 2007 Process_Step: Process_Description: Checkplots of the coverages were printed and checked against source materials for accuracy and completeness. The database information was checked visually, as well as by using various routines in ArcInfo, for accuracy and consistency. Process_Date: 2007 Process_Step: Process_Description: Metadata for the Preliminary Geologic Map of Sanchez Reservoir Quadrangle and eastern part of the Garcia Quadrangle, Costilla County, Colorado mapping project were created by Theodore Brandt, U.S. Geological Survey. Process_Date: 2007 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 5 Ordinate_Resolution: 5 Planar_Distance_Units: METERS Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 13 Transverse_Mercator: Scale_Factor_at_Central_Meridian: .9999 Longitude_of_Central_Meridian: -105.0000 Latitude_of_Projection_Origin: 0.00 False_Easting: 500000.0000 False_Northing: 0.0000 Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The data are supplied in ArcInfo export format and ArcView shapefile format. DATABASE STRUCTURE - ArcInfo ==================================== This GIS database includes related look-up tables, which store detailed attribute information. This database structure is more fully described in USGS OFR 99-438. The GIS database structure used in the database includes symbol and pattern items in coverage point, polygon (PAT), and arc (AAT) attribute tables for user convenience. ArcInfo relates for each coverage are saved in a file named .rel. Use the RELATE command with the restore argument at the arc prompt to make the relates active. Alternatively, in ArcTools, use the Relate environment: open dialog in the Manage - Relates flyout menu under the ArcTools menu to make the relates active. sanrgeo coverage: Contains all contact lines and label points for each geologic polygon. In the .pat INFO file the SOURCE item provides a numeric code used to identify the data source for the rock unit. Complete references for the sources listed are listed in the sanrgeo.ref file. The LABEL item indicates the rock unit label (abbreviation) used to label unit on map. The DESC item defines formal or informal unit name. The SYMBOL item contains the shadeset symbol number used by ArcInfo to plot a filled/shaded polygon. The symbol numbers in this item refer to the wpgcmykg.shd shadeset included with the dataset. The PATTERN item contains the pattern number used in the published version of the map. Patterns that correspond with the pattern numbers are displayed in USGS OFR 99-430. There is no ArcInfo shadeset that corresponds to these patterns. These patterns are not shown in the browse graphic of the map, but will be shown in the planned SIM report. In the sanrgeo.aat INFO file, the LINECODE item provides a numeric code used to identify type of linear feature. Linecodes less than 100 are used for contacts and boundaries that are described in the sanrgeo.con file. Linecodes greater than 100 are used for structures that are described in the sanrgeo.str file. The NAME item lists the name given to the structural feature. The SOURCE item lists the numeric code used to identify the data source for the linear feature. The SYMBOL item lists the line symbol number used by ArcInfo to plot the line (symbol numbers refer to the geol_sfo.lin lineset). Complete references for the sources are listed in the sanrgeo.ref file. Related look-up table files are sanrgeo.con, sanrgeo.str, and sanrgeo.ref. In the sanrgeo.con INFO file, the LINECODE item indicates the numeric code (a value less than 100) used to identify type of contact or boundary. The SYMBOL item lists the line symbol number used by ArcInfo to plot the line (symbol numbers refer to the geol_sfo.lin lineset included with the dataset). The TYPE item lists the major type of line (for example, contact, State boundaries, lines of latitude and longitude used for neatlines). The MODIFIER item lists the line type modifier (that is, approximate, concealed, or gradational). No entry implies 'known.' The CERTAINTY item lists the degree of certainty of contact or boundary (that is, inferred or uncertain). No entry implies 'certain.' The DESC item lists the written description or explanation of the contact or boundary. In the sanrgeo.str INFO file, the LINECODE item indicates the numeric code (a value greater than 100) used to identify type of structure. The SYMBOL item lists the line symbol number used by ArcInfo to plot the line (symbol numbers refer to the geol_sfo.lin lineset included with the dataset). The TYPE item lists the major type of line (for example, fault or fold-axis). The HORIZONTAL item refers to the type of horizontal fault movement (for example, left-lateral or right-lateral). No entry implies 'unknown' or no strike-slip movement. The VERTICAL item refers to the type of vertical fault movement (for example, normal). No entry implies 'unknown' or no dip-slip movement. The FOLD item refers to the type of fold (for example, anticline or syncline). The PLUNGE item refers to the type of plunge on fold (that is, horizontal, plunging, plunging in, or plunging out). The ACCURACY item refers to the line type modifier indicating degree of accuracy (that is, approximately located, concealed, gradational). No entry implies 'certain.' The CERTAINTY item lists the degree of certainty of structure (that is, inferred, uncertain). No entry implies 'certain.' The DESC item lists the written description or explanation of the structure. The INFO structure of these files is listed below: >SANRGEO.PAT: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE > 1 AREA 8 18 F 5 > 9 PERIMETER 8 18 F 5 > 17 SANRGEO# 4 5 B - > 21 SANRGEO-ID 4 5 B - > 25 SOURCE 4 4 I - > 29 LABEL 10 10 C - > 39 DESC 150 150 C - > 189 SYMBOL 3 3 I - > 192 PATTERN 4 4 I - >SANRGEO.AAT: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 FNODE# 4 5 B - > 5 TNODE# 4 5 B - > 9 LPOLY# 4 5 B - > 13 RPOLY# 4 5 B - > 17 LENGTH 8 18 F 5 > 25 SANRGEO# 4 5 B - > 29 SANRGEO-ID 4 5 B - > 33 LINECODE 3 3 I - > 36 NAME 150 150 C - > 186 SOURCE 4 4 I - > 190 SYMBOL 3 3 I - >SANRGEO.CON: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 LINECODE 3 3 I - > 4 SYMBOL 3 3 I - > 7 TYPE 10 10 C - > 17 MODIFIER 20 20 C - > 37 CERTAINTY 15 15 C - > 52 DESC 100 100 C - >SANRGEO.STR: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 LINECODE 3 3 I - > 4 SYMBOL 3 3 I - > 7 TYPE 10 10 C - > 17 HORIZONTAL 20 20 C - > 37 VERTICAL 20 20 C - > 57 FOLD 15 15 C - > 72 PLUNGE 15 15 C - > 87 ACCURACY 15 15 C - > 102 CERTAINTY 15 15 C - > 117 DESC 100 100 C - > SANRGEO.REF: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 SOURCE 4 4 I - > 5 SCALE 8 8 I - > 13 AUTHORS 200 200 C - > 213 YEAR 4 4 I - > 217 REFERENCE 250 250 C - sanrpts coverage: Contains points recording site-specific observations and measurements relating to stratigraphic age. In the sanrpts.pat INFO file, the PTTYPE item lists the type of point symbol (for example, strike and dip of inclined bedding). The SYMBOL item lists the marker symbol used by ArcInfo to identify the type of structural map symbol(symbol numbers refer to the geoscamp2.mrk markerset. The AGE1 item lists the first instance of age data description at a point location. The AGE2 item lists the second instance of age data description at a point location. The AGE3 item lists the third instance of age data description at a point location. The AGE4 item lists the fourth instance of age data description at a point location. In the sanrpts.ref INFO file, the SOURCE item lists the numeric code used to identify the data source. The SCALE item lists the scale of the source map. (This value is the denominator of the proportional fraction that identifies the scale of the map that was digitized or scanned to produce the digital map.) The AUTHORS item lists the author(s) or compiler(s) of source map entered as last name, first name or initial, and middle initial. The YEAR item lists the source (map) publication date. The REFERENCE item lists the remainder of the reference in USGS reference format. >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 AREA 8 18 F 5 > 9 PERIMETER 8 18 F 5 > 17 SANRPTS# 4 5 B - > 21 SANRPTS-ID 4 5 B - > 25 PTTYPE 100 100 C - > 125 AGE1 150 150 C - > 275 AGE2 150 150 C - > 425 AGE3 150 150 C - > 575 AGE4 150 150 C - > 725 SYMBOL 3 3 I - > 728 SOURCE 4 4 I - > >SANRPTS.REF: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 SOURCE 4 4 I - > 5 SCALE 8 8 I - > 13 AUTHORS 200 200 C - > 213 YEAR 4 4 I - > 217 REFERENCE 250 250 C - >Coding of LABEL and DESC attributes in the sanrgeo coverage: >LABEL | DESC >Pz | Sandstone and siltstone (Paleozoic?) >QTsf | Santa Fe Group, upper part (middle Pleistocene to Pliocene) >Qa | Stream alluvium, undivided (Holocene) >Qaa | Active stream alluvium (upper Holocene) >Qac | Alluvium and colluvium, undivided (Holocene and upper Pleistocene) >Qaf | Artificial fill (Historic) >Qai | Intermediate stream alluvium (upper and middle Pleistocene) >Qao | Older stream alluvium (middle Pleistocene) >Qay | Younger stream alluvium (upper Pleistocene) >Qc | Colluvium, undivided (Holocene and upper Pleistocene) >Qes | Eolian sand (Holocene) >Qes/Qai | Eolian sand (Holocene) over intermediate stream alluvium (upper and middle Pleistocene) >Qla | Lake sediment (Holocene) >Qlso | Older landslides (upper and middle Pleistocene) >Qlsy | Younger landslides (Holocene and upper Pleistocene) >Qts | Talus (Holocene and upper Pleistocene) >Tad | Andesite and dacite of San Pedro Mesa (middle? Miocene) >Thb | Hinsdale Formation (middle? Miocene) >Tsb | Servilleta Basalt (Pliocene) >Tsb(ls) | Landslide block of Servilleta Basalt >Tsf | Santa Fe Group, lower part (Pliocene to upper Oligocene) >Tvl | Older (lower) volcanic rocks, undivided (Oligocene) >Xg | Granitic rock, undivided (Early Proterozoic) >w | Open water >Coding of LINECODE and NAME attributes in the sanrgeo coverage: >LINECODE | NAME >1 | Contact - Certain >3 | Contact - Concealed >41 | Shoreline >81 | Map boundary >101 | Fault - Certain >102 | Fault - Approximately located >103 | Fault - Concealed >511 | Landslide scarp >563 | Quaternary fault - Certain >564 | Quaternary fault - Approximately located >565 | Quaternary fault - Concealed Auxiliary files: geol_sfo.lin: This lineset file defines geologic line types in the geologically themed coverages. wpgcmykg.shd: This shadeset file defines the cmyk values of colors assigned to polygons in the geologically themed coverages. sanresr.tif: A geo-registered raster file of the USGS Sanchez Reservoir and eastern part of Garcia, Colorado 1:24,000 scale base map. OF07-1074map.pdf: A print-optimized file for viewing and printing a graphics version of the map and accessory elements using Adobe Acrobat viewing software (version 8.0). Entity_and_Attribute_Detail_Citation: http://wrgis.wr.usgs.gov/open-file/of99-438/ Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: Publishing Service Center Address: MS 902 Box 25046 Address: Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225-0046 Contact_Voice_Telephone: 303-236-5486 Contact_Electronic_Mail_Address: webmaster@geology.cr.usgs.gov Resource_Description: Open-File Report 1329 Distribution_Liability: none Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ARCE,SHP Format_Version_Number: 9.2 Format_Version_Date: 2005 File_Decompression_Technique: GZIP TAR archive, In UNIX use the command "gunzip -c | tar xvf .tar" In Windows, use WinZip (http://www.winzip.com/) or other programs to extract the file. Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2006/1329/ Fees: none Metadata_Reference_Information: Metadata_Date: 2007 Metadata_Review_Date: 2007 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Theodore Brandt Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: U.S. Geological Survey Address: MS 980, Box 25046 Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225-0046 Contact_Voice_Telephone: 303-236-1901 Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998