Metadata:
  Identification_Information:
    Citation:
      Citation_Information:
        Originator: Clyde Wahrhaftig
        Originator: Greg M. Stock
        Originator: Reba G. McCracken
        Originator: Peri Sasnett
        Originator: Andrew J. Cyr
        Publication_Date: 2019
        Title: Extent of the Last Glacial Maximum (Tioga) glaciation in Yosemite National Park and vicinity, California
        Edition: 1.0
        Geospatial_Data_Presentation_Form: Vector Digital Data Set (Polygon)
        Publisher: U.S. Geological Survey
          Series_Name: Scientific Investigations Map
          Issue_Identification: SIM 3414
        Publication_Place: Reston, VA
        Online_Linkage: https://doi.org/10.3133/sim3414
    Description: This map shows the extent of glacier ice in Yosemite National Park and vicinity during the Last Glacial Maximum (Tioga) glaciation circa 20,000 years ago.
       Abstract: This map shows the extent of alpine icefields and associated valley glaciers in Yosemite National Park and vicinity during the Last Glacial Maximum, known locally as the Tioga glaciation, circa 20,000 years ago. During the maximum extent of the Tioga glaciation, glaciers and ice fields covered most areas in and around Yosemite National Park above 2,700 meters elevation. Glaciers in the map area occupied six major drainage basins: the Tuolumne, Merced, and San Joaquin River basins on the western slope of the Sierra Nevada, and, on the eastern slope, basins of the Walker and Owens Rivers and Mono Lake. On the western slope of the Sierra Nevada, Tioga-age glaciers extended tens of kilometers down the major river canyons. The largest of these was the Tuolumne glacier, which flowed for a distance of nearly 80 km from its source at Mount Lyell, down the Grand Canyon of the Tuolumne River and through Hetch Hetchy Valley. Smaller valley glaciers flowed down the canyon of the Merced River into Yosemite Valley, down the South Fork of the Merced River near Wawona, and down the various forks of the San Joaquin River. On the eastern slope of the Sierra, glaciers cascaded down smaller canyons cut into the steep eastern escarpment. During the Tioga glaciation, a great ice field occupied the area in and around Tuolumne Meadows, with ice thicknesses exceeding 500 m. Only steep-sided and sharp-crested peaks and ridges, and a few wind-swept plateaus near the Sierra crest, projected above the ice. Some of the ice filling the basin of the Lyell Fork Tuolumne River spilled over low passes in the Cathedral Range to augment ice in the upper Merced River drainage. Glacier ice also flowed over a pass southwest of Tuolumne Meadows and down Tenaya Canyon to join the Merced glacier in eastern Yosemite Valley. In addition to the major ice fields and valley glaciers in the Tuolumne and Merced River drainage basins, smaller, isolated glaciers existed on prominent peaks and ridges far to the west of the Sierra crest. As the glaciers moved downslope, they plucked and scoured the bedrock, leaving behind distinctive features such as tarns, streamlined bedforms, glacial polish, and striations. The vast quantities of eroded rock debris were transported to the lower ice margins, forming large lateral and terminal moraines. As the climate warmed at the end of the Last Glacial Maximum, the Yosemite landscape deglaciated rapidly, with ice receding back to the highest cirques by approximately 15,000 years ago.

      Purpose: This map was produced, over a period of more than 50 years, by scientists from the U.S. Geological Survey and the National Park Service, based on extensive field mapping and remote-sensing analyses. 
      Supplemental_Information: These data consist of two shapefiles exported from two geodatabase feature classes that describe (1) a geologic polygon showing glacial ice extent and (2) geologic points showing glacial striation orientations. This metadata file provides an overview for both these files. For more detailed metadata, please see the metadata provided with each individual shapefile.
    Time_Period_of_Content:
      Time_Period_Information:
        Single_Date/Time:
          Calendar_Date: 2019
      Currentness_Reference: ground condition
    Status:
      Progress: Complete
      Maintenance_and_Update_Frequency: As needed
    Spatial_Domain:
      Bounding_Coordinates:
        West_Bounding_Coordinate: -120.001516645
        East_Bounding_Coordinate: -118.99856528
        North_Bounding_Coordinate: 38.235935812
        South_Bounding_Coordinate: 37.37431706
    Keywords:
      Theme:
        Theme_Keyword_Thesaurus: Lithologic classification of geologic map units
        Theme_Keyword: glacier extent
        Theme_Keyword: Last Glacial Maximum
      Theme:
        Theme_Keyword_Thesaurus: ISO 19115 Topic Categories
        Theme_Keyword: environment
        Theme_Keyword: geoscientificInformation
      Theme:
        Theme_Keyword_Thesaurus: None
        Theme_Keyword: Geology
        Theme_Keyword: Physical Sciences
        Theme_Keyword: Tioga
        Theme_Keyword: YOSE
        Theme_Keyword: NPS
        Theme_Keyword: Yosemite
        Theme_Keyword: Resources
        Theme_Keyword: Glaciers.
      Place:
        Place_Keyword_Thesaurus: Common geographic areas
        Place_Keyword: Yosemite National Park
    Access_Constraints: None. Please see 'Distribution Info' for details.
    Use_Constraints: Uses of this digital geologic map should not violate the spatial resolution of the data. Although the digital form of the data removes the constraint imposed by the scale of a paper map, the detail and accuracy inherent in map scale are also present in the digital data. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
      The National Park Service shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data and related graphics are not legal documents and are not intended to be used as such. The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. The related graphics are intended to aid the data user in acquiring relevant data; it is not appropriate to use the related graphics as data. The National Park Service gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from an NPS server and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully on a computer system at the National Park Service, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. 
    Point_of_Contact:
      Contact_Information:
        Contact_Organization_Primary:
          Contact_Organization: Yosemite National Park
          Contact_Person: Greg M. Stock
        Contact_Position: Geologist
        Contact_Address:
          Address_Type: Mailing
          Address: 5083 Foresta Road Box 700
          City: El Portal
          State_or_Province: CA
          Postal_Code: 95318
          Country: United States
        Contact_Voice_Telephone: 209-379-1420
        Contact_Facsimile_Telephone: 209-379-1452
        Contact_Electronic_Mail_Address: greg_stock@nps.gov
    Data_Set_Credit: NPS, Yosemite National Park, Geology; USGS
    Native_Data_Set_Environment: Environment as of Metadata Creation: Microsoft [Unknown] Version 6.2 (Build 9200) ; Esri ArcGIS 10.6 (Build 8321) Service Pack N/A (Build N/A)
  Data_Quality_Information:
    Attribute_Accuracy:
      Attribute_Accuracy_Report: No formal attribute accuracy tests were conducted.
    Logical_Consistency_Report: No formal logical accuracy tests were conducted.
    Completeness_Report: The report is intended to describe completely the extent of glacier ice in Yosemite National Park and vicinity during the Last Glacial Maximum at 1:100,000 scale. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
    Positional_Accuracy:
      Horizontal_Positional_Accuracy: Approximately 5 meters
        Horizontal_Positional_Accuracy_Report: The position of each feature in the database is derived from a USGS 1-meter lidar data base map or with a GPS. In general, features in the database are well located.
      Vertical_Positional_Accuracy: No vertical positional data recorded.
        Vertical_Positional_Accuracy_Report: A formal accuracy assessment of the vertical positional information in the data set has either not been conducted, or is not applicable.
    Lineage:
      Process_Step:
        Process_Description: Geologic field observations were collected by Clyde Wahrhaftig in field notebooks and paper maps. Further geologic field observations were collected in field notebooks and with mobile GIS devices by Greg M. Stock and Reba G. McCracken. Greg M. Stock, Reba G. McCracken, and Peri Sasnett used the field notes and maps to create geologic feature classes in relation to 1-meter lidar imagery. Geologic information migrated to a modified GeMS geologic map database schema, and database checking and confirmation performed.
        Process_Date: Unknown
  Spatial_Data_Organization_Information:
    Direct_Spatial_Reference_Method: Vector
    Point_and_Vector_Object_Information:
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: G-polygon
        Point_and_Vector_Object_Count: 1
    Direct_Spatial_Reference_Method: Point
    Point_and_Vector_Object_Information:
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: Entity point
        Point_and_Vector_Object_Count: 690
  Spatial_Reference_Information:
    Horizontal_Coordinate_System_Definition:
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        Grid_Coordinate_System:
          Grid_Coordinate_System_Name: Universal Transverse Mercator
          Universal_Transverse_Mercator:
            UTM_Zone_Number: 11
            Transverse_Mercator:
              Scale_Factor_at_Central_Meridian: 0.9996
              Longitude_of_Central_Meridian: -117.0
              Latitude_of_Projection_Origin: 0.0
              False_Easting: 500000.0
              False_Northing: 0.0
        Planar_Coordinate_Information:
          Planar_Coordinate_Encoding_Method: coordinate pair
          Coordinate_Representation:
            Abscissa_Resolution: 0.6096
            Ordinate_Resolution: 0.6096
          Planar_Distance_Units: Meter
      Geodetic_Model:
        Horizontal_Datum_Name: D_North_American_1983
        Ellipsoid_Name: GRS_1980
        Semi-major_Axis: 6378137.0
        Denominator_of_Flattening_Ratio: 298.257222101
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        Entity_Type_Label: Attribute Table
        Entity_Type_Definition: Table containing attribute information associated with the data set.
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          Attribute_Label: Location
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              Enumerated_Domain_Value_Definition: Unknown
              Enumerated_Domain_Value_Definition_Source: Producer defined
          Attribute_Domain_Values:
            Enumerated_Domain:
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              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: RGM/GMS
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          Attribute_Label: Notes
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: {Null Value / Empty Field Entry}
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Difficult to confirm orientation; could be 180 degrees opposite
              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 100 degrees
              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 110 degrees
              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 40 degrees
              Enumerated_Domain_Value_Definition: Unknown
              Enumerated_Domain_Value_Definition_Source: Producer defined
          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 53 degrees
              Enumerated_Domain_Value_Definition: Unknown
              Enumerated_Domain_Value_Definition_Source: Producer defined
          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 75 degrees
              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 87 degrees
              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 9 degrees
              Enumerated_Domain_Value_Definition: Unknown
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          Attribute_Domain_Values:
            Enumerated_Domain:
              Enumerated_Domain_Value: Two distinct sets of glacial striations, separated by 98 degrees
              Enumerated_Domain_Value_Definition: Unknown
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    Overview_Description:
      Entity_and_Attribute_Overview: 
        The metadata file was written to provide an overview for the database files in shapefile format. For more detailed descriptions of the attributes, please see the metadata files associated with each shapefile. If you are accessing the shapefile version of this geodatabase, they are derived from feature classes and may have abbreviated or shortened field names. 

        Two shapefiles are included in this dataset: YOSE_glacier_striations.shp and YOSE_glacier_extnt.shp. 

        The YOSE_glacier_striations.shp shapefile contains the locations (UTM coordinates), elevations, and azimuths of glacial striations mapped in Yosemite National Park and vicinity. Glacial striations were measured over a period of more than 50 years by scientists from the U.S. Geological Survey (USGS) and the National Park Service (NPS). The striation measurements are published by the USGS as appendix 1 of USGS Scientific Investigation Series Map 3414, by Wahrhaftig and others (2019). 

        The YOSE_glacier_extnt.shp shapefile shows the maximum extent of glacier ice in Yosemite National Park and vicinity as it might have looked circa 20,000 years ago during the Last Glacial Maximum (Tioga) glaciation. Although it is possible that the various Tioga-age glaciers in the study area attained their maximum extents at slightly different times during the Last Glacial Maximum, for the purposes of this map we assume that they reached their maximum extents simultaneously. The maximum ice extent shown here may have occupied certain areas only briefly. This map was produced over a period of more than 50 years by scientists from the USGS and the NPS, based on extensive field mapping and remote sensing analysis. This ice extent is shown on USGS Scientific Investigations Series Map 3414, by Wahrhaftig and others (2019).  

      Reference cited:
        Wahrhaftig, C., Stock, G.M., McCracken, R.G., Sasnett, P., and Cyr, A.J., 2019, Extent of the Last Glacial Maximum (Tioga) glaciation in Yosemite National Park and vicinity, California: U.S. Geological Survey Scientific Investigations Map 3414, pamphlet 28 p., 1 sheet, scale 1:100,000, 2 appendixes, https://doi.org/10.3133/sim3414.

      Entity_and_Attribute_Detail_Citation: The entity and attribute information was generated by the authors. Please review the rest of the metadata record for additional details and information.
  Distribution_Information:
    Distribution_Liability: This database has been approved for release and publication by the Director of the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
    Standard_Order_Process: 
      Digital_Form:
        Digital_Transfer_Information:
          Format_Name: Vector Digital Data Set (Polygon)
        Digital_Transfer_Option:
          Online_Option:
            Computer_Contact_Information:
              Network_Address:
                Network_Resource_Name: https://doi.org/10.3133/sim3414
      Fees: None. No fees are applicable for obtaining the data set.
  Metadata_Reference_Information:
    Metadata_Date: 20190626
    Metadata_Contact:
      Contact_Information:
        Contact_Organization_Primary:
          Contact_Person: Greg M. Stock
          Contact_Organization: National Park Service, Yosemite National Park
        Contact_Address:
          Address_Type: Mailing
          Address: 5083 Foresta Road Box 700
          City: El Portal
          State_or_Province: CA
          Postal_Code: 95318
          Country: United States
        Contact_Voice_Telephone: 209-379-1420
        Contact_Facsimile_Telephone: 209-379-1452
        Contact_Electronic_Mail_Address: greg_stock@nps.gov
    Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata
    Metadata_Standard_Version: FGDC-STD-001-1998