Maximum Pleistocene Glacier Extents, Alaska PaleoGlacier Atlas

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: William Manley, Univ. of Colorado, INSTAAR
Publication_Date: 20020808
Title: Maximum Pleistocene Glacier Extents, Alaska PaleoGlacier Atlas
Edition: Version 1
Geospatial_Data_Presentation_Form: vector digital data
Series_Information:
Series_Name: Alaska PaleoGlacier Atlas
Issue_Identification: apg_maxgl_v1.shp, ESRI polygon shapefile
Publication_Information:
Publication_Place: Boulder, CO, USA
Publisher: University of Colorado, INSTAAR
Other_Citation_Details:
Complete Citation: Manley, W.F., and Kaufman, D.S., 2002, Alaska PaleoGlacier Atlas: Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, instaar.colorado.edu/QGISL/ak_paleoglacier_atlas, v. 1.
Online_Linkage: <http://instaar.colorado.edu/QGISL/ak_paleoglacier_atlas>
Description:
Abstract:
The Alaska PaleoGlacier Atlas is a geospatial summary of Pleistocene glaciation across Alaska. The layers in the atlas depict: 1) the extent of glaciers during the late Wisconsin glaciation (also known as the Last Glacial Maximum, about 20,000 years ago), and 2) the maximum extent reached during the last 3 million years by the northwestern Cordilleran Ice Sheet, ice caps, and valley glaciers. The atlas is targeted for a scale of 1 to 1,000,000 -- suitable for visualization and regional analyses. Former glacier extents are based on decades of field-based mapping, air-photo interpretation, and a variety of dating methods. In all, the first version combines glacial-geologic information from 26 publications and 42 source maps. Revisions will be made and released as time and resources allow.

Pleistocene glaciers once covered >1,200,000 km2, from the continental shelf bordering the North Pacific to the northern foothills of the Brooks Range. Late Wisconsin glaciers occupied 727,800 km2 -- nearly ten times the area of modern glaciers, but only 48% of the state. Alaska's glaciers expanded more than 20 times during the last 3 million years in response to cold and snowy conditions. During the late Wisconsin glaciation, when sea level fell approximately 125 m (approx. 400 ft), the Bering Land Bridge was exposed as a broad tundra plain, and much of the state escaped glaciation due to a cold but dry climate. Deposition and erosion by glaciers in the recent geologic past have greatly influenced Alaska's landscapes and ecosystems.

Purpose:
Our goal is a comprehensive and consistent overview of former glacier limits across Alaska. Our hope is to facilitate outreach, education, and interdisciplinary research in the fields of geology, geography, biology, and natural history.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 20020808
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: Irregular
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -178.715997
East_Bounding_Coordinate: -118.880905
North_Bounding_Coordinate: 70.218903
South_Bounding_Coordinate: 51.673580
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: glaciers
Theme_Keyword: Pleistocene
Theme_Keyword: Quaternary
Theme_Keyword: glacial geology
Theme_Keyword: paleoenvironments
Theme_Keyword: Late Wisconsin
Theme_Keyword: Last Glacial Maximum
Theme_Keyword: geology
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: Alaska
Place_Keyword: USA
Place_Keyword: Brooks Range
Place_Keyword: Seward Peninsula
Place_Keyword: Yukon Tanana Upland
Place_Keyword: Ahklun Mountains
Place_Keyword: Kuskokwim Mountains
Place_Keyword: Alaska Range
Place_Keyword: Alaska Peninsula
Place_Keyword: coastal ranges
Place_Keyword: Aleutian Range
Place_Keyword: Kodiak Island
Place_Keyword: Wrangell Mountains
Place_Keyword: Kenai Mountains
Place_Keyword: St. Elias Mountains
Access_Constraints: None
Use_Constraints:
It is not recommended that the data be used at a scale larger than 1 to 1 million. Dataset credit required. Use at your own risk.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: William F. Manley
Contact_Organization:
University of Colorado, Insitute of Arctic and Alpine Research (INSTAAR)
Contact_Position: Research Scientist
Contact_Address:
Address_Type: mailing address
Address: University of Colorado
Address: Institute of Arctic and Alpine Research (INSTAAR)
Address: Campus Box 450
City: Boulder
State_or_Province: Colorado
Postal_Code: 80309-0450
Country: USA
Contact_Voice_Telephone: 303-735-1300
Contact_Facsimile_Telephone: 303-492-6388
Contact_Electronic_Mail_Address: William.Manley@colorado.edu
Data_Set_Credit:
National Science Foundation (Office of Polar Programs, Arctic Sciences Section), University of Colorado, Northern Arizona University, U.S. Geological Survey, and other organizations.
Native_Data_Set_Environment:
Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 2; ESRI ArcCatalog 8.2.0.700

Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
The APG Atlas is only as accurate as the source maps. See Source Information and Process Description.
Completeness_Report:
The APG Atlas is only as complete as the source maps. Version 1 is considered sufficiently complete for public release. However, relatively small glacier systems were not included in some areas due to lack of information, including St. Lawrence Island, Horn Mountains, Shotgun Hills, Taylor Mountains, parts of the Yukon Tanana Upland, the Blackburn Hills, and the fringes of the Ahklun Mountains, central and eastern Brooks Range, and the Cordilleran Ice Sheet. Also, sufficient glacial geologic mapping is lacking for many of the Aleutian Islands.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Unquantified. Horizontal positioning errors due to georectification and digitization are smaller than errors or uncertainties in the source maps, but are considered acceptable.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: various
Publication_Date: various
Title: Available published and unpublished glacial geologic mapping
Type_of_Source_Media: stable-base material
Source_Contribution:
The APG Atlas is derived from unpublished contributions and 26 publications, for a total of 42 source maps. The APG layers are only as accurate as the contributions and data sources used to date. Further contributions, to improve the accuracy and completeness of the atlas, are encouraged.

REFERENCES AND SOURCES

Ager, T.A., unpublished glacial geologic mapping, U.S. Geological Survey.

Axford, Y. L., 2000, Late Pleistocene Glacial History of the Northern Ahklun Mountains, Southwestern Alaska [MS thesis]: Utah State University, 158 p.

Axford, Y., unpublished glacial geologic mapping, Utah State University.

Balascio, N., unpublished glacial geologic mapping, Northern Arizona University.

Beget, J.E., unpublished glacial geologic mapping, University of Alaska Fairbanks.

Brigham-Grette, J., Hopkins, D. M., Benson, S. L., Heiser, P., Ivanov, V., Basilyan, A., and Barclay, D. J., 2001, Last Interglacial (isotope stage 5) glacial and sea-level history of Chukotka Peninsula and St. Lawrence Island, western Beringia: Quaternary Science Reviews, v. 20, p. 419-436.

Briner, J.P., unpublished glacial geologic mapping, University of Colorado.

Briner, J. P., and Kaufman, D. S., 2000, Late Pleistocene glaciation of the southwestern Ahklun Mountains, Alaska: Quaternary Research, v. 53, p. 13-22.

Briner, J. P., Swanson, T. W., and Caffee, M. W., 2001, Late Pleistocene cosmogenic 36Cl glacial chronology of the southwestern Ahklun Mountains, Alaska: Quaternary Research, v. 56, p. 148-154.

Carrara, P., unpublished glacial geologic mapping, U.S. Geological Survey.

Coulter, H. W., Hopkins, D. M., Karlstrom, T. N. V., Péwé, T. L., Wahrhaftig, C., and Williams, J. R., 1965, Map showing extent of glaciations in Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-415.

Hamilton, T. D., 1986, Late Cenozoic glaciation of the central Brooks Range, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 9-50.

Hamilton, T. D., 1994 (Figs. 1, 4, 7, and 10), Late Cenozoic glaciation of Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: The Geology of North America, v. G-1, Geological Society of America, p. 813-844.

Hamilton, T.D., unpublished glacial geologic mapping, U.S. Geological Survey.

Karlstrom, T. N. V., and others, 1964, Surficial geology of Alaska, U.S. Geological Survey Miscellaneous Geologic Investigations Series Map I-357.

Kaufman, D.S., unpublished glacial geologic mapping, Northern Arizona University.

Kaufman, D. S., and Hopkins, D. M., 1986, Glacial history of the Seward Peninsula, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 51-77.

Kaufman, D. S., Manley, W. F., Forman, S. L., and Layer, P., 2001, Pre-late Wisconsin glacial history, coastal Ahklun Mountains, southwestern Alaska -- new amino acid, thermoluminescence, and 40Ar/39Ar results: Quaternary Science Reviews, v. 20, p. 337-352.

Kline, J. T., and Bundtzen, T. K., 1986 (Figs. 1, 2, 6, and 11), Two glacial records from west-central Alaska, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 123-150.

Lea, P. D., 1990, Pleistocene glacial tectonism and sedimentation on a macrotidal piedmont coast, Ekuk Bulffs, southwestern Alaska: Geological Society of America Bulletin, v. 102, p. 1230-1245.

Lubinski, D.J., unpublished glacial geologic mapping, University of Colorado.

Manley, W. F., unpublished glacial geologic mapping, University of Colorado.

Manley, W. F., and Kaufman, D. S., 2001, Paleoglaciers, paleoELA's, and paleoclimate of Seward Peninsula, northwestern Alaska, in 31rst Arctic Workshop, University of Massachusetts, Amherst, p. 75-77.

Manley, W. F., Kaufman, D. S., and Briner, J. P., 2001, Pleistocene glacial history of the southern Ahklun Mountains, southwestern Alaska: Soil-development, morphometric, and radiocarbon constraints: Quaternary Science Reviews, v. 20, p. 353-370.

Manley, W. F., Briner, J. P., Lubinski, D. J., and Caffee, M. W., 2002, Glacial history, surface exposure ages, and paleoELA's of the Yukon Tanana Upland: Preliminary Results, in 32nd International Arctic Workshop, INSTAAR, University of Colorado, p. 135-138.

Mann, D. H., and Peteet, D. M., 1994 (Figs. 2 and 9), Extent and Timing of the Last Glacial Maximum in Southwestern Alaska: Quaternary Research, v. 42, no. 2, p. 136-148.

Molnia, B. F., 1986 (Fig. 3), Glacial history of the northeastern Gulf of Alaska -- A synthesis, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 219-235.

Reger, R. D., 1979 (Figs. 1 and 2), Glaciation of Indian Mountain, west-central Alaska, Short Notes on Alaskan Geology, 1978, Alaska Division of Geological and Geophysical Surveys Report 61, p. 15-18.

Reger, R.D., unpublished glacial geologic mapping, Alaska Division of Geological and Geophysical Surveys.

Reger, R. D., and Pinney, D. S., 1996 (Fig. 3), Late Wisconsin glaciation of the Cook Inlet region with emphasis on Kenai lowland and implications for early peopling, in Davis, N. Y., and Davis, W. E., eds., The Anthropology of Cook Inlet: Proceedings from a Symposium: Anchorage, Cook Inlet Historical Society, p. 5-23.

Schmoll, H.R., unpublished glacial geologic mapping, U.S. Geological Survey.

Schmoll, H. R., and Yehle, L. A., 1986, Pleistocene glaciation of the upper Cook Inlet basin, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 193-217.

Stilwell, K. B., and Kaufman, D. S., 1996 (Fig. 2), Late Wisconsin glacial history of the northern Alaska Peninsula, southwestern Alaska, U.S.A.: Arctic and Alpine Research, v. 28, p. 475-487.

Thorson, R. M., 1986 (Fig. 3), Late Cenozoic glaciation of the northern Nenana River valley, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 99-121.

Thorson, R.M., unpublished glacial geologic mapping, University of Connecticut.

Waythomas, C. F., 1990 (Figs. 5-5 and 5-9), Quaternary geology and late-Quaternary environments of the Holitna Lowland, and Chuilnuk-Kiokluk Mountains region, interior southwestern Alaska [Ph.D. thesis]: University of Colorado, 305 p.

Waythomas, C.F., unpublished glacial geologic mapping, U.S. Geological Survey.

Weber, F. R., 1986 (Fig. 10), Glacial geology of the Yukon-Tanana Upland, in Hamilton, T. D., Reed, K. M., and Thorson, R. M., eds., Glaciation in Alaska -- The Geologic Record: Anchorage, Alaska Geological Society, p. 79-98.

Weber, F. R., and Hamilton, T. D., 1984 (Fig. 2), Glacial geology of the Mt. Prindle area, Yukon-Tanana Upland, Alaska, Short Notes on Alaskan Geology 1982, Alaska Division of Geological and Geophysical Surveys Professional Report 86, p. 42-48.

Weber, F.R., unpublished glacial geologic mapping, U.S. Geological Survey.

Werner, A., unpublished glacial geologic mapping, Mount Holyoke College.

Wilson, F.H., unpublished glacial geologic mapping, U.S. Geological Survey.

Wilson, F. H., and Weber, F. R., 2001, Quaternary geology of the Cold Bay and False Pass quadrangles, in Gough, L. P., and Wilson, F. H., eds., Geologic Studies in Alaska by U.S. Geological Survey, 1999, U.S. Geological Survey Professional Paper 1633, p. 51-71.

Process_Step:
Process_Description:
We utilized standard GIS techniques to compile the glacier limits, incorporating information from a variety of sources (see Source Information). Processing was conducted with two statewide coverages, one for each age limit, using North American Datum 1927 and an Alaska Albers projection. A first draft of the digital atlas was created by scanning, georectifying, and digitizing the map of Coulter et al. (1965). Additional maps (from six publications and unpublished mapping by WFM and DSK) were scanned and georectified. Polygons delineating former glaciers were then added and edited in ArcMap (v. 8.1 and 8.2, digitizing onscreen at resolutions better than the source maps, commonly in streaming mode with vertex spacing of 0.5-8 km). This version was distributed for community review, and subsequently updated to include limits from 19 additional publications, as well as unpublished research by the authors and 15 contributors. In sum, the digital atlas integrates information from 42 source maps.

Finally, we classified the glacier limits according to "certainty", a measure of confidence relating to both age determination and geographic position. For example, well-dated moraines were ascribed a high level of certainty, comparable to a solid line on traditional glacial geologic maps. Intermediate certainty was encoded for limits without well resolved ice-marginal features, or those with little or no direct geochronologic control (comparable to dashed lines for "uncertain" boundaries on traditional maps). A low level of certainty was attributed to arcs bounding polygons where ice limits are inferred for offshore positions, or for areas lacking detailed air-photo interpretation or significant, field-based glacial-geologic study. The measures of certainty are based on available mapping and publications, and are commensurate with the target scale of 1 to 1,000,000. In many areas of the state, significant uncertainties remain. Research through field-based efforts, remote-sensing techniques, and geochronologic methods are needed to improve the levels of certainty shown here, and at larger scales.

Process_Date: 20020806

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: 125

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Albers Conical Equal Area
Albers_Conical_Equal_Area:
Standard_Parallel: 55.000000
Standard_Parallel: 65.000000
Longitude_of_Central_Meridian: -154.000000
Latitude_of_Projection_Origin: 50.000000
False_Easting: 0.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.004096
Ordinate_Resolution: 0.004096
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.400000
Denominator_of_Flattening_Ratio: 294.978698

Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: apg_maxgl_v1
Attribute_Label: MINOR1
Attribute_Definition: Glacier code
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 103 = glacier
Enumerated_Domain_Value_Definition: See above
Attribute:
Attribute_Label: GLACIERS
Attribute_Definition: Glacier description
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: Self-evident text
Enumerated_Domain_Value_Definition: See above

Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: William F. Manley
Contact_Organization:
University of Colorado, Insitute of Arctic and Alpine Research (INSTAAR)
Contact_Position: Research Scientist
Contact_Address:
Address_Type: mailing address
Address: University of Colorado
Address: Institute of Arctic and Alpine Research
Address: Campus Box 450
City: Boulder
State_or_Province: Colorado
Postal_Code: 80309-0450
Country: USA
Contact_Voice_Telephone: 303/735-1300
Contact_Facsimile_Telephone: 303/492-6388
Contact_Electronic_Mail_Address: William.Manley@colorado.edu
Distribution_Liability:
Users must assume responsibility to determine the usability of this data for their purposes. The University of Colorado makes no express or implied warranties - including warranties of merchantability or fitness - with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the University of Colorado be liable for any incidental, indirect, special, consequential or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof or otherwise, and in no event will the University of Colorado's liability to the requestor or anyone else exceed the fee paid for the electronic service or product.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: Shapefile
File_Decompression_Technique: zip
Transfer_Size: 0.630
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <http://instaar.colorado.edu/QGISL/ak_paleoglacier_atlas>
Fees: Free. See Use Constraints and Distribution Liability.

Metadata_Reference_Information:
Metadata_Date: 20020810
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: William F. Manley
Contact_Organization:
University of Colorado, Insitute of Arctic and Alpine Research (INSTAAR)
Contact_Position: Research Scientist
Contact_Address:
Address_Type: mailing address
Address: University of Colorado
Address: Institute of Arctic and Alpine Research
Address: Campus Box 450
City: Boulder
State_or_Province: Colorado
Postal_Code: 80309-0450
Country: USA
Contact_Voice_Telephone: 303/735-1300
Contact_Facsimile_Telephone: 303/492-6388
Contact_Electronic_Mail_Address: William.Manley@colorado.edu
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile

Generated by mp version 2.7.3 on Sat Aug 10 22:09:04 2002