Metadata: Identification_Information: Citation: Citation_Information: Originator: Thompson, Robert S. Originator: Schweitzer, Peter N. Publication_Date: 1996 Title: Global gridded Pliocene and Quaternary sea-level Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 96-000 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: Description: Abstract: Global gridded elevation and bathymetry were combined with published estimates of changes in sea-level and with the results of geophysical models designed to estimate the topographic effects of the Holocene deglaciation. The combined data present, at three different scales, estimates of the distribution of land and oceans during two periods of Earth history in which climate changed significantly, the Holocene deglaciation and the middle Pliocene warm interval. The Holocene deglaciation, which began approximately 21,000 years ago, was modeled by Peltier (1994) using records of relative sea-level change. His calculations produced the data set ICE4G, consisting of 1-degree global grids of ice distribution and topography. We obtained ICE4G from the National Geophysical Data Center in Boulder, Colorado. We have rearranged ICE4G as images in which the topography is shown by colors ranging from dark blue through green to red, corresponding to bathymetry, sea-level, and higher elevations respectively. Grid-cells covered by ice are shown as gray pixels, grading to white as the elevation of the cell increases. The effect is to depict in a convenient manner the changes in ice distribution and topography shown by ICE4G. In addition to these straightforward images, we have provided 1-degree grids in which the cells values indicate the proportion of the cell above sea-level. These were calculated by first creating high-resolution estimates of Late Quaternary topography. For each 1-degree grid of topography, we created a 1-degree grid containing the differences between ancient and modern topography. This grid was expanded to 5-minute resolution through bilinear interpolation, and the resulting difference cells were added to ETOPO5 and TerrainBase. Using this 5-minute gridded estimate of paleotopography, a 1-degree grid was created in which the cell values contain the percent of 5-minute cells that are land. The middle Pliocene warm interval occurred approximately 3 million years ago. Diverse lines of evidence indicate that this was a period in which Earth's climate was significantly warmer than at present, with much smaller polar ice caps. Consequently global sea level was higher than present. There is some discussion among paleoclimate researchers as to how much higher than modern sea-level Pliocene eustatic sea-level was. We have chosen to depict a range of possible values (10, 20, 25, 30, 35, 40, 45, 50, and 60 meters above present sea level). Because global topography was affected strongly by the Pleistocene glaciation, especially in North America and Europe, we have no better estimates of Pliocene topography than the modern world. Consequently our estimates of Pliocene land distribution are based on the modern topography shown in ETOPO5 and TerrainBase, modified by subtracting the constant corresponding to each estimate of eustatic sea-level. For each of the nine estimates of Pliocene sea level, we have created a 1-degree grid in which the cell values are the percent of land cells in the 5-minute grid. We have also created images at 5-minute and 20-minute resolution showing graphically the major changes in sea-level that have been proposed, including -120 meters representing coastlines in the Last Glacial Maximum, 0 representing modern coastlines, and +35 and +60 meters representing moderate and extreme estimates of Pliocene sea-level. Purpose: These data are intended to provide paleoclimate researchers with models for global sea-level during the late Neogene in convenient formats with comparable information about the modern world ocean. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: cc3000000 Ending_Date: 1996 Currentness_Reference: The data set contains models of mid-Pliocene topography based on ETOPO5 and TerrainBase and several different estimates of eustatic sea-level fall from that time to the present. ETOPO5 and TerrainBase are essentially current, although their resolution (5 arc-minute grid-cell spacing) suggests that the modern data do not represent a clearly-defined Ending_Date. Status: Progress: in work Maintenance_and_Update_Frequency: irregular Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -180.0 East_Bounding_Coordinate: 180.0 North_Bounding_Coordinate: 90.0 South_Bounding_Coordinate: -90.0 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Topography Theme_Keyword: Bathymetry Place: Place_Keyword_Thesaurus: None Place_Keyword: Global Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: Pliocene Temporal_Keyword: Quaternary Temporal_Keyword: Recent Access_Constraints: none Use_Constraints: none Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peter N. Schweitzer Contact_Organization: Global Change and Climate History Program Contact_Address: Address_Type: mailing address Address: Mail Stop 906 National Center U.S. Geological Survey 12201 Sunrise Valley Drive City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: (703) 648-6533 Contact_Facsimile_Telephone: (703) 648-6647 Contact_Electronic_Mail_Address: pschweitzer@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: Browse_Graphic_File_Description: Global elevation and bathymetry depicted with cell (pixel) size 20 arc-minutes, based on TerrainBase (patched). The image is 1080x540 pixels. Depths are coded and colored in broad categories to emphasize the coastlines that would exist were sea-level at - 120 meters (as during the last glacial maximum, about 20,000 years ago), +25 meters (a conservative estimate of sea-level during the mid-Pliocene, about 3 million years ago), and +60 meters (the highest credible estimate of mid-Pliocene sea-level). The colors of each range of elevation (or bathymetry) are shown in Browse_Graphic_File_Type: GIF Native_Data_Set_Environment: The data set was produced using a Data General AViiON 6220 computer running the DG/UX 5.4R3.10 version of the UNIX operating system. Data_Quality_Information: Completeness_Report: Logical_Consistency_Report: Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Peltier, William R. Publication_Date: 1994 Title: Ice age paleotopography Geospatial_Data_Presentation_Form: remote-sensing image Series_Information: Series_Name: Science Issue_Identification: volume 265, 8 July 1994, pp 195-201 Online_Linkage: Online_Linkage: Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: cc19000 Ending_Date: 0000 Source_Currentness_Reference: Data are given on a 1-degree grid in the form of binary images, one per thousand years, from 21000 years before present to the present. Source_Citation_Abbreviation: ICE4G Source_Contribution: These data form the basis for our representation of sea-level changes during the Quaternary. Source_Information: Source_Citation: Citation_Information: Originator: Edwards, Margaret H. Publication_Date: 1989 Title: Global gridded elevation and bathymetry (ETOPO5): Digital raster data on a 5-minute geographic (lat/long) 2160x4320 (centroid-registered) grid Geospatial_Data_Presentation_Form: remote-sensing image Publication_Information: Publication_Place: Boulder, Colorado Publisher: U.S. National Oceanic and Atmospheric Administration, National Geophysical Data Center Online_Linkage: Larger_Work_Citation: Citation_Information: Originator: NOAA-EPA Global Ecosystems Database Project Publication_Date: 1992 Title: Global Ecosystems Database Edition: 1.0 Publication_Information: Publication_Place: Boulder, CO Publisher: National Geophysical Data Center Other_Citation_Details: EPA/600/R92/194b NGDC Key to Geophysical Records Documentation No. 27 Incorporated in Global Change Database, Volume 1 Documentation compiled by John J. Kineman and Mark A. Ohrenschall with additional contributions noted in the volume. Source_Citation_Abbreviation: ETOPO5 Type_of_Source_Media: CD-ROM Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1950 Ending_Date: 1989 Source_Currentness_Reference: The data set was published in 1989. Documentation provided by NGDC indicates the data were derived from sources produced during the period 1950 through 1980. Source_Contribution: Elevation and bathymetry used to represent images in this data set with 5- and 20-minute grid-cell spacing were derived from ETOPO5. Source_Information: Source_Citation: Citation_Information: Originator: Row, Lee W. III Originator: Hastings, David Publication_Date: 1994 Title: TerrainBase Global DTM Edition: 1.0 Geospatial_Data_Presentation_Form: remote-sensing image Publication_Information: Publication_Place: Boulder, Colorado Publisher: U.S. National Oceanic and Atmospheric Administration, National Geophysical Data Center Online_Linkage: Larger_Work_Citation: Citation_Information: Originator: Row, Lee W. III Originator: Hastings, David Originator: Dunbar, Paula Publication_Date: 1995 Title: TerrainBase Worldwide Digital Terrain Data Edition: 1.0 Publication_Information: Publication_Place: Boulder, CO Publisher: National Geophysical Data Center Other_Citation_Details: NGDC Key to Geophysical Records Documentation No. 30 Incorporated in Global Change Database, Volume 1 Source_Citation_Abbreviation: TBASE Type_of_Source_Media: CD-ROM Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1994 Source_Currentness_Reference: The CD-ROM was produced in 1994. The documentation was published in 1995. The data come from a variety of sources described in the documentation. Source_Contribution: Elevation and bathymetry used to represent images in this data set with 5- and 20-minute grid-cell spacing were derived from TBASE. NOTE: TerrainBase was patched before any calculations were made using it. See the process steps for details. Process_Step: Process_Description: Patching of data in TerrainBase to fix problem with bathymetry southeast of Halifax, Nova Scotia. The problem is shown in . Bathymetric data shown in TerrainBase version 1.0 is clearly incorrect in the region just southeast of Halifax, Nova Scotia. These data were corrected somewhat by patching in that region data from ETOPO5. The pixels changed are listed in . The programs used to patch the data were and . The process used was to manually identify pixels that appeared to be incorrect using an image-display program (xv), then use peek_topo to find out what those values were in ETOPO5. The values from ETOPO5 were planted in TerrainBase using the program poke_topo. All uses of TerrainBase in this data set were based on the patched version, not the original. Source_Used_Citation_Abbreviation: TBASE Process_Date: 19960927 Process_Step: Process_Description: Depiction of modern elevation and bathymetry. Executed color_topo using default mapping of depths to colors, with both ETOPO5 and TerrainBase (patched) as input. This produced portable pixmaps (PPM) of the data. The programs ppmtogif and ppmtopict were used to produce, respectively, GIF and PICT versions of this image. The PPM was scaled down by a factor of four using ppmscale; the resulting image has grid-cell size of 20 arc-minutes. GIF and PICT versions of this version were produced using ppmtogif and ppmtopict. The key, showing the relationship between depth ranges and colors, was generated using the program key, which displays the key in an X window. The window was captured using xwd, the output of which was converted to a portable pixmap and from there to GIF and PICT formats. Source_Code_Used: color_topo.c Source_Code_Used: key.c Data_File_Produced: mod05e.gif Data_File_Produced: mod05t.gif Data_File_Produced: mod05e.pict Data_File_Produced: mod05t.pict Data_File_Produced: mod20e.gif Data_File_Produced: mod20t.gif Data_File_Produced: mod20e.pict Data_File_Produced: mod20t.pict Data_File_Produced: modkey.gif Data_File_Produced: modkey.pict Source_Used_Citation_Abbreviation: ETOPO5 Source_Used_Citation_Abbreviation: TBASE Process_Date: 19961006 Process_Step: Process_Description: Global distribution of land surface on a 1-degree grid, every 1000 years from 21 ka to the present. The global topography data from W.R. Peltier show estimated elevation and bathymetry at 1,000-year intervals from 21,000 years ago to the present. In order to estimate the proportion of each 1-degree grid-cell that was covered by land, these data were combined with modern global topography as depicted in ETOPO5 and TerrainBase (patched). This procedure was applied to each 1,000-year interval: 1. The estimate of topography from Dr. Peltier (a 1-degree grid) was subtracted from the modern topography given in the same source data, yielding a 1-degree grid of differences between modern and ancient topography. This was accomplished using the program subtract.c. 2. The grid of differences was extended, using bilinear interpolation, to a grid mapping precisely onto ETOPO5 and TerrainBase. This was carried out by the program bilinear.c. 3. The resulting 5-minute grid of differences from modern topography was added to ETOPO5 or TerrainBase itself, producing an estimate of ancient topography on a 5-minute grid that accounted for ice loading. This was carried out by the program add_topo.c. 4. The program q1x1 was run using this estimate of ancient topography, yielding a 1-degree grid in which each cell estimates the percentage of the corresponding area of the earth's surface that was covered by land. Source_Code_Used: subtract.c Source_Code_Used: bilinear.c Source_Code_Used: add_topo.c Source_Code_Used: q1x1.c Data_File_Produced: grid00ke.txt Data_File_Produced: grid01ke.txt Data_File_Produced: grid02ke.txt Data_File_Produced: grid03ke.txt Data_File_Produced: grid04ke.txt Data_File_Produced: grid05ke.txt Data_File_Produced: grid06ke.txt Data_File_Produced: grid07ke.txt Data_File_Produced: grid08ke.txt Data_File_Produced: grid09ke.txt Data_File_Produced: grid10ke.txt Data_File_Produced: grid11ke.txt Data_File_Produced: grid12ke.txt Data_File_Produced: grid13ke.txt Data_File_Produced: grid14ke.txt Data_File_Produced: grid15ke.txt Data_File_Produced: grid16ke.txt Data_File_Produced: grid17ke.txt Data_File_Produced: grid18ke.txt Data_File_Produced: grid19ke.txt Data_File_Produced: grid20ke.txt Data_File_Produced: grid21ke.txt Data_File_Produced: grid00kt.txt Data_File_Produced: grid01kt.txt Data_File_Produced: grid02kt.txt Data_File_Produced: grid03kt.txt Data_File_Produced: grid04kt.txt Data_File_Produced: grid05kt.txt Data_File_Produced: grid06kt.txt Data_File_Produced: grid07kt.txt Data_File_Produced: grid08kt.txt Data_File_Produced: grid09kt.txt Data_File_Produced: grid10kt.txt Data_File_Produced: grid11kt.txt Data_File_Produced: grid12kt.txt Data_File_Produced: grid13kt.txt Data_File_Produced: grid14kt.txt Data_File_Produced: grid15kt.txt Data_File_Produced: grid16kt.txt Data_File_Produced: grid17kt.txt Data_File_Produced: grid18kt.txt Data_File_Produced: grid19kt.txt Data_File_Produced: grid20kt.txt Data_File_Produced: grid21kt.txt Source_Used_Citation_Abbreviation: ICE4G Source_Used_Citation_Abbreviation: ETOPO5 Source_Used_Citation_Abbreviation: TBASE Process_Date: 19961007 Process_Step: Process_Description: Global distribution of land surface on a 1-degree grid, for estimated Pliocene eustatic sea levels of 10, 20, 25, 30, 35, 40, 45, 50, and 60 meters higher than modern. For each estimate of the difference between Pliocene and modern eustatic sea-level, the program subset_etopo5 was used to subtract the estimate from the cell values of ETOPO5 and TerrainBase (lowering the land surface is equivalent to raising the sea level). The file resulting from this operation had the same dimensions and units as ETOPO5 or TerrainBase, but purported to show the global topography assuming that estimate of Pliocene eustatic sea-level, and not accounting for changes in landforms occurring during the past three million years. The program q1x1 was run using this estimate of Pliocene topography, yielding a 1-degree grid in which each cell estimates the percentage of the corresponding area of the earth's surface that was covered by land. Source_Code_Used: subset_topo.c Source_Code_Used: q1x1.c Data_File_Produced: grid10me.txt Data_File_Produced: grid20me.txt Data_File_Produced: grid25me.txt Data_File_Produced: grid30me.txt Data_File_Produced: grid35me.txt Data_File_Produced: grid40me.txt Data_File_Produced: grid45me.txt Data_File_Produced: grid50me.txt Data_File_Produced: grid60me.txt Data_File_Produced: grid10mt.txt Data_File_Produced: grid20mt.txt Data_File_Produced: grid25mt.txt Data_File_Produced: grid30mt.txt Data_File_Produced: grid35mt.txt Data_File_Produced: grid40mt.txt Data_File_Produced: grid45mt.txt Data_File_Produced: grid50mt.txt Data_File_Produced: grid60mt.txt Source_Used_Citation_Abbreviation: ETOPO5 Source_Used_Citation_Abbreviation: TerrainBase Process_Date: 19961007 Process_Step: Process_Description: Depiction of global coastlines with Pliocene sea-level estimates. The resulting images show the coastlines if eustatic sea-level were 120 meters lower, 35 meters higher, and 60 meters higher than at present. These estimates are based on modern topography; no attempt was made to represent the Pliocene configurations of landforms that may have been modified during the three million years since. Executed color_topo on ETOPO5 and TerrainBase (patched) using mapping of depths to colors found in file chg.bins. This produced a portable pixmap (PPM) of the image. The programs ppmtogif and ppmtopict were used to produce, respectively, GIF and PICT versions of this image. The PPM was scaled down by a factor of four using ppmscale; the resulting image has grid-cell size of 20 arc-minutes. GIF and PICT versions of this version were produced using ppmtogif and ppmtopict. The key, showing the relationship between depth ranges and colors, was generated using a modified version of the program key, which displays the key in an X window. The window was captured using xwd, the output of which was converted to a portable pixmap and from there to GIF and PICT formats. Source_Code_Used: color_topo.c Source_Code_Used: chg.bins Data_File_Produced: chg05e.gif Data_File_Produced: chg05t.gif Data_File_Produced: chg05e.pict Data_File_Produced: chg05t.pict Data_File_Produced: chg20e.gif Data_File_Produced: chg20t.gif Data_File_Produced: chg20e.pict Data_File_Produced: chg20t.pict Data_File_Produced: chgkey.gif Data_File_Produced: chgkey.pict Source_Used_Citation_Abbreviation: ETOPO5 Source_Used_Citation_Abbreviation: TBASE Process_Date: 19961007 Process_Step: Process_Description: Execute program q1x1 with ETOPO5 and TerrainBase as input data. Source_Code_Used: q1x1.c Data_File_Produced: grid00e.txt Data_File_Produced: grid00t.txt Source_Used_Citation_Abbreviation: ETOPO5 Source_Used_Citation_Abbreviation: TBASE Process_Date: 19961007 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Elevation, bathymetry, ice distribution, and coastline location are given using pixel values in images and, for the coastlines, vectors. Data files and images are named so as to indicate the source data used to produce them; files whose names (not including the extension that indicates the format such as ".gif" or ".pict") end with 'e' are based on ETOPO5, while those whose names end with 't' are based on TerrainBase. Entity_and_Attribute_Detail_Citation: Further information is available in the detailed metadata for each of the data products. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Peter N. Schweitzer Contact_Organization: Global Change and Climate History Program Contact_Address: Address_Type: mailing address Address: Mail Stop 906 National Center U.S. Geological Survey 12201 Sunrise Valley Drive City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: (703) 648-6533 Contact_Facsimile_Telephone: (703) 648-6647 Contact_Electronic_Mail_Address: pschweitzer@usgs.gov Resource_Description: USGS Open-File Report 96-000 Distribution_Liability: This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Metadata_Reference_Information: Metadata_Date: 19961025 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peter N. Schweitzer Contact_Organization: Global Change and Climate History Program Contact_Address: Address_Type: mailing address Address: Mail Stop 906 National Center U.S. Geological Survey 12201 Sunrise Valley Drive City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: (703) 648-6533 Contact_Facsimile_Telephone: (703) 648-6647 Contact_Electronic_Mail_Address: pschweitzer@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: 19940608 Metadata_Lineage: Record_Identifier_Type: URL Record_Combine_Method: Replace Child_Record: Child_Record: Child_Record: Child_Record: Child_Record: Child_Record: