Top contours of the South-Zone 6 coal bed (in USGS top intervals) in Central Texas

United States Geological Survey (USGS) 2011 Top contours of the South-Zone 6 coal bed (in USGS top intervals) in Central Texas AAPG Discovery Series/AAPG Studies in Geology No. 14/No. 62 vector digital data Tulsa, OK American Association of Petroleum Geologists U.S. Geological Survey 2011 Geologic Assessment of Coal in the Gulf of Mexico Coastal Plain, U.S.A. AAPG Discovery Series/AAPG Studies in Geology No. 14/No. 62 Tulsa, OK American Association of Petroleum Geologists czl6top withheld This data set is a polygon coverage of the structural top of South-Zone 6, in feet, over extent of the South-Zone 6 coal and its horizon (stratigraphic equivalent) in Central Texas only. The coverage was produced by gridding more than 350 public and confidential point- source data from the National Coal Resources Data System (NCRDS) of the USGS, using EarthVision (Version 4.0.2) software, subsequently contoured into 6-inch intervals, and imported to ARC/INFO. The 'elev_st' item for each polygon reflects a value in feet halfway between the bounding contour lines. This value represents results of gridding which averages point values within cells, therefore, public point data may not always match values represented in the top of coal structure data layer. This data set was used in the National Coal Resource Assessment Program in the regional evaluation of resources for the coal South-Zone 6 in the Gulf Coast region. The data set is useful for regional studies- not applicable to local scales. en 1970's 1997 publication date Complete None planned -97.4367 -96.8542 30.7960 30.0171 -97.436668 -96.854172 30.017075 30.796040 Theme_Keyword_Thesaurus coal coal resources coal top lignite isopach outcrop USGS Geographic Names Information System Gulf Coast Region Freestone County, TX Limestone County, TX Robertson County, TX Leon County, TX Robertson County, TX Milam County, TX Lee County, TX Bastrop County, TX Stratum_Keyword_Thesaurus Wilcox Group Paleocene-Eocene none none Peter D. Warwick mailing address

MS 956 National Center

Reston Virginia 20192 USA 703-648-6469 Geologist pwarwick@usgs.gov The stratigraphic data stored in the NCRDS has been submitted by State Geological Surveys and USGS scientists since its inception in the middle 1970's through state cooperative programs. The data for the South-Zone 6 coal bed was used with the permission and through the cooperation of coal geologists (primary contacts listed) at the State of Texas Bureau of Economic Geology and the State of Texas Railroad Commission ESRI ArcCatalog 9.3.1.3000 Shapefile The range of top values in the point-source information was 53 to 460 feet. The resultant range of the gridded surface was 182-218 feet; extrapolation was used over the x,y extent. The average absolute Z-error of the grid was 0.18 percent of the range. Topologically clean Input points were irregularly distributed over the spatial extent of the study, therefore areas of sparse data will not reflect ground truth. South-Zone 6 cumulative coal tops were selected by name from the stratigraphic data base stored in StratiFact, a relational data base manager in use by the USGS National Coal Assessment. The original data submitted to NCRDS may not have had the Zone identified, a task performed within StratiFact by examining data in cross sections. Data used were selected by geologist from the database. NCRDS, USGS 1995 NCRDS Digital Data Set on-line data base 1995 2000 publication date NCRDS- National Coal Resources Data System;BEG-Bureau of Economic Geology; RRC-Railroad Commission NCRDS- point-source data South-Zone 6 data from NCRDS printed and verified against original data sources where possible. New data collected from the BEG and the RRC, and entered into NCRDS. 1995-1998 Corrections made to NCRDS (including the new BEG and RRC data) in StratiFact. 1996-1998 Editing and correlation of individual data bases in StratiFact to eliminate data coding differences between data sets. 1998 Editing of tops and further addition and refinement of data values to place in StratiFact data bases. The data were filtered in StratiFact and filtered in EarthVision (v.4.0.2) in geographic coordinates. The data are gridded and grid parameters used were a default 182 x 218 grid, X range -95.79222 to -94.79518, Y range 32.69406 to 33.29903, extrapolation of values over specified x,y extent plus 5%. Contour intervals at irregular intervals at 50-100 ft,100-150 ft, 150-200 ft, 200-250 ft, 250-300 ft, 300- 350 ft, 350-400 ft, 400-450 ft to follow USGS Circular 891. 1999 Grid was contoured in EarthVision into 0.5-foot intervals, using 0 to 30 feet as limits. Contour file was graphically edited in EarthVision to fit the geology of the area. 1999 Grid was projected into Albers and regridded using the original graphically edited grid to decrease the cell size so that the small polygons in the limiting unioned coverage used for volume calculations will have a grid value to use for each small 402.10 - 404.97. 1999 Import of contours to ARC/INFO for the entire area, using conversion ARC/INFO AML provided by Illinois State Geological Survey, and rectangular area ARC coverage (box) to enclose polygons. Polygons graphically labeled in ARC/EDIT using midpoint value for upper and lower bounding contours. The 75, 125, 175, 225, 275, 325, 375, 425 (ft). 1999 New attribute item "top" added and calculated from the polygon value. Added item for top category and populated it by graphically selecting desired polygons by top and calculating the category value. 1999 Arc/Info coverages were projected to geographic coordinates, converted to shape Arc/View shape files and imported into Arc/View. 1999 North American Datum of 1927 Clarke 1866 6378206.4 294.98 DD_NAD83 czl6top.dbf polygon attribute table for coverage ARC/INFO Feature Class 0 OBJECTID FID OID 4 10 0 Internal feature number. Esri Sequential unique whole numbers that are automatically generated. edx_sp_ree_coal_od.sde.REE0378_czl6top_Central_Texas_South_Coal_Zone_6_Structural_Top_.area edx_sp_ree_coal_od.sde.REE0378_czl6top_Central_Texas_South_Coal_Zone_6_Structural_Top_.area Double 8 38 8 Shape Shape Geometry 8 0 0 Feature geometry. ESRI Coordinates defining the features. AREA AREA Double 8 0 0 PERIMETER PERIMETER Double 8 38 8 elev_st average top structure value of bounding contour lines ARC/INFO 125 475 ELEV_ST Double 8 38 8 source_organization Source Organization String 255 0 0 dataset_name Dataset Name String 255 0 0 hyperlink Link String 255 0 0 dateupdated Date Last Updated String 255 0 0 st_area(shape) st_area(shape) Double 0 0 0 st_perimeter(shape) st_perimeter(shape) Double 0 0 0 source_ID Source ID String 255 0 0 mailing address

P. O. Box 979

Tulsa OK 74101-0979 USA 1 800 364 2274 American Association of Petroleum Geologists 1 918 560 2665 South-Zone 6 coal bed The US Geological Survey provides these geographic data "as is". USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. USGS further makes no warrantees, either expressed or implied, as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers of the USGS, no warranty, expressed or implied, is made by USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of the delivery, installation, operation, or support by USGS. ARCE 0.063 0.063 withheld none 2011 Peter D. Warwick mailing address

MS 956 National Center

Reston Virginia 20192 USA 703-648-6469 Geologist pwarwick@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 en local time Esri ArcGIS 13.1.0.41833 REE0378_czl6top_Central_Texas_South_Coal_Zone_6_Structural_Top_ -97.436668 -96.854172 30.79604 30.017075 1 -97.436668 -96.854172 30.79604 30.017075 1 ISO 19115 Geographic Information - Metadata DIS_ESRI1.0 dataset 002 withheld Local Area Network 0.063 Shapefile Enterprise Geodatabase Feature Class Vector Simple FALSE 0 TRUE FALSE DD_NAD83 EPSG 6.18.3(9.3.1.2) 0 20230628 08375600 20230628 08375600 REE0378_czl6top_Central_Texas_South_Coal_Zone_6_Structural_Top_ 002 Projected GCS_WGS_1984 Linear Unit: Meter (1.000000) <ProjectedCoordinateSystem xsi:type='typens:ProjectedCoordinateSystem' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns:xs='http://www.w3.org/2001/XMLSchema' xmlns:typens='http://www.esri.com/schemas/ArcGIS/3.1.0'><WKT>PROJCS["WGS_1984_Web_Mercator_Auxiliary_Sphere",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Mercator_Auxiliary_Sphere"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["Standard_Parallel_1",0.0],PARAMETER["Auxiliary_Sphere_Type",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG",3857]]</WKT><XOrigin>-20037700</XOrigin><YOrigin>-30241100</YOrigin><XYScale>10000</XYScale><ZOrigin>-100000</ZOrigin><ZScale>10000</ZScale><MOrigin>-100000</MOrigin><MScale>10000</MScale><XYTolerance>0.001</XYTolerance><ZTolerance>0.001</ZTolerance><MTolerance>0.001</MTolerance><HighPrecision>true</HighPrecision><WKID>102100</WKID><LatestWKID>3857</LatestWKID></ProjectedCoordinateSystem> WGS_1984_Web_Mercator_Auxiliary_Sphere 20230628