Geographic extent of the Middle Devonian Marcellus Shale in the northeastern U.S. (Appalachian Basin) with indication of the depth of the top surface of the formation (given in feet relative to sea level). As it is obvious from the map, the by far greater portion of the formation lies deep below the surface, reaching maximum depths of more than 6000 ft near the Allegheny Front. The latter is also approximately congruent with the eastern margin of the Marcellus shale gas play.
<a href="//commons.wikimedia.org/wiki/User:Gretarsson" title="User:Gretarsson">Gretarsson</a>
CC BY-SA 4.0
<p><span class="int-own-work" lang="en">Own work</span><br>
The map was created using QGIS, with minor revisions using Adobe Photoshop.<br>
Data sources:
</p>
<ul><li>Geology: shapefile ‘Tight Oil and Shale Gas by Individual Play’ (March 2019), provided by the U.S. Energy Information Administration (download URL: <a rel="nofollow" class="external free" href="https://www.eia.gov/maps/map_data/TightOil_ShaleGas_IndividualPlays_Lower48_EIA.zip">https://www.eia.gov/maps/map_data/TightOil_ShaleGas_IndividualPlays_Lower48_EIA.zip</a>)</li>
<li>State and country borders: shapefiles (2018) provided by the U.S. Census Bureau (download URLs: <a rel="nofollow" class="external free" href="https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_state_5m.zip">https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_state_5m.zip</a>, <a rel="nofollow" class="external free" href="https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_nation_5m.zip">https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_nation_5m.zip</a>)</li>
<li>Geographical features (large lakes only): a selection of OpenStreetMap data (shapefiles, as of 21 August 2019), provided at Geofabrik (<a rel="nofollow" class="external free" href="http://download.geofabrik.de/north-america.html">http://download.geofabrik.de/north-america.html</a>)</li>
<li>Background: hillshade layer, generated from SRTM-based (SRTM GL3, 90 m resolution) digital elevation model, all provided at OpenTopography (<a rel="nofollow" class="external free" href="http://opentopo.sdsc.edu/raster?opentopoID=OTSRTM.042013.4326.1">http://opentopo.sdsc.edu/raster?opentopoID=OTSRTM.042013.4326.1</a>)</li></ul>
All data are either originally published/provided by the U.S. federal government (EIA, USCB, NASA/USGS) and thus are in the <a href="https://en.wikipedia.org/wiki/Public_domain" class="extiw" title="w:Public domain">public domain</a> or are generated by Open StreetMap contributors and distributed under the <a rel="nofollow" class="external text" href="https://www.opendatacommons.org/licenses/odbl/1.0/index.html">Open Database 1.0 License</a> which allows free use, modification and re-distribution.