Core Repository and Exploration Records

The Maine Geological Survey maintains a repository of geological drill cores and samples for research purposes. These collections are focused on hard rock mineral resources and represent projects widely scattered about Maine in both time and space. Perhaps 100,000 feet of core representing millions of dollars in recovery expense are preserved in the facility. All cores and related documentation were donated to the State at various times by their rightful owners and are now considered State records, available for public inspection. This generalized map (PDF, 1.0Mb) shows townships for which we have cores, or in some cases both cores and core logs.

Google Earth Interactive Map

Core logs for rock cores stored in the Maine Geological Survey's Core Repository are now available via Google Earth.  You will need to install Google Earth on your computer to view this data.  For help using Google Earth go to the Google Earth Help Center.

Google Earth logo
Core Locations and Logs - KML file which opens Google Earth

Core Locations

  • Cores shown on the Google Earth map were approximately located using project maps from various exploration programs. Location information was georeferenced using ArcMap, USGS topographic quadrangles, and Google Earth aerial photography. Locations should be considered approximate and for general reference only.

Core Logs

  • As rock core is obtained by drilling, it is examined by a geologist who keeps a record, or log, of features of interest along the length of the core. Such drill logs are paper records which may be best used to direct investigators to particular segments of the rock core for further study or analysis, and to connect structural or mineralogical features at depth from one hole to another.
  • The Maine Geological Survey has copies of many such exploration logs. Some of the rock core in the repository has corresponding logs, but there are also some cores for which we do not have logs. Also, there are many logs in our records for which we do not have rock core.
  • Individual core logs have been scanned and may be viewed or downloaded through the Google Earth interactive map listed above. Consolidated PDF files of all cores related to specific exploration projects are also available.

Last updated on August 27, 2012