Skip to main content
Courtland Gleeson

AZGS releases digital drill core data from the Courtland-Gleeson area, Turquoise mining district, southeastern Arizona

The Courtland-Gleeson area (Turquoise mining district) has been explored and worked since 1877, with major exploration projects and drilling periodically occurring from the 1950’s onwards. Much of the data from these projects were ultimately donated to the Arizona Geological Survey. Data from the Courtland-Gleeson area was particularly complete, with not only drill logs, but also assays, photos of core, associated reports, maps, and cross sections. From September 2019 to July 2020, AZGS’s Mineral Resources program, supported by five student workers, diligently scanned all the associated data and tabulated 25,935 m (85,087 feet or 16.1 miles) of drill data for lithology, mineralization, alteration, structure, and assays across 113 drill holes.

The data is released in several formats. The first is an interactive webmap, where all of the data is displayed for the user to easily peruse the contents. Each tab along the lower portion of the screen represents one of the tabulated spreadsheets, where the user can preview the data. The tabulated data is available for download as eight spreadsheets that include: data sources, lithology, alteration, mineralization, assays, structure point data, structure interval data, and drill hole location data. The spreadsheets are intended to be easily convertible into formats for import into modeling software for viewing drill data. Lastly, two of the geological maps that accompanied some of the data were digitized and available as map plates to provide additional geologic context for the drill holes.

The Arizona Geological Survey (AZGS) has long served as the archival repository for geological data in Arizona that may not have an appropriate home elsewhere. This digitization effort is thanks to funding from the U.S. Geological Survey’s Earth Mapping Resources Initiative (Earth MRI) and National Geological and Geophysical Data Preservation Program matched 1:1 with state funding from AZGS’s line-item appropriation.

Webmap Link

OFR-20-02 Link


This project would not have been possible without the many exploration geologists who conducted the original work that developed this rich data set. Erin Phelps, Matthew Ricker, Arielle O’Connor, Evgenia Diakonenko, and Elise Gregory served as dedicated student workers, and whose significant efforts made this project successful.

Blog post by C.A. Richardson (10/08/2020)