Monday, 7 April 2025/ Edition 53

Here we go, kicking off a second year of Core Elements!

Much like Core Elements is a free resource for geoscientists and geology enthusiasts, there are many free apps, maps, and data sets available to geoscientists. This edition will cover a few of those.

Rasoul Sorkhabi

Editor, Core Elements

Digital Geological Maps

Budimir Jevtic/Shutterstock.com

There are several international initiatives that also offer digital dynamic geological maps with global or continental coverage.

OneGeology is an international, collaborative geology project supported by 118 countries and led by UNESCO.

• The OneGeology portal provides free online access to global geoscience data.

• Best use cases: The site saves a lot of time for reconnaissance research on the outcrop geology of particular areas. The map scale is 1:1 million.

Macrostrat is “A platform for geological data integration and deep-time Earth crust research,” according to a technical report published by the American Geophysical Union. Macrostrat was funded by the U.S. National Science Foundation with support from the University of Wisconsin-Madison.

• The platform includes:

  • 2,540,323 geologic map polygons

  • 51,212 stratigraphic names

  • 35,481 rock units

  • 1,534 regional rock columns

• It encompasses more than 35,000 geological units distributed across 1,474 regions in North and South America, the Caribbean, New Zealand, and the deep sea.

• Best use cases: Macrostrat contains multidisciplinary data helpful for petrologists, stratigraphers, paleontologists, and geochronologists, among others. With data from both outcrops and subsurface formations, petroleum geologists working in North and South America will find Macrostrat especially useful.

The European Geological Data Infrastructure platform is a collaborative project on geological information across Europe.

• The portal includes Map Viewer and Data Search features.

• The subsurface data available is from thousands of experts in 37 national and regional geological surveys across Europe. More than 800 map layers are available.

• The Map Viewer has options to download GSI files, so you can include them in your data and presentations.

• Best use cases: The various geologic data are harmonized for all of Europe, so projects examining the continent as a whole or trying to draw conclusions at the regional level may find it most helpful. The database also contains environmental topics such as groundwater and soil, which are of help to researchers who need analytical data for environmental assessment projects.

U.S. Geological Survey Maps include “The National Geologic Map Database” (NGMDB) and “World Geologic Maps.”

NGMDB encompasses:

• • Map Catalog (products from more than 600 publishers)

  • MapView (interactive geologic maps)

  • TopoView (historical topographic maps)

  • Stratigraphy (stratigraphic names and charts)

  • Standards & Guides (for creating geologic maps and reports)

  • Geologic Map Schema (schema for creating digital geologic maps)

The USGS World Geologic Maps portal includes geologic maps of Africa, the Arabian Peninsula, the Arctic, Asia Pacific, Bangladesh, the Caribbean, Europe, the Former Soviet Union, the Gulf of Mexico/Gulf of America, Iran, North America, South America, South Asia, and Afghanistan.

• Best use cases: This is the best interactive online source for outcrop geology of the United States, and USGS international maps have integrated the geology of the world on a continental scale.

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Geology-Focused Apps

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There are several open-source apps that help geology students, teachers, and researchers with field work and research.

Rockd was funded by NSF and is maintained by the University of Wisconsin-Madison Macrostrat Lab. Its modules include:

• Summaries of geologic and geographic information about your location of interest

• A scanner tool that uses your phone camera to identify rock types

• Access to 140 interactive geological maps

• Paleogeographic maps

• GoDeepDive, a database of published geological literature

• A capability to measure and record geologic data such as strike and dip

• A record and log for field observations

Best use cases: Rockd is a “one-stop shop” for geologists looking to integrate various kinds of geological information, from outcrop and paleofacies maps to structural measurements.

Rock Identifier is an app that helps identify rocks based on image analysis. “Simply take or upload a photo of any rock and get accurate ID results withing seconds,” their site says.  

Best use cases: This is a great tool for amateur geologists and students making their first attempts at rock identification (and perhaps also discussing and testing the results).

Stereonet Mobile helps you collect, visualize, and analyze geological orientation data. Created by structural geologist Rick Allmendinger, Stereonet Mobile is a companion app to Allmendinger’s Stereonet 11 Program for desktop.

Best use cases: This app makes it quick and easy to plot orientation data of geologic structures for publications and reports.

Public-Access Data Sets

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Here are some online databases on minerals and geochemistry that could help inform your next project.

Mindat.org is an online database about minerals worldwide. It is operated by the Hudson Institute of Mineralogy.

• The platform includes data on:

  • 6,117 mineral species

  • 3,174 rocks

  • 410,555 localities

  • 1,603,801 occurrences

  • 1,417,705 photos

  • 2,898 articles

  • 26,066 glossary terms

Best use case: Geologists interested in chemical composition, physical properties, host rocks, and/or mineral mines will find this large database on mineralogy helpful. Mineral data are enhanced by images and published literature.

The Geochemistry of Rocks of the Oceans and Continents (GEOROC) is a database drawn from published analyses of rocks, including major- and trace-element concentrations and isotope ratios.

• Run by the Georg-August-Universität Göttingen, GEOROC contains 22,750 papers, 685,660 samples, 2,680,100 analyses, and 39,334,100 single data values.

• Best use cases: Researchers in geochemistry and critical minerals will find GEOROC useful as a global database on elemental concentrations in various rock types with references included.

EarthChem is an open data repository of geochemical data worldwide and a geochemical, mineralogical, and petrological database.

• The project is funded by the U.S. National Science Foundation and maintained by the Lamont-Doherty Earth Observatory at Columbia University.

• EarthChem encompasses three portals:

  • PetDB (data from peer-reviewed literature)

  • The EarthChem Portal (multiple data sources)

  • The Library of Experimental Phase Relations and Trace Element Distribution Experimental Database

• Best use cases: EarthChem has overlaps with GEOROC; however, it includes multiple portals, and data from each of its portals can be retrieved through Search options. The platform is useful particularly for researchers integrating geochemical data with petrological contexts.

The USGS National Geochemical Database includes geospatial data on the geochemistry of hard rocks, sediments, soils, and elemental concentrations from the continental United States.

Best use cases: Geologists and environmental scientists working on projects related to the United States will find this geochemical database critical for their research. The data locations are georeferenced for easy use and visualization.

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✉️ To get in touch with Rasoul, send an email to editorial@aapg.org.