USGS Geochron: A database of USGS geochronological and thermochronological data
When did that volcano erupt? How old are the rocks that might contain critical minerals? The USGS Geochron Database helps answer these questions by providing free, public access to more than 200,000 published measurements from over 35,000 samples of geologic time.
Geochronology, the science of measuring geologic time, reveals the timing of events that shape our planet: volcanic eruptions, mountain building, mineral deposit formation, and landscape evolution. The USGS Geochron Database is a centralized, standardized repository that integrates U.S. Geological Survey (USGS) and state geological survey geochronological data in accordance with the National Geologic Mapping Act of 1992 and its Reauthorizations.
The database includes data from 15 geochronological and thermochronological methods, spanning techniques from radiocarbon and luminescence dating to long-lived isotopic systems such as U-Th-Pb, Sm-Nd, Rb-Sr, Lu-Hf, Re-Os, and 40Ar/39Ar. New data and methods are added with regular data release updates (approximately twice per year).
The database has been compiled in partnership with state geological surveys through the STATEMAP program, Earth MRI, and with scientists worldwide. It incorporates legacy data from the National Geochronological Data Base (1976-1992) along with newly compiled datasets from published USGS and external sources.
Why Geochronologic Data Matter
Mineral and Energy Resources
Understanding when mineral deposits formed and how they evolved helps identify promising areas for exploration and assess resource potential, including critical minerals essential for clean energy technologies, national defense, and advanced manufacturing.
Geologic Mapping
Determining the ages of rock layers and intrusions provides the foundation for accurate geologic maps, which inform land use planning, infrastructure development, and resource management.
Natural Hazards
Determining when past volcanic eruptions, landslides, and earthquakes occurred helps scientists assess the likelihood and potential impact of future events.
Understanding Earth History
Calibrating the timing of events in Earth history helps scientists understand the evolution of life on Earth and distinguish between potential causes of events such as mass extinctions.
How Does Geochronology Measure Time?
Some rocks contain tiny amounts of radioactive elements that slowly change over time from one form (called the "parent") into another form (called the "daughter") through a process called radioactive decay. This change happens at a steady, known rate, like a natural clock.
When a rock is hot, the daughter elements can move away and are lost. When a rock cools enough (for example, when a volcano erupts and the lava cools), it begins to seal daughter elements inside. That's when the "clock" starts ticking. To figure out how long ago that event happened, most geochronological methods involve measuring how much of the parent and daughter elements are in the rock today.
How to Access the Database
There are three ways to access the data. All methods access the same source data.
- Database Explorer: Interactive, web-based experience with point-and-click access to geochronology information, including the ability to download data files for selected areas.
- Data Release: Complete dataset in .csv files with metadata and data dictionary.
- GIS Integration: Connect directly using "add data from path" function in GIS software.
Contributing Data to the USGS Geochron Database
The USGS Geochron Database welcomes published geochronology and thermochronology data from government agencies, academia, and industry partners. Expanding the database ensures comprehensive coverage across methods, regions, and geologic settings.
Requirements
Samples must have a sample identifier, age, location, and citation from a peer-reviewed source.
Data Compilation Templates
Method-specific Microsoft Excel templates and a user guide are available at https://doi.org/10.5066/P14SSWBH
Contact
For questions about contributing data, contact geochron@usgs.gov
Contributed datasets are reviewed and added to the database on a regular basis.
The National Geologic Map Database (NGMDB)
Argon Geochronology
From Outcrop to Ions: development and application of in-situ isotope ratio measurements to solve geologic problems
Geologic Framework of the Intermountain West
When did that volcano erupt? How old are the rocks that might contain critical minerals? The USGS Geochron Database helps answer these questions by providing free, public access to more than 200,000 published measurements from over 35,000 samples of geologic time.
Geochronology, the science of measuring geologic time, reveals the timing of events that shape our planet: volcanic eruptions, mountain building, mineral deposit formation, and landscape evolution. The USGS Geochron Database is a centralized, standardized repository that integrates U.S. Geological Survey (USGS) and state geological survey geochronological data in accordance with the National Geologic Mapping Act of 1992 and its Reauthorizations.
The database includes data from 15 geochronological and thermochronological methods, spanning techniques from radiocarbon and luminescence dating to long-lived isotopic systems such as U-Th-Pb, Sm-Nd, Rb-Sr, Lu-Hf, Re-Os, and 40Ar/39Ar. New data and methods are added with regular data release updates (approximately twice per year).
The database has been compiled in partnership with state geological surveys through the STATEMAP program, Earth MRI, and with scientists worldwide. It incorporates legacy data from the National Geochronological Data Base (1976-1992) along with newly compiled datasets from published USGS and external sources.
Why Geochronologic Data Matter
Mineral and Energy Resources
Understanding when mineral deposits formed and how they evolved helps identify promising areas for exploration and assess resource potential, including critical minerals essential for clean energy technologies, national defense, and advanced manufacturing.
Geologic Mapping
Determining the ages of rock layers and intrusions provides the foundation for accurate geologic maps, which inform land use planning, infrastructure development, and resource management.
Natural Hazards
Determining when past volcanic eruptions, landslides, and earthquakes occurred helps scientists assess the likelihood and potential impact of future events.
Understanding Earth History
Calibrating the timing of events in Earth history helps scientists understand the evolution of life on Earth and distinguish between potential causes of events such as mass extinctions.
How Does Geochronology Measure Time?
Some rocks contain tiny amounts of radioactive elements that slowly change over time from one form (called the "parent") into another form (called the "daughter") through a process called radioactive decay. This change happens at a steady, known rate, like a natural clock.
When a rock is hot, the daughter elements can move away and are lost. When a rock cools enough (for example, when a volcano erupts and the lava cools), it begins to seal daughter elements inside. That's when the "clock" starts ticking. To figure out how long ago that event happened, most geochronological methods involve measuring how much of the parent and daughter elements are in the rock today.
How to Access the Database
There are three ways to access the data. All methods access the same source data.
- Database Explorer: Interactive, web-based experience with point-and-click access to geochronology information, including the ability to download data files for selected areas.
- Data Release: Complete dataset in .csv files with metadata and data dictionary.
- GIS Integration: Connect directly using "add data from path" function in GIS software.
Contributing Data to the USGS Geochron Database
The USGS Geochron Database welcomes published geochronology and thermochronology data from government agencies, academia, and industry partners. Expanding the database ensures comprehensive coverage across methods, regions, and geologic settings.
Requirements
Samples must have a sample identifier, age, location, and citation from a peer-reviewed source.
Data Compilation Templates
Method-specific Microsoft Excel templates and a user guide are available at https://doi.org/10.5066/P14SSWBH
Contact
For questions about contributing data, contact geochron@usgs.gov
Contributed datasets are reviewed and added to the database on a regular basis.
The National Geologic Map Database (NGMDB)
Argon Geochronology
From Outcrop to Ions: development and application of in-situ isotope ratio measurements to solve geologic problems