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Argon Geochronology

Project Objectives

This project maintains the ⁴⁰Ar/³⁹Ar laboratory serving the needs of USGS geologists and other Federal agency projects. The ⁴⁰Ar/³⁹Ar geochronology laboratory in Denver is a state-of-the-art research facility for determining ⁴⁰Ar/³⁹Ar ages of minerals and rocks. This facility houses necessary equipment for sample preparation and analysis, including a high-sensitivity noble gas mass spectrometer and UV and IR lasers. The versatility of the ⁴⁰Ar/³⁹Ar method permits determining the timing of processes and events such as igneous intrusions and extrusions, ore mineralization and hydrothermal fluid circulation, metamorphic cooling and exhumation, mineral formation and recrystallization, and shallow crustal faulting. The geologist is dependent on the geochronologist for data and interpretation to determine these parameters. This laboratory develops methodology for small and difficult sample analysis often at the limits of existing mass spectrometer technology. View more information on the laboratory.

Relevance & Impact

The ⁴⁰Ar/³⁹Ar geochronology laboratory has a large impact on the Central Region, which has a high demand for ⁴⁰Ar/³⁹Ar geochronology in a variety of projects. Application of ⁴⁰Ar/³⁹Ar geochronology is invaluable in determining the absolute age of field relationships and timing of events.