40Ar/39Ar geochronology has had a profound impact on the Earth system sciences since its introduction in 1965. Here in the Argon Geochronology Laboratory at Oregon State University (OSU) we have been employing this dating method ever since 1977 with a focus on volcanism in both the marine and terrestrial environment to improve the geochronology of the ocean crust, ocean island volcanism, large igneous provinces, lunar and planetary rocks, hydrothermal minerals and clays, and so on …
Research employing K/Ar and later 40Ar/39Ar radiometric methods has a long history at the College of Earth, Ocean and Atmospheric Sciences (CEOAS). In 1969 the first Reynolds-design mass spectrometer was installed by Prof. David Tilles to undertake age determinations on lunar samples returned by the Apollo missions. Following his untimely death in 1970, Prof. Jack Dymond arrived at OSU to establish K/Ar dating in our Argon Geochronology Laboratory as well as noble gas geochemistry on terrestrial rocks.
In 1977 Prof. Robert Duncan joined the CEOAS faculty and took over the role of principal investigator for the geochronology facility, while focusing efforts toward 40Ar/39Ar dating of crustal rocks in the ocean basins. In 1980 another mass spectrometer (AEI MS-10) was added with funding from NSF and research areas expanded into dating of terrigenous sediments, vein-filling minerals (celadonite, adularia) and ocean floor basalts. In 1991 NSF provided funds for an MAP 215-50 Mass Spectrometer. Today, this instrument is in heavy use for age determinations by 40Ar/39Ar methods, predominantly detailed incremental heating experiments using a Heine resistance furnace and a Merchantek MIR10-TP CO2 laser.
At the beginning of 2007, Prof. Anthony Koppers joined the CEOAS faculty and together with Duncan now co-directs the 40Ar/39Ar facility. Following his arrival, our laboratory spaces have been upgraded and made ready for a new multi-collector ARGUS VI Mass Spectrometer funded by the National Science Foundation and installed in our laboratory in March 2012.
In the summer of 2014 the MAP 215-50 Mass Spectrometer was dismantled in order to be replaced by a second ARGUS VI Mass Spectrometer funded by the Vetlesen Foundation, CEOAS and the Research Office of OSU. This second setup is expected to be fully operational in April 2015.
Contact Dr. Dan Miggins for further information. He can be reached at his office phone (541-737-5206) or in the lab (541-737-5226).
This NSF-sponsored facility is directed by Profs. Duncan and Koppers and open to visiting scientists and students from across and outside the USA. These principal investigators have built up strong research programs with an emphasis on the geochronology of ocean basin volcanism, including the dating of the ocean floor, seamounts, volcanic islands and large igneous provinces.
For more info or requesting analyses feel free to contact us …
Students are integral to our lab. Follow their research through their project posts by clicking on the links below their names or reading the Projects page.