Crawford Elliott’s Lab
at Georgia State University
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K-Ar Geochronology Laboratory

The K-Ar lab was built by Professor Marion Wampler while he was at GATECH.  Dr. Wampler moved the lab to GSU on his retirement from Georgia Tech.  At GSU, new vacuum pumps (Turbo and mechanical), pressure gauges, electrometer, Mettler  and acid storage closet were added to enhance its capabilities to determine accurate K-Ar ages of minerals.  Since the move to GSU, the lab has supported thesis and funded research projects both within and outside GSU.  This line is one of the few remaining K-Ar labs still functioning.

The argon isotopic composition is measured using the vacuum line shown below.  Samples are heated with a resistance heater to 600oC. This line is most useful for phyllosilicate minerals.  The extracted gases are cleaned with heated titanium and by passing through two traps cooled with liquid nitrogen.  A spike of Ar-38 is added to the extracted gases.  The Ar isotopic composition  of the cleaned extracted gases together with spike is measured with a MS 10 mass spectrometer.  We measure the abundances with an high impedance Keithly Electometer and a chart recorder.   The chart recorder permits us to see if any contaminant gases are present prompting correction of peak heights. K is measured using Atomic Absorption Spectrophotometry located in the Environmental Research Laboratory in Geosciences (

Sample heated with an external resistance wound heaterArgon isotope extraction lineArgon isotope extraction line

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