EarthRef.org Digital Archive (ERDA) -- 40Ar/39Ar Age Determination 07C1694 (KOP000046

Description
This upload contains the 40Ar/39Ar geochronology age determination of sample TAM-1 4D4-06 (ALIA 111-07) from Tama'i, Samoa and was calculated using the ArArCALC freeware. The preferred age of 1.87 ± 0.01 Ma is the age plateau and is interpreted as the eruption age of the sample. An excellent age plateau (with a high probability of 97%) that is compatible with the inverse and normal isochron ages (which have only a small spreading factor of 21.7%) but is concordant with the (recombined) total fusion age. The age determination was carried out on a sample of trachybasalt (groundmass 210-300µm) in an incremental heating experiment and using the bulk laser heating extraction method. The analyses were run on a MAP215-50 mass spectrometer and the ages were calculated relative to flux monitor FCT-3 (biotite) with an age of 28.030 ± 0.010 Ma. This sample was collected by Stan Hart (shart@whoi.edu).

Instructions
This ERDA upload contains four separate 40Ar/39Ar age calculation files generated with ArArCALC. Both the XLS and PDF files are for easy viewing in Microsoft Excel or Adobe Acrobat Reader, whereas the AGE file is readable by the ArArCALC software only and the XML file is generated for the GEOCHRON online database project. For full age calculation functionality it is recommended that you open the AGE file in the ArArCALC software that is available as freeware online at http://earthref.org/tools/ararcalc.htm ...

Keywords
40Ar/39Ar, Geochronology, Radiometric Age Dating, K/Ar, Argon, Mass Spectrometry, ArArCALC, Data Reduction, KOP000046 (IGSN), 07C1694 (Experiment), SAMOA (Project), Dredging>Chain Bag (Collection Method), Ship (Platform Type), Individual Sample (Collection Object), Igneous>Volcanic>Mafic (Rock Classification), 210-300 µm (Grain Size), Seamount (Feature Type)