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40Ar/39Ar Age Determination 11C2815 (KOP000024 - Rigil Guyot, Site U1374)
File Name KOP000024.11C2815.pdf
Data Type spreadsheet
Computer Program ArArCALC 2.5.2
File Size 1.25 MB - 4 files [ pdf,xls,age,xml ]
Expert Level State-of-the-art Science
Contributor Anthony A.P. Koppers
Source Koppers et al. 2012
http://earthref.org/ERDA/KOP000024/
Description
This upload contains the 40Ar/39Ar geochronology age determination of sample 330-U1374A-64R-2 112-117 CM from Rigil Guyot, Site U1374 and was calculated using the ArArCALC freeware. The preferred age of 70.51 ± 0.22 Ma is the age plateau and is interpreted as the eruption age of the sample. Classical groundmass age spectrum with high apparent ages for the low temperature steps due to remaining alteration in this submarine basaltic material and 39Ar recoil effects. The middle section reflects the primary argon being released from the groundmass giving the eruption age of the sample, mostly free of alteration and recoil effects. The high temparature steps give lower apparent ages due to recoil effect on 37Ar when outgassing the Calcium-rich clinopyroxene and plagioclase groundmass phases. The fact that the plateau age is concordant with both isochron ages and the total fusion age provides confidence in this interpretation. The age determination was carried out on a sample of basaltic lava (groundmass 213-300µm) 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 Anthony Koppers (akoppers@coas.oregonstate.edu). Sample Description: Acid-leached Location Description: Drill Site U1372, Louisville Seamount Trail, IODP Expedition 330, Exp330
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