1
Büchner et al.
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The Lausitz Volcanic Field – link between the volcanism of Ohře Graben (Czech
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Republik) and of the Fore Sudetic Basin (Poland)
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5
Supplementary data
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7
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Analytical procedure of 40Ar/39Ar analyses that were carried out at Argon laboratory of TU
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Bergakademie Freiberg
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Whole-rock fragments (<1mm) were repeatedly ultrasonicated in deionized water, dried, and
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subsequently wrapped into Al-foil. Sample packets (~50 mg per sample) along with fluence
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monitors (Fish Canyon Tuff sanidine) were then loaded in Al discs and irradiated under Cd-
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shielding in the FRG-2 reactor at the GKSS Forschungszentrum in Geestacht, Germany.
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After irradiation, samples and monitor minerals were degassed stepwise using a high-
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temperature cell. Ar isotope abundances were measured on a GV Iinstruments Argus multi-
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collector noble gas mass spectrometer in static mode. Mass fractionation was corrected for
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by assuming linear mass dependent isotope fractionation. For time-zero intercept calculation
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and raw data reduction, an in-house developed Matlab® toolbox was used. Isochron, inverse
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isochron and plateau ages have been calculated using ISOPLOT 3.7 (Ludwig et al., 2008).
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All ages were calculated against Fish Canyon sanidine as flux monitor (28.305 ± 0.036 Ma;
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Renne et al., 2010), errors on ages are 1σ. Decay constants used are from Renne et al.
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(2010). Corrections for interfering Ar isotopes have been done using (36Ar/37Ar)Ca =
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0.000409 ± 0.000014, (39Ar/37Ar)Ca = 0.000875 ± 0.000051, (38Ar/39Ar)K = 0.0172 ±
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0.00022, (40Ar/39Ar)K = 0.004 ± 0.0002 (for details see Pfänder et al., 2010).
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LUDWIG, K. R. (2008) Isoplot 3.70. A Geochronological Toolkit for Microsoft Excel. Berkeley
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Geochronology Center Special Publication, 4, 1–76
1
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Pfänder, J., Sperner, B., Ratschbacher, L. (2010) The new Ar-Ar geochronology facility at
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Freiberg, Germany: Instrumentation, applications, and current limitations. Geophysical
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Research Abstracts, 12, EGU2010-5496
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RENNE P.R., MUNDIL R, BALCO G., MIN K. & LUDWIG K.L. (2010) Joint determination of
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40K decay constants and 40Ar*/40K for the Fish Canyon sanidine standard, and improved
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accuracy for 40Ar/39Ar geochronology. Geochim. Cosmochim. Acta, 74, 5349-5367
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RENNE P.R. & NORMAN, E.B. (2001) Determination of the half-life of 37Ar by mass
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spectrometry. Physical Review C, 63, (047302), 3 pp.
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Fig S1 Selected major and trace elements versus MgO as an index of differentiation
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Fig S2 Plateau characteristic diagrams of all samples investigated in LVF, the samples
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08/11/18-1, 08/11/18-7 and Su2-09 were analysed in the Argon laboratory of TU
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Bergakademie Freiberg
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Table S1: Locations of 77 samples obtained from the Lausitz Volcanic Field for geochemical
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analyses, with further details about the 23 locations dated using the
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study. Coordinates in German grid zone 5.
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Ar/39Ar method in this
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2