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ArArCALC Help Library |
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ArArCALC Help Library |
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2.3.7 Tables Menu
Nine different data tables are available in every ArArCALC age calculation file. Five of these tables include output data from your age calculations, whereas four tables include the input data necessary to perform the age calculations and which you can edit at any time (see also: Editing Data in ArArCALC). The calculation data tables are all located in the Data Tables worksheet and are selectable through the Tables menu. You can also use the F5, F6, F7, F8 and F9 keyboard strokes for faster navigation between the tables.
The Age Plateau data table contains calculation data for the plateau age, total fusion ages and K/Ca ratios. Note that also the MSWD, the number of increments and the total amount of 39Ar(k) in percent are given for the age plateau calculation. The uncertainties on the 40Ar/39Ar ages are defined as Internal Errors that combine the Analytical Errors with the Errors on the J-value. For completeness, the Analytical Errors and External Errors (including the error on the total 40Ar decay constant) are given as well (see also: Analytical, Internal and External Errors). The checkmarks signify the analyses included in the age plateau calculation, whereas the summed 36Ar(a), 37Ar(ca), 38Ar(cl), 39Ar(k) and 40Ar(r) components at the bottom of the table are used to calculate the total fusion (or recombined) age.
The Normal Isochron and Inverse Isochron data tables contain the calculated ratios 39Ar/36Ar, 40Ar/36Ar, 39Ar/40Ar and 36Ar/40Ar as used in the York (1969) isochron calculations. Both tables display correlation coefficients (r.i) denoting to what extend the errors used in these isotope ratios are correlated. In the example of an inverse isochron below, the correlation is minimal, because the error in the 40Ar (denominator) is small compared to the errors on 39Ar and 36Ar (the nominators). In the Statistics section the isochron calculations are further described by the convergence, number of iterations, type of calculated line, F-ratio, error magnification factor, and the number of points included in these calculations.
The Degassing Patterns data table contains for every analyses in your experiments the calculated argon components. For example, the entire measurement for the 36Ar isotope can be divided into the 36Ar(a) atmospheric, 36Ar(ca) calcium and 36Ar(cl) chlorine components, and if you are analyzing lunar rocks, also the 36Ar(c) cosmogenic component. For each individual component all increments or steps are summed, while the components themselves are summed as well (see the bottom of the table). A selection of these summed components appears in the Age Plateau data table as well (see above) and they are used to calculate the total fusion ages or to display these in the isochron diagrams (see also: Total Fusion Points in Isochron Diagrams). You can also visualize the Degassing Patterns in an interactive toolbox (see also: Degassing Patterns Toolbox).
The last data table for Additional Parameters contains an extra selection of data that may be interesting to you when judging the outcome of your argon experiments. Most notable are the decay correction factors for 37Ar and 39Ar, which are used to correct for radioactive decay occurring between the irradiation of the sample and your actual measurements. But also the absolute amount of 40Ar measured is listed here in moles, and the corrected 40Ar/39Ar, 37Ar/39Ar and 36Ar/39Ar ratios and their uncertainties.
See also ...
Contents ArArCALC Chapter 2 Function by Function Topic 2.3.1 Close Topic 2.3.2 Save Calculations Topic 2.3.3 Export for Publication Topic 2.3.5 Switch to Data Reduction Topic 2.3.6 Edit Menu Topic 2.3.8 Normal and Inverse Isochron Menus Topic 2.3.9 Heating Unit Topic 2.3.10 Import Additional Experiment Topic 2.3.11 Calculate as Flux Monitor Topic 2.3.12 Calculate as Lunar Sample Topic 2.3.14 Display Additional Statistics Topic 2.3.20 Attach Latest Master Log File Topic 2.3.22 Ka, Ma and Ga Buttons Topic 2.3.23 Table Sorting Topic 2.3.24 Table Zooming Topic 2.3.25 Delete Analyses Topic 2.3.26 Degassing Patterns Toolbox Topic 2.3.27 Copy Chart Topic 2.3.28 Save Chart Topic 2.3.29 Reset Topic 2.3.30 Recalculate
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