ThellierTool

Current version: ThellierTool4.11

The ThellierTool4.11 is an intuitive and easy-to-use software which provides the possibility to analyze a wide range of different modifications of the Thellier absolute paleointensity experiment. Besides the Arai plot for paleointensity determination, orthogonal projections of the direction, decay of NRM during thermal demagnetization and additional plots regarding alteration and multidomain checks enable the user to visualize the quality of individual determinations. Experimental checks for magnetomineralogical changes, either in-field or zero-field pTRM* checks, are evaluated regarding their differences to the corresponding pTRM* acquisition in two most commonly used ways. Furthermore, a measure for the cumulative alteration differences beginning at room temperature is calculated and the possibility to correct for magnetomineralogical changes is provided. Two different experimental methods to check for multidomain bias are supported and analyzed by the software. Intensity differences recorded by pTRM*-tail checks are calculated. Accounting for the directional difference between applied laboratory field and magnetization of the sample, the effective pTRM*-tail is determined and thus failures of Thellier's law of independence are monitored. Failures of the law of additivity, experimentally observed by additivity checks, are also evaluated by the software. The vectorial character of individual measurements is fully considered for all calculations. Uniform selection criteria for acceptance and rejection of determinations can be applied and a set of such criteria with emphasis on minimal bias due to alteration, multidomain remanence and analysis/experimental inaccuracies is suggested.

Documentation: Leonhardt, R., Heunemann, C., Krása, D., Analyzing absolute paleointensity determinations: Acceptance criteria and the software ThellierTool4.0, - art. no. Q12016, Geochemistry, Geophysics, Geosystems, 5, 12016-12016, 2004.

Contact: Roman Leonhardt

RockMag Analyzer

Current version (Release 06/05): RockMag Analyzer 1.0

The RockMag Analyzer1.0 is a software to determine rock magnetic parameters from isothermal and thermomagnetic measurements. This software was particularly designed for the output file format of the Variable Field Translation Balance (MM VFTB) and provides a graphical overview over measured isothermal remanent magnetization acquisition, coercivity curves, hysteresis loops and/or thermomagnetic curves. Various standard and non-standard rock magnetic parameters are calculated from these curves, thus, accelerating and simplifying the quantitative analysis of measured data. View options like plotting derivatives, para-/diamagnetic correction, etc. further enhance the data analysis. Procedures for smoothing and data fitting by mathematical functions are implemented. Isothermal remanent magnetization acquisition and coercivity curves can be fitted by log-Gaussian functions, hysteresis loops by hyperbolic basic functions. Curie temperature estimation from thermomagnetic curves is supported by two different automated approaches, a second derivative method and a extrapolation method. A number of additional diagrams provide composite plot of parameters obtained by different measurements, like the Day plot and Henkel plot.

RockMag Analyzer1.0 is the successor of the VFTB Analyzer (latest version: 2.0 alpha) and also supports data formats from the PM VSM/AGFM (Model 2900). A detailed manual is currently in preparation and will be available soon.

The new release 06/05 supports are larger variaty of different VFTB formats and contains two bug fixes regarding cooling curve analysis and file save

Contact: Roman Leonhardt