UPmag: MATLAB software for viewing and processing u channel or other pass-through paleomagnetic data

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Abstract

With the development of pass-through cryogenic magnetometers and the u channel sampling method, large volumes of paleomagnetic data can be accumulated within a short time period. It is often critical to visualize and process these data in “real time” as measurements proceed, so that the measurement plan can be dictated accordingly. We introduce new MATLAB™ software (UPmag) that is designed for easy and rapid analysis of natural remanent magnetization (NRM) and laboratory-induced remanent magnetization data for u channel samples or core sections. UPmag comprises three MATLAB™ graphic user interfaces: UVIEW, UDIR, and UINT. UVIEW allows users to open and check through measurement data from the magnetometer as well as to correct detected flux jumps in the data, and to export files for further treatment. UDIR reads the *.dir file generated by UVIEW, automatically calculates component directions using selectable demagnetization range(s) with anchored or free origin, and displays vector component plots and stepwise intensity plots for any position along the u channel sample. UDIR can also display data on equal area stereographic projections and draw virtual geomagnetic poles on various map projections. UINT provides a convenient platform to evaluate relative paleointensity (RPI) estimates using the *.int files that can be exported from UVIEW. Two methods are used for RPI estimation: the calculated slopes of the best fit line between the NRM and the respective normalizer (using paired demagnetization data for both parameters) and the averages of the NRM/normalizer ratios. Linear correlation coefficients (of slopes) and standard deviations (of ratios) can be calculated simultaneously to monitor the quality of the RPI estimates. All resulting data and plots from UPmag can be exported into various file formats. UPmag software, data format files, and test data can be downloaded from http://earthref.org/cgi-bin/er.cgi?s=erda.cgi?n=985.

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