Mineralogic offers quantitative geochemical and petrological data with the utmost flexibility. Mineralogic now delivers more capacity to interrogate the data in a way that benefits users seeking varied and customized post-analysis workflows.
Constructed around an automated mineralogy (AM) platform, ZEISS Mineralogic software creates textural descriptions of samples across an extensive range of scales, from crushed particle analysis to entire thin sections. Textural analysis and mineral classification are combined based on wt.% major element chemistry, offering easy-to-understand mineral libraries while reducing technical operator time.
Mineralogic is equipped with a large particle viewer (LPV) user interface. It facilitates a seamless transition between image types, including BSE, phase ID, and element heatmaps.
A complete thin section of granulite facies metagabbro from the Lewisian Gneiss Complex in North West Scotland is shown in Figure 1. This was visualized using the conventional automated mineralogy format alongside element heatmaps based on measured, quantitative chemistry at each pixel.
Figure 1. Mineralogic offers flexibility in the vizualization and export of geochemical data stored in the software database. Here a full thin section map is visualized in a) Backscattered electron (BSE) image, b) Mineralogic phase classification map, c) Quantitative EDS Fe heatmap, d) Quantitative EDS Mg heatmap. Figures b-d are analyzed at a 20 μm pixel step size. Image Credit: ZEISS Natural Resources
ZEISS Mineralogic is a scanning electron microscope (SEM) automated mineralogy system designed to acquire quantitative chemistry and automatically classify mineral phases directly from thin sections. The result is an innovative “one-stop shop” system for sample mapping. The dynamic ZEISS Mineralogic platform offers a variety of imaging detectors that can be used in conjunction with the EDS capability.
In the case presented in this article, the capabilities of ZEISS Mineralogic based on ZEISS Sigma 300 VP field emission SEM fitted with backscattered electron (BSE) imaging and two Oxford Instruments Ultim Max 65 EDS detectors using Tru-Q peak quantification are assessed.
Flexible Dataset Visualization
The LPV facilitates the visualization of large datasets, including thin sections, with stitched images and data. Individual pixels can be instantly evaluated for geochemical measurements and mineral classification.
The map view can be switched rapidly from automated mineralogy to the elemental heatmap view with a dynamic color scale threshold feature and image zoom to emphasize mineral zoning and other critical features of interest.
Figure 2 displays a Ca heatmap of a complete thin section with the threshold range selected to emphasize zoning within the garnet and a close-up image of a single garnet at the same range. The element heatmaps offer an excellent way to visualize data and simplify classification workflow on new sample types or more detailed samples.
Figure 2. a) Full thin section, quantitative Ca EDS map (20 μm pixel step size) of a high strain gneiss from the Glenelg region of Scotland. This sample charts the evolution of the rock to higher pressure through zoning of the mineral garnet, which increases in Ca towards the margin. b) A close-up image of one such garnet is imaged at a smaller pixel step size (5 μm). c) The LPV interface can be seen with the element Ca selected in the periodic table and a concentration range defined on the threshold tool. A single click allows the export of the image that is seen on the screen with the legend associated. Image showing the user interface for selecting the element of interest and color scale threshold values. Image Credit: ZEISS Natural Resources
Figure 3. Exported data from Mineralogic is designed to provide all your geochemical data with maximum flexibility. Here we see element heatmaps imported into XMapTools.
a) Quantitative EDS analysis from Mineralogic imported directly into XMapTools (garnet data from figure 2b). XMapTools enables median filtering and conversion of EDS data with many useful functions including
b) cation per formula unit (cpfu) for Ca in X site, and
c) end member grossular (Ca component) calculation.
d) Line profile data are easily extracted from the quantitative EDS dataset in XMapTools. Image Credit: ZEISS Natural Resources
This is true for samples with previously unanalyzed minerals or where processes such as fluid alteration have caused a shift in chemical composition from stoichiometric values. Element heatmaps mean it is possible to interrogate the entire sample even before establishing a mineral library. The best methods can be applied to identify the critical phases in the sample.
Data Export
Exporting data in a flexible, meaningful format is a key part of accessing such a comprehensive dataset of geochemical information. Data export from the LPV is comprised of two parts with various purposes:
- The capacity to export the image data on the screen
- The capacity to export the geochemical data for downstream workflow requirements
Image Export
The LPV enables a single-click export of the image displayed on the screen as a .png file. This is available for the BSE image, the automated mineralogy phase map, and any element heatmap. All images can be exported using the scale bar.
Phase maps also incorporate a legend while element heatmaps include the appropriate color scale. This single click is great for exporting figures. As the export will directly match the current field of view, it is possible to zoom in on a critical area, adjust the dynamic color scale, or blend heatmaps with BSE to export the exact image required.
Data Export
The data export function has been developed to offer the complete heatmap information needed for research purposes. Clicking the data export button accesses a periodic table interface and enables the selection of numerous elements of interest. After the target folder has been chosen, these data files are exported as a .csv file for each element.
Irrespective of the screen zoom or element intensity threshold, the complete dataset will be exported for each element selected, with the pixel value as collected. This offers the most powerful mechanism for exporting maps of equal size, true to the original data. The .csv file format delivers complete flexibility for import into third-party software or custom code workflows, such as Python.
Third-Party Software Integration
The flexibility of the data export feature makes it possible to import element heatmap data into a range of third-party software, including popular image and data analysis packages, such as ImageJ/FIJI and XMapTools. In the following case, the Mineralogic export was developed with the geoscience data analysis package XMapTools by Pierre Lanari at the University of Bern.
The exported Mineralogic heatmap data files can be directly imported into XMapTools as calibrated geochemical data. Numerous elements of interest can be imported, and the quantitative EDS eliminates the need to include a step to quantify using an electron microprobe.
XMapTools contains several valuable functions specific to geoscience analysis, and the extensive area mapping of geochemical data in Mineralogic offers an ideal input. In XMapTools, the element heatmaps can be modified into oxide wt%, cation per formula unit (cpfu), and end member proportions.
There is extra functionalities such as median filtering and line profile tools that seamlessly work with mapped EDS data. The XMapTools software also comes with thermodynamic calculation tools for specific samples, including calculating pressure and temperature of metamorphic rocks.
Summary
ZEISS Mineralogic builds on the foundation of quantitative automated mineralogy and takes it further. Besides mineral classification and textural analysis, Mineralogic offers complete quantitative EDS geochemical information of a given mapped sample.
The data can be easily visualized and exported, allowing the user to assemble workflows into a wide range of image and data analysis programs. The result is a scanning electron microscope system that offers users the utmost flexibility for evaluating a sample.
This information has been sourced, reviewed and adapted from materials provided by ZEISS Natural Resources.
For more information on this source, please visit ZEISS Natural Resources.