Tools to extract quantitative chemical information from chemical map and EDS linscan data.
This tool is designed to work with the outputs produced by AZtec (Oxford Instruments), but should be easily adaptable for other data formats.
At the moment chemMap remains in early development. More information will be placed here in the near future.
Currently, chemMap can be used to
- Load in quatitative (wt%) or qualitative (raw count) chemcial map data.
- Load quantitative oxide wt% data for EDS linescans.
- Calculate common ratios used in geological samples from either wt% or count data (e.g., Mg#, An). This functionality works with both linescan and map data.
- Perform k-means cluster analysis.
- Plot chemical maps, specifying a particular element or ratio. With cluster analysis performed first it is possible to produce these chemical maps for a single phase.
- Extract a transect from a chemical map.
- Separate crystals into subpopulations based on their size (cluster analysis must be performed first).
2 examples are currently provided in this repository. One focuses on a lava sample from Floreana in the southern Galapagos and, using raw count data, we identify different olivine populations (based on size) and calculate their forsterite content. The second provides quantitative map data from a gabbroic xenolith collected from Hualali volcano, Hawaii. Using this we can identify crystal populations based on composition and extract a quantitative chemical transect across a crystal.
Future planned developments include:
- Acquisition of fully quantitative chemical data from raw counts via mapping on known standard materials.
- 'Anchoring' of EDS linescans or spot analyses to maps to aid interpretation of map data and convert raw counts to quantitative chemical data.