LA-ICP-MS data files

These are the data files needed to recreate the LA-ICP-MS trace element maps of steatite accessory minerals as presented in my MPhil thesis: Chmielowski, R. M. (2024). Viking Age Steatite in Sweden: Accessory Mineral Provenancing and the Biographical Approach, Durham University.

The target user is anyone who wishes to compare this data with their own archaeological research results to determine the provenance of steatite artefacts. However, this data set would also lend itself well as part of a study to investigate the geologic history and/or metamorphic fluid flow studies in these areas. Furthermore, this dataset would lend itself well as a practice set for students learning to process LA-ICP-MS data to produce trace element composition maps of single crystals in a rock matrix as it contains a variety of mineral types and different types of crystal zoning. In all cases see the thesis itself for information about the context of the data sets, and for images of the maps I created with this raw data.

There are 32 folders, one for each trace element map created [there is no sample map M30, as it proved not to be steatite].

It is not recommended to attempt to read the .csv files yourself. Best results are obtained using a program such as Iolite4 to read and interact with the files. 

Each folder contains:

A back-scatter electron image, in .jpg format, of the mapped sample area, with a file name in the format of M1, M2, etc., were “M1” is the name of the trace element map as used in this thesis. Where possible this image was taken before the laser ablation session. If there is no “before” image then the provided jpg was taken after laser ablation.

A folder of .csv data files from the ICP-MS, where the folder name takes the format “M1 ICP-MS files”, “M2 ICP-MS files”, etc., were “M1” is the name of the trace element map as used in this thesis.

The individual ICP-MS data files are in .csv format, and were named automatically by the ICP-MS computer. 

Their names take the form of “2019-04-20sulphidemap_1”, where the numbers give the date of the experiment laser ablation session, the text gives the name for the experiment used on the day, and the number after the underscore shows where in the sequence of the files a given file takes.

The first and final set of these files correspond to the “Standards”, the laser ablation of the standard reference materials and “blanks” (laser firing, but at zero percent power, so that the ICP-MS is measuring the “background” levels of the day). There are typically, but not always 10 files for each set of standards:

 one blank

followed by two spots of the standard reference material (SRM) “Nist612”

followed by a blank

followed by two spots of the SRM “MASS1”

followed by a blank

followed by two spots of SRM “Fe-S1”

followed by one blank.

Between the standards is the map data, with each file containing the total ICP-MS analysis collected during an interval of time that was slightly longer than needed to laser ablate one row of the map. Because the ICP-MS starts analysing before the laser starts firing, and continues after it stops, each of these files have an additional “blank” period before and after the line. (Save for one example where the ICP-MS stopped early for for several rows of data.)Each of these files starts with a header section which records the name of the line, the date, and various settings of the ICP-MS. Below that is the actual comma separated data showing the time stamp, and the measured counts per second for each analysed elements.

A folder of .csv data of laser log files, from the laser computer, where the folder name takes the format “M1 laser log files”, “M2 laser log files”, etc., were “M1” is the name of the trace element map as used in this thesis.

The individual data files are in .csv format, and their file names were generated automatically by the laser computer, and take the form of “ScanLog_19-04-30_09-02-45”, where the first set of numbers is a date stamp (year, month day), and the second set of numbers is a time stamp (hour, minutes, and seconds).

The files themselves contain a series of time stamps that correspond to each time the laser fired for a specific “spot” or “line”, the cosponsoring X-Y position (in µm) of the laser stage at that moment in time, details about the laser spot size and speed of movement.

If you use this data please let me know, I would love to hear if it is being used for archaeological, geological, or educational, or other purposes.