The analysis of meteorites is an important geochemistry application for many industries, including oil and gas (where to drill), mining, environmental remediation, and even the study of the earth and how it came to be the planet it is today.
Livio Rosai, retired physicist from Italy involved in scientific research, particularly in the field of particle accelerators, conducted a study involving chemical analysis using a hand-held XRF spectrometer on different types of meteorites including carbonaceous, pallasite, metallic and Martian samples. He found that in comparison with the standard ICP-MS techniques for bulk chemical analysis of meteorites, “the XRF technique, although less used, has the advantages of simplicity, being non-destructive because not requiring sample preparation and providing quick responses.” He published a paper and compared results with literature data (when available) on similar types of meteorites. With permission from the author, below is a summary of his paper, Chemical analysis using a hand-held XRF spectrometer on different types of meteorites including carbonaceous, pallasite, metallic and Martian samples.
Meteorites, rocks that have traversed the vast expanse of space to reach Earth, offer a wealth of information about our solar system’s history and composition. X-ray fluorescence (XRF) spectrometry is a non-destructive analytical technique that identifies the individual chemical elements in a sample based on the characteristic X-ray fluorescence emitted by its atoms.
About XRF
Rosai explains that modern XRF equipment generates “an x-ray fluorescence spectrum which, by showing the number of counts as a function of energy, makes it possible to recognize rather easily the peaks characteristic of each element. In modern portable systems this recognition is done directly by the computer built into the instrument itself. The data are shown on the display of the instrument, in form of spectra or directly in terms of the percentage of concentration of the individual element, with a confidence coefficient of more than 95%.” (You can learn more about how handheld XRF technology works here.)
The XRF technique is particularly useful for examining meteorite samples as it doesn’t alter their chemical bonds and can detect multiple elements simultaneously. It is commonly used in mining and mineral analysis.
The Study
In the study, Rosai used a modern handheld XRF analyzer, capable of detecting light elements such as Silicon, Magnesium, and Aluminum, crucial for meteorite composition analysis. The spectrometer was set to ‘mining mode’, ideal for analyzing stony and iron meteorites, as it takes into account the total percentage of elements not directly recognized, referred to as ‘balance’.
Rosai’s study focused on various meteorite types, including stony meteorites (the most abundant type), stony-iron meteorites, iron meteorites, and rare Martian meteorites. A Martian meteorite is a rock that formed on Mars, was ejected from the planet, and traversed interplanetary space before landing on Earth as a meteorite. Each of these meteorite types has unique characteristics and classifications based on its composition, offering diverse insights into the early universe’s conditions.
One of the intriguing findings from the study was the analysis of a rare carbonaceous Chondrite NWA 16685 CK6, discovered in the Sahara Desert in 2022. This meteorite is thought to have condensed in the cooler outer portion of the solar nebula, indicating that it has not been heated above 50 C. This makes it one of the least depleted types of chondrites and provides a reference to which other meteorites are compared.
The study also analyzed the Sericho Pallasite, a rare stony-iron meteorite discovered in Kenya in 2017. Due to its recent discovery, there is limited literature reference for this meteorite’s composition. However, the XRF analyzer provided valuable data that can be compared with future findings.
The Martian shergottite confirms — although with concentration differences of about 30% — previous findings and in particular, besides Fe, Si, Mg, the rich presence of Al and Ca. [N. Shirai et al., Antarctic Meteorite Research, Vol. 17, p.55 (2004)]
Conclusion
Rosai’s study highlights the utility of handheld XRF analyzers in meteorite analysis, providing a non-destructive, efficient method for understanding these celestial objects’ elemental composition. It shows how handheld XRF is versatile, non-destructive, and accurate enough to be a viable alternative to traditional lab methods. The findings offer valuable insights into the early solar system and the formation of meteorites, contributing to our broader understanding of the universe.
You can read more details about Rosai’s study, including instruments used, tables of characteristics, summarized classifications and pictures of the samples analyzed, literature data, results, comparisons, and references used in his paper Chemical analysis using a hand-held XRF spectrometer on different types of meteorites including carbonaceous, pallasite, metallic and Martian samples.
References and Additional Materials
- Download the full study paper: https://www.researchgate.net/publication/261029642_Chemical_Analysis_of_Iron_Meteorites_Using_a_Hand-Held_X-Ray_Fluorescence_Spectrometer.
- Blog Articles:
- Ebook: XRF in the Field: XRF Technology for the Non-Scientist
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