At the prestigious NordSIMS laboratory in Stockholm’s Swedish Museum of Natural History, researchers apply a key tool — the lab’s CAMECA IMS 1280 magnetic sector large-geometry secondary ion mass spectrometer (LG-SIMS) — across disciplines from geochronology and geobiology to ecology and cosmochemistry.
Example: investigating zircon crystallites in samples from southern India. The researchers wished to use a common “geochronometer,” or method for determining accurate geologic age, by applying known timelines for the evolution of uranium (U) and thorium (Th) to lead (Pb) within zircon grains. However, certain tiny, anomalous patches of lead found in these samples would distort the results, “breaking” the geochronometer.
Fortunately, the LG-SIMS’s high-precision quantification of elemental and isotopic concentrations is unmatched for such studies. Its large-radius magnetic sector provides optimal transmission at high mass resolution, for ultra-high sensitivity. Its lateral resolution — down to 1-2 microns — also allows in-situ analysis of individual grains or subgrains, at a scale unresolvable by methods such as laser ablation ICP-MS.
These capabilities helped the researchers to determine a reliable geological timeline for the zircon samples — “repairing” the chronometer for future work.