New Geochemistry Technique Yields Clues about Earth’s Earliest Days
Half a century ago, in lab nicknamed the “Lunatic Asylum” in the Charles Arms Laboratory of the Geological Sciences, the late Gerald Wasserburg constructed the first-ever digital mass spectrometer. That device, dubbed the Lunatic I, revolutionized the field of geochemistry by increasing by an order of magnitude the precision with which isotope ratios could be measured; isotopes are the “flavors” of elements and vary based on the number of neutrons they have in their atomic nuclei. The Lunatic I ultimately was used to make high-precision measurements of the first lunar samples obtained by the Apollo missions. Now, in the neighboring Seeley W. Mudd Laboratory of the Geological Sciences, a building crowded with graduate students and bulky mass spectrometers, Assistant Professor of Geochemistry François Tissot carries forward the Institute’s tradition of pioneering geochemistry. Tissot, who started as a faculty member at Caltech in 2018, set out to accomplish a goal thought to be impossible: probing the isotopic ratio...