John T. Wasson, 1934–2020

John T. Wasson

John T. Wasson. Credit: UCLA.

John T. Wasson, a world-renowned expert in meteorites and lunar rocks who had a mineral named after him, died at home in Los Angeles on September 8. He was 86.

The professor emeritus of the Department of Earth, Planetary and Space Sciences at the University of California Los Angeles (UCLA) helped devise modern chemical classifications for the space debris that can fall to Earth as brief fireballs or “bolides” big enough to create an impact crater. Wasson joined the UCLA faculty in 1964 and remained active on campus, cycling into his office every day, until a stroke slowed him down in January of this year. But his impact will last for years.

Wasson co-created the UCLA Meteorite Collection — the largest collection on the West Coast — and was a passionate promoter of science in California. When, in 1975, prospectors discovered a 38-inch iron meteorite in the Old Woman Wilderness in the Mojave Desert, so heavy it had to be excavated from a remote ravine by the U.S. Marines Corps, he corralled politicians from both sides of the aisle in the state legislature to ensure it remained on display in the Golden State rather than at the Smithsonian in Washington, DC. Today a slice of California’s biggest meteorite, known as the “Old Woman,” is proudly on display in the UCLA Meteorite Collection in the Geology Building.

“While his passion for science, eloquence and warmth transformed many UCLA faculty and students into cosmochemistry enthusiasts, his dedication to the meteorite gallery helped tens of thousands of visitors gain a deeper appreciation for the secrets of the solar system,” said Miguel García-Garibay, dean of the division of physical sciences. “It is only fitting that his legacy and influence will remain forever in those celestial bodies, some of which, not surprisingly, carry the mineral ‘wassonite,’ a form of titanium sulfide that was named in his honor,” García-Garibay said.

Always a rebel, Wasson helped lead an insurrection still remembered in relevant scientific circles. In 1966, the enthusiasts who ran the venerable Meteoritical Society were swept away wholesale during elections and replaced by professionals — a sign times were changing, he said later. And for the next five decades at UCLA Wasson helped remake the science behind the global study of meteorites.

Alan Rubin, co-curator of the UCLA Meteorite Collection, said that over the decades his colleague’s work evolved through three areas of interests.

“He arrived at UCLA at the right time, during the NASA Apollo missions to the Moon when scientists were for the first time able to study lunar samples brought back from the surface,” Rubin said.

His chemical approach resulted in a memorable acronym KREEP, constructed from the letters K (for potassium), REE (rare-Earth elements), and P (phosphorus). It is the geochemical mixture found in some lunar rocks that supports the hypothesis that the Moon was originally a ball of hot magma rather than an always-cold rock.

Wasson became a global leader in the study of meteorites, and what they reveal about the formation of the solar system, Rubin said. Wasson wrote two books and published more than 300 articles on the chemical and petrologic properties of meteorites.

He became president of the Meteoritical Society and was awarded its highest honor, the Leonard Medal, in 2002. That was followed the next year by the J. Lawrence Smith Medal from the National Academy of Sciences.

Wasson became a leading expert in the relatively rare iron meteorites and the more common but amazingly varied form of space rock known as chondrites. He remained fascinated by chondrules, tiny round grains found inside chondrites, which are amongst the oldest and most basic building blocks of the solar system. He argued they were formed by repeated melting, maybe by lightning, and then stuck together within ice and dust on an asteroid.

In his later years Wasson also become interested in tektites, said his colleague Kevin McKeegan, and went hunting in Thailand and Laos for these gravel-sized glass fragments created when a meteorite hits the ground. He found they could be dispersed across a massive area, as much as 100,000 square kilometers. He argued that could be caused by air-bursts, in contrast to the classical narrative of cratering events.

— Text courtesy of The Meteoritical Society