Jason B. Saleeby, professor of geology, emeritus, passed away on January 16. He was 74 years old.
Saleeby earned his bachelor's degree from California State University, Northridge, in 1972 and his doctorate from UC Santa Barbara in 1975.
After leaving UC Santa Barbara, Saleeby set up a uranium–lead dating lab at UC Berkeley, which provided precise dates of rock samples based on the rate of decay of uranium-238 to lead-206, and uranium-235 to lead-207. (Uranium can often be found in grains of the mineral zircon, which is usually present in many types of common rocks.)
Leon Silver (PhD '55), another leader in the field of uranium–lead dating, recruited Saleeby to Caltech in 1978. Silver, a faculty member since 1955, had been a member of Caltech's geochemistry program almost since its inception and was a larger-than-life figure in the field who gained fame for his contributions to the Apollo program. Even in appearance, the two men represented a changing of the generational guard. While Silver was straight-laced and came to campus in pressed shirts and a tie, Saleeby espoused a more hippie style, sporting long hair (until the 1980s), cut-off T-shirts, and flip-flops.
Regardless of his casual dress, colleagues describe Saleeby as a hard-working professional who quickly made significant contributions to the understanding of California's geology, earning him a reputation as a leading light in the field early in his career.
"He was a rock star," remembers Brian Wernicke, the Chandler Family Professor of Geology, who joined Caltech's faculty in 1990. "No one of his generation was so good at both field geology and uranium–lead dating. Everyone else was either just a lab guy or a field guy. He killed it as both."
Saleeby had begun his career in geology less than a decade after the establishment of the theory of plate tectonics, which describes how Earth's crust is split into a series of plates that have been slowly moving for billions of years. Plate techtonics had been defined in a revolutionary series of papers between 1965 and 1968. The following year, Warren Hamilton of the U.S. Geological Survey (USGS) discovered that batholiths—giant town-sized chunks of igneous rock formed by magma being pushed to Earth's surface—could be found in arcs that resembled island chains, which form along subduction zones where one tectonic plate is pushed beneath another. The discovery meant that batholiths, which could be mapped and then dated from their zircons, could offer insight into understanding the history of plate tectonics along subduction zones.
"All of a sudden you have a tool that lets you constrain plate tectonics in the distant past," Wernicke says.
Armed with his skills in fieldwork and precision dating, Saleeby redefined the geological map of California. "Up through '82, he really just lit up the Sierra," Wernicke says. "All of a sudden, a map of shapeless blobs became a finely etched painting in detailed resolution."
Saleeby also calculated dates for ophiolites—bits of oceanic crust that have been uplifted onto continental crust—in the coastal mountain ranges of California. Much of the state's western geology is the result of oceanic crust from the Pacific Plate subducting underneath the continental crust at the western edge of the North American Plate, with magma bubbling up to the surface while bits of crust are scraped off onto the land mass. Mapping and dating ophiolites, batholiths, and smaller igneous bodies, Saleeby helped to piece together a detailed picture of the timing and way in which these events shaped California geology.
"Indeed, few Earth scientists have been able to glean as much information from rocks and structures in the field and then apply a broad range of quantitative techniques to provide constraints on their ages and origins," wrote George G. Gehrels (PhD '86) of the University of Arizona when Saleeby received the Distinguished Geologic Career Award from The Geological Society of America in 2012.
Although Saleeby also performed geologic studies in Alaska, his focus remained squarely on California. "You could put him on any geology problem anywhere, and he'd be fine. But the Sierra was in his backyard," says Elisabeth Nadin (MS '01, PhD '06), an associate professor of geology at the University of Alaska, Fairbanks, who came to Caltech for her doctorate after Saleeby encouraged her to apply.
Saleeby taught fieldwork courses at Caltech, inspiring his students with his love for the hands-on, out-in-nature side of geology.
"Field-based geological research is unique in the scientific endeavor, by virtue of the direct connections that can be made between tactile human experience and advanced scientific instrumentation and analysis," Saleeby wrote in 2012. "From the perspective of a childlike inquisitiveness of our natural environment, a life full of multidisciplinary field-based research gives one the sense that our planet is the ultimate amusement park!"
"He just loved being in the field," says Nadin, who performed fieldwork with Saleeby as a graduate student. "He'd cook for the students; he had a famous recipe for taking lots of random cans and turning it into a delicious meal. And he would wake people up in the morning by playing the bongo. He had fantastic stories about the crazy things he'd seen in the field—like one where he woke up and saw a bear squeezing his toothpaste into its mouth—things you wouldn't believe, but then you'd meet someone down the road who had been there to see it."
Friends and colleagues remember Saleeby as someone bursting with energy. An athlete and adventurer endowed with a sinewy strength, he regularly visited Caltech's gym to lift weights, practiced yoga in the courtyard outside his building on campus every day, and also surfed and snowboarded in his spare time.
"He was so excited and dynamic that he reminded me of the White Rabbit in Alice in Wonderland," Wernicke says. "Every meeting with him had this feeling of being rushed. He always had something to do."
He was also popular with his students, who remembered him as generous, caring, and inclusive. "You knew that he loved you," Nadin says. "He didn't say it, but he did so many caring things for people. You could think of him as this cool hippie dad."
Together with Silver, Saleeby established a tradition of taking graduating students to Hawai'i to study pahoehoe, which is a ropy lava. Eventually, he and his wife purchased property adjacent to Hawai'i Volcanoes National Park, where they built a tree house for guests.
"He wasn't a volcanologist, but his knowledge and love of geology went far and wide," Nadin says.
Saleeby joined Caltech as an assistant professor in 1978, became tenured faculty in 1988, and retired in 2015. He is survived by his wife, Zorka, and his son, Inyo.