I learned recently of the passing, last December, of legendary Santa Barbara geologist Tom Dibblee. In ways that were almost mystical, Tom could read the tides of rock the way ancient mariners read the sea. It was both an education and an honor to walk with him in the canyons of his native country.
This is one of two magazine profiles I wrote about Tom...
Geology is destiny. What would Santa Barbara be if it were not so tightly embraced between the mountains and the sea? Without its geology, it would not offer the dramatic vistas and backdrops, but neither would Santa Barbara have the idyllic, insulated climate. Without the climate, the area could not support such profuse and diverse vegetation, which in turn supports a host of wildlife. And let's face it, without all of these things, most of us would have settled elsewhere.
"I can remember every place I have ever been," geologist Tom Dibblee says, "but this is my native country." It is his simple answer to why these rocks mean so much more to him than any of the other 40,000 square miles of California that he has seen.
Late one winter's afternoon Tom and I sit on the crest of an alluvial fan above Mission Ridge, along with Dibblee's cartographer and friend Helmut Ehrenspeck, extrapolating the universe—as it were—from a grain of sand. Tom's long, weathered fingers alternately point across the landscape and trace contours across the map.
"Santa Barbara County is sedimentary geology," Dibblee begins. "The mountains are a very thick series of layers, mostly formed under the ocean, uplifted by crustal movements into mountains that tilt towards the south and dip under the channel."
Behind us loom Cathedral Peak and the toothy ridgeline of Mission Pines at the head of Rattlesnake Canyon. The late light picks out the exposed sandstone ledges of the Matilija formation, the oldest, hardest layer of sediment, upended to form the ridge. The Coldwater sandstone, just downhill, accounts for the rocky outcrops that are a signature background in Santa Barbara landscapes. These outcrops are counterpointed by the red clutches of toyon berries all over the hillside.
"These mountains are pretty young, geologically speaking," Dibblee says. The mountains themselves are less than six million years old, uplifted during late Miocene and early Pliocene epochs when the Santa Ynez fault developed. But the sedimentary marine deposits from which these mountains are made would have been laid down on the sea floor between 15 and 60 million years ago. Those sediments, of course, would have washed out to sea from a previous generation of mountains. And the alluvium on which we sit represents the next generation, as erosion carries grain after grain down to the sea where it will settle, solidify and return in an endless process of geologic karma.
We can see the Santa Monica Mountains 60 miles to the east, and west 20 miles to Gaviota. But while the sun sets just beyond the Channel Islands, Tom and Helmut speak mainly of the complicated piece of Santa Barbara's geological history that we are sitting on. The alluvial fan is a hill: part of ancient mud flows that gushed from Rattlesnake Canyon one particularly dark and stormy night about 50,000 years ago, sweeping up ten-ton boulders to spread its slurry across the lowlands. The mud and rocks long since solidified into a layer of conglomerate, only to be uplifted and tilted by subsequent geologic forces, then shaped and gouged by streams, and overgrown by conifers during the cold centuries and chaparral during the summers of geologic time. Even later, the Mission Ridge Fault developed and lifted a portion of the fan, redirecting streams around it.
Where the road cuts across the strata, clearly showing the alluvium sitting on bedrock that was tilted and planed flat, fossils still glint in the boulders of Matilija that tumbled intact from the ridge. Maroon circles of softer Sespe stone appear as indented circles. But even these boulders contain mixtures of older formations. "These pieces are conglomerates within conglomerates," Ehrenspeck laughs. "This is all temporary. Eventually, this will all end up in the ocean, where it will form new sedimentary deposits. Then it will come back as mountains and the whole cycle will repeat."
I've seen this view hundreds of times, but never with their eyes. In his field, Tom Dibblee is a legend of almost mythic proportions, having personally mapped more than one-quarter of California's geology. Ehrenspeck, an accomplished geologist in his own right (with a mountain named for him in Antarctica), has so far edited and published 67 multi-colored geologic maps based on Dibblee's seven decades of field work—with hundreds more to come.
To walk these hills with Tom Dibblee is to watch him communicate with the earth. He reads the land the way others read the newspaper. In the way that letters resolve themselves into words and phrases, offering up ideas and information, the ground whispers to Dibblee the secret history of the planet. The story he hears is one that few of us can even begin to comprehend: that over the long perspective of geologic time, the roiling movements of the earth are as fluid as the convection currents in a teacup; and that the firmament on which civilization is built is as tenuous as the leaves floating on the surface.
Though not quite as old, Tom is a bit like one of these rocks himself: a chunk of local history—a conglomerate of two of Santa Barbara's oldest families, the Dibblees and de la Guerras, broken off to find his own destiny down the stream of time. Born in Santa Barbara in 1911 and raised on the family's land-grant Rancho San Julian near Gaviota, Dibblee found his life's calling in tow of a geologist hired to search for oil on the property when Tom was only 13. With a degree from Stanford, he worked for oil companies for 16 years, then spent 25 years with the US Geological Survey. After "retirement" in 1977, he returned to Santa Barbara with his wife Loretta and volunteered to map the entire 1.2 million acres of the Los Padres National Forest. That contribution—worth an estimated $1 million—earned him a Presidential Volunteer Action Award from President Reagan in 1983, just one of his many honors.
That same year, friends and colleagues got together to establish the Dibblee Geological Foundation, so that Tom's hand drawn field sheets would be published. Ehrenspeck adapted color cel-animation techniques to affordably overlay the geologic color-codings and other markings on top of standard topographic maps. The Dibblee maps show fault lines, the different kinds of rock exposed to the surface, along with indicators about their tilts and trends. Among those who use them are seismologists, hydrologists, paleontologists, geographers, conservationists, planners, archeologists, hikers, oil companies and insurance agencies. But the maps are so colorful that they have been mounted more than once simply as art.
Meanwhile, Dibblee has also served since 1978 as a Research Associate at UCSB's Department of Geological Sciences, where a new generation of geologists endeavor—literally—to follow in his footsteps.
No other field geologist comes close to the number of square miles he has mapped, but Dibblee's fame derives not just from the volume of his work, but from the simplicity of his methods and the profundity of his observations. With nothing more than a blanket and food thrown into a cloth bag, he would disappear into the wilderness for a week at a time, rapidly marking up quadrangle after quadrangle (a topographic "quad" is 7 x 10 miles). He makes only one concession to the elements. "I like to be down in the cool canyons on a hot day. But on cool days like this I like to be on the ridges to get an overview," he says. "But you have to do both to see the geology."
Dibblee works without the aid of even a rock hammer or compass—just a hand lens. Yet his identifications, observations and measurements are as accurate as those taken by any high-tech expedition. He can trace the flow of an ancient streambed from the grain of an exposed outcropping of rock, or tell what kind of rock lies below from the vegetation or exposed soil covering it. He just knows what the rock is and what angles it rests at.
"He's been over every inch of this land, so he knows what he's talking about," Ehrenspeck says. "He has this incredible understanding of the interrelationship between topography, vegetation, land forms and what has happened to the rock strata underneath. And he has an uncanny sense of exactly where he is, which is extremely valuable when scrambling through impenetrable chaparral‑covered terrain. It's this intuitive knowledge of the land and everything about it which gives him the skills to interpret the geology underneath."
Some of his observations have seemed almost prescient. He and colleague Mason Hill were the first to suggest that the two sides of the San Andreas Fault had slid as much as 350 miles—simply by comparing the sequence of rock formations along its length—20 years before the horizontal movement was explained by plate tectonics. He predicted oil in a Cuyama Valley sandstone, later named the Dibblee Sands, that other geologists had written off as worthless. He and Ehrenspeck recently found remains of several ancient Southern California volcanoes previously unknown. The importance of other of Dibblee's past observations are still unfolding.
Not all of the land he maps is undeveloped. Although Tom admits the remote quads have been more fun, the urban maps are more in demand. Los Angeles city planners have digitized his maps as their official database. "The Northridge earthquake created demand for the areas I mapped long ago," he says.
Although he turns 86 this year, Dibblee is still doing field work. Among his projects for this spring, he and Ehrenspeck plan to spend several days on Santa Rosa Island finalizing notes Tom began in 1938.
Late for dinner Tom, Helmut and I reluctantly head back to the car in the twilight. Despite his age and fame, there is a kind innocence about Tom Dibblee. After spending literally decades in solitude, he is a man of few words and much humility. "It was just routine work for 60 years," he quips.
Yet there is also an obvious love between the old geologist and the old stones, a bond that is eloquent and joyful to behold. It is like an embrace when Tom stops for a moment and leans his lanky frame against the Matilija boulder, stretching to ease the pain of recently bruised vertebrae.
Helmut says, "Look at this rugged man against these rugged rocks."
I look, and I begin to read the history on Tom's face.