Patrick Gathogo knew they’d found a textbook location, the perfect spot for fossils.
And the site did not disappoint, yielding the skull of what is speculated to be a human ancestor?a find that “shook the human family tree,” according to National Geographic.
Layers of volcanic ash made the fossil easy to date, and clay-rich mudstone on the margin of an ancient lake preserved its bones.
In the Lake Turkana basin of Kenya, where the hominid skull lay hidden, Gathogo, a native Kenyan, volunteered with a team of fossil hunters. He and another geologist had interpreted the rocks to find this site, one with older sediments.
On the rocky ground, under bright morning sun, someone saw a tooth. And hours of digging uncovered the attached skull, dubbed Kenyanthropus platyops, meaning flat-faced human from Kenya.
The early stages of human evolution suddenly appeared more complex, because the skull indicated that at least two lineages of early human relatives existed as far back as 3.5 million years ago, according to a statement issued by lead researcher Meave Leakey. Conventional wisdom said modern humans descended from a species called Australopithecus afarensis, represented by a partial skeleton named Lucy.
The discovery of Kenyanthropus platyops challenged this theory.
Found in 1999, the skull’s discovery was not announced until spring of 2001. All the while, Gathogo continued his education as an undergraduate at the U.
The hoopla subsided. And regardless of any touch-ups to its lineage, human life continued unaffected, as did Gathogo’s work?for the most part.
“It was very motivating to see the impact of geology on the whole story of humans,” he said.
He graduated from the U, re-enrolling as a master’s student in geology. Now in his second semester, he plans to continue exploring the sediments near the lake, mapping them and reconstructing past environments. It’s work that could last until the end of his time, he says with a somewhat self-conscious laugh. “There is so much to be done, and I know that story will continue to become more interesting because there are so many hominids lying there.”
For Gathogo, the land’s geology is the book where this story unfolds. Rocks become the words he reads fluently.
“When I go to the field, sometimes when I look at the geology, I don’t see the dirt or the rocks. I see the habitat. I see the soil. I see a river. I see a forest,” he said.
For the winter, he resides in an office without windows, high in the William Browning Building. It’s snug, or perhaps claustrophobic?though he says he doesn’t mind. Here, the pages of Gathogo’s story are not a landscape, but black and white aerial photographs.
In the field, there are no topographical maps drawn nicely by other people, he says. A geologist’s map begins with these photos.
On paper, the rumpled landscape appears just as static to human eyes as its real counterpart. But as Gathogo moves his hands over the photo timescales blur. Millennia pass in minutes and a flurry of activity.
About 3.7 million years ago, an enormous river ran through the basin, leaving its mark in a layer of volcanic ash. The river flooded and became a lake, one of a many to occupy the basin.
Gathogo knows the lake existed, because the earth still holds its diatoms, small water dwelling creatures and fine silt.
Seasonal rivers fed the lake, flooding and drying up. His fingers follow a snake-like course, always changing because rivers are lazy. They find a new path once the sediment has built up.
There was lake here, and lake over here, he says, indicating areas to either side of the mark where the skull was found. But its graveyard was a marshy area, probably an alluvial fan built up by the seasonal rivers.
Along the same horizon in the earth where the skull lay, the team found other fossils: monkeys and pig-like creatures. The climate must have been arid, judging by popcorn-like deposits left in the soil.
After several hundred thousand years, the lake shrank, and the big river returned. It brought with it volcanic ash just as it had before, sandwiching the fossils, and making them easy to date.
Fossils, not only the rocks, reflect the changes in habitat, but this is work for paleontologists.
“As a geologist traces changes behind the rocks, a paleontologist looks at changes behind the fossils, and at the end of the day they compare notes. If they come up with the same thing, it’s usually right,” Gathogo said.
Geologists read the rocks not only for past habitats, but map the sediments like layers of cake to guide fossil hunters. It’s the geologists’ job to expand the hunt into unexplored territory.
It was Gathogo’s desire to work with the fossil people who brought him across the globe to the U, and the exotic phenomenon of snow. (He sent pictures home?flying snowflakes were greeted with particular excitement.)
“Because I was interested in this kind of geology, stratigraphy, to work with paleontologists, this is the best place to learn that,” he said. And those who understand the geology around Lake Turkana, come from outside Kenya, many from the U.
Snapshots tucked into clear plastic sheets tide him between summer visits to Africa. Pictures of his family?10 children and nieces and nephews?lined up and smiling hang alongside photos of the fieldwork. The ground is rocky, often barren, and the sunlight intense. In one slide, Gathogo’s hands treat a scalp gash, left on a worker’s head by a tree branch.
In the field, injuries can be dangerous, he explains?hospitals are far away. Gathogo shaved the man’s head and rinsed the wound in salt water.
Up until six months before he came here, the thought of leaving Kenya never occurred to Gathogo. He was the youngest child, and his father died when he was young so his mother took most of the responsibility.
“I promised myself not to go to high school because I was worried I would strain her resources,” he said. However, he did enroll in high school (which requires payment in Kenya) and did well, hesitating to tell his mother for fear of the cost of attending a university.
Gathogo began his studies at a local university in biology, but soon switched to geology.
“I got curious about the geology department because they are trying to tell stories based on rocks,” he said.
While working at the National Museums of Kenya, he met Leakey, a well-known paleoanthropologist. She invited him to go into the field with her team. There, he later met Frank Brown, dean of the college of the mines and earth sciences.
Brown and Leakey encouraged and helped fund Gathogo’s enrollment at the U. He also received scholarships.
Now, he works as a research assistant, hoping to return to Kenya after his studies finish.
His hesitant ‘yes’ indicates more discoveries from the basin are to come, but Gathogo won’t say more.
“We usually don’t publish something until we are really sure,” he said. “When you finally tell the world about something you’ve found, you don’t want to end up saying ‘oops.'”