More than 10 million years ago, when the hills just east of Irvine were thousands of feet under the ocean depths and the shoreline was near Corona, a sperm whale died and settled into the mud.
A month ago, a paleontologist monitoring work at the Frank R. Bowerman Landfill nearly 1,300 feet above sea level, saw a small bone fragment sticking out of the dirt where crews were cutting a road. The bones had been preserved in the dirt even as the land there rose thousands of feet because of geologic processes.
The paleontologist, Melissa Marcias, who works for engineering and environmental consulting company Psomas and was monitoring the site as required by state and county law, started searching for more bones in the area, at first to no avail. She nearly gave up when she stumbled upon what turned out to be 18 teeth, two pieces of skull, part of a jaw and a flipper bone.
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A crew of three to four people spent the next several days excavating the site, digging out the fossils and wrapping them in plaster jackets.
“Normally when you find whales, it’s an isolated rib or a vertebrate,” Marcias said Tuesday, as the discoveries were unveiled. “It’s pretty exciting.”
The fossilized whale, found in an area only 10 feet across and six feet back into the hillside, was likely at least 40 feet long. Today, sperm whales are 60 feet.
“That’s the biggest sperm whale we’ve found in the county, expect the bigger sperm whales, which are swimming around offshore,” said Jere Lipps, director of the Cooper Center, which stores and curates fossils found in Orange County.
Through the millennia, both baleen and toothed whales, like the sperm whale, have grown bigger, Lipps said. Before 8 to 10 million years ago, short pigmy whales roamed the oceans in areas near present-day Orange County. But ocean cooling that began 14 million years ago prompted whales to evolve bigger.
Cooling ocean waters at that time increased the temperature difference between the poles and equatorial regions, which prompted the water circulation to quicken. That caused an increase in upwelling from the deep ocean near present-day Southern California, and an increase in nutrients for plankton to feed on.
The whole food chain became more resource-rich, allowing whales to grow bigger, and even diversify into more species, Lipps said.
Fossil whales are among the most commonly discovered animals in Orange County. One complete baleen whale was found in 1986 near a residential construction site in Dana Point, and another was discovered in 1980 in San Clemente.
The fossils are frequently found on road cuts, construction sites and other sites where large volumes of dirt are getting moved.
“Construction is a real boon for paleontology because it opens up large areas we would never see,” said Mark Roeder, the senior paleontologist at Psomas. “A lot of times the bones are well preserved because they’re not at the surface where they would weather. They’re buried.”
Before the 1970s, major fossil discoveries at construction sites would shut down projects, as crews worked to preserve the bones. To prevent that from happening, paleontologists negotiated with developers and county officials to write new guidelines.
“So they could protect the resources, but also the project would get done,” Roeder said.
On-site paleontologists now monitor construction, and fossil finds are marked off while construction work continues around them. Orange County’s requirement for on-site monitors was the first in the country.
Around the same time, Orange County officials also passed a resolution requiring fossils found in the county to remain here. Until about five years ago, those fossils languished in storage, many of them unprocessed and uncategorized. Then, the county established the Cooper Center in Santa Ana, where fossils managed by Cal State Fullerton are stored and processed.
Some fossils are displayed at the Cooper Center, while others are taken to sites around the county, such as Ralph B. Clark Park in Buena Park.
Once the whale fossil is cleaned, stabilized and logged in a database, it will be displayed at the Bowerman landfill office.
Contact the writer: aorlowski@ocregister.com. Twitter: @aaronorlowski
