A Mammoth Find in Moorpark

08 April 2005 | 11:28 Code : 4909 Geoscience events
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Construction crews in Moorpark have uncovered the skeleton of a fossilized mammoth believed to be older than the ancient beasts found at the La Brea Tar Pits.
Construction crews in Moorpark have uncovered the skeleton of a fossilized mammoth believed to be older than the ancient beasts found at the La Brea Tar Pits.

Larry Agenbroad, one of the nation's foremost mammoth experts, called the find, believed to be 50% to 70% complete, "spectacular," especially if it turns out to be the rare meridionalis species, as he suspects.
"We don't find a lot of them," Agenbroad said. "And to find one [this] complete is even rarer."

An on-site paleontologist spotted small fragments of bones March 29 during grading for a 265-home development in the northern foothills of Moorpark. He immediately stopped the work to take a closer look and determined the next morning that it was a mammoth fossil, officials said.

Paleo Environmental Associates of Altadena was called in April 1 to begin digging out the skeleton, a task that should wrap up Saturday, said Bruce Lander, a partner in the firm. A team of up to eight paleontologists has been working from dawn until dusk since the discovery.

Based on sedimentation surrounding its grave, Lander estimated the mammoth's age to be between 400,000 and 1.8 million years. If that proves correct, it could be an ancestor of the Columbian mammoths discovered at La Brea Tar Pits, which are no older than 150,000 years, Agenbroad said.

The lead researcher at the Hot Springs Mammoth Site in South Dakota, Agenbroad said he suspected the beast may be of the meridionalis species because of its apparent age. Growing to 14 feet tall and weighing up to 10 tons, meridionalis was the first mammoth to reach this continent about 1.7 million years ago.

But another expert questioned whether the bones could be that of the ancient meridionalis. The older mammoth species has never been found in coastal California, said John Harris, curator of the Page Museum at La Brea Tar Pits.

The only such remains uncovered in Southern California were at Anza-Borrego Desert State Park near the Salton Sea, Harris said.

"I suspect what you have there is a Columbian mammoth," Harris said. "That is the common mammoth that you find in California."

The location of the fossil dig — a modest 15-by-20-foot hole near the center of the 350-acre construction site — became a center of media attention Thursday, as helicopters circled and television cameras rolled.

"The likelihood of anything being preserved and becoming a fossil is one in a million. So to find a fossil is a thrill, but to find the fossil of a mammoth is icing on the cake," said Trevor Lindsey of Ecological Sciences in Santa Paula, who first spotted the bones. He estimated that 50% to 70% of the mammoth's bones were present, including nearly two complete legs, ribs, a large portion of skull, a nearly 7-foot portion of one tusk and the tip of the other, and two of the animal's four molars, including one still attached to the lower jaw, which will be important in trying to determine the age of the creature.

It will take up to a year to fully clean and prepare the fossils for further study, but the age may be determined sooner, Lindsey said.

Workers also will take about 3,000 cubic yards of dirt surrounding the fossils to the lab to screen for additional bones, such as the teeth or bones of rodents, which evolve faster and are helpful to archeologists trying to date a find.

Mark Roeder, a partner in Lander's company working at the dig, speculated that the mammoth died near an ancient stream or possibly drowned and that its skeleton was soon covered in a flood, which would explain why so much of it was preserved.

"This one's really rare, because it's fairly complete," Roeder said. "When you get one like this, it's exciting. You don't mind putting in the long hours."

Lindsey said the bones were in the Saugus Formation, a soil layer between 400,000 and 1.8 million years old.

The Moorpark specimen stood 12 feet tall at the shoulder and had 8-foot curving tusks, Lander said.

Skeletal pieces will be enrobed in plaster for protection before being transported to a Santa Ana laboratory for temporary storage, he said.

There, the plaster jackets will be opened and the fossils hardened with a solution. After each piece is labeled, the entire skeleton probably will be transferred to a museum or other institution for display.

Close relatives of the Asian elephant, mammoths roamed Africa as far back as 55 million years ago. They grazed on grasses, shrubs and even small trees, ranging into Europe and Siberia before crossing an ancient land bridge into North America.

Woolly mammoths, best known for their shaggy fur coats, came later and were smaller than their earlier cousins. The last of the mammoths died out about 11,000 years ago, experts say.

Fossils are frequently uncovered during home-building, prompting the passage of regulations requiring paleontological monitors during construction.

In 2002, workers digging home sites in Simi Valley uncovered the skeletal remains of a prehistoric mastodon, a relative of the elephant. Another mastodon was found in 1997 near Hemet.

Lander said his crews have found mammoth fragments in Thousand Oaks and Simi Valley while assisting developers. He said the developer of the Moorpark project, William Lyon Homes, did the right thing by calling a halt to the work.


 

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