The fossil treasury of UCMP

18 May 2015

Last month, as part of Cal Day, they were giving backstage tours at the UC Museum of Paleontology. The day is a mob scene, but on the last tour of the afternoon I had a fine time being shown around by two of the museum’s scientists.

The collection is vast, the world’s largest university collection. Only part of it is in the Valley Life Science building. There’s also a building in Richmond, and there are great accumulations of tar-seep fossils (from La Brea and McKittrick) housed in Sather Tower—the Campanile—because they smelled too much to keep with the others.

The collection at Valley Life Sciences is housed in huge cabinets that slide along tracks to open enough space to pull out the drawers. Many of those drawers are full of microfossils.

UCMPmicros

These are a huge part of California’s heritage. It was a thorough knowledge of microfossils in the rocks of the Central Valley and Southern California that informed and guided our petroleum industry. California remains America’s fourth-largest oil and gas producing state thanks to this scientific-industrial heritage.

But naturally, the museum had some of their photogenic specimens out. This Triceratops horn, with slices sawn off to expose its interior, was a privilege to hold. Unfortunately, the Bay area has no dinosaur fossils at all, although a few marine vertebrates from Mesozoic times have been found.

triceratop-horn

This ammonoid shell was interesting because it has a beautiful set of tooth marks on it, courtesy of a mosasaur. In the corner of the photo is a drawing of the specimen, as published in a scholarly paper.

mosa-chomp

Mosasaur fossils, to my knowledge, are not known from California either. Not yet, anyway.

And this thing sitting on the floor gave me joy. It’s a stump from the world’s first forest, dug up in rocks of Middle Devonian age in upstate New York.

psaronius-erianus

The inscription reads, “Psaronius Erianus Dawson / [Hamilton Group] Tree Fern / GILBOA, Schoharie Co. NY.” The Gilboa forest was first excavated in the 1870s. When I was on About.com, I featured Gilboa in my list of geo-attractions of New York state, and I hope you’ll seek it out if you’re ever there.

This specimen was undoubtedly part of an exchange of fossils between UC Berkeley and the State Museum of New York, a traditional way for paleontologists to enrich each other’s collections. It was surely a source of pride for Joseph Le Conte, the geologist who was the University of California’s first president. His fossil collection was the nucleus of today’s museum.

Butters Canyon serpentinite

11 May 2015

I will continue to focus on serpentine rock—serpentinite—for a while longer because I’ve been visiting it a lot lately in Oakland. This post shows some exposures in the lobe of serpentinite mapped just south of Joaquin Miller Road. This bit of the geologic map shows where we are, and the five numbers are where I took the following photos.

butters-serpmap

The first photo is at the head of Hedge Lane, right off Joaquin Miller. The map says this is a blob of Leona “rhyolite,” but the ground is clearly serpentine here, on the whole street.

butters-serp1

A little farther, on beautiful bucolic Burdeck Drive, is this serpentine stonework. It doesn’t prove that there’s serpentine bedrock here, but it does suggest that some is lying around.

butters-serp2

So here we have a piece of the geologic map that’s mapped as one thing, but is clearly another. That’s the nature of geologic maps. They aren’t like street maps. They’re simplifications of a welter of vague clues in the landscape and bits of rock, surmises based on drilling records and engineering reports, and highly informed imagination. No doubt the mapper’s field notes mention “serp” where I saw it, but the area is still predominantly “rhyolite” so that’s the color it’s assigned.

Along the rest of Burdeck, the ground looks like something other than serpentinite, although no bedrock is exposed: unlike serpentine ground, the soil is thick and the oaks are vigorous. Then we join Butters Drive, just to the right of the “sp” symbol, and serpentine returns in all its blue-green, scaly glory.

butters-serp3

Here are two closeups from this exposure, testimony of mighty squeezings deep underground.

butters-serp4

butters-serp5


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