Archive for the ‘Other topics’ Category

What I marched for

24 April 2017

Saturday was Earth Day, an occasion that usually leaves me lukewarm at best. But this year it was also the day of the worldwide March for Science. A few news stories have quoted environmentalists who resented that the march happened on “their” day. But from my viewpoint, that’s the best day of the year for a science march. The Earth Day community needs the help, and the organizers are upping their game.

We should have a science march, or at least a rally, every year. This year’s inaugural march had a militant edge. So did the original Earth Day. And for centuries before that, scientific advances have shaken up establishments of all kinds. This sign, quoting Galileo’s legendary comment after the Church forced him to renounce his discoveries, was a shout-out to that long history.

The authorities can threaten people for their beliefs, but they can’t force facts to be untrue. And when Galileo muttered “Nevertheless it moves,” he was talking about the Earth.

Other signs were more contemporary, more pointed . . .

. . . and funnier.

One of my favorite geeky jokes was on Twitter: “The numbers for the Science March seem high but we won’t know until we compare it to the numbers at the placebo march that’s also happening.”

I could have marched with the group from the American Geophysical Union, which endorsed the event. I’ve been an AGU member and rabid fan since the mid-1980s. But I chose to walk with the Northern California Science Writers Association, because they represent my practice. Our little group took a side route to the march along Drumm Street, and when we got there Market Street was packed.

It took us an hour to stroll to the Civic Center. People lined the route, holding their signs and admiring ours. There was a learning fair at the other end, what we used to call a teach-in.

As I prepared to return to Oakland, incoming marchers still filled Market Street to the limits of my sight. This was not a small occasion.

There were thousands of signs. This one reminded me of an important truth.

It means that the scientific method is simply a more rigorous version of something we all do. When we face a question of any size, whether it’s choosing fruit at the market or investing our life’s savings, we make our best estimate of what to do, check the results against our expectation, and then make adjustments in how to proceed. Science is common sense weaponized, and the better we are at common sense the more we are like scientists.

One thing that stood out to me at the San Francisco March for Science was that science has more than practitioners — it has fans. When the speakers at the rally made shout-outs to NASA, they drew widespread cheers. The same for stem-cell researchers at the California Institute for Regenerative Medicine or NIH — cheers. These things deserve their applause, and I cheered them as a fan.

Although there were geologists and geology fans in the crowd, we didn’t get a chance to make or hear a cheer of our own on Earth Day. I know, we’re grownups and don’t need the adulation, but what about the kids who are into minerals and fossils? Do they sense there’s a pivotal role for them in extrasolar planetology? In evolution studies? In global sustainability, in climate studies, in remediation of polluted places, in ecology? Are geology’s strengths in earthquakes, volcanoes, floods and landslides unworthy of comment in a march for science? Does plate tectonics, with its elegance and grandeur and promise, have no fans among the rally planners?

Geologists do tend to keep their heads down. Because Earth science is too wonderful to neglect, I plan to push ahead. You are fans, and I have hundreds more stories for you.

East Bay diatomite

3 April 2017

The geologic map I rely on for this blog — U.S. Geological Survey map MF-2342 — extends north to Pinole, where it shows this little pod of rocks labeled “Tsa” and “Tdi” between Pinole, El Sobrante and Richmond.

Both units are of early Miocene age: Tsa stands for sandstone and Tdi stands for diatomite. The T stands for Tertiary, the catch-all term for Cenozoic rocks older than Quaternary, which — OK, you don’t need the whole lecture just now. The point is, I had to go see this diatomite because I didn’t know it existed in the East Bay. I’ve seen it in the Central Valley, but never around here.

Going north on I-80 you take the Appian Way exit right and immediately turn left on Sarah Drive. Down at the bottom of a valley is Pinole’s little, undeveloped Sarah Drive Park.

On the way to the hilltop, you start seeing this odd rock in the road. Pick up a piece and you’ll find it’s very light. That’s the diatomite.

The trail becomes very steep, exposing the bedrock. The hilltop affords nice views. I was especially taken with the view north.

And the view east looks up Pinole Valley toward Mount Diablo on the horizon. If you’re riding toward Sacramento on the Capitol Corridor Amtrak train, there’s a moment just east of Point Pinole where you can catch this same view of the mountain.

And there were butterflies.

So that’s all great. But here’s what’s cool about the diatomite.

Diatomite is composed of diatoms, the microscopic algae that make shells of silica. As an industrial commodity it’s also called diatomaceous earth, or DE, or kieselguhr if you’re feeling smart. As the stabilizing agent for nitroglycerin in dynamite, it made Alfred Nobel’s fortune, and that’s why we have the Nobel Prize.

As its silica content slowly turns into the crystalline mineral quartz, diatomite becomes the rock called chert. As it happens, the Pinole diatomite is about the same age as the chert in Oakland’s Claremont Shale. By some tectonic accident, it avoided being converted, and you can enjoy its lightweight charm without a trip to Los Banos.

Artifacts from the history of geology

27 February 2017

I had the good fortune last week to join a gathering of the Explorers’ Club at the great David Rumsey Map Center, a famous collection housed since 2016 in the Green Library at Stanford University. Laid out for our enjoyment were precious original maps from the 18th century West Coast exploring voyages of Vancouver, La Pérouse, Cook and more; maps from the 19th century Western surveys of Fremont, King, Powell and more; and two monuments of geologic mapping: William Smith’s 1815 map of England and Wales, and an edition of William Maclure’s 1809 map of the United States. I couldn’t resist a phone pic of that one.

macluremap

But you can examine the map online as closely as if you were holding a hand lens up to it, thanks to davidrumsey.com.

It’s hard to overstate how much effort it took to make this map, crude as it is. Geology was in a crude state at the time — Maclure distinguished only four classes of rocks, using the Neptunist scheme of Werner — and the territory of America could only be surveyed laboriously by foot, horseback, boat or coach. But this is how it began.

The 1815 Smith map, widely known as “the map that changed the world,” recently had a well-celebrated bicentennial, and strata-smith.com is where to get deeply into it. It was a rare privilege to take it in with my own eyes.

Another item that impressed me was a heavy lump of dark stuff encased in a silver box, engraved with the owner’s name in 1791. It was a genuine working lodestone.

lodestone1791

A lodestone is a naturally magnetized piece of the mineral magnetite. Not every piece of magnetite actually acts like a magnet, although of course a magnet will attract it strongly. It has to have a certain amount of impurities that, in effect, lock down its magnetization in a persistent state. It also appears to need its magnetization to be “set” by the strong field of a lightning bolt.

Lodestones were the first compasses. Mariners first learned to navigate with them around 1200. Later it was learned that you could magnetize ordinary iron by stroking it with a lodestone, although this was not permanent. Iron compass needles had to touched up periodically, and that was what this lodestone was for. A ship’s captain might keep one as a backup, but they’ve always been rare and expensive.

Not until the 1700s were truly permanent compass needles made using steel, and not until we mastered electricity did we no longer need lodestones. I have this magnetite specimen, about a thumbtip’s size, that acts as a magnet. I hesitate to call it a lodestone because nowadays you could make one by just zapping it.

lodestone

I was touched by these artifacts from a time when science was closely tied to artisanship, when everything was done by hand. Today, geologizing still benefits from the human hands and senses in ways that, say, physics and chemistry have long left behind.

The Rumsey Map Center is open to the public.