Archive for July, 2010

My serpentine letter – Updated

28 July 2010

I’ve just mailed the following letter to Assemblymember Nancy Skinner, who represents Oakland in Sacramento:

“Dear Assemblymember Skinner,

“I write in opposition to Senate Bill 624, which removes serpentine as the state rock and removes the category of state rock itself from the State Code.

“Serpentine, or as geologists know it, serpentinite, is a signature stone of California, found in most parts of the state. The reasons for its widespread distribution here are deep clues to the structure and behavior of the Earth’s crust and underlying mantle. That is to say, serpentine is a protagonist in the story of modern geology. It gives California students of Earth science at all levels, from primary grades through postgraduate studies, a handle for learning concepts as well as practicalities.

“The concepts embodied by serpentine are the joy of geologists: tectonic interactions of continents and oceans, chemical transformations of deep-seated rocks, the lubrication of earthquake faults, the rise of mineral-bearing fluids into lodes and bonanzas.

“The practicalities embodied by serpentine are relevant to many classes of citizens: Serpentine ground requires special care on the part of builders. Serpentine soil supports a set of distinctively Californian plant and animal communities. Serpentine minerals include the fibrous chrysotile, used since ancient times for fireproofing applications and mined in California during most of the 20th century. Serpentine bodies are associated with valuable mineral deposits including chromium, jade and gold (California’s state mineral).

“The familiar blue-green, shiny serpentine seen in hundreds of roadcuts is a striking remembrancer of those school lessons. The legislature was wise to make serpentine the face of California’s rocks and landscapes. The legislature was bold to make that designation in 1965, when no other American state had ever chosen a lithologic emblem.

“SB624 undoes that wisdom and unmakes that boldness for unscientific and fear-based reasons. It is unscientific in declaring that serpentine causes cancer when, in fact, only a small fraction of serpentine contains the mineral chrysotile. And only in industrial settings, in which large amounts of the powdered mineral were inhaled for years by WWII-era workers, is that one mineral linked to lung disease. SB624 is a profoundly misinformed bill.

“The result of this bill’s becoming law will be to deaden our children’s education, increase their fear of the outdoors, and open all kinds of benign land uses to mischievous litigation. Please assure me that SB624 will not get your vote.”

We’ll see what happens next week.

UPDATE: Rep. Skinner replied with a generic letter. The bill entered the maelstrom of late-session maneuvers, during which the sponsor deleted everything but a single sentence removing serpentine as the state rock, without the noisome preamble. This would have allowed her to declare victory, but for stealth reasons. In any case, the bill was shunted to the Rules Committee, where it died with the end of the session last week. But now I guess I’ll have to watch for its successor in future years.


At home with serpentine

27 July 2010

I often come upon serpentinite in people’s yards, but this home on Perkins Street really used it to advantage—or maybe the owners painted the house to match the stone.


Naturally the notorious poverty of serpentine soils is not a hazard when serpentinite is used decoratively, nor is there any exposure to fibrous dust that might be classified as EPA-labeled asbestos. Are you listening, Gloria Romero?

Save serpentine

26 July 2010

The Regional Parks Botanic Garden is a treasure in the Berkeley Hills that I visit several times a year. For 70 years it has assembled native plants from all corners of California and grows them all in one place. If you’ve spent time in the wilds anywhere in the state, you will come here and get the uncanny sense of being there again. Likewise, if you come here often, you’ll recognize its plants when you travel.

The visitors’ center has a very nice exhibit about California’s current state rock, serpentine (or as geologists call it, serpentinite).

botanic garden serpentinite

I understand that state Senate Bill 624 will come before the Assembly on August 2 (although I can’t find an official source for that). SB624 kills serpentine as the state rock. It removes the entire state code about state rocks (don’t believe claims that it will “swap the rock”). Moreover, it kills serpentine with prejudice, declaring that the stone “contains the deadly mineral chrysotile asbestos, a known carcinogen, exposure to which increases the risk of the cancer mesothelioma.” It further states that “California should not designate a rock known to be toxic to the health of its residents as the state’s official rock.” Well, geologists will tell you that most serpentine does not contain chrysotile, that chrysotile is not asbestos, and that the rock is not known to be toxic to the health of its residents. Health experts will tell you that careful studies show a very, very slight risk from environmental asbestos exposure, a risk so small that it’s academic.

That’s not a good enough reason to dethrone serpentine. A state law declaring these falsehoods to be fact could be useful for nuisance lawsuits, however, even though the proponents swear it’s only about asbestos awareness. I’m sure they’re sincere; this isn’t about intention, but consequences. In fact, asbestos education is a good reason—another good reason—to keep serpentine on the throne.

So far there has been publicity, some newspaper editorials, a radio bit or two and lots of blog postings, nearly all against SB624 and for serpentine. But state Assembly members aren’t responding, and I fear that they’ll vote for this bill out of lazy chumminess. This, then, is the week for people to contact their assemblymember. A paper, mailed letter is best, a phone call second-best, email better than nothing. Those of you on Twitter can follow developments through the hashtag #CAserpentine. All that means is, put “#CAserpentine” in the search box. I’ve posted about it before, and this will be the last time, I hope. I would rather write about timeless things. Please help, this week.

San Leandro Creek (3)

25 July 2010

San Leandro Creek supplies almost all of the water in Lake Chabot. Here’s where it enters the reservoir, at its farthest eastern end.

lake chabot

San Leandro Creek is one of only three streams that cross the East Bay hills. The other two are San Lorenzo Creek, which cuts through Castro Valley and Hayward, and Alameda Creek, which traverses Niles and Fremont.

Since Anthony Chabot built the dam in the 1870s, the creek has dumped sediment and filled in about a mile of its course, creating new level land until today it’s slowly encroaching into the lake itself. Willow Park Golf Course is built on that land.

Not much sediment comes into the lake today, now that Upper San Leandro Reservoir has dammed the creek about four miles upstream. The round pads of aquatic vegetation flank the stream channel, which runs between low, muddy banks that were underwater when I visited last month. I think the vegetation traps sediment, which supports more vegetation, so that the patches tend to grow into a circular shape, reminiscent of bacterial colonies on a petri dish.

The first two ridges in this photo are underlain by the Joaquin Miller Formation, which extends along the whole south shore of the lake between here and the park headquarters. It’s mostly shale with a few large sandstone beds, tilted steeply upward. The farther ridges are all Oakland Conglomerate, and they stand maybe 50 meters higher. They look more sparsely vegetated, which may reflect the bedrock but might just as easily be due to historic land uses.