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Andrew Alden
8,190 followers -
Writer on geological subjects: KQED, blogs, books & whaddayagot?
Writer on geological subjects: KQED, blogs, books & whaddayagot?

8,190 followers
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A few years back I showed you a view across the flat marine terrace where the old town of Clinton once sat, back in the 1850s. To really get a sense of it, walk the length of the terrace some time. Here it is on the geologic map, marked “Qmt.” The photos…

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Rocks interact with animals of all kinds. Obviously, lizards and voles and snakes and woodchucks live on rocks and/or dig under them. Humans paint on rocks and move them around and blow them up. Today, however, I’m going to talk about animals that scratch…

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Between the 1840s and roughly 1960, the Bay area made colossal amounts of dry land through “reclamation,” a euphemism for filling in marshland with whatever was handy. Oakland was no exception. Here’s a portion of the geologic map centered on Jack London…

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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…

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I’ve noted that while the San Leandro Gabbro has a presence in easternmost Oakland, it’s hard to find. The geologic map shows what seems like a lot of it, marked “Jgb” for Jurassic gabbro. But if you poke around on the ground, nearly all of those sites…

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I’ve been getting into the weeds as I work on my book manuscript about Oakland’s geology (tentative title, Deeper Oakland). Where did Oakland’s rocks come from? Specifically, how did they get from where they formed to where they are? This problem is…

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On Earth Day this year, April 22, an unknown but large number of scientists will be gathering together, in Washington and other cities, in a March for Science. I’ll be joining them somewhere in or near Oakland. Not only is science central to my being,…

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I keep saying that Oakland has geological features worthy of being put in textbooks. Today I’m here to show you that Oakland has rocks worthy of being in museums, and I’ve put them there. In 2012, I was asked to put together a set of teaching rocks for…

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Much of Oakland’s high hills consists of our local piece of the Great Valley Group, the colossal set of sedimentary rocks that runs the length of the Central Valley along its western wall. (How our piece got over here is, as they say, poorly constrained.)…

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I think about earthquakes often, almost every day. That’s part of what makes a geologist — not just visualizing the deep past, but living in the deep present. Turning seeing into foreseeing. In this post I’ll talk about a bad idea, a good idea and a…
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