Blog Profile / Oakland Geology


URL :http://oaklandgeology.wordpress.com/
Filed Under:Academics / Geology
Posts on Regator:306
Posts / Week:0.6
Archived Since:March 16, 2008

Blog Post Archive

Origins of Oakland ocher

Before Europeans came into this country, the locals treasured the ocher deposits in the East Oakland hills. Ocher is the name for a variety of clay-like, iron-rich minerals with a color range from yellow to red to brown. For tens of thousands of years, we’ve used ocher as pigments and preservative coatings. Some cultures would […]

The marine terrace of Clinton, lengthwise

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 below (1000 pixels) […]

Rubbing rocks

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 themselves against rocks — rather, rocks that animals have rubbed for […]

Old fill and made land

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 Square, Oakland’s original harbor. Reclaimed land, or artificial fill, is shown in pink. […]

Artifacts from the history of geology

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 […]

Two bits of gabbro

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 are inaccessible due to steep woods, roads or […]

The Idaho connection

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 particularly vexing for the older rocks with Mesozoic ages. The western edge of […]

A march for science

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, it’s also central to our civilization. As the March for […]

Museum-quality rocks from Oakland

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 the Chabot Space and Science Center. After […]

The Pinehurst Shale

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.) The group is well exposed in Shepherd Canyon and points […]

Notes for the Aftermath

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 current lesson. The bad idea is that when the […]

Red Rock Quarry

The Red Rock Quarry was apparently part of the Blair quarry complex in Moraga Canyon, at the west edge of Piedmont on Red Rock Road. Oakwiki reports that it was owned by the Henry Maxwell family (for whom Maxwelton Road is named). The 1947 USGS topographic map shows that the quarry was active at that […]

Siesta Valley and the De La Veaga Trail

Last week I attempted the Rockridge-to-Orinda ramble by a northern route. Was strenuous, but it got me into Siesta Valley, a place I’ve had my eye on for years, for the first time. At this time of year the sun is so low that the light is terrific. First came the climb up Tunnel and […]

2016: Pictures from a good year

Here are some nice views I enjoyed during the year. These shots are meant for clicking through to see at full size. In January, I said goodbye to the old Bay Bridge and looked forward to the day when the new bridge offers a superb platform for viewing the Oakland skyline. In February, I was […]

Oakland building stones: Gneiss

This is the last of my set of posts on Oakland building stones, although I reserve the right to come up with more. What you’re looking at below is gneiss on the wall of the Lionel Wilson Building, in City Hall Plaza. Gneiss is a fun rock, for me anyway, because when I see it […]

A hunt for silica-carbonate

The geologic map of the northern East Bay that I rely on has a few rock units that are very small and hard to notice. One of them is the ultra-purple unit designated “silica-carbonate rock.” The map shows only three small exposures — one in Oakland and two in Berkeley — but they’re close enough […]

Oakland geo-walks for out-of-towners

Next week will be the 2016 Fall Meeting of the American Geophysical Union, held in San Francisco since time immemorial — actually, since the hippie days of 1968 — and I’ve attended every year since the early 1980s. Back then it was held in Bill Graham Auditorium; next week some 24,000 people from all over […]

Oakland building stones: Lime stones

There isn’t a good word for the full variety of carbonate building stones — limestone, dolomite, marble, marlstone and travertine. Although I like the word limerock, it apparently doesn’t really exist. In any case, these rocks aren’t very common in Oakland’s buildings, the way they are in, say, Washington DC (all of those memorials, and […]

The Resilient Oakland Playbook

Last month the city of Oakland released its long-awaited resilience plan, the Resilient Oakland Playbook. “Resilience” is the 21st-century name for the concept that communities can get up quickly when they’re knocked down, and avoid being knocked down in the first place. I’ve always thought of resilience in terms of how we deal with natural […]

A geologist’s reconnoiter of Piedmont

The city of Piedmont sits surrounded by Oakland, like an organelle in a cell. I’m undecided on which organelle it might be — a mitochondrion (powerhouse)? a nucleus (brain)? Maybe just a vacuole of well-controlled living. Whatever the case, it’s a good walking town if you happen to be fit. And geologically it’s fully part […]

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