Oakland building stones: Kaiser Center’s dolomite

18 July 2016

During yesterday’s OHA walk around some of Oakland’s building stones, I was pleased to bring out an underappreciated aspect of this great city landmark.

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The Kaiser Center, like City Hall, is one of Oakland’s signature buildings. When construction finished in 1960 the curving, T-shaped office tower was so iconic that Ansel Adams is said to have photographed it, presumably giving it the same sheen of grandeur he gave Half Dome. (I couldn’t find that image, although Rondal Partridge also photographed it, which is just as good.)

The photo above shows the butt-end of the 7-acre Kaiser Center complex, at Webster and 21st streets. In the foreground is the parking structure/commercial space that holds up the wonderful rooftop garden.

The Kaiser Center is famous for its extravagant use of glass and metal, specifically aluminum, Kaiser Aluminum’s principal product and a design element dictated by Henry J. Kaiser himself. But I spoke to the group about the third element that embraces the metal and glass in a gracious unity — the white stone cladding.

As you walk around the Center, the cladding appears pleasantly rough yet perfectly homogeneous. It’s not a veneer of solid stone, nor is it some kind of textured concrete. Neither is it painted. It’s an extraordinary material. After 55 years of weather, it still looks white and crisp and fresh.

Nearly all of the cladding is out of reach. Some panels touch the ground along the curving roadway behind the main tower, but that’s too hazardous even for your typical roadside-loving geologist. However, at the left edge of the photo is a little section of wall where the architects felt obliged to extend the cladding to the sidewalk. That’s the only safe place to examine it.

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The backing is concrete, but the aggregate that makes up the face is a pure white stone. Steel scratches it, therefore it is not quartzite, which was my first guess. It has the frosty luster of a carbonate, but it doesn’t fizz under dilute hydrochloric acid (I always carry some). Therefore it is not ordinary limestone or marble. It’s something much less common: coarse-grained dolomite, a stone with its own place in Kaiser’s history.

Whereas limestone and marble consist of calcite (CaCO3), dolomite rock or dolostone consists of the mineral dolomite (CaMg(CO3)2), in which magnesium takes the place of half of the calcium. It has many industrial uses, and the Kaiser conglomerate has mined it in several different quarries.

During World War II, magnesium metal was in great demand, especially for aircraft. The supply of magnesium ore, magnesite (MgCO3), was very tight. (Magnesite was mined at this time south of Livermore, in Del Puerto Canyon.) Kaiser sought a way to produce magnesium metal from dolomite using the Hansgirg process, but the process was plagued with difficulties. The magnesium program was known as one of Kaiser’s biggest headaches.

Henry Kaiser was closely involved in the design of the Center — indeed, it’s said he intended to live there. One of his conceits was that the materials, as much as possible, should be supplied by Kaiser companies. His architect, the Los Angeles modernist Welton Becket, was noted for his use of natural stone cladding.

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I imagine that Becket and Kaiser were pleased, each for his own reasons, to showcase the exceptionally pure dolomite from Permanente Metals’ large Natividad quarry, a few miles north of Salinas. I feel quite sure that’s what this is.

More reading:

“Looking Down on Creation” in The Monthly, Nov 2006

“Five Painterly Vistas from Kaiser Rooftop Garden” in The Urbanist, Mar 2011

The Natividad quarry (bottom of the page), at Quarries and Beyond

Marks of the Oakland fault

11 July 2016

Two weeks ago I told you how the city of Hayward inadvertently destroyed a special street corner. It was an informal shrine among geologists because it so clearly displayed the creeping motion of the Hayward fault. I mentioned that Hayward still has plenty of other bent curbs.

So does Oakland. Almost nine years ago in this space, in my very second post, I said that Oakland should take over the Hayward fault and make it our own. With that in mind, here are eight places on the fault that are pretty iconic if you ask me. I present them from south to north.

1. Revere Avenue above Marlow Drive, in Sheffield Village.

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2. Encina Avenue below Castlewood Street, in Oak Knoll.

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3. Ney Avenue near Astor Avenue, just above Fontaine Street.

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4. 39th Avenue at Victor Avenue, in Redwood Heights.

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5. Medau Place near Moraga Avenue, in Montclair Village.

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6. The old firehouse on Moraga Avenue, in Montclair.

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7. Broadway Terrace just west of Route 13, in Upper Rockridge.

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8. In Lake Temescal Regional Park by the park office.

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Here are their locations, shown on the geologic map.

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There are more such places between and beyond these ones, and others in Berkeley and San Leandro too.

Changes coming to Mountain View Cemetery’s landscape

4 July 2016

Mountain View Cemetery is one of Oakland’s great civic ornaments for several reasons: its gravestones and tombs commemorate generations of historically important Bay Areans, and its plan was Frederick Law Olmsted’s second significant large-scale project in landscape design after New York’s Central Park. It’s a fine piece of open space that’s used by many different groups of people.

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I think of the cemetery as a great civic ornament for two special reasons of my own. First, it’s a superb display of Oakland’s natural landscape as the first settlers knew it.

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Second, it’s got some great exposures of Franciscan melange, the mixture of rock types that was created by the tectonic collision between the North America and Farallon plates about 90 million years ago.

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The cemetery’s operators are planning to reoccupy and develop the highest part of the grounds, the two heights in this photo taken from the Catholic cemetery next door.

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Here’s the view from up there. The cemetery proposes putting in roads and formal structures in the foreground and up on the hill beyond the fence, behind the greensward.

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The goal is to accommodate about 1500 more grave plots. A lot of dirt and rock will be dug up and moved around. The plan talks of building up the hilltop and tilting it toward the bay for better views.

The city’s master page for the proposed work is here. The draft environmental impact report is there, plus info on two upcoming hearings (July 11 for the Landmarks Preservation Board, July 20 for the Planning Commission). This month is the public’s most influential time window.

The land beyond the fence is a special bit of countryside . . .

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. . . with its own constituency.

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It also has its share of rock outcrops. To me these are precious things. Most outcrops in these hills either were blown up during development or are locked up in people’s back yards.

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I’m still thinking about what I want to tell the city. But my basic concerns are that the natural character of the land — its contours and vegetation — be respected and preserved as much as practicable. The project will affect a landmark that hundreds of thousands of people enjoy from their own windows and yards.

Olmsted considered these hills the essential setting for the elegant, transformative parkland he planned here in 1863. Mountain View was, and remains, an icon of the City Beautiful movement and a destination for landscape architects everywhere. It and Stanford University (designed in 1888) are the only major Olmsted projects in the Bay area.

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This amazing cemetery is Oakland’s cemetery. Let’s speak up to help keep it as beautiful as possible.