Oakland Geology

^{Gene Anderson photo from the Oakwiki, CC SA-BY}

The County of Alameda Administration Building at Oak and 12th Streets was designed for work, not for show. Like “Whistler’s Mother,” it’s a study in gray. And at the moment the early-1960s structure looks kind of dingy. But its design lends itself to interesting effects in stone that are apparent at close range.

When it was built, the five-story reinforced-concrete structure was said to embody “contemporary classic” style, and it’s very much of its period. The idea was to add a much-needed annex to the 1930s-era county courthouse across Oak Street — both buildings house courtrooms and are connected by a tunnel — so the Administration Building was meant to complement rather than outshine the earlier structure.

The site is on the gently sloping edge of the downtown platform of ice-age sand dunes. The front entrance on Oak Street serves the ground floor while the rear entrance on Madison serves the second story.

In design and construction, as recorded on the black granite panel on Oak Street, the Admin Building was a local product in a way we don’t see any more.

The architects were an amalgam of designers. Van Bourg, Nakamura and Associates, a young Oakland firm that later became VBN Architects, is responsible for many public buildings in the area. The Berkeley father-and-son team of Walter and Robert Ratcliff added their own gravitas and experience. The construction firm of longtime Alameda resident Ferdinand “Fred” C. Stolte, which had left its mark all over town, handled the building of the building.

It went up relatively fast, easy, and cheap at $4.4 million. The money came from the county employees retirement fund, which the county paid back on good terms.

The design of the Admin Building, first publicized in 1960, included the plaza along Oak Street as we know it today, half trees and half hardscape dotted with massive planters. The walls were clad with precast concrete panels with a “crushed granite finish,” what appears to be polished clasts of dark Sierra granite.

If I’m ever assigned jury duty here, I hope to get a closer look at it and update this post.

To all appearances this is the same kind of cladding used to good effect in the great Kaiser Center edifice and other contemporary buildings, although unlike those cases it’s polished to an even flat face.

Ground was broken for the building on 1 August 1961, and a 3-ton granite cornerstone was laid on 25 September 1962 with a time capsule inside it. The building went up without fuss or undue delay, other than a brief kerfuffle over whether to make the basement level a fallout shelter (they didn’t), a worker strike in 1962 and heavy rains that October.

The dedication took place on 19 March 1964. At the time the trees in the plaza were palms; today they’re plane trees. The Berkeley Gazette called the building “magnificent”; the Tribune noted its “grace and economy of line” although as you can see the context was not particularly about architecture.

This full-page photo caught my eye because the bottom portion shows that the entryway was different, not disabled-friendly, in the early years. It appears that the whole plaza was raised to create today’s level entrance. That would be when the pavement of granite blocks was installed.

The bronze sculpture is not original either; it replaced a fountain that used to drench unwary passers-by on gusty days, leading Supervisor Kent Pursel to complain to the newly formed County Arts Commission in 1966. Another add-on is the white panels flanking the entrance.

These continue inside the lobby. They feature the same high-grade dolomite marble used on the Kaiser Building exterior.

The picture above of the engraved granite slab shows two other attractive features of the Admin Building ground. There’s the rugged pavement of carefully blended crushed stone set in concrete . . .

and the rough-finished panels of luscious blond granite — technically, a syenite — that frame the whole.

I said earlier that the Admin Building is a local product, but this stone is not from around here, or even from California. Probably India or Brazil.

Finally, we have a few boulders in the strip along 11th Street. Plain old clean stones, individuals with personality.

The Sierra Nevada rivers fashioned them, perfect just as they are.

The newest building in central Oakland is the awkwardly named AC Hotel by Marriott Oakland Downtown, at Jefferson and 14th Streets. The AC chain purports to offer “hotels that reflect the soul of each city they are located in . . . a unique combination of quality, timeless European design, comfort and true authenticity.”

To me the “soul” of downtown Oakland is its collection of vintage buildings that range in age from the 1870s to today. Even our newest towers, residential and commercial, are vintage products of our interesting time. The AC Hotel offers a head and shoulders of sound 21st-century type, soft-finished metal and glass with restrained offsets and moderate height. And down at street level, it nods to its century-old peers.

I appreciate the dignified gray tone of this wall, its solidity and its variety of texture and form. But being a geologist, I always take a closer look.

This is not “true authenticity” or even plain old authenticity. It’s concrete that mimics fine-grained granite. To me it looks just as fake as the little plastic landscaping stones that cover spigots and hide spare keys. My aesthetics are just a personal taste, and I don’t blame the architects or anything. But there are other things to consider about concrete.

First let me say that I love concrete. It’s a miracle material that has transformed architecture. It’s a foundational technology and the single largest human-made substance. It has wonderful potential for artistic expression, like this example a few blocks away.

But the manufacture of cement, the binder that holds concrete together, is highly carbon-intensive. Every ton of cement adds about a ton of CO₂ to the atmosphere, a ratio as bad as coal. That makes concrete a major greenhouse gas contributor and a stubborn problem to solve before we can achieve a carbon-free future.

So the question I have for architects is, why use concrete when real stone can do the same job? An enlightening article by a British structural engineer argues that stone is capable of much more than we think; for instance, prestressed stone beams can outperform concrete in strength, lightness and durability. Today concrete is cheaper than stone, but its carbon footprint is over ten times greater. A straightforward carbon tax could do much to right the balance, especially if builders and architects embrace novel uses of stone.

Take a leisurely tour of downtown Oakland, and you’ll see stone everywhere, old and new, decorative and structural. There is an interesting exception: the First Presbyterian Church, at Broadway and 26th/27th Street, an English Gothic structure built with concrete facing in the early 1910s.

The Rev. Frank L. Goodspeed promised in 1912 that “it is expected to be one of the most complete and beautiful churches on the Pacific Coast.” The church elders considered stone at the time, but concrete “cast stone” was one-third cheaper. The J. C. Henderson company of Alameda manufactured 22,000 superficial feet of ashlar panels for the exterior, plus all of the custom curved pieces, window frames and so on, “no natural stone entering into the work.” They also took pains to give it a more naturalistic look:

A noticeable characteristic of the church walls is the varied tone. Not every stone is of precisely the same color. This result was achieved in the use of two different brands of cement. Santa Cruz cement is of a very light color and was used for all of the trim and the window tracery and for a third of the ashlar. Golden Gate cement, of a dark color, was used for the remainder of the work. Additional color variation was obtained by using lime rock instead of blue rock in the trim, together with white Monterey sand and some color to give a buff shade. (Concrete, Dec. 1916, p. 181)

The AC Hotel could have used some of that truly authentic old-fashioned care.

There’s a larger conversation going on about the climate-related merits of different building materials, not just concrete and stone. Good old timber has advocates, and Oakland will have a 21st-century tower with wood framing at 1510 Webster, going up now.

Mass timber claims to be climate-friendly, sustainable and all that good stuff. That part is debatable. But its light weight and speed of construction are indisputable advantages. And maybe the building’s lobby will have some really cool stone features.

I made a brief post about this fountain a few years ago — it was the first “Oakland stone landmark” post — but a reader’s question pushed me all the way into a worthy rabbit hole.

When John E. McElroy died unexpectedly on 24 March 1909 at less than forty years of age, the city of Oakland mourned a public benefactor whose unborn child would never know him. As the City Attorney, McElroy wrested back Oakland’s waterfront lands from the railroad, undoing one of the great crimes of our founder, the scoundrel Horace Carpentier. He also helped establish our reputation as a legitimate City Beautiful in a way that went beyond grand boulevards and splendid public buildings: children’s playgrounds. He was elected four times; the last time both the Democrats and the Republicans endorsed him.

Park Commissioner James Edoff, a close collaborator and friend, launched a private donation drive to honor McElroy’s memory with a large fountain in Lakeside Park. The design, by Park Commission architect Walter Reed, was submitted in March 1910. A scale model was put on display 7 July 1910, and the Tribune reported, “Granite, marble and concrete are up for the consideration of the commission and as soon as the decision is made and the funds which the city will contribute towards its erection are turned over to the commission the work will begin. It is thought that the commission will decide in favor of the use of granite in the construction.”

Bids came in that August from six companies, including the Raymond Company (whose Sierra White granite clads City Hall) and California Granite Company, and the Colusa Sandstone Company won the job. The city chipped in the majority of the $15,000 needed.

I suspect that the bids fell into two categories: the granite companies could supply their own stone while the other firms could emphasize their skills and connections.

Colusa Sandstone Company was a very successful firm whose quarries, just east of Sites and still visible today, supplied the stone and stoneworkers for some of San Francisco’s finest Belle Epoque landmarks: the Ferry Building, the Emporium Building, the Kohl Building, the Spreckels Building and more. They could arrange for premium stone from the best sources and finish it to the highest state of artisanship.

That October the Tribune reported, “The basin and other portions of the fountain will be of white marble, for which the city has provided.” Specifically, as other stories reported, it was Georgia marble.

“Georgia marble” was effectively a trademark at the time. Then and today, this stone comes exclusively from Pickens County in northwestern Georgia, west of the former gold rush town of Dahlonega and home of an annual marble festival. The Georgia Geologic Survey described the rock and the marble industry as of 1907, when the state was second only to Vermont in the value of its output. Many buildings in Washington DC use Georgia marble. The statue of Lincoln in the Lincoln Memorial sits on stone identical to the McElroy Fountain.

All the evidence points to the Georgia Marble Company’s Cherokee Quarry, located east of Tate, which at the time supplied a coarse-grained stone of white or “clouded” color with light blue-gray bands. See some of it at the historic Tate mansion on the quarry grounds.

Marble is what happens to limestone when it’s buried and subjected to the pressure and heat found several miles underground. Old geologic reports assign this marble an Early Cambrian age, making it a good half-billion years old. It was originally a body of limestone that collected on the floor of the Iapetus Ocean, which resembled today’s Atlantic in being the result of continental rifting. The metamorphism that turned this stone to marble happened later, in Ordovician time, when plate tectonics forced the coasts of the Iapetus Ocean back together. This continental collision wrinkled and folded the rocks at the heart of the Appalachian Mountains, in the inner Piedmont and Blue Ridge belts.

The bluish streaks are considered to be remnants of bedding in the original limestone. They have a little magnesium in them and a touch of iron.

Cherokee Quarry marble is exceptionally pure and notably coarse grained, both of which account for its strength and endurance.

Now that I know more about this distinctive stone, I expect to recognize it everywhere.

In June of 1911 bids were received on the tiling and mosaic work: “The marble tiling and mosaic work will be one of the most beautiful portions of the fountain. Of four colors of imported marble, the stone will be wrought into designs at the entrances in consonance with the rest of the fountain.” Marbles to be used in the tiling and mosaic are green Verdi antique, white Alaska, or heavily veined Italian, red Numidian, yellow light Sienna and nemesis marble.” (Visit the Getty Museum’s online thesaurus for more on some of these.)

Work on the mosaic was still in progress when the Park Commission formally accepted the fountain on 6 July 1911, only 16 months after McElroy’s death. The fountain was dedicated on 17 September 1911, in an elaborate ceremony attended by thousands. After a series of speeches and musical selections, McElroy’s little boy, John Jr., turned the fountain on. Then Scott’s Band played “The Stars and Stripes Forever,” followed by “America” with the crowd singing along.

Even the water is special. The fountain lies on top of a reservoir that serves the Lakeside Park grounds. It was once (and may still be) fed with groundwater from two wells nearby, perhaps in one of those nondescript little huts in the park.

The 11 years since my previous post have not been kind to this exceptional structure.