Sulfur mine creek

Lion Creek drains Laundry Canyon in the Leona Heights and Crestmont neigborhoods as well as the former Leona Quarry lands. It runs through Mills College, past Evergreen Cemetery, and into the bay at 66th Avenue — it’s the stagnant creek you see from BART just north of the Coliseum.

This is one strand of its headwaters, coming out of a former pyrite mine at the end of McDonell Avenue. The local chapter of the Society for Industrial Archeology says about this mine, the Leona Heights mine, “From the 1890’s to the mid 1930’s, iron pyrite was mined here and at the nearby Alma mine. It was processed into sulfuric acid at the Stege Works of Stauffer Chemical in Richmond (and other sites).” The photo was taken in 2003; I think it’s a little better today. The orange is iron oxides, not especially poisonous, but it looks awful. As I imperfectly understand it, sulfuric acid in the drainage water drops this mineral as it is neutralized. The acid comes from sulfur-eating bacteria in the mine environment.

Yes, Oakland has its own example of the same acid mine drainage that plagues the Appalachian states and many other lands. Every place the pioneers came to, they began mining everything they could, because that was the only way to build civilization. Sulfur is essential for gunpowder, and pyrite was the readiest source. Coal came from the Contra Costa hills, mercury from San Jose and from points north, lime from the San Mateo coast (and the local shellmounds), rock of all kinds from the Oakland Hills. This place was rich in timber and pasturage, we all know, but rich in minerals too.

Managing the lake

Lake Merritt needs a lot of care and attention to perform at its top level. This view of the pergola at its east end shows one of at least three aeration fountains in the lake. Without the oxygenation provided by these fountains, the organic matter brought in by the tides and streams, and deposited by the abundant bird population, would periodically overwhelm the natural oxygen dissolved in the water and turn the lake into a stinking anaerobic pond.

Without upkeep, this site would quickly revert to the tidal marshland that it once was. That would be nice in its way, but city-dwellers would probably complain about it. Click the photo for a postcard-type view of this end of the lake taken last weekend.

A fault runs through it: Montclair

The Hayward fault runs through the heart of Montclair, in the Oakland hills behind Piedmont. Montclair Park’s duck pond was constructed where the fault left a natural sag in the ground.

Only in seismologists’ equations, and perhaps deep down in the crust, are faults smooth, flat planes. In the world, on the surface, faults are as ragged and variable as any other geological feature. The Hayward fault is more of a zone, from a few to a hundred meters in width, with several fractures running through it. Where two strands overlap, a block of ground between them may slump in tension or rise in compression, depending on how the strands are oriented. At Montclair Park, two strands are mapped on either side of the sag basin. Lake Temescal is another example of a sag basin repurposed as a water feature. So, apparently, is Lake Aliso, the pond on the grounds of Mills College.

The first “great San Francisco earthquake” occurred 21 October 1868 on the Hayward fault. The epicenter appears to have been in southern San Leandro, and surface rupture extended from there all the way down to Fremont. In Montclair, the other direction along the fault, there was plenty of shaking of course, but no rupture of the ground from what we can tell. A trenching study, conducted along the third-base line of the little ballfield in Montclair Park, found no sign of recent movement along the fault there. But slow, silent motion does affect the fault in Montclair. The old fire station on Moraga Avenue has been rendered useless by aseismic creep, and some of the houses along the fault appear to show foundation disruption. But generally creep is invisible unless there is some structure that it affects, like the south curb of Medau Place, below. South of here, the fault crosses Route 13, reaching the other side at the head of Dimond Canyon.

Rockridge Shopping Center quarry

Halfway up Broadway, where it crosses 51st Street/Pleasant Valley Avenue, there used to be the big Bilger quarry. The Oakland Paving Company mined a body of traprock (mapped as Franciscan quartz diorite, a near-basalt), crushed it, and shipped it out via a rail spur that crossed Broadway at 42nd Street and curved toward the former depot at 41st and Shafter streets (you can see the trace in Google Maps). This is what’s left. I’m standing at the very edge of the Catholic cemetery overlooking the Rockridge Shopping Center. Beyond it is a remnant of the original hill where California College of the Arts sits. It was a family estate before it became a school; perhaps they couldn’t stand the quarry operations and decided to give the place away. Still, the views from there are very nice, and the old quarry walls beautifully display the sandstone that adjoins the traprock as well as the faulted contact between them. Click the photo for a bigger version.

The old pit holds water from the Rockridge Branch of Glen Echo Creek after it traverses the Claremont Country Club golf course. A glory hole at the other end carries the overflow into a culvert that runs down the west side of Broadway, daylighted in two small places (by the new Kaiser parking structure and along Brook Street) before it joins Glen Echo Creek proper just north of 30th Street. The photo below shows where the creek joins the pit. I think the little waterfall on the left must be drainage from the country club grounds. It’s still pretty, and both are seasonal hidden treasures. The creek is barely visible from the other side—you have to stand by that little promontory at the front corner of the Longs store.

Sausal Creek in flood

With the heaviest rains I’ve seen in years, I checked out Dimond Canyon today to assess the power of the stream in it, Sausal Creek. The water was brown and impressive. It looked about waist-deep at most. I don’t know how this stream cut the canyon, which is a gorge more than 50 meters deep with stone walls. But I have a theory involving stream capture and movement on the Hayward fault, just upstream from the gorge. At various times, the fault has pulled the canyon past different watersheds. Perhaps lakes lay upstream, or landslides formed dams, that collected enough water to give the canyon a good downcutting once in a while. I hypothesize that the stream’s watershed was once quite a bit larger, perhaps even the valley now occupied by Chabot Reservoir. But the timing has to work.

There are at least two other gorges in the Oakland foothills that appear oversized to me: the upper reaches of Cemetery Creek, along Moraga Road, and the canyon of Peralta Creek in Redwood Heights, best seen from Rettig Avenue north of 35th Avenue.

It is recorded that the early loggers who stripped the redwoods out of the Oakland hills used to float their logs down Sausal Creek to the bay. All I can say is, there must have been a lot more water in the hills back in the 1850s, because even today’s deluge couldn’t have done that.

BTW see the Friends of Sausal Creek site.

Streams: Dunsmuir Creek

Up behind Dunsmuir House, near Oakland’s eastern end past the zoo and just before Sheffield Village, is a little wooded valley with this stream in it. It’s surely the reason that Dunsmuir House was built where it was, since the old places had to rely on surface water or their own wells. The Hayward fault runs very near this spot, through the swale that Dunsmuir House sits in. I don’t know where it leads. It may be an independent stream, between Arroyo Viejo and San Leandro Creek. It may connect with Elmhurst Creek, the ditch running past the south side of the Coliseum—that’s the way the contours seem to lead. Oakland has about twenty named streams, nearly all of them culverted today.

The bedrock is supposed to be either gabbro of the Coast Range Ophiolite or quartz keratophyre at the base of the Great Valley Sequence, but I wasn’t paying close attention to it. I remember it as nondescript, like a lot of Oakland bedrock.

I took this picture in March 2005.