Archive for May, 2010

Fields of goldfields

31 May 2010

serpentine prairie

The efforts to improve Serpentine Prairie are paying off. Last year I mentioned that the heart of the prairie would be fenced in for a few years. They have also removed the non-native pines that were inappropriately planted. This photo, taken March 28, shows the prairie awash in goldfields. Early summer is the best time to see the rare Presidio clarkia in bloom up there.

Goldfields (Lasthenia spp.) is a very hardy genus that often carpets serpentine soils. Naturally it deserves its name for that alone, but it also has a deeper association with gold. The Mother Lode, running along the western flank of the Sierra Nevada, is a major fault zone, long inactive, that once marked a tectonic suture. Hot gold-bearing fluids rose along the fault and infused the country rock. Serpentinite came up the same way, in the same places. Roadcuts along state route 49 expose lots of it. So where the goldfields blooms, the odds of finding gold are significantly better than chance. Oakland has a great variety of rocks, but no gold that I know of.

Making land

18 May 2010

middle harbor point

Oakland began with a marshy waterfront; sure it was full of fish and oysters, but you couldn’t do big-time commerce there to match the transcontinental railroad depot. So the marshes were filled and the shore extended into deeper water and passages dredged until Oakland had a splendid harbor, and it still does today. Thankfully, we’ve even had the drive and funding to recreate a small example of a working shoreline here at the new Middle Harbor Shoreline Park . . . we hope. If this kind of work is done with a geomorphologist’s guidance, there’s a chance that it could age gracefully instead of sinking or slumping or washing away. With that hope, I dub this piece of land Middle Harbor Point.


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