Archive for October, 2013

Actinolite decoration

26 October 2013

I enjoy seeing some of Oakland’s more unusual rock types when they show up in people’s yards. It shows that people like our rocks.

actinbartlett

This boulder of actinolite may not actually have come from Oakland, but it could have. Perhaps a resident spotted it in a streambed and said, “I give this to me.” It’s clearly not part of a professionally assembled landscape package.

Serpentine garden

19 October 2013

This house on Melvin Court has a splendid front yard based on serpentinite: serpentinized peridotite on the right, a serpentine-lined walkway with slate in matching colors, and inlays on the path composed of serpentine medallions. The house itself is painted serpentine blue-green. Click the photo for a big version.

serpgarden450

The Oakmore district is uniformly mapped as Franciscan sandstone, but just a little farther east it’s mapped as undivided Franciscan, so we might expect a mixture of possibilities here. The neat lines on the geologic map are as much hypotheses as they are conclusions. Other outcrops nearby look like volcaniclastic rocks, and some of this home’s neighbors use it effectively. I conclude, though, that this home’s landscape was composed with imported stones rather than assembled from what was lying around. But the rocks may well be Oakland natives from just up the way, perhaps even from the Serpentine Prairie quarry.


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