Archive for the ‘oakland rocks’ Category

The Redwood Road boulder pile

13 July 2015

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Up on Redwood Road, across from the entrance to Campus Drive, there’s a pile of boulders of Leona “rhyolite,” probably from the old quarry now occupied by Merritt College, sitting under the trees. While waiting for the 54 bus one day, they waved me over and said, Look at us. I was drawn closer, ever closer to their seductive surfaces, but kept my wits about me and escaped their clutches.

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No geology lessons here, just eye candy.

Rocks of the Skyline High neighborhood

6 July 2015

Walking the hills around Skyline High School makes for a nice workout, and there are some rocks, including serpentinite, the Joaquin Miller Formation and the Oakland Conglomerate. Here’s the Google Maps topography with the photo locations.

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And the corresponding geology.

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The neighborhood centered on Balmoral Drive has lovely views, but few visible rocks. This is looking west to the Serpentine Prairie and beyond.

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But at the very end of Tartan Way we behold some mixed shale and mudstone of the Joaquin Miller Formation (Kjm).

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The area is mostly underlain by the Oakland Conglomerate (Ko), but the only glimpse of it you’ll see is on the high school grounds behind a fence.

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I think that the rocks here were examined during the construction of the homes in the late 1960s(?), because the strike-and-dip symbols are all located off the road, presumably in the excavations.

Now we’ll cross Skyline and explore the loop formed by Fernhoff and Bacon Roads. I particularly wanted to see this because it exposes the last bit of Oakland’s serpentinite I hadn’t yet visited. And at the entrance to Fernhoff Court, here it is.

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The westernmost appendix of Bacon Road also dips into it.

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But just uphill on Bacon, there’s some nice bits of Joaquin Miller again.

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The best place to see the Oakland Conglomerate is on Skyline Boulevard, specifically along the footpath in the median. Some places it’s well-bedded sandstone . . .

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. . . and other places expose the classic deep-brown conglomerate with its well-rounded river cobbles.

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There’s more along the roadside, but that’s probably not safe to visit. People drive fast here.

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Thank goodness for the path in the median! It’s a nice amenity.


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