Archive for the ‘cemetery knockers’ Category

Knocker 1 revisited

10 April 2012

In my latest serious walk through Mountain View Cemetery, I passed the first bedrock knocker I documented here as “my secret chert.” It’s no longer secret.

knocker one

Click the photo for the big version. The cemetery managers have been removing eucalyptus for some time, which I thoroughly approve. Eucalyptus isn’t a good cemetery tree: it’s messy, lanky, disruptive and incompatible with turf. But Franciscan chert is a good cemetery rock: it’s strong, silent, dignified and unfazed by anything. Anyway, now knocker 1 gets to bask in the sun again, and maybe its new visibility will gain it new friends.

Mountain View Cemetery knocker, the big one

10 April 2011

Since I featured what I called the big set of knockers (or in geology-speak, large competent blocks in Franciscan melange matrix) at Mountain View Cemetery, almost 3 years ago, the operators of the cemetery have opened a new premium section just below and removed most of the trees, unveiling the best rock on the hill. I visited it this evening. It’s still not much to look at unless you’re looking for it.

knockers

It’s mostly pale-green ribbon chert with some red chert. You might say the green rock has undergone a sea change. I’m not one of the experts in the Franciscan, but red rocks, which owe their color to trivalent iron (Fe3+), commonly turn greenish as the iron is reduced to divalent Fe2+, so I take it that this chert has undergone some challenging conditions in the ancient subduction zone that created the mixed-up melange. I find it harmonious.

green chert

Here’s a closeup. Click it for an 800-pixel version.

closeup

Stone like this doesn’t support a lot of life, being low in nutrients, but lichens have a foothold on it, especially where moisture can gather. The eastern, uphill side is like that, and the total impression, stone and sky and place and time, is most pleasing.

view

Again, click the photo for a big version. And visit the “cemetery knockers” category for the whole set.


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