23 December 2010

GoSF5: (Wildlife interlude)

Posted by Callan Bentley

“GoSF” = Geology of San Francisco

As I am sure you are aware, I’m taking this week to write up the three field trips I took last week to examine the geology of San Francisco and neighboring areas. My plan is to cover:

Introduction and overview

Seafloor basalt

Deep sea chert

Kirby Cove, Marin Headlands

(wildlife interlude) today

Graywacke turbidites

Serpentinite and mélange

Fractures and the chemistry along them

Pleistocene dunes

The San Andreas Fault and Mussel Rock

I’ve got two critters to share with you today via photos, though I saw plenty more (dolphins, seals, hawks, rats) while I was in San Francisco.


Garter Snake:

At first I thought “Garter snake… San Francisco… This might be the endangered San Francisco garter snake (Thamnophis sirtalis), but upon Googling it, I see that the eponymous endemic is rather more colorful. It’s also limited in its range to the southern side of the Golden Gate, and Marin would be out of its range. So this isn’t some rare find, but just a beautiful little snake.

Back to the geology tomorrow.