The ridge behind Woodminster Theater, in Joaquin Miller Park, is mapped as serpentinite. You start to notice this around the Moses pyramid, but as you explore you’ll find a lot more of it plus various associated metamorphic rocks.
For instance, on the Sinawik Loop Trail I spotted a fine chunk of actinolite schist, detailed below.
The ridge doesn’t have a name on the map, so I’ll give it one. It has the Moses pyramid, the Elizabeth Barrett Browning monument, the fireplace that Joaquin Miller built for his own cremation, and Lookout Point where Miller loved to contemplate Oakland and the bay. So by my decree, this is Visionary ridge.
At Lookout Point, the large boulders surrounding the viewing patio caught my eye. High-grade blocks!
A closer look showed me the garnet-muscovite-glaucophane association that marks blueschist. There was also some green (chromian) mica. Bring your magnifier, not your hammer, if you come this way.
30 June 2010 at 9:27 pm
For an update on the serpentinite-killing legislative bill, see my blog post on About.com today at http://bit.ly/cdsAQM . The bill still needs to pass the Assembly. I learned she was running for State Superintendant of Public Instruction but lost (http://www.gloriaromero.org/). Oh yes, she challenged the special interests, but in this case she’s carrying water for asbestos lawyers and opposing a useful educational asset for Earth science teachers.
19 June 2010 at 2:41 pm
Alert the troops! Sen. Gloria Romero wants
to strip serpentinite of it’s status as State rock, all because of a little asbestos. SacBee article here: http://bit.ly/9nWu7J