Coyote Point -- Geology and History

Nathaniel Fairfield

Overview

From https://parks.smcgov.org/coyote-point-recreation-area-trails 

Geology

Geological map of Coyote Point, from https://rockd.org/explore, note the east-west registration offset between the geological imagery layer and the satellite imagery layer.

Again from rockd, more detailed descriptions of the Franciscan Complex units:


From Geology of the onshore part of San Mateo County, California: A digital database (https://pubs.usgs.gov/of/1998/of98-137/)

“the Franciscan complex, [...] is composed of weakly to strongly metamorphosed graywacke, argillite, limestone, basalt, serpentinite, chert, and other rocks. The rocks of the Franciscan complex in San Mateo County were probably Jurassic oceanic crust and pelagic deposits, overlain by Late Jurassic to Late Cretaceous turbidites. Although Franciscan rocks are dominantly little metamorphosed, high-pressure, low-temperature metamorphic minerals are common in the Franciscan complex (Bailey, Irwin, and Jones, 1964), and the presence of high-grade metamorphic blocks in sheared but relatively unmetamorphosed argillite matrix (Blake and Jones, 1974) reflects the complicated history of the Franciscan. The complex was subducted beneath the Coast Range ophiolite during Late Cretaceous or Early Tertiary time, as shown by the presence of Campanian (Late Cretaceous) fossils in Franciscan sandstone in Marin County. Because of the subduction relationship, the contact between the two Mesozoic complexes is everywhere faulted (Bailey, Irwin, and Jones, 1964), and the Franciscan complex presumably underlies the entire county east of the Pilarcitos fault.”


A Geological Walk Around Coyote Point

Starting at the cove just to the west of the point next to the parking lot, looking back east at the massive chert point:



Looking west-ish at the north-west corner for Coyote Point. Three colors of chert at the base: red, green and white. Overlain by SOMETHING, is this “chert altered to clay”, or just shale? Note the Olde English bottles for scale:


Holes dug into the mudstone?. Probably some animal?


Looking north, with Mt Diablo right behind the rocky promontory:



Rock varnish?:


Interesting inter-bedding.

Layers and sheering:




A small sea cave eaten into the bluff face:



Note the mussels digging pits in the mud:

A small basalt boulder.


Shark and Ray die-off in June 2017

History

Coyote Point’s history includes Ohlone native american sites, an amusement park, a Merchant Marine cadet school, a college, a jail, and now the CuriOdyssey children’s museum, a golf course, a firing range, a playground, a marina and yacht club, and a sailboarding beach.

The E Clampus Vitus plaque -- The clampers sound like a fun bunch.


Other resources

Wikipedia -- Coyote Point Park

CuriOdyssey -- A History of Coyote Point

Coyote Point Yacht Club -- The History of Coyote Point

County of San Mateo Park Department -- Coyote Point Recreation Area History

Video episode -- Lost Parks of Northern California, Pacific City

Most detailed history (and master plan) -- Coyote Point Recreation Area Master Plan, excerpt here:

The “third basin”: