Field Trip with Susie Bartz, Tanya Atwater, and Larry Ballard

Sunday November 4, 11:00 a.m. to 5:00 p.m.
Advance registration begins Oct. 4 at synature@west.net or 805/ 693-5683
Members $10 / Non-members $25 / Children $5. Payment can be made via check or cash on the day of the field trip or in advance of the trip using a credit card online (once advance registration is completed).

Featured image, above, of lower Avila Beach: volcanic ash rock beds of the Obispo Formation. Photo by John Evarts

A low tide will allow us to explore the world-class “pillow” lavas exposed at Avila Beach, where tectonic pressures have slammed parts of an ancient mid-ocean ridge against the coast. Beyond the lavas is a little beach for resting and viewing the side aspect of the exposure, where we’ll look for parts of a classic ophiolite sequence. For contrast, we’ll also see the much younger and highly varied rocks of the Obispo Formation at the down-coast end of the beach, as well as discuss the submarine volcanics and the Avila landscape.

The walk on the lava exposure is short but difficult and very uneven, so good balance and sturdy hiking boots are necessary. We also suggest you bring binoculars, as California sea lions, harbor seals, sea otters, and black oystercatchers are often seen along the edge of the bay.

Susie Bartz is a geology educator who has worked for over 20 years with schools and community organizations to bring an awareness of earth science to the general public in outdoor settings. Tanya Atwater is professor emerita at UCSB. She is especially well known for her works on the plate tectonic history of western North America and the San Andreas Fault system. Larry Ballard is a naturalist with a focus on botany and has been a field trip leader for the Society and other organizations for two decades.