By Judith Fenley, Pepperwood Member
Pepperwood Rocks: Indeed it is so!
Reflections on a rockin’ day, at Pepperwood Preserve, Saturday,
September 6, 2014
A glimpse of how to see with a geologist’s eye opened up the
Pepperwood landscape in new ways.
We traveled far enough back in geological time to see an
image of earth with only one land mass. An
animated time warp, on-screen, journeyed through the continental shift to the
“Super Continent, Pangaea” to “Laurasia” and on to our current, yet ever-shifting
global territory map.
Variations of the Teutonic plates -- the divergent plate
boundary, the convergent plate boundary, and the transform plate boundary, are
all present in California, making our state an exceptional geological study
area.
Our Mayacama region is resplendent with rocks of all types
as well. Before our hike, we partook of
a visual and tactile rock feast. No, we
did not eat any rocks. Fondling
variations of each type of rock, readied us to head out of doors.
Identification challenged everyone. Even our instructor admitted most all rocks
looked alike, once covered with lichen and earth debris. A handy geo-hammer cracked through to a clean
surface, as needed. Igneous rock like
basalt, tuff, and granite, sedimentary rock of chert, sandstone, and shale, metamorphic
rock of greenschist, and serpentine all made their appearance. It was a rocking-out afternoon!
No fault of the rocks, fault lines made their debut as well. A flat area with a sudden rise demonstrated an earthquake upheaval (not of our recent jolt). Riparian areas gave evidence of a fault line that allowed underground moisture to nourish maple and willow trees.
Our rolling California hills
tell their geological story to a trained professional. Rebecca Perlroth, our
geology instructor and guide, was true to her promise, covering an introductory
semester of geology in a two-hour lecture.
A gifted and captivating Instructor, her power point presentation, as well
as the guided hike, tested our assimilation of her material, and held us
captive.
Our geologist-eye view sparked
my deeper curiosity. If it intrigues you
as well, I suggest you attend next year’s repeat of this offering, along with
me.
We rocked out! Here
are some pictures to prove it.