Wednesday, March 30, 2016

A Geology Field Trip to the Local Mountains and Desert (yes, GEOLOGY)

I am taking a Physical Geology course at Mesa College, as a pleasant diversion from the life sciences. San Diego County is chock full of fascinating rocks and minerals and interesting land forms. More than I ever imagined!

On March 19th, we took a day-long field trip to the Laguna Mountains, and then the local desert. Terri Groth (friend and neighbor) accompanied me. About 13 people were on the adventure, including fellow classmates and the instructor, Don Barrie.

The photos below are from Canyon sin Nombre ("canyon without a name"), not far from Indian Gorge where we camped the weekend before.

This canyon was full of fascinating geological formations and types of rocks, including igneous, sedimentary and metamorphic - a little of everything we are learning about in the class at the moment.

Varied landscape near the entrance to Canyon sin Nombre. Much of the dark brown rocks are schist, a metamorphic rock.

More of the unusual swirls and strange rock patterns.

A big dike of light-colored igneous rock filling an ancient crack.

Contrast between the darker (what I believe is schist) and the felsic, light-colored igneous rock of the dike.

Some really nice gneiss (pronounced "nice"), another metamorphic rock, the result of ultra-high temperatures and pressures deep in the Earth.

Amphibolite, another metamorphic rock. 

Schist, a metamorphic rock with course grains, and foliation (a "layered" look), the result of intense pressures.

Folding in sedimentary rocks in the Olla Formation.

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