It’s a rocky situation at Glass Mountain, California
After talking about scenery, lava tubes and caves, it’s time to show some rocks that really rock. Volcanic rocks, that is. In our first two blogs about the Lava Beds National Monument we explored the hidden world of the lava caves and the rugged surface encompassing the monument. This time we highlight the naturally occurring volcanic glass – obsidian rock. It’s a form of Rhyolite that has the highest content of silica. It is a volcanic glass prized by Native Americans for making arrowheads, knives, spear points and other tools.
This excursion took us about 30 miles south of the Lava Beds as we continued our geologic adventure at Glass Mountain.
Glass Mountain has been designated a Special Interest Area in Modoc National Forest because of its geologic formations. The area is a 4,210 acre lava flow of glassy black obsidian boulders ending suddenly in white pumice soil. Wandering around at the top of Glass Mountain, we encountered prehistoric obsidian mines along a glass flow and were amazed at the ancient quarry remains evident today. Being there was kind of surreal and made us wonder what it must have been like when this amazing landscape was being formed. Estimates are that the most recent flows of pumice and obsidian at Glass Mountain occurred less than 900 years ago.
We are not geologists or rock hounds, but this place rocks!
The drive took us through the Modoc National Forest were we also saw Ponderosa Pines for miles covered with lichens.
After wandering through the quarries we drove to Arnica Sink, a dry basin in which water-worn cobbles and pebbles are mixed with sub-angular boulders covered by a washed mantle of pumice.
Our final stop was at Medicine Lake, which was once the center of a volcano and is over 150 feet deep. It was quite a beautiful day and only a few folks were enjoying the serenity and beauty surrounding the area.
Yellow Rabbit flowers were in full bloom and dotted the landscape with yellow and orange glow. Simply beautiful!