“It was during my enchanted days of travel that the idea came to me, which, through the years, has come into my thoughts again and again and always happily – the idea that geology is the music of the earth.” – Hans Cloos
“The earth is large and old enough to teach us modesty.” – Hans Cloos
LAKE COUNTY, Calif. – Our natural physical environment changes in increments on a daily basis.
Landforms like streams are constantly changing our valleys. The work of wind, freezing, thawing and erosion from weathering are all factors in the lay of the land.
Geologists compare time and space with 1 millimeter in measurement equaling about one year in terms of geology, and around 3 feet in any direction is equal to about 1,000 years.
UC Davis geologist Eldridge Moores is quoted in an online SF Gate news article: “If you compare the distance across the country it wouldn’t be until you hit the East Coast – around Boston – that you’d reach four and a half billion years, the birth of our planet, and the very start of the geologic forces that we are still studying today.”
Lake County is rich in geologic features created by forces that are hard to fathom.
Here, we have the largest geothermal field in the world at The Geysers; a volcano, Mt. Konocti, that is about 4,000 feet in elevation; and the oldest lake in North America, our own Clear Lake, with its 44,000 acres of surface waters.
To elucidate the geology of Lake County, Dr. Harry Lyons explained in a statement for the Lake County Library's “Know Lake County" series, “We live in a clutter of marine rocks, delivered from the Pacific by forces beautifully described by a theory called plate tectonics. The position and composition of the rocks, for millions of years, have formed and subsidized the ecosystem of the Clear Lake Basin. Our dynamic landscape, powered by the San Andreas Fault System, has led to the development of our famous eutrophic lake, a favorite of biologists worldwide.”
Lake County's hills and streams house an abundance of shiny serpentine, California's state rock.
Serpentine's color ranges from green to black, and is speckled with both dark and light features. It is also abundant in the Sierra Nevada foothills and the Klamath Mountains.
According to the California Geologic Survey publications, serpentine can be metamorphic as well as igneous, containing peridotite straight from earth's mantle, which is below earth's crust.
Many other unique and beautiful rock specimens can be seen in our hills and valleys, and also in our local museums. Fluorite, scratching in at a 4 on the Mohs scale of mineral hardness is a soft mineral which is located around the world. It has been used for jewelry, glass lenses and industrially as a flux.
Mica is a lovely gem and is found in the areas of all of the three main rock types: igneous, metamorphic and sedimentary.
Because of Mica's cleavage, it contains a crystalline structure that can be split into sheets, which has made it useful as insulation.
Harking back to our classrooms and the study of rock's properties, we can recall that cleavage is the ability of a mineral to split on its planes. Magnesite veins are often found with serpentinite, and measures between 3 and 4 on the Mohs scale of hardness.
Magnesite has been identified in both meteorites and on Mars through the special instruments such as infra-red spectroscopy.
Magnesite has been used in kilns and industrial furnaces. In our county's past Pomo Indians wore and traded beautiful beads made of magnesite.
Kathleen Scavone, M.A., is a retired educator, potter, writer and author of “Anderson Marsh State Historic Park: A Walking History, Prehistory, Flora, and Fauna Tour of a California State Park” and “Native Americans of Lake County.” She also writes for NASA and JPL as one of their “Solar System Ambassadors.” She was selected “Lake County Teacher of the Year, 1998-99” by the Lake County Office of Education, and chosen as one of 10 state finalists the same year by the California Department of Education.