- KATHLEEN SCAVONE
- Posted On
Lake County Time Capsule: Archaeology and Anderson Marsh State Historic Park
LOWER LAKE, Calif. – In 1982 the state of California acquired more than 870 acres – which later swelled to 1,065 acres – in Lower Lake as the result of dedicated archaeologist Dr. John Parker and others who worked to preserve this beautiful slice of Lake County.
In 1976, under the guidance of Sonoma State University Professor Dr. David Frederickson, Parker performed an intensive archaeological survey of the Anderson Marsh area.
After a year of red tape and tremendous effort on Parker's part, Anderson Marsh was officially classified as an Archaeological District and listed on the National Register of Historic Places in 1977.
Archaeologists studying the Clear lake basin where Anderson Marsh State Historic Park is located focused on the region's American Indian technology, settlement patterns and population.
Time periods for each of the criteria were determined in part by utilizing artifact typologies and obsidian hydration dating techniques.
It has been determined that the Southeastern Pomo Indians, the furthest inland of the seven recognized Pomo language groups, lived in this area more than 12,000 years ago. There are dozens of known archaeological sites in Anderson Marsh.
Another archaeologist who has done extensive work at Anderson Marsh is Michael Newland, M.A, RPA, who is past president for the Society for California Archaeology and is staff archaeologist at the Anthropological Studies Center at Sonoma State University in Rohnert Park.
When asked the differences in the processes to determine the age of artifacts, such as carbon dating and the obsidian hydration method, he said, “Right now, floating around the atmosphere, is radioactive carbon, C14. These are naturally occurring isotopes, created by cosmic rays hitting our atmosphere. Plants take these isotopes in when they pull CO2 out the air during photosynthesis. When animals eat the plants, the C14 starts to decay at a known rate.
“Scientists have a process where they can measure how much C14 is left compared to the regular, stable carbon, and since you know how long it takes for it to decay, you can figure out how long ago something stopped taking in C14 – in other words, when it died.
“It's what's called an absolute date in archaeology – it gives you a fixed date in time, that's not dependent on anything else you might find at the site or any other similar types of artifacts.
“Obsidian hydration band analysis works a little differently. When obsidian breaks, it begins to absorb air out of the atmosphere. It does so at a generally constant rate, and it changes the color and transparency of the obsidian slightly. Each different type of obsidian has a slightly different rate – Mount Konocti obsidian is different from Borax Lake, which is different from Coso obsidian, and so on.
“When a native person made a spear point, knife, or arrowhead hundreds or thousands of years ago, they chipped and fashioned obsidian for their tools. It you take one of their tools, or one of the flakes left over from creating the tools, and take a thin sliver out of it, you can place that piece under a microscope, measure how much water has been absorbed, and estimate roughly how old it is.
There are a lot of variables – air temperature and moisture, exposure to fire, erosion – and in general obsidian artifacts were compared to each other: this piece has absorbed 3 microns, so it must be older than this other piece, which has only absorbed 2 microns. This is called relative dating, when artifacts are dated in relation with each other,” he concluded.
For more information visit Anderson Marsh Interpretive Association, http://andersonmarsh.org/ ; Dr. John Parker's Wolf Creek Archaeology page, http://www.wolfcreekarcheology.com/ ; and the Society for California Archaeology, http://scahome.org/ .
Kathleen Scavone, M.A., is an 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.