The exposure of diatomite is along one of the trail in
McArthur Burns Falls State Park. You can pay the entrance fee
for close parking or find parking elsewhere and hike in. In
either case, there is a short and easy walk along a forested
lakeside trail.
Ancient Lake Britton formed about 1.8
million years ago close to the
Plio-
Pleistocene boundary. At that time lava flows from the
Modoc
Plateau blocked the Pit River. This natural dam flooded an area
of forest much larger than the current Lake Britton, about 120
square miles. Once formed, the lake began filling with the remains
of freshwater diatoms and other lake deposits such as clay.
Diatoms are
microscopic single celled plants that grow well in any environment
with water, sunlight and soluable silica. Diatoms use silica to
form skeletons and when they die, the skeletons settle to the
bottom of the lake creating a diatomaceous ooze which later becomes
diatomite. Based accumulation rates that have been observed in
modern lakes, it is estimated that it takes about 300 years to form
1 foot of ooze. Up to 1,000 feet of diatomite, clay and volcanic
ash filled ancient Lake Britton
Over the years, the diatoms buried the trees that were drowned
by the rising waters of Ancient Lake Britton. These trees as well
as pine cones were preserved as fossils at the bottom of the
deposit and were found in the diatomite mine to the west. These
trees were preserved well enough to determine that they were pine
trees and a pine cone from the Ponderosa family was found. These
finds provide a picture of ancient flora in the area.
In the middle of the Pleistocene (about 20,000 to 30,000 years
ago) the Hat Creek Lava Flow (originating from near the Splatter
Cone Trail
(
Visit the EarthCache) covered the area protecting the diatomite
and stopping further deposition. Recent erosion by the area’s
rivers through the lava beds exposed the diatomite beds.
Uses of Diatomite
The microscopic skeletons that make up diatomite act like tiny
filters. It is used to purify syrups, fruit juices, soft drinks,
beer, wine, bottled water, vegetable oils, medicines and swimming
pools. It is also used as a mild abrasive, and filler in paint,
spackle, and concrete.
The Lake Britton diatomite deposit is one of the largest
deposits in the world that is of high enough quality to be used in
filtering products.
Logging requirements:
Send me a note with :
- The text "GC1X4EQ Ancestral Lake Britton Diatomite Deposits" on
the first line
- The number of people in your group.
- Based on the condition of the cliff, how hard do you think
diatomite is?
- From the trail, feel the diatomite and send me a description of
it
This EarthCache conforms to the
California State
Park Geocaching Guidelines as of the hidden date.
The following sources were used to generate this
cache:
- Splatter Cone Self Guided Trail Guide, Lassen
National Forest, Hat Creek Ranger District
- Falls Trail Nature Saunter at McArthur-Burney
Falls Memorial State Park, Video Transcript California State Parks,
2004
- Dupras, Don; Plio-Plestocene Fossil Trees Found
in Ancestral Lake Britton Diatomite Deposits; California Geology,
July/August 1999