Here's a rather interesting petrified log I encountered a number of years ago--a chunk of fossil wood surrounded by gold.
Here's the explanation: The petrified log is eroding from an unexploited section of world-famous gold-bearing Auriferous Gravel (lower-middle Eocene in geologic age--some 48 million years old) at a long-abandoned hydraulic mine in the western foothills of California's Sierra Nevada. It's probably from an extinct variety of Eocene sycamore, whose exquisitely preserved leaves--along with approximately 70 other species of plants identified from leaves and seeds--are frequently encountered in so-called lacustrine (lake-originated) "chocolate shales" interbedded with the dominantly fluviatile (river and stream) gold-rich gravels deposited by the Tertiary Yuba River roughly 50 to 40 million years ago.
Probably the old-time gold seekers never got around to blasting away this particular area, when in 1884 Judge Lorenzo Sawyer issued his "Sawyer Decision" which effectively abolished hydraulic mining in northern California's Gold Country.
That geology rock hammer is, of course, around a foot in length for scale.
My page: Paleobotanical Field Trip To The Sailor Flat Hydraulic Gold Mine, California
Here's the explanation: The petrified log is eroding from an unexploited section of world-famous gold-bearing Auriferous Gravel (lower-middle Eocene in geologic age--some 48 million years old) at a long-abandoned hydraulic mine in the western foothills of California's Sierra Nevada. It's probably from an extinct variety of Eocene sycamore, whose exquisitely preserved leaves--along with approximately 70 other species of plants identified from leaves and seeds--are frequently encountered in so-called lacustrine (lake-originated) "chocolate shales" interbedded with the dominantly fluviatile (river and stream) gold-rich gravels deposited by the Tertiary Yuba River roughly 50 to 40 million years ago.
Probably the old-time gold seekers never got around to blasting away this particular area, when in 1884 Judge Lorenzo Sawyer issued his "Sawyer Decision" which effectively abolished hydraulic mining in northern California's Gold Country.
That geology rock hammer is, of course, around a foot in length for scale.
My page: Paleobotanical Field Trip To The Sailor Flat Hydraulic Gold Mine, California
