The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in winter. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present a continuous record of six million years. The mean thickness of a varve here is 0.18 mm, with a minimum thickness of 0.014 mm and maximum of 9.8 mm.
The sedimentary layers were formed in a large area named for the Green River, a tributary of the Colorado River. The three separate basins lie around the Uinta Mountains of northeastern Utah:
- an area in northwestern Colorado east of the Uintas
- a larger area in the southwest corner of Wyoming just north of the Uintas known as Lake Gosiute
- the largest area, in northeastern Utah and western Colorado south of the Uintas, known as Lake Uinta
Fossil Butte National Monument in Lincoln County, Wyoming is in a part of the formation known as Fossil Lake because of its abundance of exceptionally well preserved fish fossils.
Read more about Green River Formation: Lithology and Formation, Cyclicity, Fossil Zones, Oil Shale, Trona and Nahcolite
Famous quotes containing the words green, river and/or formation:
“Annihilating all that’s made
To a green thought in a green shade.”
—Andrew Marvell (1621–1678)
“I am advised that there is an unexpended balance of about $45,000 of the fund appropriated for the relief of the sufferers by flood upon the Mississippi River and its tributaries, and I recommend that authority be given to use this fund to meet the most urgent necessities of the poorer people in Oklahoma.”
—Benjamin Harrison (1833–1901)
“Those who were skillful in Anatomy among the Ancients, concluded from the outward and inward Make of an Human Body, that it was the Work of a Being transcendently Wise and Powerful. As the World grew more enlightened in this Art, their Discoveries gave them fresh Opportunities of admiring the Conduct of Providence in the Formation of an Human Body.”
—Joseph Addison (1672–1719)