WSPC01093

• File Number: 7630.650
• Description: Wild and Scenic - Yampa River
• State: CO
• Basin: Statewide
• Date: 2/1/1977
• Author: DOI-Bureau of Mines
• Title: Mineral Reconnaissance of the Green River from Flaming Gorge Dam through Dinosaur National Monument - Colorado and Utah
• Water Supply Pro - Doc Type: Report/Study

OJ 215 8'

24,000 feet' [!,315 €I - is younger Precambrian (Uinta Mountain Group),

about 3,800 feet [1,008 ~ is Paleozoic, about 13,000 feet ~,963 ~ is

Mesozoic, and about 5,000 feet [1,524 ~ is Tertiary.u4

An abbreviated sequence of geologic features encountered from

Flaming Gorge Dam downstream on the Green River to the southeastern edge

of Dinosaur National Monument indicates first that in t~e 13-mile-long

(21-km) Red Canyon from the Dam east to Browns Park, the river has cut

into quartzites, sandstones, and conglomerates of the Uinta Mountain

("roup,pf late"Precambrian age.

The 33-mile (53 km) interval southeast through Browns Park to the

Gates of Ladore is the type locality of the Browns Park Formation. This

sedimentary formation was deposited in a continental environment during

the

Late Tertiary and is comprised of sandstones, clays, conglomerates,

volcanic tUffs~O~(Clffty tk. litt/i !I,!ett'i-l'A/ ~,'J.,ct. is')I,,,1.r1.l.41~ i,/
. "30'~'i1J r;:r/c. F':",nFlfil'.vt) I

From the Gates of Ladore southward to below the Canyon of Ladore, a

and

distance of about 15 miles (24 km), the canyon bottom is cut into the

late Precambrian Uinta Mountain Group; The deepest part of the canyon,

'measuring more than 3,400 ft (1,037m), is in this stretch of the river.

.
Below Ladore Canyon, about l~ miles (2~ km) upstream from Mitten

Park Fault, sedimentary rocks are again encountered. For the rest of.

the 31-mile (50-km) interval southeastward through the Monument, the

river flows for the most part over sedimentary rocks of Mis~issippian

4Hansen, Wallace R. Geology of the Flaming Gorge Area Utah-Colorado-

Wyoming. U.S. Ceol. Survey Prof. Paper 490, 1965, p. 15.

'.

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