WSP08184

• File Number: 8200.765
• Description: White River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 11/1/1966
• Author: USFS
• Title: Water and Related Land Resources - White River Basin in Colorado
• Water Supply Pro - Doc Type: Report/Study

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JJ~3?5

the White River uplift, Piceance Creek basin, and Douglas Creek arch.
These were formed gradually over an interval beginning near the end
of the Mesozoic and continuing through the early Tertiary.

The Piceance Creek basin lies across the central part of the White
River Basin. It is a broad structural depression which was also the
original basin of deposition for early Tertiary sediments. On the
east, it is flanked by the White River uplift, a broad dome underlain
mainly by rocks of Paleozoic age. On the west, it is flanked by
gently-dipping strata of the Douglas Creek arch.

The oldest part of the White River Basin geologically is in the White
River uplift. Here the oldest rocks crop out over small areas along
the South Fork of the White River. They consist of Precambrian schist
and granite overlain by several hundred feet of lower Paleozoic sedi-
mentary rocks including quartzite, sandstone, dolomite, and limestone.
However, the largest part of the uplift area is underlain by rocks of
Pennsylvanian and Permian age consisting of dark-gray to black shales
and gypsum overlain by more than 3,000 feet of red shales, siltstones,
sandstones, and conglomerates. Pennsylvanian and Permian rocks are
overlain by several hundred feet of alternating beds of shale, siltstone,
and sandstone of Triassic, Jurassic, and Lower Cretaceous age. This
sequence of rocks includes the Entrada, Morrison, and Dakota Formations
and crops out in relatively steep ridges in a narrow belt around the
margins of the White River uplift.

Mancos Shale of Upper Cretaceous age has a thickness of more than 5,000
feet. They consist essentially of dark gray calcareous marine shale
that weathers light gray to light yellow-brown. Selenite gypsum is
common throughout the formation.

The Mesa Verde Group crops out around the margins of the Piceance Creek
basin and consists mainly of sandstone with much interbedded shale and
several coal beds. These rocks are usually resistant to erosion and
often form prominent mesas, ridges, and cliffs. The thickness of Mesa
Verde ranges from about 2,500 feet to 5,600 feet.

The Wasatch Formation, which also crops out around the margins of the
Piceance Creek basin, consists mainly of red, purple, and gray shale
and clay with some sandstone layers. These rocks are relatively
erodible and this formation generally forms broad valleys or badland
areas between cliffs or ridges of the Green River Formation and the
Mesa Verde Group.

The Green River Formation, which crops out over most of the Piceance
Creek basin, is composed mainly of light gray to light brown shale
and marlstone with some sandstone and limestone. Oil-shale beds occur

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