USGS Logo Geological Survey Bulletin 1191
Black Canyon of the Gunnison: Today and Yesterday




Physiographic setting

Seeing the canyon

How the canyon was carved

Why the Black Canyon crosses the Gunnison uplift
The energy of the river
Why the walls are so steep
How long did it take

Rock formations—their attributes and geologic settings

Metamorphic rocks—Precambrian
   Quartz-mica schist

Igneous rocks—Precambrian
   Vernal Mesa Quartz Monzonite
   Curecanti Quartz Monzonite
   Minor quartz monzonite bodies

Great antiquity of the Precambrian rocks

The ancestral Uncompahgre highland—an ancient land surface buried and exhumed

Sedimentary rocks—Jurassic
   Entrada Sandstone
   Wanakah Formation
   Junction Creek Sandstone
   Morrison Formation

Sedimentary rocks—Cretaceous
   Burro Canyon Formation
   Dakota Sandstone
   Mancos Shale

The Laramide orogeny—a time of great mountain building

Early Tertiary deposition and erosion

An outbreak of volcanism
   West Elk Breccia
   Renewed volcanism—ash-flow tuffs of the Alboroto Group

Geologic structure

The Gunnison uplift
Fractures in rocks
Structural features confined to the Precambrian rocks
Crustal warping of Tertiary age and its possible effect on drainage


Additional reading

Painted Wall, Black Canyon of the Gunnison National Monument. Greatest cliff in Colorado, Painted Wall averages about 2,250 feet from rim to river. Cliff is carved from gneiss interlaced with pegmatite dikes. Deep fissures to right of center are controlled by weathering along joints.



1. Comparative profiles of several well-known American canyons
2. Location map of the Black Canyon area
3. The Narrows of the Black Canyon
4. Talus blocks in canyon bottom at foot of Painted Wall, August 29, 1963
5. Chasm Wall at north end of Vernal Mesa
6. Major divisions of geologic time
7. Critical stages in the development of the Black Canyon landscape
8. Rock formations of the Black Canyon area
9. Contorted gneiss, north rim of Black Canyon near Colorado State Highway 92
10. Hand specimen of Vernal Mesa Quartz Monzonite
11. Curecanti Needle, 6 miles downstream from head of Black Canyon
12. Stereogram of the Curecanti pluton
13. Pegmatite dike intruding biotite gneiss
14. Dikes of lamprophyre cutting across biotite gneiss
15. Black Canyon of the Gunnison National Monument and vicinity, Colorado
16. Ancestral Uncompahgre highland just before Entrada Sandstone was deposited
17. Stratigraphic section near mouth of Smith Fork
18. Craggy outcrops of West Elk Breccia
19. Generalized section across Gunnison uplift
20. Isolated pinnacles of quartzitic gneiss
21. Cimarron fault, north across valley of Squaw Creek
22. Block diagram showing lateral and vertical passage of a fault into a monocline
23. Structure contour map drawn at the base of the ash-flow tuff volcanic sequence

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Last Updated: 28-Mar-2006