The Dye Clan
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  • TR: Apr 2012

Sunset View Overlook (Black Canyon)

An interpretive sign at Sunset View Overlook about the Gunnison Uplift.

The Sunset View Overlook in Black Canyon of the Gunnison National Park is less than 0.1 miles from the parking area. There are several signs that explain the geology of the area as well as picnic tables.

Trip Report: April 21, 2012


Sunset View Overlook at EveryTrail

Sunset View Overlook
Sunset View Overlook

The Great Unconformity

Each layer of rock marks a span of geologic time. But often the layers representing certain spans of time are absent. Either nothing was being deposited at a given time or deposits were later eroded away and left no record of their presence. As a result, young rock may rest directly on very ancient rock. This area of contact between younger rocks and older rocks marks a gap in the geologic record. This area of contact is canned an unconformity.

The thin, light tan layer you see on the canyon rim is Entrada Sandstone, a mere 165-170 million years old. The rock immediately below is was formed in the Precambrian period and is about 1.75 billion years old, the oldest rocks in the canyon. More than a billion years is absent from the geologic record of Black Canyon!

Sunset View Overlook

The Gunnison Uplift

Have you noticed that you are standing on a broad, elevated portion of the earth's crust? This is known as the Gunnison uplift. Perhaps it seems strange that the Gunnison River cuts through the heart of this uplift instead of following an easier course north or south of here. To understand thsi, we must think back to when the Gunnison uplift first formed.

About 65 million years ago, a large section of hard Precambrian rock, deeply buried by softer sediments, was thrust upward forming a bulge on the earth's surface. This newly formed Gunnison uplift (1) and the Sawatch Range to the east (2) were immediately attacked by erosion. Streams flowed to the north.

As the eons passed, the Sawatch Range (3) was greatly eroded. Most of the soft sediments covering the Gunnison uplift were planed off, leaving a broad, flat plain over which streams meandered.

Then, repeated volcanic eruptions deposited layers of rock. Mountainous piles of volcanic debris created what we knot as the West Elk Mountains (4) and the San Juan Mountains to the south (5). Drainage was diverted around the south side of hte West Elk Mountains directly across the buried Gunnison uplift.

Once the Gunnison River resumed downcutting, it became entrenched and could no longer alter its course, even though later erosion of the softer rocks to the north and south again exposed the Gunnison uplift (6). The result is Black Canyon (7) as we see it today.

Sunset View Overlook

Preserving the View

Magnificent scenery and clear air combine to create some memorable views here at Black Canyon. Look ot the northwest. On a clear day you should be able to see Grand Mesa, 35 miles away, and Monument Mesa, 60 miles distant.

Views like this are threatened. Even here - miles away from major cities - the haze of air pollution is sometimes apparent.

Air pollution does more than just affect the view. Soils, plants, and wildlife may suffer unseen damage from dirty air. Acid rain - rainwater contaminated with airborn pollutants - can damage streams, lakes, and entire ecosystems. The full impact of this pollution may not be known for decades.

What can be done?

The National Park Service monitors visibility at Black Canyon of the Gunnison. Reducing the effect of air pollution on places like this will require use of modern technology, cooperation between government agencies and private industry, and - most importantly - conservation of energy by all of us.

How clear is the air today?

Compare the quality of visibility today with photographs taken above at Sunset View. Can you clearly see the distant detail and color?

The National Park Service is monitoring visibility at Black Canyon of the Gunnison as a part of its efforts to achieve its primary mission - to conserve the scenery, the natural and historic objects and the wildlife therein, and to provide for the enjoyment of future generations.

Sunset View Overlook
Sunset View Overlook
Sunset View Overlook
Sunset View Overlook
Sunset View Overlook