prev |
20070731blackcanyon_030.jpg |
next |
As you look across the silent gorge of the Black Canyon to the spectacular peaks of the San Juan Mountains, it may be difficult for you to imagine the violent world that created them. Although none of the major peaks seen here can be called a true volcano, all are a result of extensive volcanic activity. Beginning about 30 million years ago, a series of eruptions spewed tremendous volumes of fiery ash and molten rock. The volcanos from which debris was erupted no longer exist, but remnants do remain.
Rugged Wetterhorn Peak (second from left on the map) was at one time a conduit from which the incandescent ash was emitted. As the ash and molten rock was erupted, the chamber emptied, and the volcano collapsed to become what is now a caldera. From this point you are looking at the north rim of a major caldera which has since been uplifted to form impressive mountains such as Uncompagre Peak, (far left on map) which at 14,309 feet, is the sixth highest point in Colorado. Although the Black Canyon is located almost 30 miles from the San Juans and 28 million years younger than the mountains, its history is closely tied to the volcanic activity. The volcanic ash solidified to form a soft layer of rock, which at one time buried the ancient rock of these steep canyon walls. Two million years ago, this layer provided an easy path for the Gunnison River to follow and the process of carving the great canyon began. The river firmly established its course by cutting through the volcanic material. When it finally hit the resistant black rock you see here today, it could only continue the sculpting process. As a result a canyon was carved.