East Of Zion By Philip Hyde, Part 2
Continued from the blog post, “Nature Magazine: East Of Zion 1.”
Originally published by Nature Magazine, March 1957
(Nature Magazine was published by the American Nature Association and taken over by Natural History Magazine in 1960.)
Mission of Nature Magazine: “To stimulate public interest in every phase of nature and the outdoors, and devoted to the practical conservation of the great natural resources of America.”
A Glimpse of the Geology of Zion National Park:
Celebrating The Divine Artistry Of Falling Water Through Deep Canyons
By Philip Hyde
(View the photograph large, “Cascade, Tributary To Clear Creek, Zion National Park, Utah, 1978.”
The great architect of this beautiful landscape is moving and falling water, and to this builder and remover of the landscape can be attributed the deep canyons of the region. The violence and power of moving water is often forcefully demonstrated during a summer thunderstorm. One of the writer’s earliest and most vivid recollections of travel in this area stems from a summer visit to Zion Canyon, when he arrived in the midst of a cloudburst. The violence of the storm was enough to justify repetition of Chicken Little’s oft-quoted exclamation: “The sky is falling!” I still have a vivid mental picture of the brown torrent that was the Virgin River, gnawing great chunks from its banks, ripping out trees, carrying debris before it in the surging current. After the climax of the storm passed, the raging water quickly abated, and within a few hours the brown flood disappeared, to be replaced by the river’s normally quiet murmurings.
Even during its quieter periods, however, the river is actively working on the confines of its bed. The low resistance of sandstone to erosion, combined with the steep gradients of the streams in this region, result in a rapid deepening of the stream canyons. Because of these two factors, the stream plays a lesser part in the process of widening the canyon. Seepage of ground water, direct action of rain water, and frosts produce the curves and crenelations that add so much to the sculptured beauty of the canyon walls.
The east side of Zion National Park displays progressive steps in the erosion cycle. In the beginning of this cycle, the land is relatively flat, illustrated by the present tops of plateaus. Where a stream gathers its waters from a small area, the stream remains small, probably runs only in response to rainfall, and manages to cut only a small canyon. The east Zion area contains many examples of this phenomenon; they are within walking distance of the highway, and can be more closely studied. In many respects these small streams are miniatures of the larger ones. They demonstrate processes and effects similar to those evidenced on a larger scale by their bigger brothers.
Another most interesting feature of the Zion region is the frequent occurrence of rock pedestals on the broad stone pavements near the highway. A closer examination of such pedestals reveals that they are capped by a material differing from the soft sandstone of the base; a layer of iron oxide that geologists believe was intruded, in solution into the sandstone. Since this material is harder, and therefore more resistant to erosive forces, it has protected the softer material directly beneath it while the surrounding material was being eroded away. So, when you look at these pedestals, you are really seeing a remnant of the layers of stone that formerly covered the presently exposed surface. The balance of this material has been carried away, either as wind-borne sand, or by stream action, to be deposited as part of a sandbar somewhere downstream. Or, perhaps it will find its way eventually to the sea, to be laid down as part of a delta at the Colorado River’s mouth.
In these pedestals, as in the rest of the landscape, can be read one of the grand lessons of geology—that Nature is not at rest, but is ever active, ever changing the face of the Earth; that even the stones, cold and dead to our eyes, have their own inner life and being. In the slow passage of geologic time, the surface we look at today will pass away to join its predecessors, each succeeding layer following in its turn, until Nature decrees a major change—such as has occurred we know not how many times past—to commence the cycle again at what men are pleased to call the beginning.