SINE

I came to Grand Canyon to see the oldest rock: Vishnu Schist. Now that I have been here awhile, I can see what some geologists have said. I will read some of this to you.

CORONADO

Go ahead, Sine. You know where to find me.

AURA

I’ll try to boil it down for you later.

CORONADO

That’ll be good.

SINE

Okay. Lean back. Relax. This is long time.

AURA

Go right ahead, Sine.

SINE

So. Let’s see.

Bruce Babbitt, ed. Grand Canyon: An Anthology (Flagstaff: Northland Press, 1978), p. 134:

"...Edwin D. McKee tells the geological story of the canyon as it has been patiently pieced together by many geologists over the last century. McKee starts his tale two billion years ago, deep in the granites of the inner gorge, and works his way upward, layer by layer, to the rim. From the evidence in rocks and fossils, McKee infers an incredibly long sequence of the rise and slow destruction of immense mountain ranges, ancient seas advancing and retreating across the land, deserts and river deltas and the slow beginning and accelerating evolution of life from primitive one-celled organisms in the ancient Precambrian rocks at the bottom of the canyon.

Edwin D. McKee, Ancient Landscapes of the Grand Canyon Region (Flagstaff: Northland Press, 1931), pp. 2-13:

"… [The oldest rock on earth’s surface, the] Archean rocks [of the Inner Gorge] beneath the plateau surface approximately a mile, … [were] built up originally as great horizontal deposits of sand and mud, … [then] bent by mighty crustal movements until high mountains, probably comparable to the present Alps, were formed. Pressures from the northwest and southeast apparently folded them.…

"[Algonkian age rocks, of earth’s second great geological era, are found] along Bright Angel Canyon and in several other places in the Grand Canyon, … representing accumulations of sediments several thousand feet in thickness.... Below and to the north of Desert View (southeast of Cape Royal on the North Rim) they form the open floor of the Canyon. Everywhere the most conspicuous stratum of this series is a mud rock of brilliant vermilion color The brilliant red shades of Algonkian age found in the lower parts of the Grand Canyon were formed as muds, accumulated probably by large rivers.…

"It was during the third or middle [Paleozoic Era] in the earth’s history that all of the apparently horizontal, upper layers in the Grand Canyon walls were formed.… Some of these rocks are sandstones formed from the sands of early beaches or sand dune areas, others are shales - the hardened muds of ancient river deltas - and still others are limestones built up by accumulations of plant and animal remains on sea bottoms.… In [some] places, such as to the west of where Bright Angel Creek now flows, small mountains of red Algonkian rocks (Second Era) remained. Around and against these, sediments were then deposited. Pebbles and sands accumulated, forming a thick layer which today appears as the brown sandstone rim of the Inner Gorge. These represent the first deposits of the Third Era. But the sea was encroaching upon the land during this period, and gradually the sand deposited near shore was covered by mud and this in turn by lime far out from the beach. Today this series of sand, mud and lime is found represented in the rocks of the Tonto Platform in Grand Canyon.

"Along the Tonto Trail a few hundred yards east of Indian Gardens numerous primitive sea animals have been found buried and preserved in layers of thin shale.... [They are] some of the earliest known forms of animal life [and lived during the Cambrian Period]...

"The geologist has found that two long periods of history [following the Cambrian Period] are lacking in the great succession of ages represented by the strata in the Grand Canyon walls. These missing periods which [also] belong to the Third Era are known as the Ordovician, the time when fish first appeared in the seas, and the Silurian, the time when millipedes and scorpions became our first air breathers.... It seems probable that the Grand Canyon region was above sea level during these two ages so that no sediments were accumulated and consequently no rocks formed.

"One of the most prominent and conspicuous features of the Grand Canyon is the great red cliff of limestone about midway in its walls.… The purity of the lime [in this "Redwall Limestone"] indicates that it was built up in a relatively wide and quiet sea. Its composition represents a vast accumulation of the skeletons of ancient plants and animals. Seashells are found in great numbers, some of them preserved in delicate detail. These and other forms of ocean life clearly indicate that a great sea connection then existed between this region and that of western Canada to the north...

"Along both sides of Grand Canyon at the top, two buff and gray layers of limestone stand out as massive cliffs separated by a tree-covered slope. The upper [‘Kaibab’] of these limestones forms the plateau surface and may be seen for a great distance in every direction. Both layers were formed [during the Permian Period] as the result of vast accumulations of organic and sandy materials on sea bottoms, and in places are composed largely of the remains of marine life-shells, corals and sponges. The teeth of sharks have also been found in the upper limestone.

"During the early stages of the period when these marine animals lived and multiplied in the region, a great body of salt water extended over its surface from far to the west, remained briefly, then retreated from the area. Soon, however, marine waters advanced once more and another sea was formed with its shoreline extending eastward even beyond the region in which we now find Grand Canyon. Evidences of the second and larger sea are found beyond Flagstaff to the south, in the Painted Desert to the east, and almost to Zion Canyon to the north.

The presence of corals and sharks’ teeth not only indicate that this region was covered on more than one occasion by marine waters, but also suggests that these seas were warm and shallow. This is estimated to have been some 200 million years ago.

I put names of the books I was reading in this note so tourists get more detail.

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