Colorado River
As indicated earlier, all but one of the early river voyages began on the Green River. The Grand (Colorado) River above the confluence was neglected for some 18 years after Powell’s second voyage, until, in 1889, Frank M. Brown organized a company for construction of the proposed Denver, Colorado Canyon, and Pacific Railway. This railroad was to carry coal from mines in Colorado over a “water-level” line through the canyons of the Colorado River to the Gulf of California some 1,200 miles away; from there the coal would presumably be shipped to ports as far north as San Francisco (Dellenbaugh, 1902, p. 343-369). On March 26, 1889, Brown, president, F. C. Kendrick, chief engineer, and T. P. Rigney, assistant engineer, drove the first stake for a survey of the new line at Grand Junction, Colo., then Brown left for the East to obtain financing, and the other two plus some hired hands took off down the Grand River. After reaching the confluence they towed the boat up the Green River, thus becoming the first to make this trip upstream. They nearly ran out of food, but thanks to the hospitality of some cattlemen, they replenished their stock and after about 9 days reached the railroad at Green River, Utah. Brown, who had returned from the East, his newly appointed chief engineer, Robert Brewster Stanton, and 14 others in six ill-designed boats of cedar, rather than oak, left Green River on May 25, 1889. Against the advice of Major Powell and A. H. Thompson, Powell’s topographer on the 1871 trip, they carried no life preservers. After many mishaps, Brown and two others were drowned near the head of Marble Canyon, and the ill-fated expedition was temporarily halted. However, the indefatigable Stanton contracted for new boats built of oak and, with a reorganized party of 12, left the mouth of the Fremont (Dirty Devil) River on November 25. After many further mishaps, the party finally reached the Gulf of California on April 26, 1890. Needless to say the proposed railway was not built.
Although the Colorado River enters Canyonlands National Park about 33 river miles below Moab, most boaters or floaters begin their voyage either at Moab or near Potash, and most travelers of the White Rim Trail begin at Moab, so we will start our trip at Moab. No logs or river runners’ guides are available as yet for the reach from Moab to Potash, but below Potash some details of the geology have been described by Baars in Baars and Molenaar (1971, p. 59-87).
As noted at the beginning of this chapter, above the confluence both the Green and Colorado Rivers are very crooked, have very low grades, and are free from rapids. As with the Green, the soft rocks along the Colorado have a generally low northward dip that partly explains the river’s gentle grade and its southward flow through increasingly lower and older strata. Unlike the Green, however, the gentle dips of the strata in the canyons of the Colorado are interrupted by several gentle anticlinal ([fig. 14]) and synclinal ([fig. 26]) folds and by at least one fault. The most important of these geologic structures and other features will be noted as we journey down the river.
The first 14 miles from Moab Valley to Potash can be made either by river or by paved Utah Highway 279. This highway leaves U.S. Highway 163 near the uranium ore-reduction plant several miles northwest of Moab, leaves Moab Valley through The Portal ([fig. 68]), and follows the west bank of the river. A paved secondary road from Moab follows the east bank of the river through The Portal and through Kings Bottom, where it crosses the Kings Bottom syncline, to the mouth of Kane Springs Canyon, then becomes a gravel road that ascends this canyon southward to and beyond Hurrah Pass ([fig. 30]). High above this road north of Kings Bottom are petroglyphs and a few cliff dwellings in the vertical cliffs of Wingate Sandstone. A ranch “house” at Kings Bottom has been excavated entirely into the Wingate cliff. Convenient turnouts have been provided at several places along Highway 279 for viewing petroglyphs or other points of interest. Small viewing tubes welded to vertical steel posts having signs help visitors locate and see the features described.
THE PORTAL, in south wall of Moab Valley, through which the Colorado River, Utah Highway 279 (on right), and a paved secondary road (on left) leave the valley to enter the canyons in and above Canyonlands National Park. Rounded remnants on top are Navajo Sandstone; cliffs are Kayenta Formation and Wingate Sandstone; red slopes are Chinle and Moenkopi Formations, and perhaps a little of the Cutler Formation at the base. Light-colored patches at base of slope behind trees on left are contorted intrusions of Paradox Member of Hermosa Formation. (Fig. 68).
The Kings Bottom syncline ([fig. 30]) southwest of Moab Valley brings the Navajo Sandstone down to and slightly below water level, whereas at The Portal ([fig. 68]) the Navajo caps the southwest wall of Moab Valley. Several anticlines at or near the river from Potash to and beyond the confluence ([fig. 1]) bring up strata as old as the Rico or the unnamed upper member of the Hermosa. Between these extremes, much of the river’s course lies in strata of the Cutler Formation.
About 7 miles below The Portal, Highway 279 is joined on the right by a branch line of the Denver and Rio Grand Western Railroad completed in 1962 to haul potash 36 miles from the mine at Potash north to the main line at Crescent Junction. The railroad emerges from a tunnel at the head of Bootlegger Canyon. Two natural arches near the mouth of the tunnel—Pinto and Little Rainbow Bridge—can be reached by trail. About 3 miles farther down the Colorado is a temporary dock from which jet boats and the Canyon King, a 93-foot 150-passenger stern-wheeler, take off for points downriver during the spring and early summer, when water depth permits. The Canyon King ([fig. 69]), a small replica of a Mississippi River stern-wheeler, carries passengers about 30 miles downriver to the foot of Dead Horse Point and returns (Lansford, 1972).
About 12 miles below The Portal we reach Potash—the potash “mine” ([fig. 70]) of Texas Gulf, Inc. (See [fig. 31] and its associated text for description of operation.) Travelers down the jeep trail below Potash pass the evaporation ponds ([fig. 71]) used to separate the potash from common salt.
THE CANYON KING, a 93-foot 150-passenger stern-wheeler which hauls passengers some 30 miles below Potash and returns. Trips run during the spring and early summer, when water depth permits. Photograph by Henry Lansford, Boulder, Colo. (Fig. 69)
POTASH MINE OF TEXAS GULF, INC. at Potash, as viewed from a boat. High cliffs on right are Wingate Sandstone capped by Kayenta Formation and underlain by slopes of Chinle and Moenkopi Formations. (Fig. 70)
EVAPORATION PONDS, used to separate potash from common salt, viewed from jeep trail. Black borders are parts of plastic membranes covering bottoms of ponds. Crest of Cane Creek anticline and La Sal Mountains in right background. (Fig. 71)
Across the river east from Potash is Jackson Hole, a large rincon. Since abandonment, which shortened the river by about 3½ miles, the river has cut its channel nearly 200 feet deeper. It is comparable in size to the large rincon along Green River below Bowknot Bend ([p. 90]) but probably is somewhat younger. Both rincons may be as old as late Tertiary ([fig. 80]). Just below Potash we cross the axis of the huge Cane Creek anticline ([fig. 31]) and also leave Grand County to enter San Juan County. A mile east of this point, high on the canyon wall, is the School Section 13 uranium mine, which has yielded considerable ore and is expected to resume production sometime during 1973. It can be seen from the river or the trail, and some of the tailings are visible on the left flank of the anticline in [figure 13].
Voyagers who cross the axis of the Cane Creek anticline may observe on the right-hand (west) bank a protruding oil-well casing, some drill bits, and several shacks—all that remain of the Frank Shafer No. 1 oil test started during the winter of 1924-25 and completed by the Midwest Exploration Co. (Baker, 1933, p. 81). As described by Maxine Newell (U.S. Natl. Park Service, written commun., 1970),
The well blew in in December 1925, caught fire, and spewed burning oil 300 feet into the air. * * * The local Times-Independent newspaper called it “Mother Nature’s Christmas Gift to Grand County.” The gusher burned down the rig, a barge of equipment, and it took three months to get it under control. Then it didn’t produce.
Various 1925 and 1926 issues of the Moab Times-Independent reported that despite many efforts to plug the well, it continued to flow from 1,000 to several thousand barrels of oil per day for 6 months or more, all of which floated down the river. The last blowout occurred in 1937, after which the well was plugged with an additional 180 tons of cement.
Mrs. Newell added,
The stories told of the early-day exploration are endless and delightful. Equipment and supplies were barged down the Colorado River by the old Moab Garage Company; in winter months materials were carried by team and sled over the river ice. They would take a couple of rig timbers and pile a lot of lumber on them (they could take 10,000 feet), then we’d give them a start with a crowbar and the mules would trot all the way downhill to the well. When they’d get there they had a little trouble stopping sometimes; they would turn into the bank, unload, then put the double trees on one mule, ride the other, and head back for a new load of rig lumber.
The evaporation ponds shown in figures [31] and [71] are in Shafer Basin, a synclinal basin separating the Cane Creek anticline and Shafer dome. We cross the axis of Shafer Basin about 2 miles below the county line.
Further downstream is Shafer dome, a closed anticlinal bulge just beyond the W-shaped bend in the river as shown in [figure 29]. Parts of the dome also show up in the lower right of [figure 13] and the lower left of [figure 15]. From almost anywhere in the Goose Neck, the sharp bend of the river shown in [figure 15], we get an excellent view of Dead Horse Point some 2,000 feet above.
Robert R. Norman (oral commun. Feb. 27, 1973) described to me a small petrified forest—which he said resembles a log jam—in the eastern part of the Shafer dome, at mileage 39 (Baars and Molenaar, 1971, p. 65), just north of this point about half way between the river and the jeep trail below Dead Horse Point. He estimated that there probably are 20 to 30 logs, some of which are as large as 18 inches in diameter and more than 20 feet long, and also described a stump about 3 feet in diameter. They occur in red beds at about the middle of the Rico Formation, hence could be either Pennsylvanian or Permian in age (figs. [9], [80]). The original wood has been replaced by silica (SiO₂) and stained a dark reddish brown, as shown in [figure 72].
Mr. Norman and his brother also discovered many teeth of a primitive sharklike fish in the Rico Formation at the same general locality as the petrified wood and also in the Rico on the Cane Creek anticline. I submitted two of the teeth to Dr. David H. Dunkle, curator of the Cleveland Museum of Natural History, who reported them to be “one tooth of the cochliodont ‘shark’ Deltodus, and one tooth of the petalodont ‘shark’ Petalodus” (written commun., May 22, 1973).
About 4 miles below the Goose Neck, we enter Canyonlands National Park and remain in the park almost to the north end of Lake Powell.
About 6½ miles into the park, at the north end of a bend much like the Goose Neck, is the mouth of Lathrop Canyon, where many boaters stop for lunch and where a side road connects with the White Rim Trail ([fig. 1]).
Six and one half miles below Lathrop Canyon is the mouth of Rustler Canyon, which is joined near its mouth by Indian Creek—the creek followed by the highway leading to The Needles from U.S. 163. Within an airline distance of only 3 miles, the lower reach of Indian Creek, an intermittent stream, flows past four small rincons, three of which ([fig. 73]) are within an airline distance of only 0.8 mile. The stream has cut its new channel into the red sandstones and shales of the Cutler Formation only 15 to 20 feet deeper than the abandoned ones in the two rincons at the left in [figure 73] and only about 25 feet deeper than the one on the right. These figures suggest, at least to me, that these cutoffs probably occurred sometime during the Holocene Epoch, or age of man—that is, probably within the last 10,000 years ([fig. 80]). A detailed study of these rincons might change this estimate, particularly if, say, buried driftwood or other carbonaceous material could be found for an age determination by the radiocarbon method.
PETRIFIED LOG, near middle of Rico Formation, about 1 mile southeast of Dead Horse Point. Log is estimated to be about 18 inches in diameter. Photograph by Robert R. Norman. (Fig. 72)
RELATIVELY RECENT RINCONS ALONG INDIAN CREEK, about 3½ miles above mouth and about 2 miles east of Canyonlands National Park. Above, stereoscopic pair of aerial photographs by U.S. Geological Survey; below, sketch showing drainage changes. The stereoscopic pair can be viewed without optical aids by those accustomed to this procedure, or by use of a simple double-lens stereoscope. (Fig. 73)
THE LOOP, of Colorado River, about 5 miles northeast of the confluence. Lower canyon walls are unnamed upper member of Hermosa Formation overlain by slopes of the Rico Formation. Jointed sandy ledges at top become sandier to south, where they comprise the Cedar Mesa Sandstone. Aerial photograph by U.S. Geological Survey. (Fig. 74)
About 5 miles below the mouth of Rustler Canyon and Indian Creek, and also about 5 miles above the confluence, is The Loop—an even sharper and more symmetrical figure eight than Bowknot Bend of the Green River ([fig. 62]). An aerial view of The Loop ([fig. 74]) shows that the channels on the south loop are only about 500 feet apart and that those on the north loop are only about 1,700 feet apart. At the narrowest places, both saddles are considerably eroded—the southern one is only about 150 feet above the river, but the northern one is still about 350 feet above. Erosion of both saddles has been hastened by the facts that the axis of the Meander anticline (see [p. 108]) passes through each saddle and that an interesting reverse fault ([fig. 75]) passes through the lower and thinner southern saddle. The differences between reverse and normal faults are shown by comparing figures [56] and [76]. It seems inevitable that some day the small saddle will be cut through by the Colorado River, and a new rincon will result. Eventually, the other loop also probably will be abandoned. As one of my colleagues remarked, how wonderful it would seem, to be present at the proper moment to witness such an event, particularly if one had a time-lapse movie camera to record it for posterity!
REVERSE FAULT in southern saddle of The Loop, looking northwest from boat in river. Apparent angle of dip is 12° below horizontal. Rocks at left, above fault plane, have been shoved about 10 feet past and over those on right. Curving of dark bed near middle of fault plane is called “drag.” (See [fig. 76].) Rocks are unnamed upper member of Hermosa Formation. (Fig. 75)
CUTAWAY VIEW OF REVERSE FAULT, resulting from horizontal compression, which caused a shortening of earth’s crust. Note “drag” of beds on each side of fault plane. Low-angle reverse faults, also called thrust faults, may have displacements ranging from a few feet to many miles. From Hansen (1969, p. 116). (Fig. 76)
About a mile and a half below the south saddle of The Loop we meet the mouth of Salt Creek, which drains a large part of the Needles district. [Figure 77] was taken in Salt Creek canyon about 2 airline miles above the mouth looking southeast toward Six-Shooter Peaks and Shay Mountain, northernmost of the Abajo Mountains, on the horizon.
A mile and a half above the confluence is The Slide, a jumbled mass of angular blocks of rock that fell from the northwest canyon wall and originally probably extended all the way to the southeast bank of the river. As shown in [figure 78], it still extends nearly across the river, leaving only a narrow deep chute along the southeast bank. Just after the photograph was taken, we hit rough fast water in the chute, with waves about 2 feet high. At higher stages of the river, progressively more of The Slide is covered by water, and there is less tendency for waves to form. The date of this landslide is not known, but it is shown on a map by Herron (1917, pl. 22A) made prior to 1917 and may well have occurred during prehistoric times.
Soon we reach the confluence of the Green and Colorado Rivers (figs. [59], [60]). This important junction of two mighty rivers was noted by all previous voyagers, but their impressions of it differed considerably. Powell (1875, p. 56) remarked:
These streams unite in solemn depths, more than one thousand two hundred feet below the general surface of the country. The walls of the lower end of Stillwater Cañon are very beautifully curved [see [fig. 67]], as the river sweeps in its meandering course. The lower end of the cañon through which the Grand comes down, is also regular, but much more direct, and we look up this stream, and out into the country beyond, and obtain glimpses of snow clad peaks, the summits of a group of mountains known as the Sierra La Sal [La Sal Mountains]. Down the Colorado, the cañon walls are much broken.
Dellenbaugh (1902, p. 277) gave a fuller description but concluded: “In every way the Junction is a desolate place”—an appraisal with which I disagree. The most colorful account I have read is that of Captain Francis Marion Bishop, a member of Powell’s 1871 expedition, who recorded in his journal for September 15, 1871 (1947, p. 202):
Well, we are at last, after many days of toil and labor, here at the confluence of the two great arteries of this great mountain desert. No more shall our frail boats dash through thy turbid waters, Old Green, and no more shall we press on to see the dark flood from the peaks and parks of Colorado. Grand and Green here sink to thy rest, and from thy grave the Colorado de Grande shall flow on forever, and on thy bosom henceforth will we battle with rock and wave. One can hardly tell which is the largest of the two rivers. Neither seems to flow into the other, but there seems to be a blending of both, and from their union rolls the Colorado River.
SALT CREEK CANYON, looking southeast from point on rim 2 miles above mouth. Lower ledges are limestones in unnamed upper member of Hermosa Formation; slope and upper cliff are Rico Formation capped by remnants of Cedar Mesa Sandstone. Horizon shows Six-Shooter Peaks in center and Shay Mountain, northernmost of Abajo Mountains, at right. Photograph by E. N. Hinrichs. (Fig. 77)
THE SLIDE, which partly blocks the Colorado River about 1½ miles above the confluence. View downstream. (Fig. 78).
Cataract Canyon heads at the confluence, but the rapids do not appear until we leave Spanish Bottom some 3½ miles below. Between The Loop and Spanish Bottom, the Colorado River follows closely the axis of an anticline. Along this reach the rock strata dip downward away from the river, as shown in [figure 61]. This fold was noted by Powell and some of his men, and Bishop (1947, p. 203) reported in his journal for September 16, 1871:
He [Steward] is at a loss how to account for the folded appearance of the strata here. But doubtless will find some explanation. Says the dip recedes from the river cañon, and thinks it is a fissure. Maj. [Powell] thinks it is owing to an upheaval, and that the beds next to the river have broken up from the mass, etc., etc.
Forty-four years later Harrison (1927) named this structure the Meander anticline and concluded that the weight of the rocks on each side of the river had squeezed underlying beds of salt in the Paradox Member of the Hermosa Formation and caused them to move upward along the river, where the confining strata had been removed by erosion. Harrison’s theory was accepted by Baker (1933) and most later workers in the area. Thus we have what may be termed an erosional anticline, whose axis, or crest, follows the river. Erosional anticlines also occur elsewhere, as along the Eagle and Roaring Fork valleys of central Colorado. Mutschler and Hite (1969) suggested that this zone of weakness in Canyonlands overlies and follows a break in the hard Precambrian ([fig. 80]) rocks that underlie the area at great depth. At any rate, Powell was on the right track even though he was totally unaware of the underlying salt or the deep-seated fault.
Smooth water continues from the confluence to Spanish Bottom, where the Old Spanish Trail comes down to the river from the west and continues up Lower Red Lake Canyon to the east. As mentioned earlier, this is about the south end of the Meander anticline, and an intruded chunk of the Paradox Member, mostly gypsum, occupies part of the mouth of Lower Red Lake Canyon, as shown in [figure 79].
The remaining 10 miles or so of Cataract Canyon within Canyonlands National Park contains many rapids and should be traversed only under the leadership of experienced river guides. If and when Lake Powell reaches its maximum level, it will extend to within about a mile of the park, but at present (1973) it heads near the mouth of Gypsum Canyon, about 5 miles below the park.
GYPSUM PLUG of Paradox Member, intruded along south end of Meander anticline at mouth of Lower Red Lake Canyon. Common salt has been removed by solution, leaving residue of gypsum and some shale. Photograph by Donald L. Baars. (Fig. 79)
GEOLOGIC TIME SPIRAL, showing the sequence, names, and ages of the geologic eras, periods, and epochs, and the evolution of plant and animal life on land and in the sea. The primitive animals that evolved in the sea during the vast Precambrian Era left few traces in the rocks because they had not developed hard parts such as shells, but hard shells or skeletal parts became abundant during and after the Paleozoic Era. (Fig. 80)
The Age of the Earth
The Earth is very old—four and a half billion years or more according to recent estimates. Most of the evidence for an ancient Earth is contained in the rocks that form the Earth’s crust. The rock layers themselves—like pages in a long and complicated History—record the surface-shaping events of the past, and buried within them are traces of life—the plants and animals that evolved from organic structures that existed perhaps three billion years ago.
Also contained in rocks once molten are radioactive elements whose isotopes provide earth scientists with an atomic clock. Within these rocks, “parent” isotopes decay at a predictable rate to form “daughter” isotopes. By determining the relative amounts of parent and daughter isotopes, the age of these rocks can be calculated.
Thus the results of studies of rock layers (stratigraphy), and of the progressive development of life (paleontology), coupled with the ages of certain rocks as measured by atomic clocks (geochronology), attest to a very old Earth!