CRATER LAKE Circular of General Information 1936

CRATER LAKE
National Park

LOCATED in southern Oregon, on the very crest of the Cascade Range, Crater Lake National Park takes its place among the Nation's most unique scenic wonderlands. It is a gem of rare excellence, possessing unity of form and color. At Crater Lake visitors observe beauty in its truest sense and experience a profound. inspirational appeal. With an air of mystery, tranquillity now prevails where once unfathomable power was displayed. It is a shrine before which all may, with an attitude of reverence, penetrate the veil of the unknown to meet the realities of nature. The park now embraces an area of 250.52 square miles, or 160,333 acres, and was established by act of Congress on May 22, 1902.

The lake rests in the very heart of a mighty mountain whose destruction resulted in the formation of a vast crater in which the waters accumulated. This body of bluest of waters in the world has no known inlets or outlets and is dependent entirely on precipitation for its great depth. It is 6 miles wide, 2,000 feet deep, covers an area of 20 square miles, and has a circular shoreline of 26 miles, with multi-colored lava cliffs reaching out of mystic blue depths for another 2,000 feet.

Mountain trails lead to the summits of high points about the rim and down a thousand feet to the shores of the sea of silence. At the water's edge, motorboats and rowboats are available for those who wish to see more of the lake or try their hand at trout fishing. Regular boat trips are planned to Wizard Island, the perfect little crater rising above the surface of the lake. For those who do not descend the trail to the water's edge there is a motor drive around the rim of the lake. Every turn presents a different view. The constantly changing color and the contrasts of lava cliffs and blue water are beautiful beyond description.

Wizard Island, Crater Lake. Crawford photo.

DISCOVERY AND HISTORY

Legend says that the Klamath Indians believed Crater Lake was once a weird, ghostly amphitheater where the gods were forever embroiled in conflict, sporting in its blue waters and dwelling on its rocky heights and in its mystic depths.

Pioneers came slowly to southern Oregon, its sparse population in the early fifties living in constant dread of Indian wars. Miles of mountain region had never been explored when a party of California prospectors came to the mining village of Jacksonville. This was the only settlement in the region and owed its existence to the discovery of gold nearby. The Californians while preparing a journey into the mountains remained secretive regarding their mission. The purpose of their trip, however, was betrayed by a member of the party to a group of Oregon miners who learned that the strangers were searching for a "Lost Cabin Mine", believed to be near the head of the Rogue River. Without delay, the Oregon miners decided to follow the Californians into the wilds, despite persistent efforts of the latter to evade them. Later, when the food supplies of both parties were running low, John Wesley Hillman, leader of the Oregon party, succeeded in uniting the two forces, and the search for the mine was postponed in order to hunt for game.

Thus it was on June 12, 1853, that Hillman, who had gone on some distance ahead of the hunting group, happened to ride up a deep canyon which, judging from its depth and width, he thought would lead to a higher slope. Letting his mule pick its way upward, he kept peering through the woods for game. Then suddenly the animal stopped, halting at the very rim of a deep blue lake. As the rider looked down he beheld a scene of unsurpassed beauty. Other members of the party soon joined their leader, and they agreed to call the body of water Deep Blue Lake.

In the excitement of gold stories and Indian wars, Crater Lake was for gotten for several years. There were no more visits by white men until 1862 when a party of six unsuspecting miners, led by Chauncey Nye, happened upon the place while on a prospecting trip and believed they had made a new discovery, only to learn afterward of Hillman's visit. A third "discovery" was made in 1865 by a party of soldiers from Fort Klamath. They called the body of water Lake Majesty. This name was changed to Crater Lake in 1869 by visitors from Jacksonville.

Some years later, in 1872, William Gladstone Steel came to Oregon. The story is told that when Steel was a schoolboy in Kansas he had heard of the discovery of Crater Lake and had made a resolution that he would sometime see the western wonder. He spent 9 years in Oregon before he could find anyone who had heard of Crater Lake; several more passed before he found a person who had actually seen it. It was not until 1885 that he was able to visit the place which he found to be even more beautiful than he had anticipated. The result was that Judge Steel conceived the idea of setting aside the lake and the region thereabout as a national park. He began an immediate agitation for this. Though the task was not an easy one and there was much opposition from certain quarters, Steel was undaunted by the rebuffs and continued his efforts unselfishly and with personal sacrifice over a period of 17 years. Success crowned his work when the park was established by an act of Congress, approved May 22, 1902. Judge Steel thereafter devoted his life to the development of the park and became one of its first superintendents. Later he became park commissioner.

Soon after Steel's first visit, soundings were taken on the lake under the direction of Capt. C. E. Dutton of the United States Geological Survey. Over a month was spent in the work, with the deepest sounding recorded at 1,996 feet.

The first survey for a road system within the park was made in 1910 and 1911; 2 years later the entrance roads from Medford and Klamath Falls were built. Though these roads were very primitive when compared with those now developed, they served the needs of that time when travel was yet dependent principally on horses and wagons.

GEOLOGICAL STORY

Visitors to Crater Lake find that they have to ascend continuous pumice slopes, which rest on a vast lava plateau, in order to reach the rim of the marvelous lake. It is evident that a mighty mountain once stood where now rests a lake of unbelievable blue, 2,000 feet in depth, on all sides of which perpendicular lava cliff walls rise from 500 to 2,000 feet.

In 1896 the Mazama Club, a mountain-climbing group of Portland, Oreg., visited the lake, and, with fitting christening ceremonies, gave to the hypothetical mountain which no man ever saw the name of Mount Mazama. It is evident that the former mountain, and in fact the entire Cascade Range extending from northern Washington far south into northern California, is part of a series of tremendous lava flows. In late geological ages molten rock poured out over an area of more than 200,000 square miles, extending into Oregon, Washington, Montana, Idaho, northeastern California, and northwestern Nevada. This vast lava plateau, the most extensive on the North American Continent, resulted from extensive fissure flows. The dominant trend of the great fissures or cracks is north to south, which accounted for the building of the Cascade Range on the plateau foundation along these lines. Those who have seen the Columbia River Gorge have noted the layer upon layer arrangement of the lava which forms the plateau base.

As the volcanic cones of the Cascade Range, which include Mount Rainier (14,408 feet), Mount Adams (12,326 feet), Mount Baker (10,750 feet), Mount Shasta (14,161 feet), Mount St. Helens (9,697 feet), and Mount Lassen (10,453 feet) were being built by the extrusive forces of vulcanism, the mountain in the remnant of which Crater Lake now rests was formed. The extrusive lava outpouring, piled layer upon layer, supplied a foundation upon which pumice, volcanic ash, agglomerate, and successive eruptions formed the high volcanic peak. The radiating slopes of this peak are covered with a huge mantle of debris, transported by glaciers and by running water. The adjacent gorges and canyons display spectacular exposures of mud flows, pumice, and tuff. Although the surface of the region has been changed by erosive forces, the cessation of vulcanism has been so recent that the remaining portion of the mountain and its radiating slopes must today appear similar to the general outlines prevailing prior to its destruction and the development of the lake.

Crater Lake should be considered in relation to the mighty volcanic cone which was built by alternate stages of explosive emanations and quiet extrusive flows during a long period of time. Upon examination of the cliffs bordering the lake we find layer upon layer of fragmental material. These walls with their bands of lava appear like sections of a layer cake. Although the layers seem to be roughly horizontal when viewed from the rim, they really slope gently away from the lake. This is true not only at one place but everywhere around the rim. The bands are neither uniform in thickness nor in character. One may be composed of andesitic lava, 5 to 10 feet thick, while the next one may be composed of pumice or volcanic agglomerate, 15 or more feet thick. These layers, 39 of which are visible at certain localities, represent successive periods of volcanic activity. Each accumulation means a new eruption.

Molten lava may be spilled out as broad flows of molten rock, or forced upward by deep-seated forces within the earth. These latter extrusions may cause the volcano to break forth in new places on the mountain side. That this has happened to the old Crater Lake mountain is evidenced by the lava filling of the cracks or fissures which have formed resistant bands of lava rock, called dikes, which cut across the previously formed bands or layers. Molten rock is forced upward and outward, and as it cools it solidifies and develops masses of rock harder and more resistant to disintegration and decomposition than the surrounding rock material in which it discordantly rests. The forces of weathering and erosion attack the softer bordering material, leaving the resistant filling of the fissures as protruding ridges. There are many illustrations of such dikes to be seen within the rim of Crater Lake, the most spectacular of which is the Devil's Backbone. Removed from the rim of the lake, there are a number of adnate cones which grew upon the lower slopes of the old mountain. Timber Crater, Crater Peak, and Union Peak are a few of the more spectacular representatives.

With the exception of the dikes, the lava formations all slope gently from the rim of the lake. This indicates that there must have been a source for the material somewhere within the area now occupied by Crater Lake. The significance of this statement is paramount, for it suggests the existence of a volcano where Crater Lake now rests. The angle at which the layers of volcanic material slope away from the rim affords a method of estimating the former height of this mountain. By careful calculation geologists have arrived at a figure ranging from 12,000 to 15,000 feet for the elevation of Mount Mazama. This would indicate that the former mountain was on a par with the other mighty volcanic peaks of the Cascade Range.

Pinnacle formations in Wheeler Creek Canyon. Grant photo.

WORK OF STREAMS AND GLACIERS

Students of earth history have found unmistakable evidence that streams and glaciers were present on the mighty mountain during the course of its building and also in subsequent time. In the layers forming the rim of the mountain there is evidence of wear by rushing water as shown by the cutting of valleys and by the accumulation of water-carried ash, pumice, bombs, and boulders.

In many places on the radiating slopes of the rim may be found exposures polished rock, smoothed and planed by the scouring action of moving ice which carried with it sand, pebbles, and boulders. These evidences of glaciation are not to be confused with similar structures, produced by flow structure in the fast cooling molten masses. At Discovery Point the protruding rock is polished and scratched. Parallel grooves, resulting from glacial flow, appear, and some 30 to 40 feet below there is another exposure of polished rock. The crest of the rim in many other places exhibits similar glacial characteristics. One who walks along the Path of Nature to Discovery Point has an excellent opportunity to read the story recorded in the rocks and to differentiate between the confusing structures. First, one sees glacial striae on the upper surfaces of many lava flows; next, a pseudostriation, produced by both flow banding and fracturing of the hot, molten lava mass. Farther along the trail Mother Nature has placed these two confusing structures side by side. The glacial striae are seen at right angles to the flow banding of the lava, and elsewhere within the same lava flow the striae are seen parallel with the banding. By studying the inner wall one finds that glacial accumulation and the resulting scour occurred during the building process, and that after the maximum accumulation ice formed on the surface of the mountain and wore down the sides, forming typical glacial, U-shaped valleys.

The visitor, without examining the rocks in detail, may see clearly the effects of glaciation. From most points on the rim it is possible to look across the lake and observe the two giant, U-shaped notches which cut the rim between Garfield Peak and Cloud Cap. Kerr Valley and Sun Valley, both over a thousand feet deep, are smooth sided and exhibit the typical characteristics of glacial channels. The notches do not represent the head-waters of streams. They are cross sections of valleys which once extended much farther up the slope of the former mountain, having had their beginning in glacial feeding grounds which disappeared with the destruction of the central portion of the mountain.

What is the significance of these evidences of glaciation both on the rim and buried beneath the successive flows of lava? What part do they play in the story of Crater Lake?

In the first place, they definitely establish the existence of the theoretical mountain, called Mount Mazama. There unquestionably was a mountain on which the glaciers formed and down whose slopes the ice moved, gouging out U-shaped valleys and polishing the lava rocks. Furthermore, this was an intermittently active volcanic cone. Periods of glaciation were interspersed with periods of vulcanism. Lava flows descended the ice slopes, melting the glaciers and filling the valleys. As proof of this sequence of events, we find at Llao Rock a well-developed U-shaped valley filled with lava. This is termed a "plugged valley" by students of vulcanism. It is believed that beneath the massive lava flow or plug, some 1,000 feet in thickness, will be found marks which a glacier always leaves, polished glacial boulders, and striated-rock surfaces.

RECORDS OF VEGETATION

In addition to the story of vulcanism and glaciation, the rocks of the inner rim and the radiating slopes disclose a record of former advances and retreats of vegetation. Some 20 miles both to the east and to the west of the rim of the lake, logs turned to charcoal have been discovered, buried under 60 to 70 feet of volcanic ash and pumice. Hundreds of these charcoal specimens have been discovered buried in a prostrate position. Many display the presence of pitch and the cellular structure of the original living trees. The vegetation advanced up the side of the mountain during a period of volcanic inactivity when conditions existed favorable for vegetative growth. The most significant discovery which has been made at Crater Lake was the finding of such a stump of a pine tree, in an upright position, within the present rim of the lake, during the summer of 1933. The top portion of the stump was found to be carbonized, while the lower part and radiating roots were uncarbonized and partially decomposed. This find in place substantiates the concept that forests grew on the slopes of the old mountain and that the pumice and ash hurled from the fiery crater fell, while still hot, on the slopes and covered the standing trees and preserved portions of them in a carbonized condition. The tree was growing upon a glacial surface, its roots penetrating a glacial deposit. Cool ash, pumice, and bombs tumbled down the slope from above and covered the roots and the base of the tree. At a subsequent time, hot volcanic ejecta, pumice, ash, and dust settled around the tree so fast that air was excluded, combustion was prevented, and carbonization resulted. Afterward glaciers ground down over the mantle of volcanic debris which had covered and carbonized the tree. The huge crater was formed at a later date, and it was widened in all directions by the breaking away of the inner lava walls. The resulting erosion of the inner rim slope has shifted the rim crest outward so that now the specimen is located within the crater rim. This fascinating discovery will be preserved in place as an exhibit.

Further search for previous existence of vegetation has revealed a thick soil zone with fine fragments of charred vegetal materials underlying some 50 feet of pumice just beneath the crest of the rim at Pumice Point. Above Cleetwood Cove vegetal remains are covered to a still greater depth by pumice and lava. The evidence is at hand to establish the fact that the intermittent volcano recurrently was clothed with vegetation, and that vulcanism, glaciation, and the retreats and invasions of vegetation played their roles in the interesting drama.

DESTRUCTION OF THE MOUNTAIN

It is evident that a great catastrophe has occurred, and a mighty crater remains where the top of the mountain formerly stood. Three theories have been advanced to explain the destruction of the mighty mountain and the origin of the lake.

Many geologists believe that the top was blown off by a series of terrific explosions and that the land surface in all directions was covered with successive showers of fragmental material, pumice, and ash. The mountain slopes are covered with a thick mantle of pumice and semisorted fluvioglacial material which indicates that extrusive volcanic debris was moved and sorted by the action of glaciers and running water. Others contend that the absence of huge blocks of lava adjacent to the rim or scattered as erratics on the radiating slopes discounts the explosive concept. Adherents of the explosive concept present the idea that decomposition and disintegration have been very active and that much of the explosive material hurled down the radiating slopes has been broken down and removed. They contend that the present land surface shows evidence of excessive weathering and erosion of the mountain slope. Examination of new road cuts during recent field work has shown that in many places the pumice is only a veneer which masks a blocky horizon of large fragments beneath.

The second theory regarding the disappearance of the volcanic cone suggests that the mountain collapsed or was engulfed. This concept presupposes that the molten rock within the earth-magma sank, and, as it withdrew, the top of the mountain was remelted and a yawning, bowl-shaped depression some 4,000 feet deep was left. Those who propose the collapse theory hold that the volume of the mountain top which has disappeared amounts to some 17 cubic miles, and that such a great mass, if removed by explosion, would have thickly covered the radiating slopes and produced a symmetrical, conical base.

Closely associated with the collapse concept is the third theory which holds that the seething molten mass of lava in the crater of the volcano fused and undermined the walls and gradually produced the wide cauldronlike crater without tremendous explosions. In the volcanoes of the Hawaiian Islands huge craters are constantly being enlarged by a similar caving-in process, and the lava lakes rise and fall sometimes more than a thousand feet. The walls are undermined, causing huge spawls to tumble in and contributing to the widening of the bowl-like depressions or craters.

It is possible to conceive that one of the above forces may have prevailed in the formation of the crater at Crater Lake, or that a combination of these forces destroyed the ancestral mountain. In any event, the rock layers inside the crater wall are clearly exposed, and have been sharply broken around the entire rim area. This fracturing and falling in of huge spawls resulted in the widening of the crater. The precise details of the story are not yet fully known and remain a challenge to scientists. This feature causes eminent students of earth history from all over the world to travel far in order to examine this most unique laboratory of vulcanism, glaciation, and vegetative adaptation.

Whatever the cause, a huge crater developed some 4,000 feet deep. Then, as the final gasp of vulcanism, the Wizard Island cinder cone grew in the base of the crater. The sounding of the lake in 1886 presented information which points to the existence of two lesser cinder cones which are now covered by water.

Shortly after the destruction of Mount Mazama and the formation of Wizard Island and the lesser cones, Crater Lake itself came into existence. The water of Crater Lake is derived from the rain and snow falling directly over the crater surface, and from snow blowing into the huge depression. The conditions of evaporation, seepage, and the precipitation are in a state of balance which make possible this deep basin of water and the maintenance of approximately a constant water level. A very fine adjustment of natural forces prevails, and the lake might never have been formed if any one of the significant events in the chain of circumstances had been materially different.

The mute display of power and the mystery concerning the origin tend to add an atmosphere of charm to the entire setting of the unbelievably blue water. Color is an outstanding characteristic of Crater Lake. Among spectacular lakes of the world no depth of color and brilliance of blue are more striking. The blue of the deeper water is brought out in contrast with the shades of green displayed in the narrow, shallow areas along the margin. The deep blue of the lake is believed to be caused chiefly by the scattering of light in water of exceptional depth and clearness. In addition, the water surface is walled around with sheer cliffs, rising from 500 to 2,000 feet above the water surface, and this prevents observation of the lake from a normal perspective. The color is thought to be due to the same cause that produces the blue of the sky.

The beauty of color and the unity of form possessed by Crater Lake present a vision which will never be forgotten. It is truly a place of tranquillity, born of the tumultuous forces of fire and explosion. But still the lake possesses its moods. One finds that the coloring and appearance change from hour to hour and from season to season as the angle of the sun's rays changes. To come to know this most marvelous lake is a cumulative experience. Its air of weird mystery and charm always prevails.

Naturalist guiding a party of visitors over the Rim Trail.