Geological History of Crater Lake, Crater Lake National ParkU.S. Government Printing Office, 1912 - 29 Seiten |
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active volcano andesites ANNA CREEK Ashland basalts borders caldera canyons Cascade Range Castle cinder cone Cleetwood Cove Cloudcap copyrighted by Kiser coulees CRATER LAKE NATIONAL crest to shore Danger Bay depth DEVILS BACKBONE Dikes Dutton Cliff EAGLE Cove Eagle Crags fissure GEOLOGICAL HISTORY Geological Survey GLACIER PEAK head of Cleetwood HISTORY OF CRATER inner slope Kerr Notch Kilauea Kiser Photo Klamath Falls LAKE AS SEEN LAKE NATIONAL PARK lava field lava stream Llao Rock Medford miles molten material moraine Mount Shasta mountain Oreg OREGON outer slope Palisades Phantom Photograph copyrighted portion PUMICE POINT RAILROAD Red Cone region RIDGE rim of Crater road Rogue River Roundtop RUGGED CREST SECTION OF CRATER shown in figure side snow southern Spring steep streams of lava summit Sun Creek surface topographic TUFF United States Geological Upper Klamath Lake Victor Rock volcanic cones volcanic conglomerate water's edge western Wineglass Wizard Island
Beliebte Passagen
Seite 8 - The eye beholds 20 miles of unbroken cliffs ranging from over 500 to nearly 2,000 feet in height, encircling a deep blue sheet of placid water, in which the mirrored walls vie with the originals in brilliancy and greatly enhance the depth of the prospect. The first point to fix our fascinated gaze is Wizard Island, lying nearly 2 miles away, near the western margin of the lake. Its irregular western edge and the steep but symmetrical truncated cone in the eastern portion are very suggestive of volcanic...
Seite 10 - The variation in the altitude of the rim crest is 1,460 feet (from 6,759 to 8,228) with seven points rising above 8,000 feet. The crest generally is passable, so that a pedestrian may follow it continuously around the lake, with the exception of short intervals about the notches in the southern side. At many points the best going is on the inner side of the crest, where the open slope, generally well marked with deer trails over beds of pumice, attbrds an unobstructed view of the lake.
Seite 27 - ... probable outline of Mount Mazama. Wonderful as the lake, encircled by cliffs, may be, it serves but to conceal in part the greatest wonder — that is, the enormous pit or caldera which is half filled by the lake. The caldera is 4,000 feet deep. An impressive illustration of it is seen in figure 15 which was prepared from a photograph of a model of Crater Lake now in the United States National Museum. The water surface is represented by glass, so that one may see through to the bottom and get...
Seite 6 - Medford by private conance 80 miles to Crater Lake affords a good opportunity to observe some of the most important features of this great pile of lavas. The Cascade Range in southern Oregon is a broad irregular platform, terminating rather abruptly in places upon its borders, especially to the westward, FIG.
Seite 15 - ... its shape the Wineglass, reaches from crest to shore. The best views of the rim are obtained from a boat on the lake, which affords an opportunity to examine in detail the position and structure of the cliffs. They are composed wholly of volcanic conglomerate and streams of lava arranged in layers that dip into the rim and away from the lake on all sides. Both forms of volcanic, material are well exposed on the trail descending the inner slope, and, although most of the cliffs are of lava, many...
Seite 12 - ... up to the very crest. The glaciers armed with stones in their lower parts, that striated the crown of the rim, must have come down from above, and it is evident that the topographic conditions of to-day afford no such source of supply. The formation of glaciers requires an elevation extending above the snow line to afford a gathering ground for the snow that it may accumulate, and under the influence of gravity descend to develop glaciers lower down on the mountain slopes. During the glacial...
Seite 25 - ... occur at intervals all around the lake and radiate from it, suggesting that the central volcanic vent from which they issued must have been Mount Mazama. There is another important feature concerning the kinds of volcanic rocks and their order of eruption and distribution about the rim of Crater Lake that is of much interest to the geologist. All the older lavas comprising the inner slope of the rim, especially toward the water's edge, are andesites. The newer ones, forming the top of the rim...
Seite 6 - It is surmounted by volcanic cones and coulees, which are generally smooth, but sometimes rough and rugged. The cones vary greatly in size and are distributed without regularity. Each has been an active volcano. The fragments blown out by violent eruption have fallen about the volcanic orifice from which they issued and built up cinder cones.
Seite 7 - After following northward for some 20 miles along the eastern foot of the range, it ascends the eastern slope, along the castled canyon of Anna Creek to the rim of Crater Lake. From Medford or Gold Hill, the trip is a trifle shorter by the Rogue River road. It affords some...
Seite 10 - Reference has already been made to the glacial phenomena of the outer slope of the rim. There are scattered bowlders upon the surface, and also in piles of glacial moraine (fig. 7) which contain besides bowlders much gravel and sand. Such glacial drift is spread far and wide over the southern and western portion of the rim, extending down the watercourses in some cases for miles to broad plains through which the present streams have carved the deep and picturesque canyons already observed on the...