Geological Survey Professional Paper 296

Geology of Glacier National Park And the Flathead Region, Northwestern Montana  http://www.nps.gov/history/history/online_books/geology/publications/pp/296/abstract.htm

 

GEOLOGY OF GLACIER NATIONAL PARK AND THE FLATHEAD REGION NORTHWESTERN MONTANA

By CLYDE P. ROSS

This report summarizes available data on two adjacent and partly overlapping regions in northwestern Montana. The first of these is Glacier National Park plus small areas east and west of the park. The second is here called, for convenience, the Flathead region; it embraces the mountains from the southern tip of Glacier Park to latitude 48° north and between the Great Plains on the east and Flathead Valley on the west. The fieldwork under the direction of the writer was done in 1948, 1949, 1950, and 1951, with some work in 1952 ... Читать дальше »

Geological Survey Professional Paper 296

Geology of Glacier National Park And the Flathead Region, Northwestern Montana

 

 

POST-BLACKFOOT EROSIONAL FEATURES



Although the Blackfoot surface may have reached its culmination as recently as the early part of the Pleistocene epoch, it has since been attacked so vigorously that in many places its remnants have not been identified with assurance. Only the major features of the somewhat complex post-Blackfoot history are known. Those features related primarily to stream erosion are described here; features of glacial origin being touched upon in later pages.



After the Blackfoot surface was formed, rejuvenation took place, and streams cut deep valleys in the mountains, reducing the nearby plai ... Читать дальше »

 

Photos.

 

GEOMORPHOLOGY

GENERAL FEATURES OF THE GEOMORPHOLOGY

The deformation that reached a climax in the Lewis overthrust was followed by uplift and accelerated erosion early in Tertiary time. The major structural features trend northwest and had a marked effect on the development of the initial drainage pattern. Erosion by the streams thus started has produced ranges and groups of ridges with trends that are influenced by structure. The steep faults that border several of the ranges made great contributions to outlining the mountain masses. Irrespective of whether these faults are normal or reverse, they constitute large, persistent fractures ... Читать дальше »

INTERPRETATION OF THE STRUCTURE

GENERAL STRUCTURAL FEATURES

In the foregoing, available data in regard to the structural features present are summarized. Much remains unknown or obscure, but enough facts have accumulated to form a basis for discussion and to cast serious doubt on some of the concepts suggested by previous workers, who were under the disadvantage of having only the results of preliminary reconnaissances to work with. The concepts advanced below constitute attempts at interpretation of the observed structural features. Speculations as to the fundamental reasons for the formation of the structural features involve consideration of the origin and constitution of the earth and are beyond the scope of this report.

The accumulation of great thicknesses of sedimentary r ... Читать дальше »

INTERPRETATION OF THE STRUCTURE

GENERAL STRUCTURAL FEATURES

In the foregoing, available data in regard to the structural features present are summarized. Much remains unknown or obscure, but enough facts have accumulated to form a basis for discussion and to cast serious doubt on some of the concepts suggested by previous workers, who were under the disadvantage of having only the results of preliminary reconnaissances to work with. The concepts advanced below constitute attempts at interpretation of the observed structural features. Speculations as to the fundamental reasons for the formation of the structural features involve consideration of the origin and constitution of the earth and are beyond the scope of this report.

The accumulation of great thicknesses of sedimentary r ... Читать дальше »

 

http://yadi.sk/d/_KkuRGNsDNi33  Photos

 

MOUNTAIN-BUILDING STRUCTURAL FEATURES

In the Paleocene or somewhat afterwards, conditions changed drastically from those outlined above. Broad warpings of the earth's crust so gentle that the resulting structural features have to be inferred rather than seen were succeeded by violent movements in which the rocks were tightly folded and eventually extensively fractured. Thrusts and normal faults of the first magnitude resulted from a series of earth movements that have not entirely ceased even yet. In the summary that follows, the structural feature ... Читать дальше »