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Oregon Geology

Sixth Edition

Elizabeth L. Orr and William N. Orr

Publication Year: 2012

Because Oregon sits on the leading edge of a moving crustal plate, a striking diversity of geologic events have molded its topography. Over a century of study, a deeper understanding of the region’s tectonic overprint has emerged. In this timely update to the 2000 edition, Elizabeth and William Orr incorporate that new knowledge, addressing current environmental problems and detailing tectonic hazards. “Caught between converging crustal plates,” the Orrs write, “the Pacific Northwest faces a future of massive earthquakes and tsunamis.”

A comprehensive treatment of the state’s geologic history, Oregon Geology moves through Oregon’s regions to closely examine the unique geologic features of each, from the Blue Mountains to the Willamette Valley, from the high lava Plains to the Coast Range.

The book includes biographical sketches of notable geologists. It is lavishly illustrated and includes an extensive bibliography.

Published by: Oregon State University Press

Title Page, Copyright Page

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pp. 5

Relief map of Oregon

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pp. 6

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p. 7-7

In our periodic revisions of Oregon Geology, we are invariably challenged by the need to address new ideas and trends in research. Since the last edition in 2000, many revolutionary models and theories have been put forward, leaving us to select those which might have lasting..

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p. 8-8

Thanks to the many colleagues who reviewed all or portions of the text and diagrams, thus helping us to avoid errors: Cal Barnes,...

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Life on the Edge

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pp. 9-17

Geology is the story of how the earth has evolved through time. Some processes such as volcanism, landslides, or earthquakes are sudden, highly visible, and catastrophic while erosion, deposition, or changing climates...

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Blue Mountains

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pp. 18-47

The Blue Mountains physiographic province lies almost entirely in Oregon with only small portions projecting into southeast Washington and westcentral Idaho. Covering an area of 55,000 square miles, the triangular-shaped region is defined on the east by the...

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Klamath Mountains

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pp. 48-75

The Klamath Mountains is an elongate northsouth trending physiographic province extending a distance of 250 miles from a narrow point near the southern tip of the Willamette Valley to the northern end of the Sacramento Valley in California. The Oregon Klamaths are...

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Basin and Range

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pp. 76-95

The Basin and Range across southcentral Oregon is only a small northern portion of a vast region that covers parts of Utah, Nevada, Idaho, Oregon, Arizona, California, New Mexico, and Mexico, encompassing an area of 300,000 square miles. The Oregon Basin and...

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Owyhee Plateau

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pp. 96-109

Covering the extreme southeastern corner of Oregon, the Owyhee physiographic province reaches into southwestern Idaho and northern Nevada. In Oregon, the plateau lies almost completely within Malheur County. It...

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High Lava Plains

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pp. 110-129

The geologically young High Lava Plains is an elevated desert plateau 50 miles wide and 150 miles long. Centrally located in Oregon, it borders five other regions. The Blue Mountains lie to the north, the Basin an...

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Deschutes-Umatilla Plateau

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pp. 130-153

The Deschutes-Umatilla province extends nearly 200 miles westward from the Blue Mountains to the Cascade Range and is 100 miles at its widest. The region slopes gently northward from elevations of 4,000 feet toward...

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Cascade Mountains

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pp. 154-185

The 600-mile-long Cascade Mountains from northern California through Oregon, Washington, and British Columbia provide some of the Pacific Northwest’s most dramatic scenery. Touching all other provinces in Oregon except for the Blue Mountains...

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Willamette Valley

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pp. 186-211

The Willamette Valley and Puget Sound lowland stretches from Cottage Grove, Oregon, to British Columbia in Canada. In Oregon, the Willamette Valley is an elongate basin which narrows at either end before pinching...

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Coast Range and Continental Margin

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pp. 212-246

Moderately high mountains, terraces, rocky headlands, sandy beaches, and an offshore shelf and slope all contribute to the complex topography of the Coast Range and continental margin. From the Olympic Peninsula of Washington, the province continues southward...


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pp. 247-288


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pp. 289-304

E-ISBN-13: 9780870716829
E-ISBN-10: 0870716824
Print-ISBN-13: 9780870716812
Print-ISBN-10: 0870716816

Page Count: 304
Publication Year: 2012