G145 Blue Mountain Objectives

1) Differentiate between the terranes of the Eastern Blue Mountain Province and describe

the tectonic processes that emplaced them.

WESTERN BLUE MOUNTAIN PROVINCE

4) Provide the names and general distribution of the terranes that underlie the Western Blue Mountain area.

5) Describe the Tertiary history of volcanic activity in the Western Blue

Mountains.

6) Provide a stratigraphic sequence of the following formations in the Western Blues and describe their general lithologies (rock types):

Mascall Fm.

Columbia River Basalt Group (Picture Gorge Basalt Fm.)

John Day Fm.

Clarno Fm.

7) Discuss the importance of the Tertiary rocks of the Western Blues in terms of providing a history of floral and animal evolution in North America.

8) Give an overview of the effects of the Pleistocene Epoch on the Blue Mountain Province.

Klamath Mtns

1) Know the difference between normal, reverse and thrust faults

2) Why are the terranes in the Blue Mtns separated by thrust faults? What is the mechanism that caused this situation?

3) Explain what the Klamath-Blue Mtn. lineament is and why it is important in understanding the geologic history of Oregon.

4) Know the relative tectonic history of the Klamaths

Age of rocks (in general) When were they “glued”

Aprox when they were emplaced Relative location of oldest to youngest

When were they rotated

5) What evidence suggests the Sierras, Klamaths, Blues and Coast Range were all accreted together?

6) What is the Josephine Ophiolite and why is it important

7) What is the Nevadan Orogeny, when did it occur and why is it important?

8) When did most of the sea stacks and terraces form in So. Oregon?

Field trip guide to the Josephine ophiolite and the Klamaths: See class web page