Geology of the Columbia River Gorge : Travel the Gorge

What's Going On

May 2013

S	M	T	W	T	F	S
29	30	31	1	2	3	4
5	6	7	8	9	10	11
12	13	14	15	16	17	18
19	20	21	22	23	24	25
26	27	28	29	30	31	1

Search for Events Category:
Start Date:
End Date:

GEOLOGIC HISTORY OF THE GORGE

From: The Geologic History of the Columbia River Gorge: Information Brochure.U.S. Army Corps of Engineers, Portland District, and the U.S. Department of the Interior, U.S. Geological Survey

(We tried, but we couldn't tell it better.TTG)

KA-BOOM!
40-20 million years ago ( Eocene to Miocene)

Thousands of volcanic eruptions piled layers of volcanic ash, lava, and mudflows over the region, creating the Ohanapecosh Formation. These rocks weathered into slippery red clay and greenish rocks visible near Stevenson, Washington.