CentralOregonGeoscienceSocietyfiles.sitebuilder.name.tools/d4/80/d4807247-5dd9... · Basalt &...

A  roadside  view  of  Oregon  and  Washington  geology  

Assembling  the  Northwest:

Marli  B.  Miller  Dept.  of  Earth  Sciences  University  of  Oregon  

Central  Oregon  Geoscience  Society  

Note: Due to file size limitations on the COGS website, this slide set has been reduced in length and some images have been compressed.

Beach'4'

sandstone*

shale*

limestone*

Sawtooth  Peak,  elev  9179  

Driving'east'on'I.84'

Driving'east'on'WA.14'

Area*>*77,000*square*miles*Volume*>*52,000*cubic*miles**17?6*Ma,*94%*by*14.5*Ma*

Followed"path"of"the""Ancestral"Columbia"River"

Multnomah*Falls*Drops'620'feet'in'two'falls'over'flows'of'Grande'Ronde'Basalt'of'the'Columbia'River'Basalt'Group'

Early"Columbia"River"Gravels"

Wanupum'Basalt'Wanupum*Basalt*

16'–'15.6'Ma'Grande*Ronde*Basalt*

15.6'–'15'Ma'

Eagle'Creek'Fm'

Maximum*flood*crest*nearly*100’*above*Vista*House*