Corvallis Geology Map

I have been informed by various geobloggers, notably and most delectably by Silver Fox, that today is geologic map day. So here's the geology of my little burg:

Mappable units include, from youngest to oldest,

• Qtl- Quaternary terrace, low (Willamette gravels and other sediments)
• Qtm- Quaternary terrace, mid-level
• Qth- Quaternary terrace, high
• Ti- Tertiary intrusive (Mafic, mostly diabasic in texture)
• Ts- Spencer Formation (near-shore marine deposits)
• Tf- Now classified as Tyee, turbidite deposits called Flournoy Formation at the time.
• Tsr- Siletz River Volcanics

Other features:

• The Corvallis Fault has uplifted older Tsr with respect to younger sedimentary units along the slash from upper right to lower middle
• Pediments are identified by diagonal cross-hatching
• Areas of particularly high slope (and thus high mass movement risk) are identified with dark gray shading

Chip Ross Park, where I went with Dana Last week, is near the top of the image, to the right of the "Tsr" label, and with the little "apostrophe" of shading to mark a steep slope. Avery Park, where we went next, is at the bottom on the right. You can see the full map and legend in zoomable flash format here. Scroll down a bit, and above the line "Select an image to view / download," click on the first image.