A geological map of Valley County, Idaho

Geology and Payette Lake


Geologists tend to have a strange time sense. Mostly, they live in the present, year-to-year, decade to decade, like the rest of us. But their profession also requires them to live in geologic time, in epochs spanning millions of years. A geologist would look at Payette Lake in both ways: a beautiful, blue and blessedly…

Map of Lituya Bay, showing extent of damage from tsunami (USGS)

The Other Great Alaskan Earthquake


Sixty years ago this month, on the quiet evening of July 9, 1958, the Fairweather Fault in Southeastern Alaska shifted 21 feet laterally and three feet vertically, a ML 7.8 earthquake. The violent shaking caused a massive landslide at the head of the Lituya Bay, on the northeasterly wall of Gilbert Inlet. From as high…

Now THIS is a time suck!

Geology 101: WC’s New Internet Toy


WC can report a new and entertaining way to waste time assiduously study on the internet. Sometime in 2016, the United States Geological Survey created an on-line, interactive geological map of Alaska. If you are a geologist, professional or amateur, it’s about as cool a toy as the Series of Tubes™ has to offer. WC…

Looking southwest across the middle Pahsimeroi Valley at the Lost River Range

Notes on the Pahsimeroi Basin


When WC moved to Idaho a few years ago, WC knew it was a state that has an extensive basin and range province. “Basin and range,” for non-geologists, is a patter of alternating steep mountains and broad, mostly flat valleys. The mountains and valleys all extend northwesterly, mostly parallel, and are major geoform of the…

This diagram shows the Georgetown terrane, in green, joining Australia around 1.6 billion years ago during the formation of the supercontinent Nuna. Credit: Geology, https://doi.org/10.1130/G39980.

Back When Australia Was Part of North America


Long-time readers of this blog understand that the continental plates are in a very, very slow dance around a earth-sized, spherical skating rink. They collide, separate, collide, and separate again in a supercontinent cycle that’s been going on for perhaps 3 billion years. Collisions among the continental plates create supercontinents; the supercontinents rift apart. The…

Blue-gray areas were flooded during one or more of the Missoula Floods

One More Glacial Lake and Megafloods


Glacial Lake Ahtna dominated Alaska’s southcentral region during the Ice Age. Utah’s massive Lake Bonneville triggered the Bonneville Flood. But both Lake Ahtna and Lake Bonneville, stupdendous flood events themselves, were mere pikeminnows in comparison to the sturgeon that was Glacial Lake Missoula, which was not only a bigger flood event but happened as many as 80…