View of Okmok's ash plume emitting from multiple vents near intracaldera Cone D, taken at about 1:30 pm on August 3, 2008 by Jessica Larsen, Alaska Volcano Observatory, Geophysical Institute

Oh, Sure, Blame Alaska


Now Alaska is being blamed for the fall of the Roman Republic. Sheesh. WC doesn’t remember that being discussed at all Edward Gibbon’s classic Rise and Fall of the Roman Empire. . An environmental researcher named Joe McConnell and his colleagues examining ice cores from northern Greenland found volcanic ash and sulfuric acid in ice layers laid…

Hell's Canyon from the Oregon Side. The Seven Devils Mountains are in the background. The gorge is visible just to the right of trees, but not the Snake River

Geology 101: The Columbia River Basalt Group


WC’s Geomorphology instructor, a visiting professor from Columbia University, told WC’s Geomorphology class on the first day, “There is some really intereting geology in the Pacific Northwest. Unfortunately, it’s all buried under thousands of feet of basalt.” That’s a slight exaggeration, but when you stand at the Hell’s Canyon Overlook, above the Snake River Gorge,…

Little Salmon River Valley at Pollock, Idaho

Geology Is Messy: The Little Salmon River


The Little Salmon River – and it really is little in comparison to Idaho’s Salmon River – run mostly north from New Meadows to Riggins, at the confluence of the Little Salmon and the Salmon, about 45 river miles. It follows a fault that marks part of the suture created when the Seven Devils Terrane…

November 2002 Quake Fault Trace Crossing Richardson Highway

Now This Was an Earthquake


On November 3, 2002, just a little after noon, WC was upstairs at his home in Fairbanks, working on his email. Mrs. WC was downstairs doing chores. The whole house gave a very strong, sudden and sharp jerk. There was a pause. And then continuously, for two minutes and 18 seconds, the house thrashed around…

Source: 5/14/20 Barry Arm Landslide Working Group Letter

The Barry Arm Problem


WC has written before about this summer working on the R/V Acona for the University of Alaska’s Institute of Marine Science. One of the research projects involved a trip to Lituya Bay, in the northwestern part of of Southeast Alaska. In 1958, an earthquake and consequent landslide created what was then the largest tsunami –…

Buried and then partially exposed gravel bar, Salmon River Canyon, Idaho

Geology 101: How Conglomerates Happen


A lot of sedimentary rocks are composed of other sedimentary rocks. But no rock is more obviously composed of other rocks than conglomerate.1 Geology’s technical language is both an annoyance and sometimes lovely. The language can be a barrier to understanding. WC’s geology text described conglomerate as A coarse-grained clastic sedimentary rock that is composed…

Kilauea lava flow entering the ocean, January 2003

Nawww


Growing up in Fairbanks, WC’s friend Donnie Ensinger had the annoying habit of listening to you attentively, then scrunching up his face and saying, “Nawww” in a tone that conveyed both skepticism and smart-ass.1 It could be infuriating, but it could also be pretty funny. Memes didn’t exist at the time, but if they had,…

Exotic Terranes of Eastern South-central Alaska; the arriviste is green-colored. A lot of geologists would extend the Yakutat Terrane west to the Ragged Mountain Fault. (Based on NPS Wrangell-St. Elias – A Collage of Terranes)

The Yakutat Terrane: A Geologic Arriviste


Arriviste — someone who is just beginning to arrive, esp. an ambitious or ruthlessly self-seeking person, who has recently acquired wealth or social status. You may think that “arriviste” is a strange term to apply to a geologic terrane, but stay with WC on this and he will explain himself. An exotic terrane is a piece of…

Waimea Canyon from the lower lookout, Kauai, Hawai'i

Erosion Always Wins: Kauai


In WC’s Geomorphology class, on the first day, the professor (whose name WC has forgotten) told us, “If you only take one thing away for this course, it should be this: Erosion always wins.” If you need proof of that claim, you should visit Kauai, the oldest of the principle islands of the Hawai’ian Islands.…

Upper Hulls Gulch Trail, looking east, Autumn 2019

Boise Front Notebook: Geology is Messy


The Boise Front is the local name for the foothills that rise steeply up behind Boise to the southwest side of the Idaho Batholith. It’s a dramatic setting; a wall of steep mountains that appear to go straight up, immediately behind the city. The reality is much more complex.  Boise lies on the northern edge…

A slice through Earth’s mantle under the Andes. © Jonny Wu, University of Houston

The Answer Is Blowing in the (Mantle) Wind


Geology went through a Kuhnian revolution in the 1960s and 1970s, with the emergence of plate tectonics as an explanation, as a mechanism, driving what geologists were observing in the field. Plate tectonics has settled in as a credible, definitive and confirmable explanation of everything from vulcanism to oceanic trenches. But it’s also an incomplete…

Granodiorite, with an intrusive vein of quartzolite, Payette River canyon, Idaho

Geology 101: Granite Is Hard!


Non-geologists think of granite as – sorry – monolithic. Igenous rock that cools underground, right? You know, as opposed to lava, which cools on the surface. Well, geology is messy. And granite is messy, even for geology. Yet the kind of “granite” matters, because the chemical composition of rock determines how it weathers, how quickly…

Idaho Batholith at Lick Creek Summit, northeast of McCall, Idaho

Geology Is Messy: The Idaho Batholith


The Idaho Batholith is a vast chunk of granite that dominates central Idaho. It’s some 15,400 square miles of rock. People talk about it as if it’s a gigantic, homogenous lump of stone. It’s not. Geology is complicated. Most, but not all, geologists agree the Batholith was formed when the Pacific Plate subsumed under the…

A schematic model that links the slab hole with other physiographic features. The view is from the east, and theJuan de Fuca slab is shown in blue. The propagator wake (bold gray line underneath Oregon) causes a weakness in the slabalong which a tear is propagating. The High Lava Plains (contours in Oregon) lie above the southern edge of theslab hole. The Gorda slab rotates clockwise, causing intraplate seismicity in the Gorda region.

Untangling Oregon Volcanism


Most of Oregon is igneous rock. Pretty recent igneous rock, as geologists measure time. It’s almost embarrassing. While some of it is pretty well understood, parts of all that volcanism are unexplained. The stratovolcanoes of the High Cascades? Subduction of the Juan de Fuca Plate and Pacific Plate. The lava that flowed into the Pacific…

Acipenseriform fish with ejecta clustered in the gill region. (A) X-ray of a fossil sturgeon head (outlined, pointing left; FAU.DGS.ND.161.115.T). (B) Magnified image of the X-ray in A showing numerous ejecta spherules clustered within the gill region (arrows). (C and D) Micro-CT images of another fish specimen (paddlefish; FAU.DGS.ND.161.29.T), with microtektites embedded between the gill rakers in the same fashion.

The Best Evidence Yet for the Dinosaur Killer


Archaeologist Robert A. DePalma, working in Southcentral North Dakota, has found the best evidence yet that the dinosaur killer, the huge meteor that struck the Yucatan Peninsula, leaving the Chicxulub crater, did indeed kill the dinosaurs. He has found, entombed in the rocks of the Hell Creek Formation, the archaeological equivalent of a smoking gun.…

Wright's Point from the east; photo credit Twilight, via Creative Commons License

Geology 101: Inverted Topography


As you drive south across the Harney Basin on Oregon Highway 201, you can’t miss Wright’s Point. The very long, very narrow, steep-sided ridge sticks out 10 miles into the basin, rising 250 feet above the flat lakebed. The much-diverted Silvies River loops around the easterly end of Wright’s Point, headed further south to Malheur…

The Other Crater Lake


WC is back from a week-long trip to the easterly side of the Oregon Cascades, where the scenery is very, very good but services do not include internet. This is the first of several posts from the trip. Crater Lake, in the Oregon Cascades, is justly famous. That remnant of Mt. Mazama is a near-perfect…