AnthropoceneMan#Today, digging these…
Illustrations from Charles Lyell’s Elements of Geology…
Dr. William Purdom, who founded the Geology Department at Southern Oregon State College (now SOU) was a mineralogist extraordinaire (still is) and a keen laboratory geologist.
Infamous for his “dozen white minerals” final exam and “yes, the axes of rotation displayed in the pear blocks is accurate” and espresso during the 8 hours of optical mineralogy labs a week…he was the prof who determined whether you stated in geology or plunked out and went for geography.
He taught some of the most critical make/break classes, and through his hard efforts, humor, and flawless teaching style, made you fall in love with the sport of geology.
His Rocks for Jocks/Shake and Bake course was a university favorite.
At its heyday, the department graduated about 10 very well instructed students per year…and that attention (especially in labs and fieldwork) well prepared us for careers in the discipline…with or without higher degrees.
Watching The Fire Within for the first time tonight…and in opening scenes is Harry Glicken in all his awkward glory. I haven’t seen him in 35 years…but there he is.
He is not addicted to the danger in the way the Krafft’s seemed to be…he was a true scientist and scholar. No doubt he was there to help with understanding the hazards…not sure how he got hooked up with the Kraffts.
I didn’t hear of his death, only 3 years after working with him, until much later…when I worked with another Cascades Volcano Observatory temp service alumnus. I was saddened, but not surprised.
Like watching a ghost who haunts a crime scene…I truly believe he had a wish to assuage his guilt at having escaped St. Helens’ fury.
The footage of St. Helens in early days is worth watching.
Good movie…like volcano porn. But the Kraffts seem more like Team Zisseau than Team Cousteau.
I met Harry X. Glicken in 1988, when I too had a temporary job working at the Cascades Volcano Observatory.
He was a friendly sort, but nervous …and over lunch one day he told me about being the one who should have died in the St. Helens eruption. I didn’t realize that what I saw before me was the embodiment of survivor guilt. His notorious eccentricity was partly the manifestation of this guilt.
He was a talented volcanologist, had the most impressive and impeccable education and work history, and yet could not find a place at the USGS during the Reagan era. It was then that I began to understand that a career in #volcanology would be a bridge too far from my starting point.
Harry was a brilliant sort, and he was able to secure other opportunities to pursue his passion.
He unfortunately died a few years later in a debris flow from Mt. Unzen in Japan.
The #ColumbiaRiverBasalt Group (#CRB) forms a dominant feature across the #PNW.
Dr. Marvin Beeson who taught and conducted research at #PortlandStateUniversity set the stage for understanding the CRB through his pioneering application of geochemistry to understand the evolution, structure, and extent of the CRB.
His research, and that of his many graduate students, led to many important, fundamental breakthroughs in understanding the geology of the CRB and the geologic history of NW #Oregon. He was widely considered the foremost expert on the #geology of the Basalts and was widely sought as a geologic consultant by U.S. Geological Survey, state agencies, municipalities, and private sector companies.
In honor of Dr. Beeson, his many colleagues at the #USGS and OR Water Resources this web page was dedicated to publishing his work.
https://or.water.usgs.gov/projs_dir/crbg/sources.html
Vintage Nick Zentner gives a quick tour of the CRB and why it is uniquely impressive.
Vicky VeritasWilson Cycle Phase 4 - Episode 4 - Collision and Collapse
“Tuzo was indeed an amazing man. His scientific interests were in the building of mountain ranges and moving of continents, and he certainly had a huge and long-lasting effect on Earth Science. But even more, his talent was in moving another type of mountain: those ideas in men’s and women’s minds that lock us into past patterns of behaviour and prevent visualization of new possibilities.”
~ Gordon F. West and others, from “John Tuzo Wilson: a man who moved mountains.”
‘The final stage of the Wilson Cycle involves continental-continental collision and the formation of giant mountain belts. And yet it’s how these giant mountain belts get exposed at the surface that allows us to study the Wilson Cycle in its entirety. Now we are going to explore the rocks which are formed deep within the mountain building stages of the Wilson Cycle and discover how these rocks are exposed at the surface today.
~ Professor Dougal Jerrom - intro to Episode 4
In the video below, “Wilson Cycle Phase 4 -Episode 4 -Collision and Collapse”, we finish our trip with Professor Dougal Jerrom, and the team of researchers in search of evidence for the collision and collapse of the Caledonian orogeny in the Caledonides Mountains. This series has kept the last and best for the finale, and it is a mind-blowing conclusion. I really recommend you watch the 29 minute video for yourself. It is well worth your time!
We first stop to look at some eclogites, and Norway has the best in the world - “the jewel in the crown of Norway” and are under its protection. These are ultra-high pressure metamorphic rocks that have been formed 100 km. or more deep in the subduction zone, and are especially stunning with coarse-grained “pegmatic” texture, deep green orthopyroxene, bright red garnet, and a white mineral coesite, a metamorphic index mineral indicates they underwent extremely high pressure. As Professor Jerrom says, discovering how these rocks were exposed is one of the most fascinating geology stories yet.
This starts with the subduction of oceanic crust underneath oceanic crust. The subducted slab is being pulled down by its own weight, and the two continents are approaching each other. The upper portion of the slab is still buoyant (see the model below, and the model in the video they run in the CEED lab) and doesn’t want to go down, so the slab breaks off and sinks through the mantle. The upper slab springs back up in a process called “eduction” (the reverse of subduction) and brings the deep metamorphic rocks back up where they are exposed during the collapse portion of the Wilson Cycle.
The late stages of subduction and collision build mountains as high as 3 km., but they are gravitationally unstable. The crust is thickened and getting heavier, and the upper level goes back into extension even as the lower crust is still thickening because of its own weight. This happens EVEN AS MOUNTAIN BUILDING IS STILL OCCURRING. Lots of erosion fills the basin with thick sediments up to 25 km. We see a giant detachment fault that is slowly denuding the top of the mountain of sedimentary rock that is sliding down a fault plane of metamorphosed rock. So mountains can quickly (in geological time) be stripped and the deeper crustal rocks exposed by isostatic rebound. We see this happening to day in the Himalayas Tibetan Plateau.
We are taken up close to a “textbook” active detachment fault with gouge, grain-size reduction, and fluid circulation. By studying the magnetism of the fractures of the fault and comparing it with the magnetism in this part of the world, tells us that the fault was reactivated, and also tells us about the end of the Caledonian, and the beginning of a new Wilson Cycle!
“So we’ve seen all the gems of knowledge stored in the rocks of Norway from the mountains to the fields tell us about this major cycle in Earth’s history, but it doesn’t end here because it’s happening again today with the north Atlantic opening and Norway is the place we could come back to in millions and millions of years in the future to understand the closure of that ocean and the mountain building event that would form the next Wilson Cycle.’
~ Professor Jerrom Dougal closes the series.
Wilson Cycle Phase 4 - Episode 4 - Collision and Collapse: https://youtu.be/pFuW4MtXhIM
The video introduces a paper published in the 90s that outlines the process of subduction and eduction, by Torgeir B. Anderson (yes, the same Torgeir that has been providing all the information on our journey) et al. Highly informative https://www.researchgate.net/publication/229872945_Subduction_and_eduction_of_continental_crust_major_mechanisms_during_continent-continent_collision_and_orogenic_extensional_collapse_a_model_based_on_the_south_Norwegian_Caledonides
#JohnTuzoWilson #LegendsOfGeology #TheWilsonCycle #Caledonides #Norway #WatchTheDamnVideo #PlateTectonics #SubductionAndEduction #OrogenicCollapse #eclogites #geology #Science #NorwegianGeologyRocks @geology
The Wilson Cycle - Episode 4 - Collision and Collapse
#ScienceSunday #Geology #LegendsOfGeology #Rocks #Minerals #Magma
Canadian petrologist Norman L. Bowen (developer of Bowen’s Reaction Series), used experiments and observations of natural rocks in the early 1900s to describe the sequence of crystallization of common silicate minerals from a typical basaltic magma undergoing fractional crystallization.
Bowen's Reaction Series is able to explain why certain types of minerals tend to be found together while others are almost never associated.
#LegendsOfGeology #Geology #Geologist #Volcanoes #Volcanology
Don Swanson was the Scientist in Charge at both the CVO and HVO. Here he is giving informal talk at a Mt St Helens Research Symposium that I crashed in 1987…literally had no right to be there amongst legends. Richard Waitt gave a memorable talk about hydrology and others about soils development in still recently erupted clastic deposits. Later got to work at the CVO…a dream come true.
#OldSchool #Geology #FieldTrip in #ColumbiaRiverGorge #Oregon #Geology #LegendsOfGeology
John Elliott Allan leads field trip to an outcrop of the Columbia River Basalt Group (member unknown) in the 1960s.
JAE was #Oregon ’s first State #Geologist (in the 1930s) and founder of the Geology Dept. at Portland State University (the U by the Slough) where he taught, advised and wrote numerous books on Oregon Geology and articles for The Ore Bin and other publications into the early 1990s.
