Relive Important Archive Articles

A large number of important articles get buried over time as new articles are added to our website, so here’s a chance to review and relive some of our most important articles. We think you might enjoy reviewing these timeless features.

Palagonite Maar Near Hood River

Palagonite Maar Just west of Hood River is a distinctive, short (<500 m) section of stratified orangeish oxidized volcanic tephra and highly fractured lava bombs.  This mixture of oxidized volcanic particles ranging down to sub-micrometer sizes mixed with the larger lava bombs is a palagonite tuff. This deposit is the result of a “phreatic” eruption when lava erupted explosively from a volcanic vent through water, like a lake or groundwater. The rapid heating expansion of water to steam blew the rising lava out of the vent as tephra (volcanic rock fragments) ranging from ash-size to volcanic bombs (blobs of lava) up to several inches in diameter.  Rapid oxidation of the water-quenched tephra turned the iron content to rust, producing the orangeish color of the tephra. The lava bombs were heavily fractured due to rapid cooling of the blob as it came in contact with the water and as it flew through the air. The tephra deposits dip inward on either side of a central gap toward the gap, with NE dips in the western section and NW dips in the eastern section, forming an inverted cone that converges downward toward the central gap. This feature is a “maar” deposit; an inverted cone of tephra and lava resulting from rapidly rising magma interacting with groundwater causing a steam-driven explosive eruption that builds the surrounding maar.  The vent of this maar was in the area of the central gap.

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Missoula Flood Rhythmites

Lake Missoula filled many times and emptied catastrophically in many Missoula Floods. Rhythmite sequences [a series of repeated beds of similar origin] at numerous localities provide this evidence: slack-water rhythmites in backflooded tributary valleys below the dam indicate multiple floods, and varved rhythmites in Lake Missoula attest to multiple fillings of the lake. Below the dam, most slack-water rhythmites are graded beds deposited by flood bores surging up tributary streams. They grade upward from coarse sand and gravel to silt, with occasional ice-rafted erratics. The tops of some rhythmites are marked by thin paleosols, or buried soil horizons, which indicate a period of subaerial exposure. Thus, each rhythmite represents a separate flood event, and each deposit records multiple floods. The most complete record occurs at Sanpoil Valley, an embayment on the north side of Lake Columbia, where varved rhythmites document 89 flood events, with the period of time between floods initially increasing to a maximum of about 50 years and then decreasing to less than 10 years. Thousands of varves were deposited in Lake Missoula. At the best-known Ninemile locality near Missoula, about 40 rhythmites consist of varves overlain by a sand/silt layer. The varves were deposited on the floor of Lake Missoula, and the sand/silt layers represent subaerial exposure and deposition in a stream. The number of varves in each rhythmite varies from 9 to 40, decreasing regularly upward, and the total number of varves is just less than one thousand. An interpretation of these data would suggest: [1] Lake Missoula filled and emptied [in a catastrophic flood] about 40 times, [2] it took 9 to 40 years to fill the lake, each successive lake requiring less time, and [3] the process was repeated over a period of about one thousand years. Because Ninemile is about in the middle of the very long lake, the record here would not provide a complete history of the lake. Correlating Ninemile with the downstream record would suggest these events were in the latter half of the entire flood history.

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Washington’s Ice Age Floods – ESRI Story Map

The Washington Geological Survey (formerly the Division of Geology and Earth Resources) has just released an ESRI story map about the Ice Age Floods in Washington. The story map: “tells the story of cataclysmic outburst floods that shaped the landscape of the Pacific Northwest during the last ice age. With imagery, maps and video, this story map follows the devastating deluge of the Missoula floods as it tore across the landscape, from its origins in western Montana to its terminus at the Pacific Ocean. Sites along the Ice Age Floods National Geologic Trail are featured, with an emphasis on flood features in Washington State.” Entitled Washington’s Ice Age Floods, it is best viewed on a desktop or laptop computer. Mobile devices will not show all of the content. It is navigated by scrolling your mouse through the slides. There are a few animated sections that may take a second or two to load. [weaver_iframe src=’https://wadnr.maps.arcgis.com/apps/Cascade/index.html?appid=84ea4016ce124bd9a546c5cbc58f9e29′ height=600 percent=100]

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13,000 Year-Old Human Footprints Found on BC Island

Big feet. Little feet. A heel here. A toe there. A digitally enhanced photo of a footprint found at Calvert Island, British Columbia that researchers dated to 13,000 years old. Credit Duncan McLaren Stamped across the shoreline of Calvert Island, British Columbia, are 13,000-year-old human footprints that archaeologists believe to be the earliest found so far in North America. The finding, which was published Wednesday in the journal PLOS One, adds support to the idea that some ancient humans from Asia ventured into North America by hugging the Pacific coastline, rather than by traveling through the interior. “This provides evidence that people were inhabiting the region at the end of the last ice age,” said Duncan McLaren, an anthropologist at the Hakai Institute and University of Victoria in British Columbia and lead author of the study. “It is possible that the coast was one of the means by which people entered the Americas at that time.” Dr. McLaren and his colleagues stumbled upon the footprints while digging for sediments beneath Calvert Island’s beach sands. Today, the area is covered with thick bogs and dense forests that the team, which included representatives from the Heiltsuk First Nation and Wuikinuxv First Nation, could only access by boat. At the close of the last ice age, from 11,000 to 14,000 years ago, the sea level was six to ten feet lower. The footprints were most likely left in an area that was just above the high tide line. “As this island would only have been accessible by watercraft 13,000 years ago,” Dr. McLaren said, “it implies that the people who left the footprints were seafarers who used boats to get around, gather and hunt for food and live and explore the islands.” They found their first footprint in 2014. While digging about two feet beneath the surface in a 20-square-inch hole, they saw an impression of something foot-shaped in the light brown clay. In 2015 and 2016, they returned and expanded the muddy pit. They discovered several more steps preserved in the sediment. The prints were of different sizes and pointed in different directions. Most were right feet. When the team was finished they had counted 29 in total, possibly belonging to two adults and a child. Each was barefoot. The researchers think that after the people left their footprints on the clay, their impressions were filled in by sand, thick gravel and then another layer of clay, which may have preserved them. Using radiocarbon dating on sediment from the base of some footprint impressions, as well as two pieces of preserved wood found in the first footprint, Dr. McLaren and his team found them to be 13,000 years old. That would make them the oldest preserved human footprints in North America. “It’s not only the footprints themselves that are spectacular and so rare in archaeological context, but also the age of the site,” said Michael Petraglia, an archaeologist from the Max Planck Institute for the Science of Human History in Germany who edited the paper for PLOS One but was not involved in the work. “It suggests an early entrance into the Americas.” Dr. Petraglia said the footprints also provided strong evidence for the coastal movement hypothesis and he added that they may have traveled the so-called “Kelp Highway,” a hypothesis that underwater kelp forests supported ecosystems down the North Pacific coast that helped ancient seafaring people hunt, develop and migrate. “The work is important because it shows the ‘real’ people, not just artifacts or skeletal remains,” said Steve Webb, a biological archaeologist at Bond University in Australia. “However, the footprints are limited in number and don’t shed light on activities or movement that tell us very much.” He added that future hunts for footprints should keep in mind that not everyone from this time period walked around barefoot. If anthropologists are too busy searching for soles, toes and arches, they might miss clues from those who wore animal skin shoes. Reprinted from New York Times – Earliest Known Human Footprints in North America Found on Canadian Island By NICHOLAS ST. FLEUR, March 28, 2018

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Nova – Mystery of the Mega Flood

Monument Valley, the Grand Canyon, Niagara Falls: these ancient wonders show how nature’s forces have shaped the face of our planet on a vast timescale, how great landmarks are the work of millions of years of slow, imperceptible erosion by wind and water. But here, across 16,000 square miles of Washington State, abrupt rips and scars in the landscape defy this explanation. What could have formed these tall canyons and immense dry waterfalls? What could have gouged out these gigantic potholes? Whatever happened, the forces unleashed here created one of the Earth’s most enigmatic landscapes. For more than a century, scientists have been grappling with this geological mystery, descending through thousands of years of Earth’s history in a struggle to uncover, layer by layer, how this landscape was formed. Now the clues point to a sequence of events culminating in a massive natural catastrophe. Explore the features and reasoning that lead to the recognition of the “Missoula (Outburst) Floods” and helped to solve “The Mystery of the Megaflood (Spokane Floods or the Bretz Floods)” 

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Ice Age Map Pacific NW

Ice Age Flood Simulation Video

An interesting, 4 minute captioned video from UC Santa Cruz (ingomar200) of a satellite-view computer simulation illustrating flood paths and transient lakes of an Ice Age Flood. The video shows a physics-based computer simulation of the Great Flood from Glacial Lake Missoula about 15,000 years ago. At the time, an ice dam blocked the Clark Fork River near the Idaho-Montana border and backed up a lake about equal in volume to Lake Huron. When the ice dam broke a cataclysmic flood scoured much of central Washington State leaving a vast region covered with erosional remnants.

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Front Porch: Water etches interesting stories on landscape

I have always loved the ocean. I spent my growing-up years in, on or at least somewhere near the Atlantic Ocean and its various bays. The feel of ocean water, its movement, how it smells and all the amazing life that it supports – wonderful. And whenever I looked over the ocean’s horizon, it wasn’t scary, but rather full of potential for what was just beyond what I could see. When I moved to Spokane – clearly, no ocean, but lots and lots of freshwater lakes and rivers. I have spent I can’t tell you how many of my adulthood hours, swimming in Lake Coeur d’Alene, Lake Pend Oreille, Priest Lake, etc. And sailing. And walking along riverbanks. And tossing sticks into whatever body of water, fast moving or still, that was before me, for our dog to fetch. Water is wonderful. As a young bride, newly relocated to Eastern Washington, lo those many years ago, I took my first drive to Seattle with my husband. Heading up the Sunset Hill, passing Four Lakes, then Fishtrap, then … yikes. Where did the water go? There was a long stretch – broken up briefly by Sprague Lake and Moses Lake – of what was the thirstiest landscape I’d encountered. It wasn’t until we crossed the Columbia River and drove up and past the Vantage Grade did I begin to see deciduous trees and bigger leafy plants that suggested the rainfall amounts required to support them. It got lush and humid and wet as we drove west. We were heading to … water! I just endured that unappealing stretch of land between Fishtrap and the Columbia over a number of years driving back and forth to Seattle. Not only was it dry, it was essentially treeless. One friend of like mind said it was best just to drive through there at night because the view would be just as interesting. So much for being young and stupid. It was still kind of dry for my taste, but I began to appreciate how the sunlight hit the terrain at different times of year and in different weather conditions. It still wasn’t water, of course, but it kind of grew on me. It’s hard to live in this neck of the woods and not learn about the wonderful Columbia Basin Project that brought irrigation to east-central Washington (ah, water!), which produces amazing amounts of agricultural products for export and to feed us all. But what really sold me on that, to me, foreign scenery was back when I worked at Eastern Washington University and I met the terrific Bob Quinn, professor of geography, who loved the environs of the state’s east side with a zeal and passion I couldn’t possibly imagine. He gave me some information, and I began to read about this landscape I’d so easily dismissed – land that was scoured by massive floods some 18,000 to 13,000 years ago (the last Ice Age), floods from glacial Lake Missoula that carved out the canyons and created braided waterways now known as the Channeled Scablands of Eastern Washington. The floods were cataclysmic, with estimates indicating that 500 cubic miles of water that was 2,000 feet deep, burst forth at 386 million cubic feet per second – all headed this way, and beyond, in one darn big rushing, gushing explosion. And then it built up and did it over and over again. That’s a lot of water. I began looking at the landscape differently as I drove through, marveling at the magnificence of that creation, and saw that it has its own beauty – not to mention a heck of a back story. How ignorant of me to just have ignored all that geologic magnificence because it didn’t fit into my preferred norm. I thought about that again on our most recent drive to Seattle to visit our son. Clearly, I am no longer a young adult full of not-burdened-by-knowledge opinion and attitude, but an older person with a fair number of miles on her and, I hope, a greater realization that everything deserves a second look – and also, that a little research is also a good thing. Because I read a book and some supporting literature, I discovered things that gave me a different set of eyes with which to see a particular section of the world around me. I’m trying still, even in my old age, to keep doing that. Never too old to read a book and learn something. Or to change a mind. The Spokesman Voices correspondent Stefanie Pettit can be reached by email at upwindsailor@comcast.net

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Earth Appears to Have a 27.5-Million-Year ‘Heartbeat’

Geologists have been investigating a potential cycle in geological events for a long time. A recent analysis on the ages of 89 well-understood geological events from the past 260 million years show a catastrophic 27.5 million year pulse in eight clusters of world-changing geologic events over geologically small timespans. This pulse of clustered geological events – including volcanic activity, mass extinctions, plate reorganizations, and sea level rises – is incredibly slow, a 27.5-million-year cycle of catastrophic ebbs and flows. As you can see from the graph, some of those times were tough – with over eight of such world-changing events clustering together over geologically small timespans, forming the catastrophic ‘pulse’. “These events include times of marine and non-marine extinctions, major ocean-anoxic events, continental flood-basalt eruptions, sea-level fluctuations, global pulses of intraplate magmatism, and times of changes in seafloor-spreading rates and plate reorganizations,” the team writes in their paper. These cyclic pulses of tectonics and climate change may be the result of geophysical processes related to the dynamics of plate tectonics and mantle plumes, or might alternatively be paced by astronomical cycles associated with the Earth’s motions in the Solar System and the Galaxy. Luckily for us, the research suggests we have another 20 million years before the next ‘pulse’. 

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