Ancient ‘land bridge’ that connected Siberia to US wasn’t what it seems
The boggy landscape of the Bering land bridge may have allowed some ice age animals to cross easily, while others stayed in Asia. The Bering land bridge that spanned between Siberia and Alaska during the Ice Age was more of a Bering land bog, new research finds. The discovery could help explain why some animals, such as birds, easily crossed the land bridge, while others, like woolly rhinos (Coelodonta antiquitatis), didn’t make the migration. The land bridge, now submerged under the Bering Strait between Alaska and Russia, was above water from about 36,000 years ago to 11,000 years ago. Scientists thought it might have looked a lot like the grassy, arid steppe landscape in Siberia and Alaska at the time — but no one had ever investigated the ocean floor where the “bridge” once stood. Last year, researchers led by University of Alaska Fairbanks geologist Sarah Fowell set out on the research vessel Sikuliaq to extract cores of sediment from the floor of the Bering Sea. It was the first attempt to reconstruct the ancient landscape and climate of the land bridge. The researchers presented their results today (Dec. 10) at the annual meeting of the American Geophysical Union in Washington, D.C. Instead of a grassy steppe, they found a marshy landscape crisscrossed by rivers and dotted with little lakes. “We were looking for several large lakes,” Fowell said. “What we actually found was evidence of lots of small lakes and river channels.” Lake sediments were apparent in the ocean floor cores, as were pollen, small fossils, ancient DNA and organic matter. The pollen and fossils revealed that the landscape hosted trees and mosses. The researchers also found egg cases from water fleas (Daphnia), a freshwater crustacean. This marshy environment may have been particularly welcoming for some species such as birds, but there were also spots where there was evidence of larger mammals making the migration. One site hosted mammoth DNA. Bison are also known to have crossed from Eurasia to North America during the time that the land bridge existed, and horses are known to have made it from North America to Eurasia. “Even if it was mostly floodplains and ponds, the grazers were around, just uphill following higher, drier areas,” Fowell said. However, the environment may have been less conducive for species that did not make the move between continents, such as the woolly rhino (a Eurasian native), American camel (native to north and central America), and the short-faced bear (native to North America). “The watery, wet landscape could have been a barrier for some species,” said Jenna Hill, a geologist with the U.S. Geological Survey who is also presenting research on the Bering Sea core data at the AGU meeting, “or a pathway for species that actually travel by water.” Further research will be needed to understand the full impact of the environment on migration. Republished from an article by Stephanie Pappas in Live Science
Explore Lake Roosevelt National Recreation Area
The Lake Roosevelt National Recreation Area serves as a striking landmark that narrates a dramatic geological history shaped by colossal natural forces. Greatly influenced by the Missoula Floods, this area, part of the Ice Age Floods National Geologic Trail, reveals not only stunning landscapes but also insights into the Earth’s geological story. Understanding this region offers a glimpse into the powerful events that occurred between 13,500 and 18,500 years ago, as well as the enduring environmental significance of these features. Lake Roosevelt and Grand Coulee Dam Lake Roosevelt, created by the Grand Coulee Dam in the 1930s, serves multiple purposes: from water storage and hydroelectric power generation to recreation and wildlife preservation. The lake provides a crucial habitat for various species and supports a vibrant ecosystem and is home to a range of fish species, including walleye, rainbow trout, and Kokanee salmon. The surrounding lands offer habitats for birds and other wildlife, contributing to ecological balance. With over 400 miles of scenic shoreline, the 150 mile long goes from Grand Coulee nearly to the Canadian board and is a haven for outdoor enthusiasts. The lake offers expansive waters perfect for various forms of boating. Anglers can enjoy abundant fishing opportunities year-round. 32 different campgrounds such as Spring Canyon close to Grand Coulee, WA offer numerous places to extend your overnight stays with these stunning landscapes. Historical Heritage The Lake Roosevelt area holds historical significance for the Confederated Tribes of the Colville Reservation and the Spokane Tribe of Indians, highlighting the intertwined relationship between Native heritage and the natural landscape. The National Park Service (NPS) supports Bureau of Reclamation management of Bakes Lake, Coulee Dam, and Lake Roosevelt. NPS works with Washington State Parks throughout the Grand Coulee Corridor and along with the Tribes and Washington Department of Natural Resources, oversees recreation on the water and lands of Lake Roosevelt NRA. Our collective efforts work to ensure that these natural treasures are preserved for future generations. Visitors to the area can engage with a variety of programs and informational resources that enhance their understanding and respect for the environment. Power in Nature The Grand Coulee and Lake Roosevelt National Recreation Area stand as remarkable examples of nature’s power and the intricate tapestry of geological history. From the cataclysmic Missoula Floods that sculpted the landscape to the thriving ecosystems supported by Lake Roosevelt, this region offers an unparalleled opportunity for exploration and discovery. Whether you are an avid hiker, a passionate angler, or a curious geology enthusiast, this area provides not only recreational activities but also a deeper connection to the Earth’s history. As we delve into the breathtaking scenery and rich cultural heritage of this national recreation area, we are reminded of the dynamic forces that shape our world. The Grand Coulee and Lake Roosevelt invite each visitor to engage with the past while understanding the importance of stewardship for future generations. This stunning landscape not only captivates the eye; it expands our knowledge of nature and our place within Ice Age Floods National Geologic Trail.
Coyote Canyon Mammoth Dig
The Coyote Canyon Mammoth Dig is an active paleontological excavation site in the Horse Heaven Hills near Kennewick, Washington. It’s a significant project that sheds light on the history of the Ice Age floods in the Tri-Cities area. The dig focuses on the unearthed remains of a Columbian mammoth that lived approximately 17,500 years ago. The mammoth’s carcass was buried in Touchet beds, a geological formation laid down by ancient floods. The site sits at an elevation of 1040 feet above sea level, which is considerably higher than the current elevation of the Columbia River, which is only 350 feet above sea level about 7 miles north. Scientists estimate that Lake Lewis, a massive glacial lake that existed during the Ice Age, reached a maximum surface elevation of over 1200 feet above sea level at the time the mammoth perished. This substantial difference in elevation hints at the immense power of the Ice Age floods that swept across the region. Another fascinating aspect of the Coyote Canyon Mammoth Dig is the discovery of a vast pile of erratic rocks. Initially thought to be a small cluster, the collection of these displaced rocks has grown to extend into several adjacent dig units. A dig unit, for those unfamiliar with archaeological and paleontological fieldwork, is a standardized square measuring 2 meters by 2 meters that archaeologists and paleontologists use to meticulously excavate and collect data. The MCBones Research Center, a non-profit organization, spearheads the Coyote Canyon Mammoth Dig. They offer educational tours for schools and other groups, providing a firsthand look at this significant paleontological excavation. These tours are a great opportunity to learn more about the Ice Age floods, mammoths, and the meticulous work of paleontologists. For more information about the Coyote Canyon Mammoth Dig, including details about tours, visit the MCBones Research Center website at www.mcbones.org.
Volunteers Help Shape the IAFI!
We’re reaching out to ask for your help. As we work toward our mission of promoting public awareness and education about the Ice Age Floods, our chapters have been facing a significant challenge: a shortage of active member volunteers willing to step into leadership roles or assist with essential chapter functions. Many of our current leaders are in their 70s and 80s, and the demands of their roles are becoming challenging. While our dedicated leaders works to maintain our organization’s momentum, we need support to ensure our continued growth and success. Your involvement will be crucial in helping to: Organize events: Assist with planning field trips, chapter functions, and speaker series. Provide administrative support: Help with recordkeeping, website updates, and newsletter contributions. Engage with the community: Connect with local schools and media outlets to spread awareness about our mission. Contribute fresh perspectives: Share your ideas and expertise to help us adapt to a changing world. Here are some ways you can get involved: Volunteer for events: Help plan and execute field trips, workshops, and conferences. Join a committee: Contribute to our leadership team and help make important decisions. Share your expertise: Offer your skills in areas like marketing, communications, or technology. By becoming more involved, you can: Strengthen your chapter: Contribute your time and skills to make your local chapter more vibrant and effective. Share your knowledge: Bring new ideas and contemporary skills to our organization. Support the organization: Help IAFI achieve its goals and become the foremost provider of Ice Age Floods information. No matter your level of experience or commitment, we welcome your participation. Whether you can volunteer a few hours a month or are interested in taking on a leadership role, your involvement will make a significant difference. The involvement of many will lighten the load on the few, and also bring a much-needed infusion of energy and fresh perspectives. We believe that by working together, we can strengthen our organization and better serve our mission of promoting public awareness and education about the Ice Age Floods. Your participation is essential. To get involved, please contact your local chapter through the IAFI.org website
Bitterroot Valley Glacial Erratics
Two glacial erratics in the Bitterroot Valley, the Lone Rock School erratic and the Rome Lane erratic, were deposited during the last high stand of Lake Missoula about 13,000 years ago. Both these glacial erratics are easy to visit. At the extreme Southern end of the Bitterroot Valley is beautiful Lake Como named after its Italian alpine counter part by Father Ravalli a Jesuit Black Robe tasked with bringing literacy and Jesus to the native Salish people in 1845 via St Mary’s Mission in nearby Stevensville. Lake Como is a beautiful place for lunch and a hike/bike on the trail around lake including a beautiful waterfall a the head of the lake. Several mountain glaciers coalesced here and neighboring drainage to make the largest mass of ice calving into the lake south of the Flathead lobe of the Cordilleran ice sheet at Polson. This mass exited the mountains, floated into and calved into Glacial Lake Missoula. This was the primary iceberg generator for the Bitterroot Valley. As they floated out into the lake and melted they dropped large rocks called erratic onto the lake floor, which is now the surface of the valley. Lone Rock School Erratic The easiest one to find is the Lone Rock School erratic. From Stevensville, proceed north on the Eastside Highway, county road 269, to the junction with county road 268, turn right. Follow county road 268 until you reach the Lone Rock School on your left; the erratic is the large boulder in front of the south side of the school, and behind the fence (see map below). The Lone Rock School erratic is 69” tall, 58” wide, 85” long, and weighs in at about 8.5 metric tons or about 18,700 lbs. This large erratic is a type of granite called quartz monzonite. The minerals that make up this rock type are, in order of abundance, plagioclase (calcium and/or sodium rich) feldspar, orthoclase (potassium rich) feldspar, biotite (dark mica), and quartz. If you look closely you will see that the quartz typically stands out in relief with respect to the other minerals and that its surface has been polished to a smooth finish. This is the result of dense glacial ice grinding over the surface of the rock. Rome Lane Erratic The Rome Lane erratic measures 47” tall, 117” long, 96” wide, and weighs in at about 13 metric tons or about 28,600 lbs. The Rome Lane erratic is almost identical to the Lone Rock School erratic; it to is quartz monzonite granite with approximately the same minerals and mineral proportions. The observation that both erratics are of similar rock type suggests that they came from a similar source region. There are sources of quartz monzonite granite in both the Sapphire and Bitterroot Mountains, which is the source of these erratics? Since we know that the erratics were carried to the shores of glacial Lake Missoula by glaciers, we can rule out the Sapphires as a possible source because we know that no glaciers in the Sapphire Mountains ever reached the shores of Lake Missoula. So, the erratics had to come from the Bitterroot Mountains where the quartz monzonite granite lies anywhere between 5 and 20 miles from the ancient shoreline of Lake Missoula. That means glaciers carried the erratics for distances of up to 20 miles (32.2 km) before reaching the shores of glacial Lake Missoula. Which at an average velocity of 5 meters per day (normal for most valley glaciers with the exception of rare bursts in velocity up to 75 meters per day) would take about 18 years. Which Erratic is Oldest? The quartz grains on the surfaces of the Rome Lane erratic are polished to a smooth shine and stand out in relief above the other minerals, similar to the Lone Rock School erratic. However, the quartz grains exposed on the top surface of the Rome Lane erratic seem to exhibit higher relief than the quartz grains exposed on any other side of the Rome Lane erratic and/or the top surface of the Lone Rock School erratic. Why is this? Rainwater is slightly acidic and acidic fluids can break down some minerals, such as feldspar, and turn them into clay. Quartz, however, is very resistant to acidic fluids and as a result takes longer to break down or weather. It is this difference in weathering rates between feldspar and quartz that causes the quartz grains to stand higher than the feldspar grains. So, based on this relationship we can say that the greater the relief between quartz and feldspar on a rock surface, the longer that surface has been exposed to the elements i.e. rain and wind. With that in mind, which erratic’s top surface has been exposed longer? If you answered Lone Rock, you are correct. As it turns out the Lone Rock School erratic was dug up and moved from its original location, about ¾ of a mile to the south of where it sits today, to commemorate the Lone Rock Schools’ centennial in 1985, in fact upon its excavation portions of the erratic broke off and remain buried. So what is the top surface of the Lone Rock School erratic today may well not have been the top surface before 1985, and our mineral weathering hypothesis fits the facts.
Was the 1700 Cascadia earthquake one or many ruptures?
It’s generally accepted that a massive Cascadia earthquake occurred along the British Columbia-Washington-Oregon-N. California coast on January 26, 1700. The earthquake was a result of a rupture of the plate boundary between the North American plate overriding and subducting the Juan de Fuca plate. The evidence for the magnitude and precise timing of the quake includes tsunami deposits and dendrochronology dating at many places along that coastline, and records of a “ghost” tsunami at several locations in Japan. In a Sept. 24, 2024 presentation for Central Oregon Geoscience Society, Diego Melgar of University of Oregon explained earthquake modeling that is seeking to match the earthquake evidence. It turns out there may be millions of possible scenarios where an initial 8.1 to 9.2 magnitude quake followed by up to 5 lesser magnitude aftershocks up to months later could potentially fit the data. That’s not really good news for the Cascadia region, because multiple giant quakes would be no less hazardous than one enormous one. The geological history of the Cascadia subduction zones suggests that it experiences very large earthquakes every few centuries (between every 240 years and every 500 years). The question now is whether these temblors always occur as a single huge earthquake or if sometimes they’re a series of very big ones. Better understanding the nature of the earthquake(s) is important for estimating future tsunami hazards and for developing building codes, disaster response plans, and other critical earthquake-dependent planning. Diego expects continued modeling that considers data from turbidites and tsunami deposit thicknesses may help narrow the possible scenarios, but he stresses that even an 8.1 magnitude quake can be quite devastating. “The tsunami might not be as large from an 8.1, but the shaking can be really intense,” Melgar said. “It’s just dangerous in a different way. Indeed, a decade in which giant quakes hit every two or three years might even be more devastating to people living in the region than a single quake hitting every few hundred years. That’s why it’s important to get to the bottom of which scenario is more likely.” View the recording of Diego’s presentation here or read the “Was a humongous Cascadia earthquake just one of many?” article in Live Science by Stephanie Pappas here.
J Harlan Bretz – His Personal Memories
Glenn Cruickshank recently met with Dean Kiefer. who shared a copy of J Harlan Bretz’s 4-volume memoirs in scanned .pdf format. Glenn converted them to text that also made them searchable. They are a very interesting read, though a bit stream-of-Bretz-consciousness in some sections. Still historically interesting, and a good add to our repository. Click the links below and enjoy! J Harlan Bretz Memories – Part 1 – 1972 J Harlan Bretz Memories – Part 2 J Harlan Bretz Memories – Part 3 J Harlan Bretz Memories – Part 4 – 1975
Video – How Earth Has Changed in 1.8 Billion Years
Among the planets in the Solar System, Earth is unique for having plate tectonics. Mapping our planet through its long history creates a beautiful continental dance — mesmerizing in itself and a work of natural art. This is the first time Earth’s geological record has been used to look so far back in time in an attempt to map the planet over the last 40% of its history. The work, led by Xianzhi Cao from the Ocean University in China, is now published in the open-access journal Geoscience Frontiers. Our planets rocky surface is split into fragments (plates) that grind into each other and create mountains, or split away and form chasms that are then filled with oceans. There are 4.6 billion years of plate motion to investigate, and the rocks we walk over contain the evidence for how Earth has changed over this time. This is a first attempt at mapping the last 1.8 billion years of Earth’s history – a leap forward in the scientific grand challenge to map our world. Modelling our planet’s past is essential if we’re to understand how nutrients became available to power evolution. Apart from causing earthquakes and volcanoes, plate tectonics also pushes up rocks from the deep earth into the heights of mountain ranges. This way, elements which were far underground can erode from the rocks and end up washing into rivers and oceans. From there, living things can make use of these elements. A number of critical metals – like copper and cobalt – are more soluble in oxygen-rich water. In certain conditions, these metals are then precipitated out of the solution: in short, they form ore deposits. Many metals form in the roots of volcanoes that occur along plate margins. By reconstructing where ancient plate boundaries lay through time, we can better understand the tectonic geography of the world and assist mineral explorers in finding ancient metal-rich rocks now buried under much younger mountains. Such a model will allow us to test hypotheses about Earth’s past. For example, why Earth’s climate has gone through extreme “Snowball Earth” fluctuations, or why oxygen built up in the atmosphere when it did. Indeed, it will allow us to much better understand the feedback between the deep planet and the surface systems of Earth that support life as we know it. Excerpted from a Science Alert article by Alan Collins, Professor of Geology, University of Adelaide
A New Class of Plate Tectonics – Lithospheric Dripping
Crinkles and divots in the surface of Earth on Türkiye’s Central Anatolian Plateau are the smoking gun for a newly discovered class of plate tectonics. Beneath a depression called the Konya Basin, Earth’s crust is slowly dripping deeper into the planetary interior, a process that is gradually shaping the surface geology of not just the basin, but the plateau that surrounds it. It’s called lithospheric dripping, a phenomenon that has only recently been discovered here on Earth, and geologists are still figuring out the different ways it manifests. When the lower portion of Earth’s rocky crust is heated to a certain temperature, it starts to go a little gooey. Then, like honey or syrup, it slowly oozes downward – a bit like a pitch drop experiment, but much bigger and slower. As this drop descends, it pulls the planetary crust down with it. This creates a depression, or basin. Then, when the drop detaches into the mantle, the surface rebounds, bulging upwards, with a widespread effect. The Central Anatolian Plateau is known to be uplifting over time. Previous research suggests that it has gained around a kilometer (0.6 miles) in altitude over the past 10 million years thanks to the release of a crusty drip. But then there’s the Konya Basin, which is subsiding downwards at a rate of around 20 millimeters (0.8 inches) per year. That doesn’t sound like much, but a sinking patch of ground in a region that is rising upwards warrants further investigation. The broader region of the plateau is in the throes of the rebound phase of the lithospheric drip process, after having dropped its gooey molten load into the mantle. The Konya Basin? That’s a smaller, second drip forming. “As the lithosphere thickened and dripped below the region, it formed a basin at the surface that later sprang up when the weight below broke off and sank into the deeper depths of the mantle,” says Earth scientist Russell Pysklywec of the University of Toronto. “We now see the process is not a one-time tectonic event and that the initial drip seems to have spawned subsequent daughter events elsewhere in the region, resulting in the curious rapid subsidence of the Konya Basin within the continuously rising plateau of Türkiye.” Excerpt from a Science Alert article By Michelle Starr
The Case for Rapid and Recent flooding in the Upper Grand Coulee
24Sep2024 – This month we are honored to have Dr. Karin Lehnigk, Postdoctoral Researcher at Georgia Tech, as our speaker. Upper Grand Coulee, the largest flood-carved canyon in the Channeled Scabland, has long intrigued scientists and non-scientists alike. Due to its large size, researchers have thought that it likely took multiple glaciations to incise upper Grand Coulee. However, recent geochemical dating and hydraulic simulations of flooding in and around upper Grand Coulee suggest that the canyon was carved by <10 floods, and that this erosion took place entirely during the last Ice Age. The young age and rapid growth of upper Grand Coulee indicates that the Missoula Floods were exceptional agents of landscape change, even compared to other highly-erosive events. The Channeled Scablands of eastern Washington is a perfect location to see how surface processes have changed the appearance of the landscape. Huge glacial outburst floods during the last ice age (Fraser) carved impressive canyons into the basalt bedrock, and the ice, water, and deposited sediment have left a complicated trail to decipher. Karin performed cosmogenic nuclide exposure dating on flood-transported boulders to determine what path the floods took at different points in time. Additionally, she simulated individual flood events by hydraulic modeling over various topographic reconstructions, to constrain the discharges of these floods. Her previous work has focused on river network geometry, using the shapes of fluvial networks on Mars to understand how volcanic activity influenced the movement of water during episodic meltwater floods. Originally from Virginia, Karin was drawn to geomorphology by the range of landscapes she encountered throughout the Mid-Atlantic. She completed her PhD at UMass Amherst, where she studied the landscape impacts of outburst floods in the Channeled Scabland, as well as in Nepal and Norway. She is currently investigating water/sediment interactions in outburst floods in the Himalaya and on Mars, as well as hazards from modern dam-break floods, as a postdoc at Georgia Tech.