Could a Glacial Outburst Flood Repeat the “Younger Dryas” Cooling Event?
An ancient flood seems to have stalled the circulation of the oceans, plunging the Northern Hemisphere into a millennium of near-glacial conditions. Thirteen thousand years ago, an ice age was ending, the Earth was warming, the oceans were rising. Then something strange happened – the Northern Hemisphere suddenly became much colder, and stayed that way for more than a thousand years. For some time, scientists have been debating how this major climatic event – called the “Younger Dryas” – happened. The question has grown more urgent: Its answer may involve the kind of fast-moving climate event that could occur again. This week, a scientific team made a new claim to having found that answer. On the basis of measurements taken off the northern coasts of Alaska and Canada in the Beaufort Sea, the scientists say they detected the signature of a huge glacial flood event that occurred around the same time. This flood, they posit, would have flowed from the Arctic into the Atlantic Ocean and shut down the crucial circulation known as the “Atlantic meridional overturning circulation” (or AMOC) – plunging Europe and much of North America back into cold conditions. “Even though we were in an overall warming period, this freshwater, exported from the Arctic, slowed down the vigor, efficiency of the meridional overturning, and potentially caused the cooling observed strongly in Europe,” said Neal Driscoll, one of the study’s authors and a professor at the Scripps Institution of Oceanography. The work, published in Nature Geoscience, was led by Lloyd Keigwin of the Woods Hole Oceanographic Institution along with researchers at that institution, Scripps and Oregon State University. The result remains contested, though, with other researchers still arguing for different theories of what caused the Younger Dryas – including a very differently routed flood event that would have entered the ocean thousands of miles away. Nonetheless, the story is relevant because today, we’re watching another – or rather, a further – deglaciation, as humans cause a warming of the planet. There is also evidence that the Atlantic circulation is weakening again, although scientists certainly do not think a total shut-off is imminent, and are still debating the causes of what is being observed. Either way, the new research underscores that as the Earth warms and its ice melts, major changes can happen in the oceans. And could happen again. The researchers behind the current study, working on board the U.S. Coast Guard Cutter Healy, analyzed sediments of deep ocean mud, which contain the shells of long-dead marine organisms called foraminifera. In those shells, the scientists detected a long-sought-after anomaly recorded in the language of oxygen atoms. The shells contained a disproportionate volume of oxygen−16, a lighter form (or isotope) of the element that is found in high levels in glaciers. That is because oxygen−16, containing two fewer neutrons and therefore lighter than oxygen−18, evaporates more easily from the ocean but does not rain out again as readily. As a result, it often falls as snow at high latitudes and is stored in large bodies of ice. “This is the smoking gun for fingerprinting glacial lake outbursts,” Driscoll said. And that means the findings may also represent the trigger for the Younger Dryas. The thinking is that as the ice age ended and the enormous Laurentide ice sheet atop North America began to retreat, the resulting meltwater fed a bevy of large lakes atop the depressed surface of the continent. That included the massive glacial Lake Agassiz, which stretched from the Great Lakes northwestward across much of Canada. The approximate maximum extents of major glacial lakes that formed from the retreat of the western Laurentide Ice Sheet. (Shannon Klotsko, Scripps Institution of Oceanography, University of California at San Diego) Prior research had shown that for a while, much of the resulting freshwater drained down the Mississippi River and into the Gulf of Mexico. But at some point, as the ice sheet continued to shrink, the flow of water appears to have been suddenly rerouted to the north or to the east, where it could do more potential damage to the ocean circulation in the Atlantic. There has long been scientific debate about where all the meltwater actually entered the ocean, though – with some contending that it would have occurred through the St. Lawrence River, which flows past today’s Montreal and Quebec City and thus out into the Atlantic. The new research holds that, instead, the floodwater exited through the Mackenzie River, which stretches across today’s Northwest Territories, emptying straight into the Arctic Ocean. It would certainly have been an enormous flow of fresh water. “I would say somewhere between the Mississippi and the Amazon,” Keigwin said. That could have interfered with the Atlantic circulation, which is crucial because it carries warm water northward, and so heats higher latitudes. Eventually, the waters of the circulation become very cold as they travel northward, but because they are also quite salty, they sink because of their high density and travel back south again. Freshening is therefore the Achilles’ heel of the circulation. And the new study argues that although the glacial water would have entered the seas very far away near the present Alaska-Canada border, it would have then circulated around the Arctic, eventually traveling south past Greenland and entering the key regions that are crucial to the overturning circulation, which tend to be off Greenland’s southern coasts. Not everyone is convinced, though – including some researchers who have previously published results suggesting that the outburst flood or flow was instead to the east, through the St. Lawrence River. “They have produced a nice signal of the release of freshwater into the Arctic Ocean, but the conclusions are based on an uncertain chronology which, when trying to tie together events so closely, requires some independent confirmation,” Peter Clark, an Oregon State University geoscientist who has published evidence supporting the St. Lawrence River theory, said in an email. Anders Carlson, Clark’s co-author and colleague at Oregon State University, sent a geological study finding that, as he put
First People in the Americas – When? How?
When and how did the first people come to the Americas? The conventional story says that the earliest settlers came via Siberia, crossing the now-defunct Bering land bridge on foot and trekking through Canada when an ice-free corridor opened up between massive ice sheets toward the end of the last ice age. But with recent archaeological evidence casting doubt on this thinking, scientists are seeking new explanations. One dominant, new theory: The first Americans took a coastal route along Alaska’s Pacific border to enter the continent. A new geological study provides compelling evidence to support this hypothesis. By analyzing boulders and bedrock, a research team led by the University at Buffalo shows that part of a coastal migration route became accessible to humans 17,000 years ago. During this period, ancient glaciers receded, exposing islands of southern Alaska’s Alexander Archipelago to air and sun — and, possibly, to human migration. The timing of these events is key: Recent genetic and archaeological estimates suggest that settlers may have begun traveling deeper into the Americas some 16,000 years ago, soon after the coastal gateway opened up. The research will be published online on May 30 in the journal Science Advances. “People are fascinated by these questions of where they come from and how they got there,” says lead scientist Jason Briner, PhD, professor of geology in UB’s College of Arts and Sciences. “Our research contributes to the debate about how humans came to the Americas. It’s potentially adding to what we know about our ancestry and how we colonized our planet.” “Our study provides some of the first geologic evidence that a coastal migration route was available for early humans as they colonized the New World,” says UB geology PhD candidate Alia Lesnek, the study’s first author. “There was a coastal route available, and the appearance of this newly ice-free terrain may have spurred early humans to migrate southward.” The findings do not mean that early settlers definitely traversed Alaska’s southern coast to spread into the Americas: The project examined just one section of the coast, and scientists would need to study multiple locations up and down the coastline to draw firmer conclusions. Still, the work is exciting because it hints that the seafaring theory of migration is viable. The bones of an ancient ringed seal — previously discovered in a nearby cave by other researchers — provide further, tantalizing clues. They hint that the area was capable of supporting human life at the time that early settlers may have been passing through, Briner says. The new study calculates that the seal bones are about 17,000 years old. This indicates that the region was ecologically vibrant soon after the ice retreated, with resources including food becoming available. Co-authors on the research included Briner; Lesnek; Charlotte Lindqvist, PhD, an associate professor of biological sciences at UB and a visiting associate professor at Nanyang Technological University; James Baichtal of Tongass National Forest; and Timothy Heaton, PhD, of the University of South Dakota. A landscape, touched by ice, that tells a story To conduct their study, the scientists journeyed to four islands within the Alexander Archipelago that lie about 200 miles south/southeast of Juneau. The team traveled by helicopter to reach these remote destinations. As soon as the researchers arrived, Briner knew that the islands had once been covered by ice. “The landscape is glacial,” he says. “The rock surfaces are smooth and scratched from when the ice moved over it, and there are erratic boulders everywhere. When you are a geologist, it hits you in the face. You know it immediately: The glacier was here.” To pinpoint when the ice receded from the region, the team collected bits of rock from the surfaces of boulders and bedrock. Later, the scientists ran tests to figure out how long the samples — and thus the islands as a whole — had been free of ice. The researchers used a method called surface exposure dating. As Lesnek explains, “When land is covered by a glacier, the bedrock in the area is hidden under ice. As soon as the ice disappears, however, the bedrock is exposed to cosmic radiation from space, which causes it to accumulate certain chemicals on their surface. The longer the surface has been exposed, the more of these chemicals you get. By testing for these chemicals, we were able to determine when our rock surfaces were exposed, which tells us when the ice retreated. “We use the same dating method for huge boulders called erratics. These are big rocks that are plucked from the Earth and carried to new locations by glaciers, which actually consist of moving ice. When glaciers melt and disappear from a specific region, they leave these erratics behind, and surface exposure dating can tell us when the ice retreated.” For the region that was studied, this happened roughly 17,000 years ago. The case for a coastal migration route In recent years, evidence has mounted against the conventional thinking that humans populated North America by taking an inland route through Canada. To do so, they would have needed to walk through a narrow, ice-free ribbon of terrain that appeared when two major ice sheets started to separate. But recent research suggests that while this path may have opened up more than 14,000 years ago, it did not develop enough biological diversity to support human life until about 13,000 years ago, Briner says. That clashes with archaeological findings that suggest humans were already living in Chile about 15,000 years ago or more and in Florida 14,500 years ago. The coastal migration theory provides an alternative narrative, and the new study may mark a step toward solving the mystery of how humans came to the Americas. “Where we looked at it, the coastal route was not only open — it opened at just the right time,” Lindqvist says. “The timing coincides almost exactly with the time in human history that the migration into the Americas is thought to have occurred.” The research was
Uncovering a Columbian Mammoth
There’s a Columbian Mammoth hiding out in Coyote Canyon down Kennewick way, and MCBONES Research Center Foundation is working to uncover his/her hiding place. For a small contribution you can tour this hide-and-seek site, or you can volunteer to help uncover the hidden mammoth. Sound interesting? Find out more in this short video produced by Mark Harper of “Smart Shoot“, or visit the MCBONES website. The Mid-Columbia Basin Old Natural Education Sciences (MCBONES) Research Center Foundation provides local K-12 teachers and their students, as well as other volunteers, an opportunity to actively participate in laboratory and field-based research in paleontology, geology, paleoecology, and other natural sciences primarily within the Mid-Columbia Region of southeast Washington State.
Global Human Migration Paths and Timing
There is considerable controversy regarding when humans first migrated into the Americas and whether they might have been in the local area during any of the Ice Age Floods. This 2016 video, produced by reputable sources, doesn’t answer that question, but it is an interesting and instructive visualization of human migration paths and timing over the past 200,000 years.
IAFI – GuideStar Bronze
Ice Age Floods Institute was recently recognized for our transparency with a 2018 Bronze Seal on our GuideStar Nonprofit Profile! GuideStar is the world’s largest source of information on nonprofit organizations. More than 8 million visitors per year and a network of 200+ partners use GuideStar data to grow support for nonprofits. In order to get the 2018 Bronze Seal, Ice Age Floods Institute shared important information with the public using our profile on GuideStar. Now our community members and potential donors can find out more about our mission and programs. Check out our GuideStar Nonprofit Profile and tell us what you think.
The Cerutti Mastodon Site – A Bretz Type Controversy of Our Time
In March, while visiting San Diego, I went to the San Diego Museum of Natural History in Balboa Park and toured the remarkable Cerutti Mastodon Site exhibit. This controversial exhibit of a mastodon site is notable for its claim that the mastodon’s bones were broken by humans 130,000 years ago, making it far older than any other such site in North America. The signs at the beginning of the exhibit read as follows; “The Cerutti Mastodon discovery. A San Diego find reveals the earliest evidence of of human life in North America. In 1992, paleontologists from the San Diego Natural History Museum were surveying a highway construction site to identify and salvage any fossils that might be unearthed. “Field paleontologist Richard Cerutti spotted some bones and tusks. Exploring further, the team discovered that these were bones of a mastodon-an extinct relative of elephants. “But Richard noticed something unusual. The bones were mysteriously broken and the pieces separated. “It took 22 years for scientists to solve the riddle. Once they did, they realized that this local site is evidence of human presence on this continent 130,000 years ago-much earlier than we thought possible. “In 2014, scientists made a new discovery about the age of the Cerutti Mastodon Site. How did this happen? Scientists figured out the age of the mastodon bones using radiometric dating. It’s a way of telling how old a rock or fossil is by measuring its radioactive isotopes. “A radioactive isotope transforms into an isotope of a different element over time. If you know the rate at which the “parent” isotope transforms into its “daughter” isotope, measuring the parent-daughter ratio tells you how old the material is. “Scientists used a method that measures the ratio of the radioactive isotope uranium-234 to its daughter isotope thorium-230. Dramatic improvements in this method have made it a highly accurate means of dating very old materials- up to 500,000 years. In 2014, scientists used this method to date bones at the Cerutti Mastodon Site. “The results were clear. The bones are approximately 130,000 years old.” More than two decades after the Cerutti mastodon’s discovery in southern California in 1993, USGS scientist Dr. James Paces was sent several bones of unknown age. The specimens were important because they came from a site with abundant evidence of processing by ancient humans. Advances in analytical capabilities and the understanding of processes that incorporate natural uranium and its decay products in fossil bone provided archaeologists with a radiometric dating tool that, at least in some cases, could confidently and accurately determine ages for these older materials. After analyzing nearly 100 subsamples from multiple specimens, Dr. Paces determined that the mastodon bones—which were still fresh when someone fractured them using hammerstones and rock anvils—were covered with sediments 131,000 years ago, give or take about 9,000 years. This result indicates that some form of archaic humans arrived in the Americas more than 100,000 years earlier than scientists had thought possible. Following the dating of the bones officials at the Natural History Museum began making plans for a permanent exhibit about the discovery. The exhibit opened in 2017. It is very thorough and includes bones, alleged hammerstones, and anvil rocks from the original mastodon site as well as numerous photos and interpretive panels. When J Harlen Bretz first announced in the 1920’s his theory that the scablands of eastern Washington State had been carved out by a cataclysmic flood he met stiff opposition. What he was proposing was so far out of the mainstream of geological thinking of the time that many scientists couldn’t accept it. Schooled in uniformitarianism they believed that earth’s landforms were all created by slow gradual processes operating over time and that an event of the magnitude Bretz was proposing just wasn’t possible. They tried to come up with alternative explanations for the facts Bretz presented that fit in with their current frame of reference. Yale University geologist Richard Foster Flint famously said of certain flood features in the scablands that they presented “a picture of leisurely streams with normal discharge.” The claim by San Diego’s Natural History Museum that the Cerutti site is 130,000 years old is likewise far outside what many scientists of our time are ready to accept. Other similar sites are much younger. For example Sequim’s famous mastodon site is only 13,800 years old. If the San Diego Natural History Museum is correct it totally rewrites the history books about humans in North America. It places humans in North America during a previous interglacial period. It would establish that humans had long since been in North America during the time of the comparatively recent ice-age floods. Critics of the Natural History Museum, and there are many, point to things like what they consider to be a lack of lithics from the site. Others speculate that the signs of bone breakage observed at the site may have been caused by some other creature besides humans or by modern day construction equipment. But the Natural History Museum counters that none of the critics have provided a satisfactory alternative explanation for the evidence that they’ve presented. Cerutti and his team of researchers and the San Diego Natural History Museum remain unequivocal in their conclusion: The Cerutti Mastodon Site is a 130,000 year old archaeological site. – by Mark Sundquist, Puget Lobe Chapter “Ideas without precedent are generally looked upon with disfavor and men are shocked if their conceptions of an orderly world are challenged.” J Harlen Bretz 1928 “Extraordinary claims require extraordinary evidence – each aspect requires the strongest scrutiny,” Chris Stringer
Jökulhlaups in Alaska’s Wrangell-St. Elias National Park
A recent Smithsonian Magazine article gives some interesting insights to present-day Jökulhlaups (glacial outburst floods) that are but minuscule relatives of the cataclysmic Ice Age Floods. Iceberg Lake was on the edge of a western tributary of the Tana Glacier, but in 1999 the lake suddenly vanished. Dammed on its southern end by ice, the water, with persistently warming temperatures, had bored a hole under the ice and escaped through tunnels to emerge ten miles away and empty into the Tana River. The sudden drainage of a glacier-dammed lake is not uncommon. “Some lakes in Wrangell-St. Elias regularly drain,” Loso said. Hidden Creek Lake, for instance, near McCarthy, drains every summer, pouring millions of gallons through channels in the Kennicott Glacier. The water gushes out the terminus of the Kennicott, causing the Kennicott River to flood, an event called a jokulhlaup—an Icelandic word for a glacial-lake outburst flood. “The Hidden Creek jokulhlaup is so reliable,” said Loso, “it has become one of the biggest parties in McCarthy.” But the disappearance of Iceberg Lake was different, and unexpected. It left an immense trench in the ground, the ghost of a lake, and it never filled up again. The roughly six-square-mile mudhole turned out to be a glaciological gold mine. The mud, in scientific terms, was laminated lacustrine sediment. Each layer represented one year of accumulation: coarse sands and silts, caused by high runoff during the summer months, sandwiched over fine-grained clay that settled during the long winter months when the lake was covered in ice. The mud laminations, called varves, look like tree rings. Using radiocarbon dating, Loso and his colleagues determined that Iceberg Lake existed continuously for over 1,500 years, from at least A.D. 442 to 1998. “In the fifth century the planet was colder than it is today,” Loso said, “hence the summer melt was minimal and the varves were correspondingly thin.” The varves were thicker during warmer periods, for instance from A.D. 1000 to 1250, which is called the Medieval Warming Period by climatologists. Between 1500 and 1850, during the little ice age, the varves were again thinner—less heat means less runoff and thus less lacustrine deposition. “The varves at Iceberg Lake tell us a very important story,” Loso said. “They’re an archival record that proves there was no catastrophic lake drainage, no jokulhlaup, even during the Medieval Warming Period.” In a scientific paper about the disappearance of Iceberg Lake, Loso was even more emphatic: “Twentieth-century warming is more intense, and accompanied by more extensive glacier retreat, than the Medieval Warming Period or any other time in the last 1,500 years.” Loso scratched his grizzled face. “When Iceberg Lake vanished, it was a big shock. It was a threshold event, not incremental, but sudden. That’s nature at a tipping point.” One of the most startling, and devastating, consequences of this rapid melting of the ice was the Icy Bay landslide. The Tyndall Glacier, on the southern coast of Alaska, has been retreating so quickly that it is leaving behind steep, unsupported walls of rock and dirt. On October 17, 2015, the largest landslide in North America in 38 years crashed down in the Taan Fjord. The landslide was so enormous it was detected by seismologists at Columbia University in New York. Over 200 million tons of rock slid into the Taan Fjord in about 60 seconds. This, in turn, created a tsunami that was initially 630 feet high and roared down the fjord, obliterating virtually everything in its path even as it diminished to some 50 feet after ten miles. “Alder trees 500 feet up the hillsides were ripped away,” Anderson says. “Glacial ice is buttressing the mountainsides in Alaska, and when this ice retreats, there is a good chance for catastrophic landslides.” In other ranges, such as the Alps and the Himalaya, he says, the melting of “ground ice,” which sort of glues rock masses to mountainsides, can release enormous landslides into populated valleys, with devastating consequences. “For most humans, climate change is an abstraction,” Loso says when I meet him in his office, which is down a long, dark, heavily beamed mine building in Kennecott. “It’s moving so slowly as to be basically imperceptible. But not here! Here glaciers tell the story. They’re like the world’s giant, centuries-old thermometers.” Read the entire article “A Daring Journey Into the Big Unknown of America’s Largest National Park” online at SmithsonianMag.com
NASA Image of the Day: Channeled Scablands
To the non-geologist, the landforms on the Columbia Plateau in eastern Washington might look more like another planet than Earth. Boulders lie strewn across the landscape, amid towering cliffs and plunging holes. Winding channels scar the bedrock. Through the eyes of a geologist, however, the landforms of the so-called Channeled Scablands reveal a past punctuated by violent floods. The network of channels is visible in a natural-color image (below) derived from the Operational Land Imager (OLI) on Landsat 8. The image is a “best-pixel mosaic,” which means it is composed of small parts of many images captured between 2013 and 2018. The technique makes it possible to strip away clouds and haze. The mosaic was then draped over data from NASA’s Shuttle Radar Topography Mission (SRTM) to show the topography. The channels appear dark brown compared to lighter surrounding areas, but they are not wet. (The water-filled Snake and Columbia Rivers are much darker by comparison.) Instead, these channels take on a dark color because the overlying loess has been eroded, exposing underlying volcanic basalt. The massive prehistoric floods that eroded this landscape were not always obvious to scientists. Geologist J Harlen Bretz described in 1923 how water could have sculpted the features. “The channeled scablands are the erosive record of large, high-gradient, glacier-born streams,” he wrote in a research paper. He added: “The magnitude of the erosive changes wrought by these glacial streams is nothing short of amazing.” But for decades, his explanation remained controversial. Scientists have since gained an even better understanding of the events that took place during the last Ice Age 10,000 to 20,000 years ago. As the edge of the Cordilleran ice sheet advanced southward, it formed an ice dam rising about 600 meters (2,000 feet) high along the Clark Fork River. Glacial Lake Missoula grew behind the ice dam and ultimately contained as much water as Lake Erie and Lake Ontario combined. When the dam broke, more than 500 cubic miles of water tore across the region at about 80 miles per hour. The dam grew and broke several times, and the repeated flooding carved out grooves, potholes, and the long channels known as “coulees.” On September 2, 2017, the OLI on Landsat 8 acquired this detailed image of Potholes Coulee. This horseshoe-shaped canyon was formed when floodwaters dropped more than 260 meters (850 feet) in less than 5 kilometers (3 miles) from the Quincy Basin to the Columbia River Valley, stripping away topsoil and eroding the basalt. In modern times, irrigation networks that pull water from the Columbia River have made agriculture productive in places where this rich soil remains. References and Related Reading Bretz, J.H. (1923) The Channeled Scablands of the Columbia Plateau. The Journal of Geology 31(8), 617–649. NASA Earth (2012, February 16) The Legacy of the Megaflood. Accessed April 18, 2018. National Geographic (2017, March 9) Formed by Megafloods, This Place Fooled Scientists for Decades. Accessed April 18, 2018. The Pleistocene Post (2011) Potholes Coulee. Accessed April 18, 2018. The Seven Wonders of Washington State (2015) The Channeled Scablands. Accessed April 18, 2018. Texas University at Austin (1978, June) The Channeled Scabland. Accessed April 18, 2018. U.S. Department of the Interior, Bureau of Reclamation, Columbia Basin Project. Accessed April 18, 2018. NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey and topographic data from the Shuttle Radar Topography Mission (SRTM). Story by Kathryn Hansen. Reprinted from Earth Observatory Instrument(s): Space Shuttle – SRTM Landsat 8 – OLI
6 New ‘Nick On The Rocks’ Episodes
6 new short episodes of ’Nick On The Rocks’ aired on PBS this past winter! Each of these gems are short enough to be taken in by even the busiest of us, and yet have enough information to whet the appetite of even the most intensive of us. Nick is masterful in his presentations and who he draws in to help. Watch them all, you won’t be disappointed. Lake Chelan – Battle of the Ice Sheets (w/ Chris Mattinson) Click HERE to watch. 5 minutes. Chasing Ancient Rivers (w/ Steve Reidel) Click HERE to watch. 5 minutes. Seattle Fault (w/ Sandi Doughton) Click HERE to watch. 5 minutes. Bridge of the Gods Landslide (w/ Jim O’Connor) Click HERE to watch. 5 minutes. Columns of Basalt Lava Click HERE to watch. 5 minutes. Ancient Volcanoes in the Cascades (w/ Daryl Gusey) Click HERE to watch. 5 minutes.
Central Oregon Geoscience Society (COGS) Formed
The Central Oregon Geoscience Society (COGS) has formed as a central-Oregon based, non-profit organization promoting a greater awareness and understanding of the geological sciences through technical presentations, field trips and educational outreach to schools. Plans are to have 8 presentations per year (5 in the spring, 3 in the fall), field trips in the late spring through early fall. Presentations are held at Deschutes Brewery Tap Room (upstairs), 1044 NW Bond Street in Bend. Join us at 6:00 PM for food and beverages, presentation at 7:00 PM. COGS held its inaugural presentation on March 27 with Bart Wills, U.S. Forest Service, speaking on Geothermal Exploration at Newberry Volcano. The next presentation will be on April 24th with Adam Kent, Oregon State University, speaking on Mount Hood: Confessions of an interesting Boring Volcano. Bob Jensen will lead COGS’s inaugural field trip in April exploring the geology of the upper and lower loop trails in Riley Ranch Nature Reserve. This trip will allow a look into the Deschutes River channel where over five million years of Central Oregon’s geologic past are exposed. The wide variety of volcanic and erosional features within the Riley Ranch Nature Reserve makes it one of the most geologically interesting park in the Bend Park & Recreation District system. Keep abreast of upcoming plans via the website CoGeoSoc.org.