Mima/Desert/Biscuit Mounds – An (Possible) Explanation
If you’ve visited the Rowena Crest Viewpoint at Tom McCall Preserve, west of The Dalles in the Columbia River Gorge, you may have noticed the many dome-shaped earthen mounds that cover the Rowena Plateau. These mounds are broadly circular and are surrounded by collections of basalt rock fragments. If you’ve visited the spring wildflower mecca of Catherine Creek on the Washington side of the Gorge, you may have also wondered at what caused the stripes of black rock extending down the slopes above the area. Tens of thousands of similar soil mounds cover large areas of the high desert lands of north-central Oregon, often in swarms that number in the hundreds. These mounds can be round or elongated, can range from a dozen feet to more than 60 feet in diameter atop the rocky Columbia River Basalt bedrock, and are typically surrounded and separated from each other by rings or stripes of basalt rock fragments. The mounds also appear similar to those at Mima Mounds Natural Area Preserve near Olympia, WA. There have been many suggested causes for the creation of these mounds, from burial mounds, to Pleistocene pocket gophers, to plants or glacial sun cups trapping wind-blown sediment, to sorting by earthquake vibrations, to turbulence at the base of ice-age floods flowing over the landscape. Research by two Oregon graduate students, Clark Nelson of Oregon State University and John Baine Pyrch of Portland State University, independently came up with what may be the most likely explanation for the origins of these enigmatic features. Their theses suggest desert mounds and their rock rings formed through a process of natural sorting, where fine soil material is pushed up into mounds and associated rocks are pushed out to the edges to form rings through countless cycles of wetting/drying and freeze/thaw during the wetter and colder period of the late Pleistocene. Clark Nelson cut a trench through a mound that exposed layers of soil and volcanic ash whose lack of mixing discounts the pocket gopher theory. Nelson also found that slope angle less than or greater than 10 degrees determined whether the features would form rounded mounds vs. elongated stripes. Pyrch showed the strips to be distinct from common talus slopes, because no obvious source of rock exists at the head of the talus stripe. He also observed that rocks within these stripes are sorted, unlike talus slopes, suggesting the same ice age freeze-thaw origins as soil mounds and rock rings. You can read more detailed articles about these enigmatic features in these articles: Mystery of the Desert Mounds Great Pyramids of the Gophers: Mima Mound Mystery Solved Similar processes are also thought to be responsible for the “patterned ground” found in periglacial environs. However these various types of features may have formed, we can be certain how the few mounds in the center of the parking circle at Rowena Crest Viewpoint came to be. They were man-made during the construction of the viewpoint and made to look like the mounds that cover the Rowena Plateau. At least one origin has a definitive answer.
Must See Floods Features in Northern Idaho
SOME LOCAL NORTHERN IDAHO ICE AGE FLOODS and GLACIAL FEATURES Purcell Trench – This structurally formed valley became the passageway for the Purcell Ice Lobe that divided into five glacial sub-lobes. The east moving sub-lobe blocked the Clark Fork River forming Glacial Lake Missoula, the source of the Ice Age Flood waters. Other sub-lobes modified and deepened the basin now occupied by Lake Pend Oreille or helped define several important N-S transportation routes. The Purcell Trench is visible from City Beach in Sandpoint and Schweitzer Mountain Rd. Hwy 95 follows the Purcell Trench from Sandpoint to beyond Bonners Ferry. Cabinet Gorge – Contact of Pleistocene Ice and Glacial Lake Missoula Water – Although the contact of the Pleistocene Ice and the lapping waters of Glacial Lake Missoula was in flux as the glacier advanced and retreated, the Cabinet Gorge is considered by many to be a likely location of the terminus of the Clark Fork sub-lobe that blocked the drainage of the Clark Fork River. Evidence of glacial erosion and till deposits indicate glaciation; however, flood deposits on the south side of the river attest to Ice Age flooding. Cores taken during the construction of the Cabinet Gorge Dam suggest multiple stages and events of ice damming. An AVISTA maintained viewpoint at the Cabinet Gorge Dam with Ice Age Floods signage provides an excellent location to ponder the formation and disintegration of the ice plug blocking the Clark Fork River. Glacial Striations – Striations can be viewed along Hwy 200 east of Hope and on the south side of Castle Rock east of Clark Fork. Glacial/Flood Related Erratics – Large and small erratics cover the glacial and flood modified landscape. Large erratics can be seen along Hwy 200 east of Clark Fork, in Sandpoint’s City Beach and in Farragut State Park. A large pile of erratics excavated from flood deposits are visible on the west-side of Hwy 95 south of the Hoodoo Channel. A giant ice-rafted flood related erratic weighing over 1,600 tons is located on the east-side of Hwy 41 near Twin Lakes. Lake Pend Oreille – Cross-section morphology, depth, and sediments – This is where it all started! Lake Pend Oreille is the largest lake in Idaho and the deepest lake in the Pacific Northwest and the 5th deepest in the US. The lake level is 2062 ft above sea level with depths over 1,000 feet and an additional layer of over 1,500 feet of glacial-fluvial deposits going to bedrock, with the surrounding terrain as high as 6002 ft. The glacially modified U-shaped bedrock valley, cut to approximately 600 feet below sea level, was formed by the Pend Oreille glacial sub-lobe. This glacial sub-lobe was up to 4,000+ ft. thick and 30+ miles wide. It was the ice plug responsible for blocking the Clark Fork River. It collapsed catastrophically as often as about every 10-60 years, releasing 40-100 Ice Age Floods. The location of the lake is probably related to an old river valley controlled by faults. The Lake Pend Oreille basin was carved by the repeated advances of Pleistocene ice and scoured by ice age floods. With the waning of ice age flood waters, the basin was, and continues to be, filled with glacial outwash and flood deposits. The lake is dammed at the south end by thick glacial and flood deposits the mark the beginning of the “Outburst Deposits”. There is a pullout on Hwy 200 approximately one mile west of Hope with signage already established that provides a great view looking south across Lake Pend Oreille to the Green Monarch Mts. Another view of the former ice plug location along Hwy 200 is the mouth of the Clark Fork River at the Clark Fork Drift Yard. Giant Current Dunes or MegaRipple Marks – One of Bretz’ most important pieces of evidence for catastrophic flooding was the “giant current dunes.” These large-scale bedforms appeared as patterns of parallel ridges and swales on many aerial photographs in the flood channels in the scabland of Washington, but had escaped recognition from the ground because of their size. Giant Current Dunes are visible west of Clark Fork near Castle Rock; however, the most prominent and visible Giant Current Dunes are located several miles east of Spirit Lake along Hwy 54 where the highway cuts through the dunes showing their undulating profile. The location of many of the telephone poles on the crest of these dunes accentuates these landforms. The dunes form transverse to the current direction, and form cusps that are convex upstream, with arms that point downstream. Furthermore, the size of the cusps appears to decrease in the direction of lower velocity. Internally, the dunes consist of gravel and pebble foresets. Giant current dunes exhibit an asymmetrical profile with the downstream (lee) slope steeper than the upstream slope. Crests range from 20 to 200m apart and heights range from 1 to 15m (Baker and Nummedal, 1978) and are among the largest measured throughout the Floods area. The Spirit Lake current dunes can also be easily recognized from the air by their characteristic pattern, accentuated by vegetation. This dune field is immediately in the path of the breakout from Lake Pend Oreille, and experienced some of the highest energy flows. Rhythmites – Rhythmites are glaciolacustrine sediments associated with flood events and are useful in attempting to determine the number of Ice Age Floods. A 112-foot cross-section of rhythmites is located at the junction of East Fork Creek and Lightning Creek approximately 6.5 miles northeast of Clark Fork along Lightning Creek Road (NF-419). Proglacial Deposits – This type of deposit is found associated with most of the drainages on the south side of the Clark Fork Valley and extend from the mouth of the Clark Fork River to nearly Thompson Falls in Montana. These sediments are glacio-fluvial deposits deposited in contact with the ice and therefore provide evidence of glaciation in the Clark Fork River drainage. The associated geomorphic features formed by these deposits are referred to as “kame deltas”. The gravel pit associated with Dry Creek (approximately 8 miles west of Clark Fork
Grand Coulee Field Trip
Grand Coulee Field TripExploring the Ice Age Floods and Geology of the Grand Coulee AreaGrand Coulee Field TripExploring the Ice Age Floods and Geology of the Grand Coulee AreaGrand Coulee Field TripExploring the Ice Age Floods and Geology of the Grand Coulee AreaGrand Coulee Field TripExploring the Ice Age Floods and Geology of the Grand Coulee AreaGrand Coulee Field TripExploring the Ice Age Floods and Geology of the Grand Coulee AreaGrand Coulee Field TripExploring the Ice Age Floods and Geology of the Grand Coulee Area Click here to download, complete and print a Liability Waiver required of all attendees The Grand Coulee system is a geologic wonderland created by the ice-age interplay of geology, ice and massive floods. In a 2+ day (Sept 19-20 +) car-caravan field trip we will explore many of the unique features leading to and resulting from that interplay. Prepare to have your minds blown. Click Here for the field trip guide. Since this is our first Grand Coulee field trip, please bring a copy to help keep us on track.Please note: the sequence of days and route directions may be changed to adjust for scheduling issues. Dry Falls Plunge Pool – Ominski Grand Coulee at Steamboat Rock Dry Falls Lake Dry Falls Channeled Scabland – Bjornstad Field Trips Upper Grand Coulee Field Trip Car Caravan Lake Lenore & Great Blade – Bjornstad Northrup Cnyn Flood Deposits Million Dollar Mile, Upper Grand Coulee Ranger David McWalter Monster Rock – Ephrata Fan Grand Coulee Dam Steamboat Rock Sunset Local Lodging Information There are multiple quality lodging options available in the area, from campgrounds, motel and hotel rooms to fully furnished cabins with kitchens. Book lodging reservations using links below. Sun Lakes – Dry Falls Camping/Cabin options Lodging on site at Sun Lakes – Dry Falls State Park Sun Lakes – Dry Falls State Park: standard tent & RV campsites can be reserved through WA.Parks.gov. Availability may be limited. Campsite fees: Standard $20-$30, Partial utility $30-$40, Full-utility $35-$45 Sun Lakes Park Resort: adjacent to the state park, standard tent & RV campsites and fully furnished cabins with kitchens (maps). Other Local Lodging options Local inn & hotel lodging options Best Western Rama Inn: Motel rooms in Ephrata (26 minute drive to Sun Lakes State Park) Soap Lake Spa and Resort: Motel rooms in Soap Lake (23 minute drive to Sun Lakes State Park) Masters Inn: Motel rooms in Soap Lake (23 minute drive to Sun Lakes State Park) BW Rama Inn Soap Lake Resort BW Rama Inn Lobby Soap Lake Resort Cabin BW Rama Inn Room Soap Lake Resort Room BW Rama Inn Breakfast Soap Lake Resort Restaurant BW Rama Inn Pool Soap Lake Resort Jacuzzi BW Rama Inn Sauna Blue Lake Resort: Cabins (four minute drive from Sun Lakes State Park) Sun Village Resort: Cabins, RV sites (four minute drive from Sun Lakes State Park) Banks Lake Lodge: Basic motel rooms, cabins, RV sites (six minute drive from Sun Lakes State Park) Ala Cozy Motel: Basic motel in Coulee City (six minute drive from Sun Lakes State Park) Local Dining Information Dining options range from excellent restaurants to local pubs and burger joints. Here are a number of simple to hearty dining options: Sun Lakes Park Resort (adjacent to the State park): Duke’s Diner: takeout window serveing breakfast sandwiches, coffee, espresso, burgers, sandwiches, hotdogs, shakes and smoothies. Multiple restaurants in Coulee City (six minute drive from the State Park) Multiple restaurants in Soap Lake (spectacular 23 minute drive from Sun Lakes State Park) Multiple restaurants in Ephrata (spectacular 26 minute drive from Sun Lakes State Park) Multiple restaurants in Grand Coulee (spectacular 37 minute drive from Sun Lakes State Park)
Lyle Cherry Orchard Trail Geology Recording
The Lyle Cherry Orchard Trail is a moderately strenuous trail being developed in the Columbia Gorge by Friends of the Columbia Gorge. They envisioned having a number of interpretive stations along the trail to inform and educate trail users. A station could focus on a single topic, such as the geology, plants, animals, indigenous and cultural history of the area. But they found that the cost of interpretive signs would be prohibitive, would be expensive to maintain and might not last long. So they started brainstorming for better ways to realize thier vision. The came up with a plan to place trailside posts, resembling basalt columns, with a QR code the user could scan with their smartphone that would connect to an informative recording about that location. Friends hopes to have the trail work and information stations finished by 2024. Then everyone will be able to experience the beauty along the Lyle Cherry Orchard Trail with a deeper understanding of their surrounding through the recordings. Renee Tkach, a Friends coordinator of the project, contacted Lloyd DeKay, president of the IAFI Columbia Gorge Chapter, about doing a recording for the first station about the geology of the area. They took a very windy hike together on the still somewhat challenging trail to the first station, where they talked about the focus of a recording and took a number of photos to document the views. At home Lloyd developed a script that everyone reviewed and agreed upon. Then began a few frustrating hours of recording and editing to produce a 4:30 minute recording. Since the original plan was for a 3:00-3:30 minute recording, Friends will now review the recording and decide if it’s OK or needs to be shorter and where to cut back. This method may also be an easier, economical and useful way to provide information at other floods sites throughout the region. Significant advantages include the relatively low cost and long life of the information station, and ability to provide both video and audio clips for a number of features on a webpage linked to the QR code, and the ability to modify and update the presentations as new or updated information becomes available.
Outburst Floods GSA Penrose Conference Visits West Bar
The 2023 GSA Outburst Floods Penrose Conference made a field trip stop on Tuesday afternoon, June 6, at Ken Lacy’s (IAFI Wenatchee Valley Erratics Chapter member) home, for a spectacular overview of the West Bar Current Megaripples that can be seen well from that vantage point. The 75 conference attendees were all at the conference by invitation only. They were accompanied by organizers Jim O’Connor, Isaac Larsen, Joel Gobiner, Vic Baker, Richard Waitt, Jerome Lesemann. The purpose of the conference was to review the current outburst floods fieldwork being done, encompassing the range of science conducted both on Earth and elsewhere in the solar system. The timing of the conference coincided with the 100th anniversary of J Harlen Bretz’s first publication on the Channeled Scabland, and took place at Camp Delany, which occupies a spectacular flood-carved setting at the foot of Dry Falls in Grand Coulee, Washington. The conference was meant to review past and present work, as well as help chart the future science on outburst floods through presentations, discussions, and multiple field trips. Everyone who shared Ken’s hospitality were in particularly good humor, as considerable amounts of cookies, popsicles, and bottled water were consumed. There were many comments about how well the meeting was going and how lots of new insights were being discussed. These kind of comments suggest that the meeting was being extremely well received. Ken was also pleased to talk to Justin Radford, along with his USGS Research Geologist… nice to see them in attendance.
Sea levels from the Maximum of the Last Ice Age to the Present Day
The Wenatchee Valley Erratics’ next program will be on Tuesday, June 13 at 7:00 PM at the Wenatchee Valley Museum and Cultural Center, 127 South Mission St., Wenatchee. Erratics’ member Kirk Laird will talk about “Sea levels from the Maximum of the Last Ice Age to the Present Day.” His presentation will focus on information directly available from NOAA’s Tides and Currents Office, and from NOAA’s Office of Satellite Altimetry. The 400 foot change in sea level over the last 22,000 years is directly attributable to the melting of continental and montane glaciers. With degrees in both Geology and in Oceanography, Kirk has observed earth science issues his entire life. And for the last 25 years, he has paid very close attention to the status of the oceans, in particular. This is a hybrid meeting. You can attend in-person at the Museum. Or you can participate via a Zoom link: https://us02web.zoom.us/j/84520197937 Please sign in at 7:00 PM, June 13! The program is free and open to the public.
Erratic in the Bitterroot
An 8 ton erratic left behind by Glacial Lake Missoula in the Bitterroot Valley on the property of a local rancher was relocated to serve as the focal point of an outdoor kiosk exhibit at the Ravalli County Museum at the former County Courthouse, 205 Bedford Street in Hamilton. Unlike their counterparts at other location along the National Geologic Trail, erratics in this part of the Ice Age Floods did not come from Canada nor did they travel as far, but the action of the floodwaters and iceberg rafts is equally evident despite more shallow waters. There are similar erratics found elsewhere in Bitterroot, on the campus of the University of Montana, and at the Bison Range. The outdoor display tells the same story as other locations on the Ice Age Floods National Geologic Trail but also includes information on two other National Park Service trails that pass through this area – the Nez Perce and the Lewis and Clark National Historic Trails. The museum has other indoor exhibits of historical interest and about Glacial Lake Missoula.
Little Money Creek Gulch Fill
Mounds of soil, sand, gravel, and other coarse materials covered with light vegetation can be seen in the side gulches all along the Flathead River where tributaries drained into what was Glacial Lake Missoula. They were deposited by currents eddying into the slower water in these gulches and also by the drop in velocity of the streams carrying deposits from higher elevations on the far side of the river along the path of the escaping floodwaters. The flow of floodwaters through this narrow valley was estimated by J.T. Pardee at between 8 and 10 cubic miles per hours – more than the combined flow of all modern rivers in the world. Similar gulch fill can be seen in many locations along this beautiful stretch of the river, which today generally flows smoothly and looks completely flat. There are numerous pull-outs along MT 200 between Perma and Paradise; the view pictured here is at mile marker 91.
Puget Sound Area has a Glacial Story to Tell
Although the Seattle region was not impacted by the large floods from Glacial Lake Missoula, Glacial Lake Columbia, or other glacial lakes east of the Cascades, the Puget Sound region has its own glacial story to tell. It’s interesting that J Harlen Bretz, who first imagined that a massive flood produced the Floods features in the Columbia Plateau, also did his PhD on “Glaciation of the Puget Sound Region”. The Puget Lobe of the Cordilleran Ice Sheet advanced and retreated over the Puget Lowland at least seven times during the Quaternary Ice Age. In the process, it left behind rocks, sediments, and other geologic clues that tell the intriguing story of ice, proglacial lakes, and flooding across the landscape near Seattle. Snoqualmie Falls, near North Bend, WA east of Seattle is a popular tourist destination. At the falls, the Snoqualmie River plunges 82m over a wall of volcanic rock. Few tourists, however, understand the role that the Puget Lobe of the Cordilleran Ice Sheet played in the formation of the falls. Prior to glaciation, Snoqualmie Falls did not exist, instead, the river flowed in an incised channel east of the current falls. As the Puget lobe advanced into the Puget Lowland about 18,700 years ago, the glacier’s eastern margin blocked drainage from rivers flowing out of the Cascades, including the Snoqualmie River. A large glacial lake known as Glacial Lake Snoqualmie formed over North Bend and over the Snoqualmie Valley. Tokul Creek, one of the tributaries, formed a thick underwater delta in the lake as its sediments poured into Glacial Lake Snoqualmie. When the Puget Lobe retreated, Glacial Lake Snoqualmie drained to the west and the Snoqualmie river attempted to follow its original channel. However, the original course of the river was blocked by the delta deposits from Tokul Creek and the river was forced to flow over a narrow band of rocks from an eroded volcano further to the south. Snoqualmie Falls flows over this volcanic rock today, but since the last glacial maximum, cataract recession has rapidly eroded the rocks back to a 200m wide band of andesite and volcanic breccia. Behind the thin volcanics is a thick layer of soft alluvium. At the current rate of recession, the Snoqualmie River will erode through the volcanic rock in about 7,200 years. When that happens, the river will hit the alluvium and the falls will quickly devolve into a series of rapids. You might want to hurry to see the falls before they disappear! Other glacial lakes were formed at the southern margin of the Puget Lobe near modern day Seattle. As the Puget Lobe advanced south, it dammed rivers and streams that were flowing north. In places, the bluffs surrounding modern Puget Sound hold a record of the advancing glacier and the pro-glacial lakes backed up by the ice front. One good place to view these sediments is from the beach at Discovery Park in Seattle. A layer cake of sedimentary units records the pre-glacial river system, the advance of the ice, the damming of the proglacial lakes, and the retreat of the ice sheet to the north. At the base of the cliffs the Olympia Formation records the pre-glacial environment of north-flowing rivers and streams. The Lawton Clay layer indicates the formation of proglacial lakes. The Esperance sand represents a period of glacial retreat. The glacier that repeatedly covered the Puget Lowland left behind multiple geologic clues for us to interpret. The Puget Lobe of IAFI welcomes members from other chapters to join us as we explore the glacial history of the Puget Lowland.
McBones – Ice Age Floods Mammoth Dig
The Tri-Cities area, home to the Lake Lewis Chapter of IAFI, is inching its way into spring and it’s time to say goodbye to winter. And for some of us, it’s time to begin the 2023 dig season at Coyote Canyon, the resting place of a 17,500-year-old Columbian mammoth. Coyote Canyon is just a few miles southwest of Kennewick in the Horse Heaven Hills. Last month we cleaned up the winter erosion and set up the field equipment so work can begin in earnest in April. Several bones, yet to be identified, were partially exposed last fall and hopes are high for exposing and removing them this summer. This elephant relative was deposited on the west side of Coyote Canyon during one of the earlier Ice Age floods and is buried by possibly six layers of floods sediment. Numerous erratic rocks have been found among the bones. Just before the pandemic temporarily paused work at the site, a local high school girl was assigned the task of identifying rock types of a cluster of small erratics buried near the animal’s left shoulder blade. She then identified outcrops of the same types of rocks in northern Idaho, at or near the ice dam. Finally, she documented her work with a poster and presented it at the 2019 GSA conference in Portland, Oregon. With digging comes tourism. As usual, public tour lists have filled for spring and summer-fall tour reservations will open on June first. To sign up for a tour the public can visit our new website, www.mcbones.weebly.com. School and private group tours are also available. At the time of this writing, we have scheduled six public tours, 30 elementary class tours and 13 group tours, including one for vision impaired and one for non-English speakers. All of our presentations emphasize the importance of the Ice Age floods to the mammoth story at Coyote Canyon.