"Beyond the mouth of the canyon, tucked behind rocky ridges and overshadowed by the sheer granite faces and spires of the Bitterroot Mountains of Western Montana lies a geologic anomaly. Montana Bureau of Mines and Geology, Butte, Montana. A large southeast portion of the refuge contains higher, more uniform elevations while north and west portions of the refuge have lower, more diverse elevations. 26. By R. Ernest Anderson, Published on 01/01/59. The Idaho Batholith, primarily in Idaho, extends more than 16,000 square miles. Undisturbed valley fill shows that tectonic movement since the early Pliocene has been slight or that the entire valley floor has moved as a single unit. These deposits are well-rounded, and sorted gravel and sand with a minor amount of silt and clay. 1948 "The Gold Placers of Montana", Memoir No. Sediment is coarse colluviums near the fronts of mountains with finer-grain alluvial fill deposits that interfinger with floodplain silts and clays. Top subscription boxes – right to your door, © 1996-2021, Amazon.com, Inc. or its affiliates. Help others learn more about this product by uploading a video! Surficial geology evidence suggests Tertiary fill in the Bitterroot Valley may be up to 4,000 feet thick in some locations (Lankston 1975). The sheer cliffs of the mountains of the Bitterroots were formed as millions of years of exposure to water in all its erosive forms carved the rock. Mountains on the eastern side of the Bitterroot Valley are buttressed with granitic rocks from the area of Willow Creek, south to the area southwest of Lost Trail Pass, where the Sapphire Mountains merge with the Bitterroot Mountains, and the Sapphire granites connect with the Idaho batholith. The structural basin of the Bitterroot Valley has accumulated a considerable thickness of Tertiary sediments capped in most places by a layer of Quaternary materials. Please try again. Region: Bitterroot Mountains. Lonn notes that the earthquake activity that separated the Bitterroots and Sapphires occurred about 50 million years ago. The unusually straight front of the Bitterroot Range is a zone of large-scale faulting (Langton 1935, Pardee 1950); however, the Bitterroot Valley shows little … This same process of grinding and buckling plates is what has formed not only the Bitterroot Mountains, but many mountain ranges around the world. If they cracked a great many chunks, they would eventually have noticed that most of the granite is very pale gray. Prime members enjoy FREE Delivery and exclusive access to music, movies, TV shows, original audio series, and Kindle books. West of the river is the commanding Bitterroot Range. On the west are the Seven Devils Mountains and Hells Canyon of the Snake River. Last week I headed to the crest of the southern Laramie Range to enjoy another Indian Summer day, hoping to capture the glowing yellow aspen leaves with my point-and-shoot camera. The Sapphire Mountains are mostly Belt rocks with localized occurrences of granitic stocks. One of the most rugged stretches of the Rocky Mountains, the Bitterroots are composed of granite shed from the Idaho batholith (a large granite intrusion) and carved into jagged, 2,700-meter-high peaks by glaciers during the last ice age. The river reach immediately upstream from the refuge has a complex pattern that is characterized by numerous braided channels that spread over a wide area of the valley bottom. Geology . Mining historian Kerby Jackson introduces us to a classic mining work in this important re-issue of “A Geological Reconnaissance of the Bitterroot and Clearwater Mountains of Idaho and Montana”. Excerpt from A Geological Reconnaissance: Across the Bitterroot Range and Clearwater Mountains in Montana and Idaho In spite of the forbidding aspect of these mountains, the earliest explorers of the Cordilleran region, Lewis and Clarke, led their expedition across them, choosing the Lolo trail from the Bitterroot Valley to the present site of Lewis ton, where they wintered. To get the free app, enter your mobile phone number. Enter your mobile number or email address below and we'll send you a link to download the free Kindle App. during the last glacial advance (Weber 1972).The Bitterroot River has an inherently unstable hydraulic configuration and high channel instability, particularly between the towns of Hamilton and Stevensville (Cartier 1984, Gaeuman 1997). These surfaces appear to have been at least partly shaped by glacial Lake Missoula, which reached an elevation of 4,200 feet and covered the Bitterroot Valley near the refuge 15,000–20,000 years B.P. Materials in these terraces are well-rounded and sorted gravel of predominantly granitic, gneissic, and Belt sedimentary origin (Lonn and Sears 2001). The Bitterroot Valley is a Late Cretaceous structural basin that was partly filled at its deepest point by more than 1,640 feet of Tertiary sediments. Full content visible, double tap to read brief content. The zone of non-vegetated gravels associated with this main braided channel system has widened and straightened since 1937 (Gaeuman 1997). One of the high points in the geologic history of the Bitterroot valley, or one of the lowest depending on which side of the fault line you were on, came when the earth cracked at the edge of the Idaho Batholith pulling the Sapphire Mountains off the top of the Bitterroot Mountains about 40 to 50 million years ago. A specimen of pink granite, its source identified by codes applied by a geologist. B edrock in the Bitterroot Mountains is mostly granite. "Collectively, the many landscape and hydrological changes in the Bitterroot Valley since the Presettlement period have dramatically altered the physical nature, hydrology, and vegetation communities of the Lee Metcalf NWR." Ross (1947 #772) speculated that no range-front fault is present along the eastern flank of the Bitterroot Mountains. Mining historian Kerby Jackson introduces us to a classic mining work in this important re-issue of “A Geological Reconnaissance of the Bitterroot and Clearwater Mountains of Idaho and Montana”. 1975). Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. On the west side, the bold and craggy Bitterroot Mountains rise abruptly as a remarkably even face, cut by deep parallel U-shaped canyons which were carved by glaciers. Basin-fill deposits consist of unconsolidated to semi-consolidated Tertiary and As such, some type characters and images might suffer from slight imperfections or minor shadows in the page background. These surfaces are younger (late Pleistocene) alluvial outwash terrace and fan complexes of well-rounded cobbles and boulders in a matrix of sand and gravel deposited in braided-stream environments that formed between and below the dissected remnants of older fans. Together, active river movements and a braided river channel pattern create low riverbanks and natural levees that encourage chutes and other avenues of river overflow. The following is taken from a report by Heitmeyer, Artmann and Frederickson (2010) describing the geology and physiography of the Refuge: "The Bitterroot Valley, where the Lee Metcalf Refuge is located, is a north-trending basin bounded by the Bitterroot Mountains on the west and the Sapphire Mountains on the east. Sahinen, Uuno Mathias. 2 GEOLOGY, WATER RESOURCES, BITTERROOT VALLEY, MONT. Included are also details on the numerous gold, silver and copper mines of this region. A complex network of minor channels occurs in the valley floor including the floodplain lands on the refuge (figure 10). Then you can start reading Kindle books on your smartphone, tablet, or computer - no Kindle device required. These mountains, like the rest of the Rockies, were formed by a combination of geologic forces, starting with plate tectonics. Channel deposits of the ancestral Bitterroot River lie beneath the valley center.Low terrace alluvium occurs as outwash, or alluvial fans, below the mouths of tributaries on both sides of the valley (Lonn and Sears 2001). If Lewis and Clark ever cracked a chunk to expose a fresh surface, they saw a very pale rock glittering in the sunlight that reflected off a crystal surface. There is also an array of amazing wildlife and sunsets, so be sure to bring your camera. T. he spectacular Bitterroot Mountains northwest of Sula expose granite rocks of the Idaho batholith, a major geologic feature that consists of a series of igneous intrusions that pushed their way toward the surface between about 80 and 53 million years ago. The Bitterroot Valley is a basin about 65 miles long from north to south and as much as 10 miles wide. Mountains on the east side and the northern Bitterroot Mountains are made up of metacarbonates, argillites, and quartzites of the Belt Supergroup (Smith, 2006). A larger tributary fan is present where North Burnt Fort Creek enters the Bitterroot River floodplain; this fan is much larger than the alluvial fans along the floodplain margin that grade into the Sapphire Mountains. The elevation of the valley floor ranges from about 3,900 feet above mean sea level (amsl) in the south to about 3,200 feet amsl near Missoula. The Atlanta Lobe and the Bitterroot Lobe of the Idaho Batholith (Figure 1) are separated by Middle Proterozoic Belt Supergroup metamorphic rocks in the Salmon River Arch (Evans and Green, 2003). Their loftiest summit, Trapper Peak(s), which the Corps of Discovery would have seen on September 7, 1805, tops out at an exceptional 10,157' DED. Floodplain alluvium is mostly well-rounded gravel and sand with a minor amount of silt and clay derived from the edges of the neighboring terraces and fans. Your recently viewed items and featured recommendations, Select the department you want to search in, No Import Fees Deposit & $9.48 Shipping to Singapore. The Sapphire Mountains are mostly Belt rocks with localized occurrences of granitic stocks. To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Geology of the Bitterroot and Clearwater Mountains of Idaho and Montana, CreateSpace Independent Publishing Platform (October 16, 2015). Unavailable since 1904, this publication offers rare insights into the geology of this region of Idaho and Montana. The Atlanta lobe … It also analyzes reviews to verify trustworthiness. The most influential were the glaciers. Note: This edition is a perfect facsimile of the original edition and is not set in a modern typeface. Canyon Peak - a Ben Johnson photo. Bulletin N. 213. the size of Connecticut) in northeast Washington, northern Idaho (the panhandle), and western Montana. After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. The unusually straight front of the Bitterroot Range is a zone of large-scale faulting (Langton 1935, Pardee 1950); however, the Bitterroot Valley shows little sign of recent tectonic activity (Hyndman et al. Most of the refuge is mapped as Qal alluvial deposits of recently active channels and floodplains. The Bitterroot Mountains run north and south along the border of Montana and Idaho in southwestern Montana. Streams heading in U.S.G.S. Jun 21, 2020 - Explore Bitterroot Cabins, LLC's board "Hiking the Bitterroot Mountains", followed by 3492 people on Pinterest. There was a problem loading your book clubs. "References for citations above are here. The Bitterroot Range is a mountain range and a subrange of the Rocky Mountains that runs along the border of Montana and Idaho in the northwestern United States. The origin of the gneissic rocks on the eastern border of the Idaho batholith in the Bitterroot Range, near Hamilton, Mont., has long been in dispute. Please try again. Despite limited changes in river shape north of Stevensville, the river stretch along the refuge has maintained a highly dynamic, instable channel form due to its geological, topographic, and hydraulic position. Summit elevations of surrounding mountains range from 6,000 to 8,000 feet amsl in the Sapphire Range and exceed 9,500 feet amsl in the Bitterroot Range.The Bitterroot Mountains are composed of granitic rocks, metamorphic materials, and remnants of pre-Cambrian sediments of the Belt series. In addition to this widening, severe bank erosion is common, but numerous cutoff chutes counteract some lateral bend displacement. Channel fragmentation appears to be controlled by irregularities in the respective elevation gradients of the valley.About 10–15 miles north of Stevensville, the Bitterroot River channel is more confined, compared to its highly braided form farther south. We don’t share your credit card details with third-party sellers, and we don’t sell your information to others. Description: Believed to be the largest fire in recorded U.S. history, the Great Fire of 1910 burned about three million acres (approx. History and Culture of the Bitterroot Valley. Broadmoor Colorado Springs Relaxing on Deck Lake Overlook VR180 VR 180 3D nIS n12t 24s. Minor amounts of Qaty (younger alluvial outwash terrace and fan complex deposits from the late Pleistocene) occur next to the Bitterroot Valley alluvium on the north end of the refuge. The Bitterroot Mountains are not very high compared with the Rockies in Colorado or Canada. Unavailable since 1904, this publication offers rare insights into the geology of this region of Idaho and Montana. Its geology is complex and diverse. The majority of studies (a few of which are cited here) have focused on the prominent mylonite zone along the range front. It’s fall and already the sun is low enough to make things sparkle -- leaves on trees, crystals in rocks. A mapping method known as LIDAR that was being used to look at floodplains in the Bitterroot Valley turned up when two Montana Bureau of Mines and Geology … Alluvial fans are present in many locations along the Qafy geomorphic surfaces on the east side of the refuge. Reviewed in the United States on August 29, 2017. These mountains and the rich montane Bitterroot Valley date to nearly 90 million years before the present (B.P.) Please try again. The structure of the Bitterroot Valley itself has been You're listening to a sample of the Audible audio edition. Characteristic species of riparian, gallery forest habitat; requires snags for nesting and eats free-flying insects and fruit. 1903 Mineral Deposits of the Bitterroot Range and Clearwater Mountains, Montana. Our payment security system encrypts your information during transmission. The Bitterroot Mountains' geology of exposed granite, towering glaciers, meandering streams, alpine lakes, steep canyons and ridges make for stunning scenery for hikers and campers. The spectacular Bitterroot Mountains northwest of Sula expose granite rocks of the Idaho batholith, a major geologic feature that consists of a series of igneous intrusions that pushed their way toward the surface between about 80 and 53 million years ago. Idaho County spans the River of No Return and Selway-Bitterroot Wilderness and includes both the eastern and western borders of the state. Bibliography of Previous Geologic Mapping in the Bitterroot Valley (see Figure 2) Anderson, R. E., 1959, Geology of lower Bass Creek Canyon, Bitterroot Range, Montana: Missoula, University of Montana, M.A. We work hard to protect your security and privacy. Surface water is softer, as a rule, and contains less dissolved solids than the ground water. Elevations on the Lee Metcalf National Wildlife Refuge range from about 3,230 feet on its north end to about 3,260 feet on its south end at the river (figure 11). Bitterroot Range Cabinet Mountains Centennial Mountains Chalk Buttes Coeur D' Alene Mountains Crazy Mountains Gallatin Range Garnet Range Glaciers in Glacier National Park Gravelly Range John Long Mountains ... Geology.com does not grant permission for any use, republication, or redistribution. This report describes, in a preliminary way, a belt of country extending westward from the Bitterroot Valley, across the dividing range and the rugged mountains of the Clearwater system, down to the fertile plateaus which border the canyon of Snake River. Qafy surfaces extend along the Bitterroot Valley on both sides of the refuge. Government Printing Office, Washington. This is known as a "young" fault as far as geologic time is concerned. Anderson, R. Ernest, "Geology of lower Bass Creek Canyon Bitterroot Range Montana" (1959). The range spans an area of 24,223 square miles (62,740 km ) and is named after the bitterroot (Lewisia rediviva), a small pink flower that is the state flower of Montana. The topographic variation within the refuge is related to the historical channel migrations of the Bitterroot River and its tributaries, scouring and natural levee deposition along minor floodplain channels, and alluvial deposition. thesis, 75 p. Barkman, P. E., 1984, A reconnaissance investigation of active tectonism in the Bitterroot The geomorphology of the Grave Peak area, located in Idaho along the arcuate highland between The Crags and the northern Bitterroot Range, shows evidence of massive ice accumulations such as the Grave Peak ice cap, associated Big Sand Creek Piedmont lobe, and the extensive valley glaciers of Brushy Fork and East Fork of Moose Creek. The historical floodplain at the refuge was characterized by the following: (1) multiple abandoned channels (for example, Barn and Francois Sloughs) that were connected with the main river channel during high-flow events; (2) small within-floodplain channels (for example, Rogmans and Swamp Creeks) that received water from ground water discharge and occasional overbank backwater flooding during high-flow events; (3) entry of two mountain- or terrace-derived major tributaries to the Bitterroot River (for example, North Burnt Fork Creek and Three Mile Creek); (4) slightly higher elevation inter-drainage point bars, natural levees, and terraces; and (5) alluvial fans (figure 7). Recommended Citation. The Bitterroot Mountains are composed of granitic rocks, metamorphic materials, and remnants of pre-Cambrian sediments of the Belt series. Lyden, Charles J. Bring your club to Amazon Book Clubs, start a new book club and invite your friends to join, or find a club that’s right for you for free. (Heitmeyer et al 2010). Little is known about the Quaternary history of this fault. There's a problem loading this menu right now. These minor channels appear to flow from ground water discharge, which promotes erosion at slope bases and headwater retreat of small channel head cuts on the floodplain. The Bitterroot Valley extends about 120 miles from the confluence of the east and west forks of the Bitterroot River south of Darby to its junction with the Missoula Valley and Clark Fork River 5 miles south of Missoula. There was an error retrieving your Wish Lists. Parts of it reach into Montana south of Stevensville and into the Bitterroot Mountains. (Hodges and Applegate 1993). Contributions to Economic Geology, 1902. See more ideas about hiking, montana, mountains. You might not see it the first time you explore Blodgett Canyon, or even on the next visit: a granite arch, high on the southern wall of the canyon. Unable to add item to List. The Bitterroot and Sapphire Mountains. 'Water in the Bitterroot Valley is of satisfactory chemical quality for domestic, stock, municipal, and most industrial uses. The Idaho Batholith is composed of Cretaceous granite and granodiorite and covers approximately 35,000 km2in central Idaho; it is roughly 320 kilometers long by 120 kilometers wide, and 8 kilometers thick. Lindgren regarded these rocks as the product of stresses related to a normal fault along the front of the range with an eastward dip of about 15°. About 100 million years ago, the west coast of North America ran through western Idaho. Brief content visible, double tap to read full content.
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