This allowed liquid water to seep into minuscule cracks present in the ice dam.
Saranac, Michigan, 2 September ; d.
Homewood, Illinois, 3 Februaryglacial geology, origin of limestone caves, Earth science education. In a series of papers in the s and s, Bretz formulated and defended the hypothesis that cataclysmic flooding during the last Ice Age produced the unusual landscape of the channeled scabland region of eastern Washington State.
The controversy lasted until the s and s, by which time overwhelming field evidence combined with new understandings of flood mechanics, erosion, and sedimentation to convince most geologists that immense flooding was indeed the cause of the channeled scabland landscape. His father dabbled in farming but worked mainly in a store variety and furniture and in an undertaking business, both of which he owned.
The young J Harlen Bretz his original given name was Harley had intense interests in amateur astronomy and in exploring the natural environment around the family farm, including the nearby Grand River. He attended Albion College, where he studied biology and received an AB degree in At Albion he also met classmate Fanny Challis, who became his wife in Subsequently, as a high school teacher in Flint, Michigan, Bretz developed a strong amateur interest in glacial geology.
He organized his mostly self-financed field studies of glacial geology in the Puget Sound region into a PhD dissertation, which was awarded summa cum laude from the University of Chicago in Bretz was appointed assistant professor of geology at the University of Washington for the — term.
An urgent appeal from Salisbury to help with field-oriented teaching at the University The physical characteristics of the channeled scablands of eastern washington Chicago induced him to move there in at the starting rank of instructor, but by he had moved up to the tenured rank of associate professor.
In his summer field course for advanced students initiated a study of the channeled scabland landscape in eastern Washington. He proposed that a huge late Pleistocene flood now dated at about sixteen thousand years ago emanated from the margins of the nearby Cordilleran Ice Sheet, which then covered much of western Canada, extending from Alaska down to Puget Sound and the northern parts of Washington State, Idaho, and Montana.
Named the Spokane Flood for its then-presumed source area, this cataclysm neatly accounted for numerous interrelated aspects of the channeled scabland landscape. The immense volumes of floodwater, up to meters about feet deep, were recorded by high-level spillways that developed when preflood valleys were inundated beyond their capacities, inducing the floodwater to spill over divides from one valley to another.
Over a region of about by kilometers about to feet this process joined various preflood valleys into an anastomosing complex of dividing and rejoining channels.
|LAKE MISSOULA AND ITS CATASTROPHIC FLOODS||Level IV ecoregions in the Columbia Plateau.|
Anastomosing refers to an interlacing network pattern of branching and reuniting channels. Bretz also interpreted great mounds of fluvial gravel in the scabland channels to be subfluvial river bars, deposited in somewhat slower-moving portions of the floodwater.
Farther downstream the flood passed through the Columbia Gorge, then formed a huge gravel delta at the location of present-day Portland, Oregon, and finally passed on into the Pacific Ocean. All this proved too much for the geological community of the time.
At the 12 January meeting of the Washington D. His oral presentation was followed by six other talks, all of which were sharply critical of the flood theory. Among the many geologists who published papers opposing the Spokane Flood hypothesis, some of the best-known are Oscar E.
Resolution of the controversy came gradually, initially with the recognition by Joseph Thomas Pardee of a plausible source for the huge amounts of floodwater.
In the s Pardee showed that the ice-dammed Pleistocene glacial Lake Missoula, holding about 2, cubic kilometers cubic miles of water, formed in northern Idaho and western Montana and subsequently drained very rapidly to the channeled scabland.
Eventually, the accumulating field evidence became overwhelming, particularly when Bretz and others synthesized new data obtained by the Bureau of Reclamation during the development of the Columbia Basin Irrigation Project in the s.
Especially important for convincing the skeptics was the discovery that giant current ripples cap many of the scabland gravel mounds that Bretz had correctly interpreted in the s to be river bars.
Resembling the relatively tiny ripple marks that form along the sandy bottoms of active rivers, the giant scabland ripples occur in trains of twenty or more, with individual ripples of up to 10 meters some 33 feet in height and meters in spacing.
Instead of sand, these ripples are composed of flood gravel and boulders up to a meter in diameter. The debates of the s and s over the origin of the channeled scabland are important to geology for methodological reasons.
The prolonged nature of the Spokane Flood controversy arose in part because of the adherence of many geologists to substantive and epistemological notions of uniformitarianism, a principle that was erroneously thought to underpin their science.
According to the most common, mistaken applications of the uniformitarian principle, cataclysmic processes, such as those responsible for the origin of the channeled scab-land, were considered to be unsuitable topics for scientific investigation.
To counter this presumption of uniformitarianism, Bretz could provide only meticulously described field evidence for those willing to seriously consider it. After a decade of near-continuous research on the channeled scabland, Bretz turned to other studies, beginning with participation in the Louise A.
Boyd Expedition to East Greenland in Work on the surficial geology of the Chicago region led to two monographs. These outline ingenious analyses of the draining of Glacial Lake Chicago, a predecessor of modern Lake Michigan.
He argued eloquently for the origin of many cave features by processes of groundwater circulation below the water table.
His cave studies in seventeen U. His insights and energy were important to the late-twentieth-century resurgence of karst geomorphic and hydrologic studies in the United States.
While a faculty member at the University of Chicago from to and in subsequent semiretirement, Bretz supervised the field geology training of more than three hundred graduate students, including the future geological luminaries M.
King Hubbert, William C.The channeled scablands of eastern Washington were created by floodwaters from a huge glacially dammed lake. true When a tributary glacier melts it leaves a hanging valley above the main glacial valley.
The Channeled Scablands ecoregion contains the coulees and Channeled Scablands of Washington carved out by the cataclysmic Missoula floods, from Wenatchee to Spokane, including public land within the Lake Roosevelt National Recreation Area States/Provinces: Washington, Oregon, Idaho and British Columbia. Mar 08, · Channeled Scablands. The heart of Washington’s portion of the Columbia Plateau – and a landscape without parallel anywhere else in the region for its strangeness – is the tract of eroded. Geographic setting of the Channeled Scablands, eastern Washington. Fig. 3.—Vertical dikes of basalt cutting lava flows. These are the fissures now filled with solidified material that once served as conduits through which molten rock reached the surface.
parts of Washington, Oregon, and Idaho. The part of the lava field that underlies the Scab lands in eastern Washington is a sa ucer shaped area of about 15, square miles almost completely surrounded by mountains and nearly encircled by three rivers - the Columbia, the Spokane, and the Snake (Fi g.
2, page 3). The Channeled Scablands have a rectangular cross section, with flat plateaus and steep canyon sides, and are spread over immense areas of eastern Washington. The morphology of the scablands is butte-and-basin.
Vegetation zones and soil characteristics in vernal pools in the channeled scabland of eastern Washington Article (PDF Available) in Great Basin Naturalist 54(3) · .
David Alt's book is an excellent resource for anyone interested in exploring Lake Missoula features.
Glacial lake sediments with varves near Missoula, MT. The most prominent visible remains of the late Ice Age Floods are the Channeled Scablands of eastern Washington. 10 washington's channeled scabland (4) a glacial advance (the "Scabland Glacial Lobe") far beyond the limits accepted by everybody but the author of that theory.