Single parent dating lake fork idaho
This feedback cycle eventually weakened the ice dam so much that it could no longer support the pressure of the water behind it, and it failed catastrophically.
This process is known as a glacial lake outburst flood, and many such events have occurred in recorded history.
Geologist J Harlen Bretz first recognized evidence of the catastrophic floods, which he called the Spokane Floods, in the 1920s.
He was researching the Channeled Scablands in Eastern Washington, the Columbia Gorge, and the Willamette Valley of Oregon.
Glacial deposits overlaid with centuries of windblown sediments (loess) have scattered steep, southerly-sloping dunes throughout the Columbia Valley, ideal conditions for orchard and vineyard development at higher latitudes.
Both Pardee and Bretz continued their research over the next 30 years, collecting and analyzing evidence that led them to identify Lake Missoula as the source of the Spokane Flood and creator of the Channeled Scablands.Bretz coined the term Channeled Scablands in 1923 to refer to the area near the Grand Coulee, where massive erosion had cut through basalt deposits.Bretz published a paper in 1923, arguing that the Channeled Scablands in Eastern Washington were caused by massive flooding in the distant past. Pardee, had worked with Bretz and had evidence of an ancient glacial lake that lent credence to Bretz's theories.His most compelling argument for separate floods was that the Touchet bed deposits from two successive floods were found to be separated by two layers of volcanic ash (tephra) with the ash separated by a fine layer of windblown dust deposits, located in a thin layer between sediment layers ten rhythmites below the top of the Touchet beds. By analogy, since there were 40 layers with comparable characteristics at Burlingame Canyon, Waitt argued they all could be considered to have similar separation in deposition time.The two layers of volcanic ash are separated by 1–10 centimetres (0.4–3.9 in) of airborne nonvolcanic silt. The controversy whether the Channeled Scabland landforms were formed mainly by multiple periodic floods, or by a single grand-scale cataclysmic flood from late Pleistocene Glacial Lake Missoula or from an unidentified Canadian source, continued through 1999.