Cordilleran Section - 98th Annual Meeting (May 13–15, 2002)

Paper No. 0
Presentation Time: 2:15 PM

150+ YEARS OF ALPINE AND GLACIAL GEOMORPHOLOGY IN THE UNITED STATES: ORIGIN AND EVOLUTION OF A PSEUDOSCIENCE AKIN TO ASTROLOGY


SCHAFFER, Jeffrey P., Math, Sci & Engin, Napa Valley College, 2277 Napa-Vallejo Highway, Napa, CA 94558, jeffschaffer@interx.net

In 1847 Agassiz proposed that ice sheets originated locally (e.g., Scandinavia, Alps) rather than growing southward from the North Pole. Thus began the late-Cenozoic uplift/glacial erosion paradigm: ranges rose, ice accumulated, glaciers developed, and these widened and deepened canyons. William Morris Davis studied at Harvard and later as a professor there became America’s foremost proponent. Whitney, Brewer, and King studied under Dana at Yale. These three became the Geological Survey of California. In 1862 Brewer wrote up a Sierran miner’s tale that fit his Yale view of late-Cenozoic uplift. In 1863, when they actually entered the range, they recorded evidence contrary to uplift. However, the tale, with an imaginary geologic cross section, entered Whitney’s 1865 report, which was repeated in articles and textbooks. Over time, estimates of perceived uplift increased. Flint (1971) proposed thousands of m of post-Miocene uplift for the world’s ranges. Huber (PP1197, 1981) proposed 3450 m of Sierran uplift at 2800 m Minaret Summit, so initially it lay 650 m below sea level. Like Ransome (1898, Bull 89), Huber removed older strata that argued against uplift, but he then used several false assumptions to support his hypothetical model, which has become the foremost paper on Sierran uplift. As uplift estimates increased, so did deepening by glacial erosion. Matthes (PP 160, 1930) created a theoretical model of Sierran uplift and Yosemite Valley glaciation, based on Davis’ views, and Harvard’s Kirk Bryan used it to defend Davisian geomorphology. From ca. 1960+, evidence for major glacial erosion has become increasingly imaginary. Mass wasted deposits atop glaciers ca. equal amounts of glacial sediments, but with the exclusion of mass-wasted debris, 100% of the debris is attributed to glacial erosion. Likewise, fjords and fjord lakes correlate with Cenozoic extension, but with the exclusion of tectonics, 100% of the deepening is attributed to glacial erosion. (In cratons, tropical weathering fronts have operated for 100-1000+ m.y., and ice sheets have removed deep regolith to create the Great Lakes, etc.) Until mass wasting and tectonics are acknowledged, alpine and glacial geomorphology in the US and elsewhere will stay a pseudoscience like astrology, both utilizing mathematics and modeling.