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The erosion factor in the emplacement of the Keystone thrust sheet (South East Nevada) across a land surface

Published online by Cambridge University Press:  01 May 2009

M. R. W. Johnson
M. R. W. Johnson
Affiliation:
Grant Institute of Geology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW
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Summary

The Keystone/Muddy Mountain thrust of South East Nevada provides a spectacular example of a thrust sheet that has travelled across the earth's surface for a distance of at least 25 km, probably as much as 50 km. Along the thrust a Palaeozoic to early Mesozoic succession (> 4 km thick) has moved over a channelled erosion surface cut into Jurassic aeolian sandstone. Clasts in the channels are stratified, with those in upper layers being easily matched with the rocks in the thrust sheet – thus the clasts ‘herald’ the approach of the sheet. The clasts are only weakly deformed by the thrusting which belongs to the Sevier-Laramide orogeny.

Erosion appears to be a significant if not crucial factor in the emplacement of the Keystone thrust sheet. Adopting an erosion rate of 1 mm/a (in accord with Alpine and Himalayan estimates) and a rate of thrusting of 5 mm/a (in accord with estimates from the Canadian Rockies) it follows that the thrust sheet was ‘half-eroded’ after travelling about 25 km.

It is concluded that large displacement (i.e. > 25 km) may be impossible without erosion and one of two ‘erosion models’ would greatly facilitate transport up to 50 km, which is the likely maximum displacement.

Type
Articles
Information
Geological Magazine , Volume 118 , Issue 5 , September 1981 , pp. 501 - 507
Copyright
Copyright © Cambridge University Press 1981

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References

Adams, J. 1980. Contemporary uplift and erosion of the Southern Alps. New Zealand Bull. geol. Soc. Am. 91, 2–4.2.0.CO;2>CrossRefGoogle Scholar
Armstrong, R. L. & Oriel, S. S. 1965. Tectonic development of Idaho-Wyoming thrust belt Bull. Am. Assoc. Petrol. Geol. 49, 1847–66.Google Scholar
Brock, W. G. & Engelder, T. 1977. Deformation associated with the movement of the Muddy Mountain overthrust in the Buffington windows, southeastern Nevada Bull. geol. Soc. Am. 88, 1667–77.2.0.CO;2>CrossRefGoogle Scholar
Burchfiel, B. C. & Davis, G. A. 1968. Source terrain of the Keystone thrust plate, southern Nevada and southeastern California. Geol. Soc. Am. Program & Abstracts. Ann. Mtg. 41–2.Google Scholar
Clark, S. P. & Jäger, E. 1969. Denudation rate in the Alps from geochronologic and heat flow data. Am. J. Sci. 267, 1143–60.CrossRefGoogle Scholar
Davis, G. A. 1973. Relations between the Keystone and Red Spring thrust faults, eastern Spring Mountains, Nevada Bull. geol. Soc. Am. 84, 3709–16.2.0.CO;2>CrossRefGoogle Scholar
Elliott, D. 1976. The energy balance and deformation mechanism of thrust sheets. Phil. Trans. R. Soc. Lond. A 283, 289–312.Google Scholar
Gilluly, J. 1949. Distribution of mountain building in geologic time Bull. geol. Soc. Am. 60, 561–90.CrossRefGoogle Scholar
Longwell, C. R. 1926. Structural studies in southern Nevada and western Arizona Bull. geol. Soc. Am. 37, 551–84.CrossRefGoogle Scholar
Longwell, C. R. 1949. Structure of the northern Muddy Mountain area, Nevada Bull. geol. Soc. Am. 60, 923–67.CrossRefGoogle Scholar
Longwell, C. R., Pampeyan, E. H., Bowyer, B. & Roberts, R. J. 1965. Geology and mineral deposits of Clark County, Nevada. Bull. Nev. St. Bur. Mines 62.Google Scholar
Menard, H. W. 1961. Some rates of regional erosion J. Geol. 69, 154–61.CrossRefGoogle Scholar
Mehta, P. K. 1980. Tectonic significance of the young mineral dates and the rates of cooling and uplift in the Himalaya. Tectonophysics, 62, 205–17.CrossRefGoogle Scholar
Price, R. A. 1974. Large-scale gravitational flow of supracrustal rocks in southern Canadian Rockies. In Gravity and Tectonics (ed. De Jong, K. & Scholten, R.). New York: John Wiley & Sons.Google Scholar
Raleigh, C. B. & Griggs, D. T. 1963. Effect of the Toe in the mechanics of overthrust faulting Bull. geol. Soc. Am. 74, 819–30.CrossRefGoogle Scholar