923 resultados para Duffy, John L.


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Detrital modes determined on 68 sandstone samples from CRP-3 drillcore indicate a continuation of the dynamic history of uplift-related erosion and unroofing previously documented in CRP-1 and CRP-2/2A. The source area is identified very strongly with the Transantarctic Mountains (TAM) Dry Valleys block in southern Victoria Land. Initial unroofing of the TAM comprised removal of much of a former capping sequence of Jurassic Kirkpatrick basalts, which preceded the formation of the Victoria Land Basin. Erosion of Beacon Supergroup outcrops took place during progressive uplift of the TAM in the Oligocene. Earliest CRP-3 Oligocene samples above 788 metres below the sea floor (mbsf) were sourced overwhelmingly in Beacon Supergroup strata, including a recognisable contribution from Triassic volcanogenic Lashly Formation sandstones (uppermost Victoria Group). Moving up-section, by 500 mbsf, the CRP-3 samples are depauperate quartz arenites dominantly derived from the quartzose Devonian Taylor Group. Between c. 500 and 450 mbsf, the modal parameters show a distinctive change indicating that small outcrops of basement granitoids and metamorphic rocks were also being eroded along with the remaining Beacon (mainly Taylor Group) sequence. Apart from enigmatic fluctuations in modal indices above 450 mbsf, similar to those displayed by samples in CRP-2/2A, the CRP-3 modes are essentially constant (within a broad data scatter) to the top of CRP-3. The proportion of exposed basement outcrop remained at < 20 %, indicating negligible uplift (i.e. relative stability) throughout that period.

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Front Row: Michael W. Darland, Thomas W. Pederson, Eric A. Peper, C. Matthew Chelich, Fernando J. Canales, Robert F. Murray, Kevin V. Williamson

2nd Row: Richard L. Carter, Paul W. Griffith, Scott D. Weir, Kenneth J. Vigiletti, Jonathan K. Menegay, Kevin A. Morgan, David L. Price, Bill Mills, James F. Derks

3rd Row: swimming coach Gus Stager, Jon Beach, Kevin Machemer, Brent Campbell, Lance Weissmann, Matt Kanzler, Tom D. Dudley, Jr., R. Scott Crowder, III., Walter H. Gage, III, diving coach Dick Kimball

Back Row: Rich D. Hitt, Jr., Jamie Gentile, John L. Spaid, Mark McMann, Mike Wilson, Michael W. Dauw, John E. Slykhouse, Eric Yamauchi, Andy Griffith, Thomas D. Ernsting, Bruce Temme

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This report gives biological and physical oceanographic data from baseline work, and studies of dredged and undredged sediments before and after dredging (9-meter contour) for beach nourishment at Panama City Beach, Florida. These studies were designed to show major short-term environmental effects of offshore dredging and included analyses of hydrology, sediments, and benthos. (Author).

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Includes bibliographical references.

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Mode of access: Internet.

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"This report was prepared for the Unemployment Insurance Service, U.S. Department of Labor under Contract Number 99-7-0805-04-138-01 with Mathematica Policy Research, Inc. The authors of this report are John L. Czajka, Sharon K. Long and Walter Nicholson ..."

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"June 1972."

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National Highway Traffic Safety Administration, Washington, D.C.