273 resultados para Beckman-Quarles
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A multi-proxy study including sedimentological, mineralogical, biogeochemical and micropaleontological methods was conducted on sediment core PS69/849-2 retrieved from Burton Basin, MacRobertson Shelf, East Antarctica. The goal of this study was to depict the deglacial and Holocene environmental history of the MacRobertson Land-Prydz Bay region. A special focus was put on the timing of ice-sheet retreat and the variability of bottom-water formation due to sea ice formation through the Holocene. Results from site PS69/849-2 provide the first paleo-environmental record of Holocene variations in bottom-water production probably associated to the Cape Darnley polynya, which is the second largest polynya in the Antarctic. Methods included end-member modeling of laser-derived high-resolution grain size data to reconstruct the depositional regimes and bottom-water activity. The provenance of current-derived and ice-transported material was reconstructed using clay-mineral and heavy-mineral analysis. Conclusions on biogenic production were drawn by determination of biogenic opal and total organic carbon. It was found that the ice shelf front started to retreat from the site around 12.8 ka BP. This coincides with results from other records in Prydz Bay and suggests warming during the early Holocene optimum next to global sea level rise as the main trigger. Ice-rafted debris was then supplied to the site until 5.5 cal. ka BP, when Holocene global sea level rise stabilized and glacial isostatic rebound on MacRobertson Land commenced. Throughout the Holocene, three episodes of enhanced bottom-water activity probably due to elevated brine rejection in Cape Darnley polynya occured between 11.5 and 9 cal. ka BP, 5.6 and 4.5 cal. ka BP and since 1.5 cal. ka BP. These periods are related to shifts from warmer to cooler conditions at the end of Holocene warm periods, in particular the early Holocene optimum, the mid-Holocene warm period and at the beginning of the neoglacial. In contrast, between 7.7 and 6.7 cal. ka BP, brine rejection shut down, maybe owed to warm conditions and pronounced open-water intervals.
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We analyzed sediment from Ocean Drilling Program (ODP) Site 1144 in the northern South China Sea to examine the weathering response of SE Asia to the strengthening of the East Asian Monsoon (EAM) since 14 ka. Our high-resolution record highlights the decoupling between continental chemical weathering, physical erosion and summer monsoon intensity. Mass accumulation rates, Ti/Ca, K/Rb, hematite/goethite and 87Sr/86Sr show sharp excursions from 11 to 8 ka, peaking at 10 ka. Clay minerals show a shorter-lived response with a higher kaolinite/(illite + chlorite) ratio at 10.7-9.5 ka. However, not all proxies show a clear response to environmental changes. Magnetic susceptibility rises sharply between 12 and 11 ka. Grain-size becomes finer from 14 to 10 ka and then coarsens until ~7 ka, but is probably controlled by bottom current flow and sealevel. Sr and Nd isotopes show that material is dominantly eroded from Taiwan with a lesser flux from Luzon, while clay mineralogy suggests that the primary sources during the Early Holocene were reworked via the shelf in the Taiwan Strait, rather than directly from Taiwan. Erosion was enhanced during monsoon strengthening and caused reworking of chemically weathered Pleistocene sediment largely from the now flooded Taiwan Strait, which was transgressed by ~8 ka, cutting off supply to the deep-water slope. None of the proxies shows an erosional response lasting until ~6 ka, when speleothem oxygen isotope records indicate the start of monsoon weakening. Although more weathered sediments were deposited from 11 to 8 ka when the monsoon was strong these are reworked and represent more weathering during the last glacial maximum (LGM) when the summer monsoon was weaker but the shelves were exposed.
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Back Row: Dick Lindenfeld, Frank Gusich, Robert Rosema, Mike Smith, William Ross, Dennis Connell, Scott Hulke, Tom Alexander, ?, Jim Schmitz
8th Row: Ed Woolley, Tom Huiskens, Paul Seymour, Reggie McKenzie, Donald Shaw, Jim Brandstatter, Mike Oldham, Fred Grambau, Tom Beckman
7th Row: Guy Murdock, Fritz Seyferth, Bruce Elliott, Allen Carpenter, Mike Keller, Dave Zuccarelli, Dana Coin, Preston Henry, George Mans
6th Row: Michael Taylor, Tom Darden, Tom Nieman, John Wolff, Gerald Dutcher, Ed Baldwin, Glen Doughty, William Taylor, Louie Lee*
5th Row: Bill Berutti, Thomas Takach, Lance Scheffler, Dick McCoy, Pete Newell, Dan Parks, Bill Harris, Greg Harrison, Jim Young*
4th Row: George Zuganelis, Paul Staroba, Jim Betts, Jack Harpring, Marty Huff, Ed Moore, Don Moorehead,Tim Killian, Frank Maloney*,
3rd Row: Henry Hill, Robert Ritley, Joe Lukz, Timothy Wadhams, Richard Brown, Eric Federico, Mark Werner, Dan Dierdorf, Robert White, Chuck Stobart*
2nd Row: Jerry Hanlon*, Dick Hunter*, Gary Moeller*, Larry Smith* Morris Abrahams, Jerry Imsland, Joe Jones, Barry Pierson, Richard Caldarazzo, Al Francis, Peter Sarantos, Werner Hall, Mike Hankwitz, coach Bo Schembechler
Front Row: Phil Seymour, Frank Titas, Bob Baumgartner, Tom Curtis, captain Jim Mandich, Brian Healey, John Gabler, Garvie Craw, Cecil Pryor
* = assistant coaches
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Back Row: Trainer Mike Willie, Assistant coaches Frank Maloney, Jerry Hanlon, George Mans, Tirrel Burton, Gary Moeller, Dick Hunter, Chuck Stobart, Jim Young, Larry Smith, Manager Neil Hiller, Head Trainer Lindsy McLean
5th Row: Tom Ferchau, John Pighee, Greg Ellis, Bob Mogulich, Tony Smith, Tom Poplawski, Mark Duffy, Bill Moran, Bill Haslett, Don Eaton, Carroll Damron, Bob Swan, Coach Bo Schembechler
4th Row: Bill Ross, Gary Coakley, Bob Rosema, Mike Smith, John Cilluffo, Randy Logan, Tom Kee, Bill Hart, Tom Coyle, Jack McBride, Jerry Schumacher, Jim Coode, Bo Rather, John Daniels
3rd Row: Frank Gusich, Bruce Elliott, Butch Carpenter, Tom Beckman, Mike Oldham, Reggie McKenzie, Fritz Seyferth, Dana Coin, Tom Huiskens, Jim Brandstatter, Dave Zuccarelli, Preston Henry, Paul Seymour, Scott Hulke
2nd Row: Greg Harrison, Bill Berutti, Ed Baldwin, Tom Nieman, Lance Scheffler, Jerry Dutcher, Fred Grambau, Tom Darden, Glenn Doughty, Guy Murdock, Mike Keller, Bill Taylor, Mike Taylor, John Wolff
Front Row: Marty Huff, Pete Newell, Ed Moore, Dan Dierdorf, Tim Killian, Jack Harpring, Co-captain Henry Hill, Co-captain Don Moorhead, Paul Staroba, Werner Hall, Dick McCoy, Bill Harris, Phil Seymour, Jim Betts.
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Back Row: Jim Young, Ron Sydlowski, Dave Brandon, John Thomas, Jon Cederberg, Jovan Vercel, Jon Cherry, Lonnie Taylor, Mike Holmes, Howard Staveran, Jim Lyall, Jim Johnston, Chuck Stobart
7th Row: Art Fediuk, Walt Sexton, Kevin Masterson, Bill Moran, Gary Hainrihar, Walt Williamson, Jim Armour, Barry Dotzauer, Don Warner, Larry Johnson
6th Row: Gary Moeller, Larry Gustafson, Harry Banks, Dave Elliott, Tom Drake, Don Coleman, Paul Seal, Greg Koss, Doug Trozak, Clint Haslerig, Craig Mutch, Larry Smith
5th Row: Curtis Tucker, Geoff Steger, Mike Hoban, Mark Duffy, Dave Gallagher, Ed Shuttlesworth, Bob Thornbladh, Al West, Tom Slade, Kevin Casey, George Mans
4th Row: Jerry Hanlon, John Pighee John Middlebrook, Jim Coode, Randy Logan, Gary Coakley, Larry Cipa, Jack McBride, Tom Poplawski, Tony Smith, Alan Walker, manager Chuck Quebbeman
3rd Row: Don Eaton, Bob Rosema, Scott Hulke, Tom Kee, Bill Hart, Jerry Schumacher, Tom Coyle, David (Bo) Rather, Greg Ellis, Clint Spearman
2nd Row: Dick Hunter, Fred Grambau, Reggie McKenzie, Tom Beckman, Fritz Seyferth, Mike Taylor, Alden Carpenter, Jim Brandstatter, Mike Keller, Paul Seymour, coach Bo Schembechler
Front Row: Guy Murdock, Glen Doughty, Tom Darden, Dana Coin, Bill Taylor, Bruce Elliott, Frank Gusich, Mike Oldham, Dave Zuccharelli
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Mode of access: Internet.
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Mode of access: Internet.
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2372 entries.
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"5th edition."
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Mode of access: Internet.
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Mode of access: Internet.
