Antarctica A Keystone in a Changing World (2008) / Chapter Skim
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Late Cenozoic Climate History of the Ross Embayment from the AND-1B Drill Hole: Culmination of Three Decades of Antarctic Margin Drilling--T. R. Naish, R. D. Powell, P. J. Barrett, R. H. Levy, S. Henrys, G. S. Wilson, L. A. Krissek, F. Niessen, M. Pompilio, J. Ross, R. Scherer, F. Talarico, A. Pyne, and the ANDRILL-MIS Science team
Late Cenozoic Climate History of the Ross Embayment from the AND-1B Drill Hole: Culmination of Three Decades of Antarctic Margin Drilling--T. R. Naish, R. D. Powell, P. J. Barrett, R. H. Levy, S. Henrys, G. S. Wilson, L. A. Krissek, F. Niessen, M. Pompilio, J. Ross, R. Scherer, F. Talarico, A. Pyne, and the ANDRILL-MIS Science team
Pages 71-82
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From page 71... ...
, but even in McMurdo Sound, where of advance and retreat of the grounded ice margin preserved Oligocene and early Miocene strata are well cored, the late in the AND-1B record the evolution of the Antarctic ice sheet since a profound global cooling step in deep-sea oxygen isotope records ~14 m.y.a. A feature of particular interest is a ~90-m-thick interval of diatomite deposited during the warm Pliocene and representing an extended period (~200,000 1 Antarctic Research Centre, Victoria University of Wellington, Wel years)
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From page 72... ...
E Cretaceous 1988 742 67°33S 75°24'E -416 m 316 m 53% mudst, diamict - ? Eo-Olig 1988 743 66°55'S 74°42'E -989 m 97 m 22% diamict - Pleistocene ODP 188 2000 1166 67°42'S 74°47'E -475 m 381 m 19% claystone - L Cretaceous O'Brien, Cooper, Richter et al., 2001 Antarctic Peninsula Barker, Camerlenghi, Acton et ODP 178 1998 1097 66°24'S 70°45'W -563 m 437 m 14% diamict - E Pliocene al., 1999 1998 1098 64°52'S 64°12'W -1010 m 47 m 99% mud - Holocene 1998 1099 64°57'S 64°19'W -1400 m 108 m 102% mud - Holocene 1998 1100 66°53'S 65°42'W -459 m 111 m 5% diamict - Pleistocene 1998 1102 66°48'S 65°51'W -431 m 15 m 6% diamict - Pleistocene?
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From page 73... ...
In the early 1970s two drilling platforms were available. The second yielded the first oxygen isotope measurements The Glomar Challenger operated by the Deep Sea Drilling on deep-sea calcareous microfossils, providing the first Project and a land-based system put together for the Dry evidence of dramatic ocean cooling and global ice volume Valley Drilling Project, an initiative of the United States, increase at the Eocene-Oligocene boundary (Shackleton and Japan, and New Zealand to explore the late Cenozoic history Kennett, 1974)
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From page 74... ...
Provide new knowledge on the Neogene tectonic the Cenozoic history of the Antarctic ice margin and climate evolution of the West Antarctic Rift System, Transantarctic from the Ross Sea, Prydz Bay, and Antarctic Peninsula sec- Mountains, and associated volcanism. tors (Table 1)
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From page 75... ...
CHRONOSTRATIGRAPHY OF "AND-1B" representing more than half of the last 7 Ma. Thus the AND 1B record provides several highly resolved "windows" into A preliminary age model for the upper 700 m of drill core the development of the Antarctic ice sheets during the late constructed from diatom biostratigraphy (Scherer et al., Cenozoic.
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From page 76... ...
: This STRATIGRAPHY regionally extensive discontinuity is correlated with top of a ~60-m-thick interval late Miocene volcanic sandstone (LSU Prior to drilling the MIS target, five distinctive reflectors 7) and the base of a 150-m-thick, high-velocity (3000 ms–1)
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From page 77... ...
STRATIGRAPHIC ARCHITECTURE The 1285-m-long AND-1B drill core provides the first highresolution, late Neogene record from the Antarctic margin (Figure 4) as well as the first long geological record from under a major ice shelf.
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From page 78... ...
Once a magnetostratigraphy glacially influenced facies in the upper parts, culminating in is developed for this section of the core together with new 40 a GSE at the glacial maximum. Ar/39Ar ages, further sedimentological and petrographic work should provide an important history of Antarctic ice sheet behavior during the "big" late Miocene, Mi-glaciations Major Chronostratigraphic Intervals and of Miller et al.
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From page 79... ...
a sharp-based massive diamictite with ice shelf. Our preliminary age model suggests that the cycles variable amounts of volcanic glass (subglacial to grounding in this interval may have formed in response to orbital forczone)
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From page 80... ...
The AND-1B core has the potential to contribute significant new knowledge about the dynamics of the West Antarctic SUMMARY ice sheet (WAIS) and Ross Ice Shelf and Ice Sheet system, Repetitive vertical successions of facies imply at least 60 as well as contributing to understanding the behavior of fluctuations of probable Milankovitch duration between the EAIS outlet glaciers during the late Cenozoic.
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From page 81... ...
In Antarctica: A Keystone in a Changing World Drilling Program, Initial Report 178, http://www-odp.tamu.edu/ -- Online Proceedings for the Tenth International Symposium on Ant publications/178_IR/178TOC.HTM. arctic Earth Sciences, eds.
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From page 82... ...
In Late Cenozoic Antarctic paleoclimate reconstructed from volcanic ashes Antarctica: A Keystone in a Changing World -- Online Proceedings for in the Dry Valleys region of southern Victoria Land. Geological Society the Tenth International Symposium on Antarctic Earth Sciences, eds.
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