Antarctica A Keystone in a Changing World (2008) / Chapter Skim
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The Significance of Antarctica for Studies of Global Geodynamics--R. Sutherland
The Significance of Antarctica for Studies of Global Geodynamics--R. Sutherland
Pages 115-124
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From page 115... ...
The African hemisphere con Antarctica is significant in the global relative platetains spreading ridges in the Indian and Atlantic Oceans motion circuit because it geometrically connects the African that allow relative plate motions to be determined, and the and Pacific hemispheres along a path that can be directly motions are shown by studies of seamount chains to be well reconstructed at past times from seafloor and continental approximated by a single hotspot (absolute) reference frame records (Figures 1 and 2)
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From page 116... ...
The Pacific, because Antarctica is part of a closed plate-motion hypothesis is presented and then tested against crustal geolcircuit that includes Australia and New Zealand. ogy of the Antarctic continent, the geometry of seafloor in This paper presents a model for the block motion the South Pacific plate-motion circuit, and the global motions of Marie Byrd Land relative to the East Antarctic craton of plates relative to hotspots.
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From page 117... ...
120 craton Basin Arbitrary points within the plate boundary 74 zone show the motion of the Marie Byrd 56 26 Land plate relocated (pink dotted) relative to South 44 500km Pole Thurston the East Antarctic plate using the proposed 90 Island kinematic model (Table 1)
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From page 118... ...
. Pacific-Marie Byrd Subglacial Basin Byrd Land spreading is constrained by numerous magnetic anomaly and fracture zone picks (Cande et al., 1995; Cande South of the Ross Sea the Byrd Subglacial Basin is a region of and Stock, 2004)
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From page 119... ...
with only a slightly larger plate movement and the Australia Antarctica boundary is relatively long, so the implications for global plate motions are relatively small. During this 74-56 Ma time, oblique convergence occurred adjacent to Thurston This was a time of tectonic quiescence within New Zealand, Island and a subducting microplate, the Bellingshausen plate, with the only records of tectonic activity coming from the moved independently to Marie Byrd Land until ca.
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From page 120... ...
, hotspot motion and the Antarctic deformation model of this paper (Table 1)
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From page 121... ...
: the preferred model is given in Table 1; the second is the same, but assumes no intra-Antarctic motion during IMPLICATIONS FOR GLOBAL SUBDUCTION BUDGETS the interval 74-44 Ma. The relative motions of oceanic plates in the Pacific hemi- It is clear from Figure 8 that the model of Antarctic sphere can be determined from magnetic anomalies within motion is significant for the computation of global subducthe Pacific, based upon the assumption of symmetric spread- tion rates and directions for the interval 74-50 Ma.
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1998. motion of Marie Byrd Land relative to East Antarctica to be Influence of subglacial geology on the position of a West Antarctic ice stream from seismic observations.
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1986. Cenozoic global plate motions.
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2001. Subglacial Sediments: A regional geological template for ice flow in West Antarctica.
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