Constraining the amplitude of late Oligocene bathymetric changes in Western Ross Sea during orbitally-induced oscillations in the East Antarctic Ice Sheet: (1) Implications for glacimarine sequence stratigraphic models

被引:20
作者
Dunbar, G. B. [1 ]
Naish, T. R. [1 ,2 ]
Barrett, P. J. [1 ]
Fielding, C. R. [3 ]
Powell, R. D. [4 ]
机构
[1] Victoria Univ Wellington, Antarct Res Ctr, Wellington, New Zealand
[2] GNS Sci, Lower Hutt, New Zealand
[3] Univ Nebraska, Dept Geosci, Lincoln, NE 68588 USA
[4] No Illinois Univ, Dept Geol & Environm Geosci, De Kalb, IL 60115 USA
关键词
cape roberts project; oligocene; paleobathymetry; sequence stratigraphy; glaciomarine facies; Antarctica;
D O I
10.1016/j.palaeo.2007.08.018
中图分类号
P9 [自然地理学];
学科分类号
0705 [地理学]; 070501 [自然地理学];
摘要
Late Oligocene shallow glacimarine sequences recovered from western Ross Sea, Antarctica by the Cape Roberts (drilling) Project display orbitally-influenced cycles of advance and retreat of a laterally-extensive ice sheet across the continental shelf, in concert with changes in contemporary water-depth. During interglacial periods, when the glacier terminated on land, the coastline was largely ice-free and wave-influenced, and sediments accumulated in hydrodynamic equilibrium with the contemporary wave-climate., Here, we present estimates of paleobathymetry from intervals of three Milankovitch-duration glacimarine sequences (9, 10 and 11) that accumulated in open ocean conditions. We utilise an approach where the percentage of mud (< 63 mu m fraction) in bulk sediment is related to the wave-induced bed shear stress, and for a given wave climate, water depth (e.g. [Dunbar, G,B. and Barrett, P.J., 2005. Estimating palaeobathymetry of wave-graded continental shelves from sediment texture. Sedimentology 52, 253-269.]). Particle size-derived changes in paleobathymetry for the three late Oligocene sequences were between 20-40 and 60-90 in. These water depth changes are consistent with the magnitude of contemporary global eustatic sea-level changes of 30-40 in estimated from far-field continental margin and deep-marine ocean proxy records. On the basis of our bathymetric constraints we contribute to a conceptual stratigraphic model for shallow glacimarine sequences, whose depositional architecture is controlled by a combination glacier advance and retreat and changes in relative sea-level. (C) 2007 Elsevier B.V. All rights reserved.
引用
收藏
页码:50 / 65
页数:16
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