Predictions of global changes in relative sea-level caused by retreat of 

 the Antarctic Ice Sheet from its 18,000 year B.P. maximum to its present size 

 are calculated numerically. When combined with the global predictions of 

 relative sea- level change resulting from retreat of the Northern Hemisphere 

 ice sheets, the results may be compared directly to observations of sea- level 

 change on the Antarctic continent as well as at distant localities. The com- 

 parison of predictions to the few observations of sea-level change on Antarc- 

 tica supports the view that the Antarctic Ice Sheet was larger 18,000 years 

 ago than at present. The contribution of the Antarctic Ice Sheet to the total 

 eustatic sea-level rise is assumed to be 25 m (25% of the assumed total 

 eustatic rise). If as little as 0.7 m of this 25 m rise occurred between 

 5000 year B.P. and the present, few mid- oceanic islands would emerge. If the 

 Antarctic Ice Sheet attained its present dimensions by 6000 year B.P. however, 

 and if the volume of the ocean has remained constant for the past 5000 years, 

 numerous islands throughout the Southern Hemisphere would emerge. It is sug- 

 gested that a thorough study of Pacific islands, believed by some to have 

 slightly emerged shorelines of Holocene age, would yield useful information 



about ocean volume changes during the past 5000 years, and hence on the 

 glacial history of the Antarctic Ice Sheet. (Authors). 



057 CLOETINGH, S. 1988. "Intraplate Stresses: A Tectonic Cause For Third- 

 Order Cycles in Apparent Sea-Level?," Wilgus, C. K., Hastings, B. S., Kendall, 

 C. G., Posamentier, H. W. , Ross, C. A., and Van Wagoner, J. C, eds . , Sea- 

 Level Changes: An Integrated Approach . Special Publication No. 42, Society of 

 Economic Paleontologists and Mineralogists, Tulsa, OK, pp 19-30. 



Thermo -mechanical modeling demonstrates that tectonically induced 

 vertical motions of the lithosphere may provide an explanation for third-order 

 cycles in apparent sea-level deduced from the seismic stratigraphic record of 

 passive margins. The interaction of fluctuations in intraplate stresses and 

 the deflection of the lithosphere caused by sedimentary loading can produce 

 apparent sea- level changes of as much as 100 m at the flanks of passive 

 margins . 



In general, stress variations of a few hundred bars associated with 

 local adjustment of stresses at passive margins suffice to explain a 

 significant part of the stratigraphic record associated with short-term 

 variations in sea-level on the order of a few tens of ms . To induce short- 

 term apparent sea-level fluctuations with magnitudes on the order of 50 m or 

 more, which occur less frequently in the record, changes in stress level in 

 excess of one kbar are required. These larger fluctuations in apparent sea- 

 level could be related to major reorganizations of lithospheric stress fields 

 due to rifting and fragmentation of plates, dynamic changes at convergent 

 plate boundaries, of collision processes. A fluctuating horizontal stress 

 field in the lithosphere can explain contemporaneous changes in apparent sea 

 level in neighboring depositional environments. In principle, it implies the 

 possibility of regional correlations in different basin settings. Specific 

 short-term fluctuations in the curves of Vail and others can be associated 

 with particular plate tectonic reorganizations of lithospheric stress fields. 

 The seismic stratigraphic record may provide a new source of information on 



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