Glacial lineations show that the final movement of glacier ice over the 

 western two-thirds of the area was toward the southeast, from the direction of 

 the White Mountains. This glacial advance entered the sea and deformed 

 previously-deposited beds of the Presumpscot Formation when sealevel was at 

 least 40 ft above its present position relative to the land. It is named the 

 Kennebunk glacial advance from glacially-deformed marine beds exposed near 

 Kennebunk, Maine. 



Ice of the Kennebunk advance was impeded in its movement by a rugged 

 upland region northwest of the coastal plain. Local bedrock relief of up to 

 1000 ft finally separated the thinning ice into detached valley-filling seg- 

 ments, which melted simultaneously over an area at least 25 mi wide from 

 southeast to northwest. During this time of final deglaciation, the marine 

 transgression reached its maximum extent. A line of deltas and delta fans 

 built by meltwater streams marks the inland limit of marine submergence. The 

 strandline of maximum submergence now increases in altitude toward the north 

 at about 2 ft/mi, providing one linear component of postglacial differential 

 upwarping. 



Marine submergence may have been in progress 11,800 year B.P., based on 

 one C'"" age determination on marine shells from Waterville, Maine. Pollen 

 stratigraphy implies that re-emergence was in progress 7,000-8,000 year. B.P. 

 Emergence was accompanied by differential upwarping toward the northwest, 

 presumably the result of postglacial isostatic recovery of the Earth's crust. 

 At some time between 7,000-8,000 year B.P. and 4,200 year B.P. the coast of 

 southwestern Maine was emerged at least 2 ft. and perhaps 8-9 ft greater than 

 present. Progressive submergence has continued from then to the present time. 



If eustatic sealevel has been near its present position for the past 

 5,000 years, as is suggested by accumulating evidence, then either the 

 isostatic movement of the coast of Maine has reversed its direction, or other 

 tectonic movements are causing coastal subsidence. (Author). 



024 BLOOM, A. L. 1967. "Pleistocene Shorelines: A New Test of Isostasy," 

 Geological Society of America . Bulletin No. 78, pp 1477-1494. 



Recent geophysical studies of glacial isostatic deformation overlook the 

 same fact that was overlooked in earlier studies: The loads of ice that were 

 applied to continents during glacial ages were not loads added to the Earth's 

 crust, but were loads transferred from the oceanic 70 percent to the glaciated 

 5 percent of the crust by the hydrologic cycle. A realistic model of glacial 

 isostasy must be represented by a balance, in which glaciated areas totaling 

 about 5 percent of the Earth's surface have loads of 140 to 170 bars added or 

 removed on a time scale of 10'' years, while synchronously the oceanic 70 per- 

 cent of the Earth's surface has a load of 10 to 12 bars or more removed or 

 added on a similar time scale. The subcrustal mass transfer involved in such 

 a balance is not well represented by harmonic equations, for the water and ice 

 loads are not symmetrically disposed on the Earth's surface. 



The suitability of the proposed balance model depends on whether the 

 ocean floor will respond isostatically to a load of as little as 10 bars. 

 Evidence from Lake Mead, Arizona, and Lake Bonneville, Utah, suggest that the 

 continental crust, at least, does deform under a regional load of 10 bars or 

 less . 



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