The Earth's Shifting Crust by Charles Hapgood - wire of information

i6s
EARTH'S SHIFTING CRUST
years. If we assume that the lag was the same during the
growth of the icecap, we can see that there may have been
an enormous excess of matter on the crust when the Scandi-
navian icecap reached its apogee.
In another way, Daly shows how slowly the compensating
flow that permits adjustment takes place. He refers to the
fact that erosion from a continent or large island appears to
create negative anomalies (deficiencies of mass) on the land
and positive anomalies in the sea (97:297-98). This is so
because the crust does not adjust as rapidly as erosion takes
place. Yet we can easily see that the accumulation of ice is
faster than the weathering of rock and the deposition of
sediments in the sea.
The geophysicist Beno Gutenberg has made a number
of statements that strongly support the same conclusion. In
discussing the zone within the earth where adjustment is
carried on, he says:
... It is inferred that this depth represents (in geologically
stable regions) the critical level below which strain is nearly reduced
to zero by subcrustal flow in periods of, say, 100,000 years (194:316).
The period of 100,000 years indicated by Gutenberg appears
to be a multiple of the time required for the growth of
a vast continental icecap. In another place, he refers directly
to the lag between the growth or retreat of an ice sheet and
the adjustment of the crust. After listing other ways in which
the isostatic balance of the crust may be disturbed, he adds:
A probable instance ... is the lag in complete compensation
of the load provided by the Pleistocene ice sheets. This is shown by
the recoil of the tracts unloaded by the melting of the ice (194:319).
He remarks, further:
The processes by which isostasy is maintained must be extremely
slow, and consequently, this equilibrium is liable to disturbance by
geological events (194:318).
Gutenberg and Richter, in their volume on The Sets-
mici'y of the Earth, express the known facts about adjust-