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

50
EARTH'S SHIFTING CRUST
rates of decay, the proportions of the three elements in a
sample of sediment change with time, and thus it is possible,
by measuring the remnant quantities of the three elements,
to date the samples.The samples are obtained by taking long
cores from the bottom of the sea. A core is obtained by lower-
ing a coring tube from a ship. It pierces the bottom sediments
and obtains a cross section of them. The ionium method per-
mits dating back as far as about 300,000 years.
Among the materials first dated by Urry's method were
some long cores that had been taken from the bottom of the
Ross Sea in Antarctica by Dr. Jack Hough during the Byrd
expedition of 1947-48. These cores showed alternations in
types of sediment. There was coarse glacial sediment, as was
expected, and finer sediment of semiglacial type, but there
were also layers of fine sediment typical of temperate climates.
It was the sort of sediment that is carried down by rivers from
ice-free continents. Here was a first surprise, then. Temperate
conditions had evidently prevailed in Antarctica in the
not distant past. The sediment indicated that not less than
four times during the Pleistocene Epoch, or during the last
million years, had Antarctica enjoyed temperate climates. (See
Figure XI, p. 306.)
Then, when this material was dated by Dr. Urry, it became
had occurred at
plain that the numerous climatic changes
very short intervals. Moreover, it appeared that the last ice
age in Antarctica started only a few thousand years ago.
Hough wrote:
The log of core N-5 shows glacial marine sediment from the pres-
ent to 6,000 years ago. From 6,000 to 15,000 years ago the sediment is
fine-grained with the exception of one granule at about 12,000 years
ago. This suggests an absence of ice from the area during that period,
except perhaps for a stray iceberg 12,000 years ago. Glacial marine
sediment occurs from 15,000 to 29,500 years ago; then there is a zone
of fine-grained sediment from 30,000 to 40,000 years ago, again sug-
gesting an absence of ice from the sea. From 40,000 to 133,500 years
ago there is glacial marine material, divided into two zones of coarseand
two zones of medium-grained texture.