Evening star., 1941-05-02
Melting Glaciers
Threaten Beauty Of
Parks in Rockies
Ice Rivers Retreotine
Is to 100 Feet Yearly,
Scientist Reports
BY THOMAS r. HENRY.

Glaciers in the United States and
the Canadian Rockies are retreating
at q rate of from 25 to 100 feet a
year, threatening the scenic beauty
of Glacier National Park and some
Of the favorite tourist resorts of
Western Canada.
They also are growing thinner,
90 an accelerated retreat can be
expected in the future.
This was the substance of a re-
port submitted to the American
Geophysical Union here today by
DR.. F. E. Matthes, chairman OF the
Glacier Research Committee.
Few of these glaciers are more
than three miles long. This means
that within the present generation
they may disappear. The same gen.
eral picture is presented by the
European and New Zealand Alps
In the former, the ice rivers are
much longer, so they can be expected
to persist for centuries.
Warmer Climate Responsible.
Perhaps the fastest retreat is that
experienced in Mount Rainier Ma
tional Park where the rate is be-
tween mile and a mile and half
each year. Most of the Alaskan
glaciers are melting rapidly, al
though a few of the larger ones
actually are advancing.
The general reason, according to
the report, is that the climate is
getting warmer, although the process
by no means is steady from year TO
year. The melting in Europe,
measurements show, started about
1850 and the rate has been greatly
accelerated since 1920. The Ameri-
can glaciers, for which old records
are not available, probably started
retreating at about the same time
after a short period of advance.
These mountain glaciers still
persiSting south of the Arctic Circle
are believed to be remnants of the
Ice age, approximately 10000 years
ago, when great ice sheets eX-
tended far to the south.
Measurements Made YearIys
It has not, however, been steady
warming up and there have been
long periods when the mountain
glaciers have advanced for GEN.
tury or more. They never have
ben able to get a sufficient start 20
cover any great part of the low
lands. Each era of warmer climates
has pushed them back a little
further.
According to some biologists, the
world still is in the last stages of
the ice age and the warming up will
continue, with occasional recessions,
until the ice sheets have vanished.
Today careful measurements are
made of the major glaciers in
America and Europe every year.
Iron Clock of Ages Set.
An iron clock of ages is being set.
The new timepiece of eternity was
described to the American Physical
Society meeting here by DrS. Robley
D. Evans, Clark Goodman and Pat
rick M. Hurley of the Massachusetts
Institute of Technology.
1t is magnetic iron ore, common
almost everywhere on earth. BY
means of this dollar watch" it is
hoped to tell the age of any part of
the earth.
Widely distributed in rocks are the
elements uranium and thorium.
Their atoms constantly are explod-
ing, shooting off atoms of the sun
gas, helium, and degenerating into
lead. The rate of this change is
known. Hence physicists in the past
have been able to determine the age
Of the earth-or of the period which
has elapsed since its crust hardened
by comparing the amount of lead
TO the amount of uranium and thor
luln in given rock.
Application Difficult.
The difficulty has been that rocks
to which this method is applicable
are very rare. Uranium degenerates
into one kind of lead, thorium into
another. Both are different from
ordinary lead, which is from 10 to
80 times as abundant in any deposit. !
Where only small amounts of lead
are present in association with |
uranium or thorium the separation |
Is practically impossible and subject |.
to errors which invalidate the con-
cluSionS.
Helium atoms released by the ex-
ploding radioactive atoms are |
trapped in the rock and if all of |
them stayed there they would indi-
cate the precise age Of the forma-
ton. There is only one kind of |
helium of any consequence. A sec
ond form is so rare that it need not
be taken into consideration.
But helium is gas and slowly
leaks out of rocks where it is
trapped. The Massachusetts Insti- |
tute of Technology workers first |
determined that the rate of escape |
depends on the kind of mineral and
that the gas is held almost indef1-
nitely by magnetic iron ore, one Of
the most common constituents of
the earth'S crust.
There are certain formations
containing iron ore which also con-
tain uranium lead in sufficient
quantities to be dated. 1t has been
found that the dates given by the
helium in the iron check quite |
closely with the lead dates.