The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1924-02-16
SURFACE CRUST OF
EARTH is SHRINKING
When Ground Wrinkles Result Is Mountain Chain-RockS
Formed Beneath Water Now Found in Air.
BY DAVID DIETZ
Science Editor Of The Times
Copyright by David Dietz)

tCOpyrlSnt by DAVID DletD
m HE atmosphere. rain. rivers.
II glaciers and oceans, as we have
- seen, are continuously at work
wearing away the land.
II these forces were the only ones
at work. the continents would be lev
eled into featureless plains stretch.
/ ing from ocean TO ocean and all the
sedimentary rocks would be in even
| layers upon the ocean bottom.
But & second group of forces coun-
| terbalances the work OF the first
group. This second group tends TO
/ uplift the land.
As a result Of these forces. we find
/ the continents marked with great
/ chains Of mountains We find layers
! Of sedimentary rocks which formed un-
der water now lifted high above sea
| Levers nd bent and buckled and twisted
| out Of their original shape.
| We also fnd a third type 81 rock
whose formation was brought about
| by these forces.
! Due to Contraction
The forces which cause the pubHft-
/ ing OF the continents and the noun
tain ranges upon them, are due to the
contraction Of the earth, many geolo-
gists believe.
Contraction is thought to be due to
loss Of heat and to molecular rear
rangement OF the materials in the in
| terror CT the earth.
tho ~ o7Ytoy
| crust or surface Of the earth becomes
/ too large for It, Consequently, 1t col
| lapses Parts sink. Other parts are
/ bucIIed up into great wrinkles by
/ this sinking
Biologists know that the cont.
nents are composed Of lighter rocks
such as the GRANTEES, while the ocean
! beds are composed Of heavier rocks
| known as basalts.
Consequently In the @ rc-adjust-
ments due to shrinkagt. the heavier
ocean beds tend to sink while the
lighter masses composing the CONT
nents are pushed up and elevated.
Biologists have a theory known as
the theory of isostasy. According to
this theory, the crust of the earth is
considered as floating. so to speak
upon the molten but rigid interior of
the earth.
According to this theory, the heav-
Ter materials. such as the ocean beds,
settle down because Of their weight.
This causes the lighter materials, the
continents, to rise.
Because of the rigidity Of the earth
the contraction process cannot be a
gradual one.
Strain Is Tremendous
It is periodic The tendency toward
shrinkage sets up tremendous strains
These strains next get so great that
the material gives way to them.
The shrinkage first sets up strains
which cause small movements of por-
tons of the earth's surface. The diff.
ference Of elevation caused by these
small warnings is usually only several
hundred feet.
These small warnings in time set
up strains which cause a breaking
and greater REIMBURSEMENT between
the rising and settling portions.
At these times, the shortening, fold
ing and breaking Of the earths crust
causes the rise of great mountain
ranges.
Biologists believe that eight read
justments Of this nature have taken
place in North America in the course
of the worlds history
Finally there are the great periods
OF major establishments when the con
tinents are lifted as units above sea
level.
Biologists believe there have beer
six such major readjustments in the
worlds history.
Next article in series Earthquakes.