Montana oil and mining journal. [volume] (Great Falls, Mont.) 1931-1953, 1941-03-08

11C--zzssA. :
Montana is known the Land of the Shin
ing Mountains because IL is studded with not
one but several mountain uplfts The value Of
OF these mountains goes beyond their beauty and
tourist attraction and beyond the gold and other
precious metals found in them for the upheaVal
of these mountains has bucked the otherwise
level plains of Montana into a series Of struc-
lures. domes or traps suitable for trapping oil.
Hundreds of the structures formed have not
yet been tested
The effect Of the uplifting of the Rocky
Mountains described in our article last week.
is shown by the illustration herewith. Gigantic
pressures coming from the west were so great
that they not only buckIed mp the earths sur
face for hundreds of miles but actually shunted
an entire mountain range ont across the pFearAe7
for from 80 to 40 miles This, one OF the most
marvellous phenomena I'm geological history, Is
known as the Lewis Overthrust."
Tins in the foothills of the mountains we
have sharply folded structures such as MIX RaV-
err anticIine, near Browning and west OF Gut
Bank oil field that is actually In the over
thrust belt The Turner Valley field in Alberta
is in the over-thrust Wells drilled through the
Younger Cretaceous formations find the lower
Cretaceous the JurasSic and the Madison hn1 ,
stone of CarbOniferous age in place. from tno
Madison lime the drill goes back INTO tne OEe-
taceOus.
Away from the mountains the East, the
over.thrust disappears but the beds are SHARPLY
folded and fractured Wherever the stresses were
greater than the formation could stand, Fault"
ING occurred The mis- alignment of the forEna-
tons, caused by the mOunSaAn building tDsCS s
to break and faulting is to be found everywhere
in greater lesser degree.
IT has been said that ''fauIting and oil fields
go together like ham and eggs. lnere may -
exceptions TO prove the rule that every great
oil field is faulted and while the faults may nOt
be visible the surface OF the GROUND Ih0y a.
freoentsy present in the lower more brittle Deos'
This folding, breaking and grinding Of the
earth's surface is going ON at all times as evL-
denced by the fact that there are dozens Oh
earthquakes every day Of the year, somewhere An
the United States Montana has had SOME S,OOO
earthquakes in the last decadeor since ,ss
began counting them. Earthquakes record Slips
or breaks in the formations which breaks are
called FAULETNG. The movement IN Haut
may be a few feet and 1T may be InouS1no Aece
or more The movement a fault line can DC
in any direction: mp or down sideways.
The beds Of sediments laid down by alternate
periods of oceans and dry land covering Ghe CON-
tinent, may be Iikened TO layer CAKE bFeaA
LAYER cake i'm two and raise one side one lAyer
higher than the other and we have the Aoe1.a
illustration of fault except that faults are ses-
dom vertical. The cake will probably not DreaA
in q straight line: neither do faults Cd necessary
Along known faults arc OF the greatest
oil fields in the world. The BALCONIES fault is per
haps the best known. Along 1t are many gre1t
oil fields the fault serving a barrier 70 mart
migration of oil The Whittier fault In the
Los Angeles basin Of California is one OF many
faults which explain the presence OF OH traps.
In addition TO the many Los Angeles basin heius
are the fields of the Mexia fault zone In IexaS;
the Salt Creek field in Wyoming; the Cromwen
field in Oklahoma; the Bellvue ana homer
fields in louisiana and scores OF others.
At one time, oil men were afraid of faults,
thinking they allowed oil to escape. Now they
seek out faults, ideal traps for oil and gas.