Pullman herald. [volume] (Pullman, W.T. [Wash.]) 1888-1989, 1890-11-01
ANCIENT Lake, BONNEVILLE.
Great Salt Lake the Largest Survivor OF
an Ancient Inland Sea.

Great Salt Lake the Largest Survivor OF
an Ancient Inland Sea.
The largest of the ancient lakes at
present known is Lake Bonneville, the
second in size has been named Lake La
hontan. Lake Bonneville was situated
on the east border of the Great Basin,
principally in Utah, and extended from
few miles north of the Utah Idaho
boundary $50 miles southwark. 1t
flooded all the valley of Great Salt lake,
together with the Sewer and Escalante
deserts in southern Utah. 1t was 1875
miles broad and 1000 feet deep, where
Great Salt lake is now situated. The
site of the temple at Salt Lake City was
then submerged $50 feet.
Lake Bonneville overhowed northward
and became tributary to Snake river,
which flows into the Columbia. At va
rious stages its waves and currents
formed terraces and gravel bars on the
mountain slopes which confined it. These
still remain as fresh and perfect as when
they were formed, and are in part the
records from which the geologist has
been able to determine the history of the
ancient lake. We know that it rose with
many fluctuations until it had depth of
about 900 feet, but did not overflow.
Then a change of climate caused it to
contract its borders, and possibly to be-
come completely desiccated. In the
lower stages of this desiccation it was
broken into separate water bodies, which
must have been more or less saline.
Another great climatic change caused
the basin to be refilled to higher level
than before and to overflow. The water
found an outlet at the north end Of
Cache valley, Idaho, and, as we have
said, became tributary to the Columbia.
The lake continued to overflow until the
waters had cut down their outlet $40
feet. During this period, unless there
were some peculiar conditions near the
point of discharge, the lake must have
been fresh. The discharge of the lake
was finally stopped by climatic change
which lowered its surface below the bot
tom of the outlet. and again the basin
became partly if not wholly desiccated.
This second low water period has con-
tinued to the present day, and Great Salt
and Sewer lakes are the representatives
of ancient Bonneville.
The largest of these representatives of
the ancient sea is Great Salt lake. In
1850 it covered 1850 and in 1869 2, 166
square miles. Its maximum depth is
about fifty feet and its mean depth ap-
proximately fifteen feet. These recent
changes in area are due to small varia-
tons in climate, similar in character to
the changes which produced the great
expansions and contractions of the lake
in ancient times. With change in vol
ume there is change in density; that is,
the strength of the brine increases with
decreased area, and decreases when the
lake expands. In 1850 its waters con-
tanned about twenty two parts, by weight,
of saline matter in solution to 100 parts
had decreased to a little less than Is and
in 1873 to little more than IA per cent.
This change in salinity fas accompanied
by increased area.
The waters of the cean contain $40
per cent. of total ssts IN kt'u+ion. Great
Salt lake, Therefore, nares .,yas six
times as saline as thee ocS essz.e1 be So, the
ocean, too, it holds many substanc> in
solution; the principal ones are common
salt, or sodium chloride, and sodium sui
phate; besides these there are small per
centages of potassium, magnesium, etc.
The influence of temperature on the
solubility of certain saline substances is
well illustrated by this dead sea of Utah.
In summer its waters are clear and
transparent, but as cold weather comes
on it becomes milky or opalescent,
owing to the precipitation of sodium
sulphate in an extremely fine condition.
In the depth of winter, when the temper
allure of the atmosphere above the lake
falls far below freezing, an immense
quantity of sodium sulphate is precipi-
,ated and is thrown ashore by the waves
until thousands of tons accumulate on
the beach. When the temperature rises,
the salt thus precipitated is again dis
solved. This natural process of frac-
tional srystallization produced by lower
ing of temperature, is instructive, and
should suggest to those who are attempt
ing to manufacture salt in Utah prac-
teal method of treating the natural
brines in order to obtain common salt
free from sodium sulphate. Lake Sewer
Is also highly saline, and during the arid
season sometimes evaporates to dryness.
Israel G. Russell in Overland Monthly.