Download Palouse History notes File

ENTRY TASK
• Name a piece of physical
evidence that supports the
existence of a mega flood.
CHANNELED SCABLANDS
WHAT DID WE LEARN FROM THE
VIDEO?
• When were the scablands first
recognized?
• Who developed the theory of a mega
flood?
• What were the flaws with his theory?
• Where did the water come from?
• The water rushed from ______ to _____?
EVIDENCE OF A MEGA
FLOOD
INFORMATION AND MATERIALS FROM
GLACIALLAKEMISSOULA.ORG
LAND DEFORMATION
• What is land deformation?
• The changing of the earth’s
crust.
WHAT CAUSES LAND DEFORMATION?
• Volcanoes
• Earthquakes
• Flood
• Weathering and Erosion (wind, water,
ice, gravity)
GRADUALISM
• Charles Darwin is credited with defining
geological gradualism.
• He stated that large changes are a result of
small changes adding up over time.
• This theory stemmed from his theory of
evolution. Small changes in genetics will
show large changes in a species over time.
WHAT DARWIN NOTICED
• He witnessed an eruption on Mount
Osorno.
• He survived an earthquake in Valdivia.
• He made observations on weathering
of rocks and the crystallization of lava.
CORAL REEF THEORY
• He suggested that corals grow around islands,
but over long periods of time the sea floor can
subside. The coral would continue to grow
whereas the island would be washed away, so
leaving the coral reef alone to be observed
now. Darwin’s theory was instantly accepted by
the geological community. -
VOLCANIC ISLAND THEORY
• volcanoes are usually formed when lava
repeatedly erupts so layers of volcanic rock are laid
down successively building up the cone. At the
time, many geologists believed a volcano grew up
because of pressure from below and the crater
then subsided. Darwin’s idea was right. Darwin
almost struck on a much bigger idea, his
observations led him to believe the earth’s crust
was moving, rising in some places and subsiding in
others.
• The Autobiography of Charles Darwin
by Charles Darwin (Edited by Francis Darwin), The
Thinker's Library: 1929
• Charles Darwin, Geologist
by Sandra Herbert, Cornell University Press: 2005
• Darwin
by John van Wyhe, Andre Deutsch: 2009
• Darwin
by Adrian Desmond & James Moore, Penguin: 1991
• Journal of Researches
by Charles Darwin, 1839 (any edition)
• On the Origin of Species
by Charles Darwin, 1859 (any reprint - 2nd edition
preferable)
GLACIAL LAKE MISSOULA
• The horizontal lines etched into the
hillside are evidence that a prehistoric
lake once filled the valley.
• The parallel lines represent the ancient
shorelines of Glacial Lake Missoula.
• The highest known shorelines are found
at an elevation of 4,200 feet.
• If the lake existed at this level today,
the city of Missoula would sit beneath
950 feet of water.
CLARK FORK RIVER
• When it burst through the ice dam and
exploded downstream, the waters of
Glacial Lake Missoula ran at a rate of 10
times the combined flow of all of the current
rivers in the world!
• The fast draining waters left many features
similar to features seen along creeks and
rivers today, but on an exaggerated scale.
CAMAS PRAIRIE RIPPLES
• In 1942, Geologist Joseph T. Pardee
identified these unique parallel ridges found
in the Camas Prairie as "giant" ripple marks.
•
• With an average height between 13-30 feet
these ripple marks would dwarf any ordinary
ripple mark you might find on a beach or in
a river today.
• The Camas Prairie ripple marks were formed
as the deep and swift flowing water from
Glacial Lake Missoula raced through the
failed ice dam at speeds up to 50 miles per
hour.
CHANNELED SCABLAND
• The floodwaters from Glacial Lake Missoula
moved through eastern Washington forever
changing the landscape by stripping away
topsoil, picking apart the bedrock, and
carving an immense channel system into
the land.
• This area, known as the Channeled
Scablands, provided geologists with the first
clues of the catastrophic nature of the Ice
Age Floods.
POTHOLES
PALOUSE FALLS
DRY FALLS
• During the Ice Age floods, water over
300 feet deep poured over the 350foot cliffs of Dry Falls.
• At three miles wide, Dry Falls is five
times the width of Niagara Falls.
FLOOD DEBRIS
FLOOD DEBRIS
• After stripping away 200 feet of
topsoil, the flood ripped away
huge boulders from the underlying
lava rock.
• These boulders were picked up
and carried in the floods only to
be stranded in fields and prairies
when the floodwaters subsided.
TEMPORARY LAKES
• By looking at flood sediments from Glacial
Lake Missoula, geologists try to calculate the
number floods and subsequent fillings of the
glacial lake.
• Many layers of glacial lake sediments are
found situated on top of one another; each
layer represents a separate filling of the lake.
• The exact number of floods that occurred is
still unknown, but evidence shows that it
happened on possibly 40 different
occasions.
COLUMBIA RIVER GORGE
• The floods left a visual legacy that can be
seen all along its path, though few places
are as grand as the waterfalls of the
Columbia River Gorge.
• The floodwaters did not create the Gorge,
rather, they scoured and steepened its
walls. Creek junctions with the Columbia
were torn away, leaving the creeks to
plunge over the lip of the newly cut gorge in
a series of spectacular waterfalls.
ERRATIC
• As glaciers scour the landscape, they pick
up massive boulders and move them far
from their point of origin.
• When the glacier that formed Glacial Lake
Missoula's dam burst, uncountable boulders
embedded in its ice were carried along with
the floodwaters.
• As these ice blocks melted, the boulders
dropped out of the flow. Today, boulders
with origins in the mountains of Montana
and British Columbia can be found along
the flood paths as far away as Oregon's
Willamette Valley.
WALLULA GAP
• This is a gap that prevented the great floods from
heading directly to the Pacific ocean.
• Because the constriction at Wallula Gap was only 1
mile wide, the flood waters back-flooded into the
Pasco Basin.
• Formed, for a short period of time, Lake Lewis.
ONTO THE PACIFIC
• After racing through the Columbia
River Gorge and backwashing
into Oregon's Willamette Valley,
the floodwaters ended its journey
at the Pacific Ocean near Astoria,
Oregon.
• New studies are revealing what
became of the floods sediments
as the waters mixed with the
Ocean.