Transcript The Rocky Mountains

The Rocky Mountains
by
Geologic events
• The Rockies are composed exclusively of
layered sedimentary rocks.
• These include limestone, dolomite,
sandstone and shale, among others.
• Sedimentary rocks cover approximately
75% of the worlds surface.
• Regular sedimentation has been shattered,
older rocks lie on top of younger rocks.
SOURCE: Mountainnature.com. http://www.mountainnature.com/geology/Deposition.htm. Accessed 11/10/09.
Mountain Types
• The Rockies include
Matterhorn mountains.
• Glaciers have scoured
the peak.
• Other types of
mountains are
dogtooth, sawtooth,
castellate, anticlinal,
synclinal, and complex
SOURCE: Mountainnature.com.
http://www.mountainnature.com/geology/platetectonics.htm. Accessed
11/10/09.
Geologic Forces
• In some places the formation of the mountains ripped
through to the magma, which pushed through the older
rocks
• This is called an igneous intrusion of dacite porphyry.
• This one is called Tooth of Time in Northern New Mexico
and was formed in the Tertiary Period of the Cenozoic era
some 22-40 million years ago
SOURCE: Tooth of Time. http://www.absoluteastronomy.com/topics/Tooth_of_Time#encyclopedia. Accessed 11/10/09.
Extent of the Rockies
• The orogony that caused the Rockies moved from the
ocean inland
• This mountain belt protects the craton which is called The
Great Plains
• It affects the weather and helps much of the United States
in its ability to produce large amounts of food
• It is formed by the tectonic plates thrusting the continental
shelf inward toward the continental interior, producing giant
thrust faults hundreds of miles long, as if one block of
continental crust was simply pushed over the top of another
SOURCE: Google Answers. Plate Tectonics-Rocky Mountains. http://answers.google.com/answers/threadview/id/181294.html. Updated 3/26/03. Accessed 11/10/09.
The mountains
themselves have
unpredictable
weather.
Snowfalls end in
June at the
mountain peaks
and start again in
August.
But the peaks also provide many valleys with good grazing land
for horses and cattle and ensure water for the growth of plants
and animals.
Limestone is a very common sedimentary rock of
biochemical origin. It is composed mostly of the
mineral calcite.
(Source:Limestone. http://www.galleries.com/Rocks/limestone.htm. Updated 2009, accessed 11/10/09.)
Dolomite rock is one of the sedimentary rocks that
undergoes a significant mineralogical change after it
is deposited. The process is not metamorphism, but
something just short of that.
(SOURCE:DOLOMITE. http://www.galleries.com/minerals/carbonat/dolomite/dolomite.htm. Updated 2009. Accessed 11/10/09)
Sandstone is sand cemented together into rock. It is a
clastic sedimentary rock. It is composed mostly of
medium-grain sand
.(SOURCE: About Sandstone. http://geology.about.com/od/more_sedrocks/a/aboutsandstone.htm. Accessed 11/10/09.)
Shale is a claystone that is fissile, splitting in layers.
Shale is usually soft and does not crop out unless
harder rock protects it.
(Source: Shale. http://geology.about.com/od/rocks/ig/sedrockindex/rocpicshale.htm. Accessed 11/10/09.)
The Tooth rises from the valley floor
creating a sheer vertical face unable to
support substantial plant life. Both its
pinkish-gray color and its unusual shape
make it a particularly notable geological
landmark. It was well-known among the
overland traders on the Santa Fe Trail.
ABOUT MY GEOLOGIC
FEATURE
The Tooth was formed when magma
from the Earth's mantle rose through older rock layers via
convection and slowly cooled. Over thousands of years, the older
sedimentary rock eroded and left the harder igneous formation.
The sedimentary rock acted as a mold for the intrusive magma,
causing it to harden and cool where the sedimentary rock was
strongest.
HOW DO WE KNOW THE AGE OF THE ROCKIES?
•The formation of the Rocky Mountain structures in late
Cretaceous through Eocene time is that plate of oceanic
lithosphere was underthrust horizontally along the base of the
North American lithosphere.
•The horizontal components of the motion of this plate are known
from paleomagnetism
•The edge of the region of flat slab can be estimated from
reconstructed patterns of volcanism.
(SOURCE: Peter Bird. Formation of the Rocky Mountains, Western United States: A Continuum Computer Model. http://www.sciencemag.org/cgi/content/abstract/239/4847/1501. 3/25/88. Accessed
11/10/09)
ROCKY MOUNTAIN CLIMATE
VARIANCES
From the Alpine Tundra
(SOURCE:
http://www.terragalleria.com/parks/np.rocky-mountains.3.html)
To high mountain lakes
(SOURCE: http://www.terragalleria.com/parks/np.rocky-
mountains.3.html)
And tree lines that go from pines to
aspens
(SOURCE: http://www.terragalleria.com/parks/np.rocky-mountains.3.html)
Rocky Mountain Surprises
To rivers flowing with water that was ice just
hours before
(SOURCE: http://www.terragalleria.com/parks/np.rocky-mountains.3.html)
And hidden cantons hiding Native American
history.
(Source: http://dori-stories.com/places/nm/slides/More%20Philmont%20Indian%20Writings%20Petroglyphs.html
The Rockies provide some of the most interesting and exciting areas
in the United States.