The Geological World Around Mt. Shasta, CA. By Kathryn Pimentel
Transcript
The Geological World Around Mt. Shasta, CA. By Kathryn
Pimentel
Mount Shasta 14,179 ft. (4,322 m) Currently dormant Last
eruption: 1786 Surrounding area contains igneous rocks from past
eruptions Part of the Cascades (Volcano Discovery, 2012)
Mt. Shasta taken by me on July 7, 2013 from Montague,
California
How Mt. Shasta Formed All of the volcanoes in the Cascade range
have formed because of the movement of the Gorda crust moving under
the North American Plate. This created a zone of subduction and
formed Mt. Shasta (Siskiyous, 2001). (Siskiyous, 2001)
In the Surrounding Area... From molten rivers stemming from Mt.
Shasta that, over time, broke down the rock in the surrounding
area; creating Table Rock in Little Shasta, California (approx. 30
miles aways). Considering the molten river was much hotter than the
existing rock, the rock was broken down to create a flat- topped
mountain of sorts. Since then, Table Rock had been inhabited a by
local Indian tribe, the Karuk, where many artifacts have been found
(Obsidian arrowheads, etc.)
Table Rock in Little Shasta, CA. Taken by me on August 1, 2013.
Mt. Shasta in the background.
A collection of Obsidian arrowheads found near Table Rock.
Currently located at a local museum in Montague, CA. Picture taken
by me, August 1, 2013.
The Rocks of Table Rock... The flat part of Table Rock is
composed of Igneous rock that accumulated after the molten river
flowed around original rock formation. The specific rock type over
Table Rock is Basalt.
Another Life Form: The Shasta Daisy Classic perennial flower
Grows in clusters of 2-3 ft tall and 1-2 ft wide Not considered
intrusive (as some daisies are) They are native to the area and
have not changed very much over time. (Old Farmers Almanac,
2012)
A small bloom of a Shasta Daisy in Montague, CA. Taken by me
August 1. 2013.
The three rock samples I studied all turned out to be Igneous
extrusive (meaning that they cooled quickly above ground) Picture
1: Pumice Picture 2: Granite Picture 3: Basalt Rocks Surrounding
Table Rock
Pumice Super porous Probably spread from the last eruption of
Mt. Shasta (1786). Broken down from natural weathering and human
damage. Photo taken by me. August 1,2013.
Granite Very strong rock Easily polished Weathering was most
likely done by humans Most likely found here from Mt. Shastas last
eruption. Photo taken by me August 1, 2013.
Basalt The top of Table Rock is composed of Basalt Very, no
crystal structures Found because of the molten river that stemmed
from Mt. Shasta. Photo taken by me August 1, 2013.
References Mt. Shasta Volcano, nd. Retrieved from: http://www.
volcanodiscovery.com/mount_shasta.html. August 4,2013. Geology of
Mt. Shasta, nd. Retrieved from: http://www.siskiyous.
edu/shasta/geo/fig4.htm. August 4, 2013 Old Farmers Almanac, June
5, 2012. Retrieved from: http://www.
almanac.com/plant/shasta-daisies. August 4, 2013. Sabalow,Ryan. How
a Mount Shasta Eruption Might Occur, December 11, 2011.
http://www.redding.com/news/2011/dec/17/how-a-mt-
shasta-eruption-might-occur/. August 3, 2013.