geology of mount rainier. 14,410 feet high an active volcano that affects the weather, rivers,...
TRANSCRIPT
Geology of Mount Rainier
• 14,410 feet high
• An active volcano that affects the weather, rivers, valleys, and habitats
• Formed by FIRE and ICE
National Park ServiceMount Rainier National Park Mount Rainier
is:
National Park ServiceMount Rainier National Park Mount Rainier
is:
•Highest peak of
the Cascade Range
National Park ServiceMount Rainier National Park
View from South: Mount St. Helens (foreground)
Mount Rainier (background)
Mount Rainier is:
•An Active Volcano
National Park ServiceMount Rainier National Park Mount Rainier
is:
•Last eruption in 1894
National Park ServiceMount Rainier National Park Volcanism
Subduction of the Juan de Fuca plate
National Park ServiceMount Rainier National Park Volcanism
National Park ServiceMount Rainier National Park
•Stratovolcano – “strato-” indicates layers of flows
•90% lava flows, 10% block and ash flow
•Mostly andesite, some dacite – silica content is between 61 – 64%
•Viscous lava flow that usually erupts violently, not “flowing” like that of a shield volcano
National Park ServiceMount Rainier National Park
Images by Pat PringleWashington DNR
Orting
LAHAR• Mudflows or lahars are the biggest hazard from the volcano
• They are created when lava meets…
National Park ServiceMount Rainier National Park
HAZARDS
National Park ServiceMount Rainier National Park Volcanism…
…and Glaciation
National Park ServiceMount Rainier National Park Volcanism…
…and Glaciation
What’s a Glacier? A glacier is mass of
ice that shows evidence of movement, or “flows”.
25 named glaciers on Mount Rainier
More ice than all other Cascade volcanoes combined
National Park ServiceMount Rainier National Park
Largest surface area: Emmons (4.3 miles2)Lowest Terminus: Carbon (3,600 feet)
Deepest Ice: Carbon (700 feet)
National Park ServiceMount Rainier National Park
How are Glaciers Formed?
• Snow accumulation > ablation
• Snow compresses
• The mass of ice is called a glacier when it begins moving downhill
National Park ServiceMount Rainier National Park
National Park ServiceMount Rainier National Park
How Lava Flow Ridges are Made
During the Pleistocene (“Age of Ice”), glaciers on Mount Rainier were much more voluminous than they are today.
Glaciers filled all of the valleys on the mountain
National Park ServiceMount Rainier National Park
How Lava Flow Ridges are Made
Lava flows on the path of least resistance
On Mount Rainier, lava flowed along the sides of the glaciers
Lava flows piled on top of each other
National Park ServiceMount Rainier National Park
Ridge-Capping
How Lava Flow Ridges are Made
Over time, glaciers slowly melted
This exposed the ridges created by old lava flows
There are 23 ridges visible on Mount Rainier
National Park ServiceMount Rainier National Park
Ridge-Capping
National Park ServiceMount Rainier National Park Take Home
Points
•Lava builds ridges, glaciers carve valleys – together they shape a unique landscape
•Mount Rainier influences processes both within and beyond the park boundary
•An active stratovolcano
National Park ServiceMount Rainier National Park
that’s all
National Park ServiceMount Rainier National Park
References
Driedger, Carolyn. U.S. Geological Survey. Answers to Commonly Asked Questions about Mount Rainier Glaciers, 2008 Seasonal Training Notebook, Mount Rainier National Park. June 2004.
Frequently Asked Questions, 2008 Seasonal Training Notebook, Division of Interpretation at Paradise, Mount Rainier National Park.
Geology of Mount Rainier, National Park Service, U.S. Department of the Interior. 2008 Seasonal Training Notebook, Mount Rainier National Park.
”Geology Overview”. G:\Education\Curricula\Mountain Geography & Cultures Curriculum\Fuji Rainier lessons 2008\Geology Overview.doc. Revised July 9, 2008.
Lescinsky, D.T. and Sisson, T.W. “Ridge-forming, ice-bounded lava flows at Mount Rainier, Washington”. Geology: April 1998: v. 26: no. 4: p. 351-354: 6 figures.
Primary Interpretive Themes, 2008 Seasonal Training Notebook, Mount Rainier National Park.
Sisson, Tom. U.S. Geological Survey. Mount Rainier’s Geology, 2008 Seasonal Training Notebook, Mount Rainier National Park.
Some slides and text taken from “NPS_05” by Tom Sisson, “VolcanoesRockGREEN” by Jennifer Ledenican, and “Living with a volcano in your backyard” by Christina Hamilton.