Chapter 1 - Plate Tectonics Shape Our Land and Sea
Plate Tectonics - theory that was developed in the 1960s
A peek inside the earth
Crust- thin layer of the earth
Mantle -layer below the crust.
Lithosphere- the crust and mantle together and is broken up into plates.
Asthenosphere- is partially melted and is viscous.
Core- Center of the earth 9000F or 5000C
The Lithosphere is broken up into 12 major plates. There are also a few smaller plates. The plates are always moving slowly. The asthenosphere is very hot and plates move because of convection. Plates can move 1 to 6 inches a year. At plate boundaries, Volcanoes form.
Divergent Plate Boundary - plates are moving against each other
Convergent Plate Boundary- are where two plates collide. (Sometimes a oceanic plate collides with a continental plate, and since the oceanic plate is denser and thinner, it slides underneath- this is called subduction.
A subducting plate can cause a lot of heat and pressure. This causes the release of heat to the surface. Magma rises to the surface, creating volcanoes. (Sometimes plates just slam into each other and create volcanoes. Sometimes, plates just grind each other, creating earthquakes)
Hotspots are small hot regions inside a plate (yellowstone is an example- magma is flowing to the top for some reason)
750 million years ago Rodinia broke apart, the rift was at the western edge of Idaho today. An ocean formed there. (Some of the oldest rocks in the pnw can be found there). Pangea formed 200 million years ago. Pangea broke apart and atlantic ocean formed. An rocky oceanic plate subducted under the north American plate. Sediments were scraped off to form Oregon and WA. 7 and 4 million years subduction became steeper and cause the edge to fold. The Olympic mountains are the crest of that fold.
Alaska is complicated. It's filled with all sorts of crazy rocks from everywhere.
Review of Rodinia and Pangea - the big basin in montana --when Rodinia broke apart it created a basin. Sediments rushed into the basin. These belt rocks are near Montana and Idaho in glacier national park.
Currently the Juan de Fuca plate is subducting into the north American plate, creating the active cascade mountains.
Another plate is subducting in Alaska, that is forming the Aleutian Islands. Alaska coastal mountains.
Exercise; Cut Candy Bar and watch plate tectonics
3 Types of Rocks
Igneous Rocks- have formed from the cooling of molten rock - think basalt
Sedimentary Rock - when small sediments of rock are pressed tightly into rock
Metamorphic Rock- when heat and pressure forms into new rocks
The rockies were formed 90 million years ago. The rockies are a fold and thrust belt. The rocks on the top of the rockies are old - probably half a billion years older (western Montana and Idaho- glacier national park.
The Coast range mountains (Olympics, Oregon coast range and Klamath Mountains)- Lots of recycling of rock is happening.
Cascade Mountains - volcanoes
Denali is highest mountain in alaska. The brooks range- Artic National Wildlife Refuge
The Alaska range contains Denali
The coast mountains in Canada are highest mountains near a coast (some only 10 miles)
Mt Rainier- 14,411 feet - if it erupted, huge mudslides were cascade down the mountain. 26 glaciers and has a huge network of glacier caves, formed from volcanic gas.
Mt hood 11, 249 feet
Borah Peak 12,668 in Idaho
Things to tell if a glacier has been around- Grooves, U shaped Valley, Hanging Valley, Horns (mounatains), Cirques, Moraines
1986 Hubbard Glacier dam broke- huge and powerful flood.
Volcanoes
Shield Volcanoes-
Stratovolcanoes
Cinder Cones
Volcanic Domes
1989 a jet plane flew over active mount redoubt. It nearly destroyed the engines.
Mt St Helens -1980
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The Mating Game
Lava Tubes in Lava Beds National Monument Park in North Eastern California
Crater Lake in Oregon is the Caldera of Mt Mazama. It is the ninth deepest -lake in the world.
Newberry Volcano- Shield volcano -geothermal energy
Mt Novarupta and Mt Katmai -statovolcanoes in Alaska -Ask Build up - The Valley of Ten Thousand Smokes is part of the Katumai NAtional Park and Preserve
Richter Scale is logarithmic.
1964- Great Alaskan Earthquake near Anchorage Alaska. It was a 9.2.
1960 -9.5 earthquake in Chile
Basins and Plateaus
Basalt Columbia Intermontane-100,000 square miles across Washington, Oregon, Idaho and area of northern Neveda (259,000)- used to be a ocean of hot lava flows. Multomah Falls, oregon side of columbia gorge..An interesting feature of basalt is that when it cools, it can form vertical columns of 5, 6 or 7 sides.
1783- eruption in Iceland that lasted 8 months and produces 3 cubic miles of lava. It killed 10,000 and starved half the countries livestock.
It is not known why flood basalts' happen. There is the big plume theory, the delamination theory (lower part of lithosphere splits off and sinks into mantle), Theory of both
Mega Flood- 16,000 years ago near the end of the ice age. Channeled Scablands -Glacial Lake Missoula was a lake formed in montana. 2,000 feet deep and 200 miles long. Flood water raced at 65 mile per hour. 13 -70 flood occurred.
Snake River Plain is flat 400 mile-long depression containing basalt rocks. Geologists believe that snake Inidan plain formed in the same plume of magma that caused the Columbia river basalt. The great rift zone (50 miles long)- contains craters of the moon national monument and preserve. It has volcanoes, ropy, basalt and lava tubes.
Magma plumes experiment - oil and water to make lava lamp
magma basalt columns - let cornstarch solution dry out in sun
Climate - latitude, nearness to ocean, altitude, and Jet-streams
Seattle is cloudy because the jet stream carries air from the west, and lots of evaporated clouds. Seattle has Mediterranean climate - Jet stream moves to Canada during the summer- that is why it is so dry.
It tends to rain on the mountains because the moist air rises to get over the mountains, but as it condenses in to cool air, it rains. Rain Shadow. Chinook Wind- a warm chinook wind can melt a foot of snow in a day. 1979, Loma, Montana - the temperature rose from -56 degrees to 49 degrees F. Montana 1980 great falls 47 degree F in just 7 minutes.
Pineapple express - warm moist air. --polar night and midnight sun
Aurora borealis caused by solar wind with earth's upper atmosphere. Particles are attracted to south and north poles, due to magnetic attraction.
Rain Gauge experiment
Fog experiment - match, ziplock bags, cup and icecubes
Cape disappointment is foggiest place in US. Warm air passes over colder ocean.
Watershed- a land area that drains into a river or stream
Yukon, Columbia -Snake River system. Columbia river system is 4th largest river in US by water volume. Due to rapids (settlers had to portage) and large sandbars, 2,000 boats have sunk in Columbia river.
Fish- Chinook (king), Chum, Coho, Pink and Sockeye - anadromous-- Hell Canyon is deepest canyon in US.
Hydroelectric Dams- pressure can burst the swim bladders in fish, increase temperature in water. Largest salmon was caught in Kenai river in Alaska- it weighed 100 pounds. -Elwha Restoration
Yukon River - 1,982miles in Alaska interior- Barges are an efficient form of transportation
Ecosystems Tundra- plain where soil below surface is frozen. Temperate rainforest- rainforest in temperate zone. -epiphytes, mosses, ferns and lichens 39 - 54 degrees F. High level of biomass. Alaskan Rainforest has Fjords
Features of Olympic Forest - 8 species of fern, 500 year old trees that are over 200 feet tall (Douglas firs, hemlocks), Glacial flour of rivers - roosevelt elk, black bears, marmots, bats and river otters
birds - woodpeckers, marbled murrelets and spotted owls
Bracket fungus- honey mushrooms in Malheur National Forest in Eastern Oregon is considered world biggest organism- 8,000 years old and cover 2,224 aces
Nurse Logs- 96% of big spruce and hemlock start on nurse logs. 1 in 10,000 becomes a tree.
Tundra- permafrost -in summer tundra turns to marsh and pools water, Lichens are good food for caribou.--Artic tern Migrates between Arctic circle and antartica--experiences more sunlight then any other creature.
Terrarium Experiment
The coast- ocean temperatures impact climate. Alaska is warmer because warmer water is hitting it from the south. Pacific Currents are colder. Upwelling- When colder, denser, nutrient rich water rises to the ocean surface. Colder water has more nutrients than warmer water - phytoplanton. half the world's fisheries happens where upwellings happen.
Coastlines don't have distance because they are almost impossible to measure due to complexity. Reedsport Oregon - A wave energy park, using nuoys algal bloom - phytoplanton multiply out of control - Kelp are incredible underwater seaween forests. Kelp harvested for algin, alginic acid, nori or carageenan, Kelp love rocky surfaces and can grow a foot a day. Marine mammals - cetaceans (whales, dolphines and porpoises)
pinnipeds (walruses, seals and sea lions)
Estuaries
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