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Essential Questions:
Essential Questions:
- How are Alaska's natural systems interconnected?
- How have Alaska's natural systems changed over time?
- How does digital information change our understanding of natural systems?
- How does knowledge of natural systems inform our understanding of cultural systems?
- How does knowledge of natural systems relate to the roles of educators?
ENGAGE
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| Blue Mouse Cove, Glacier Bay - C. Good |
Massive mountains hunkering down under the weight of colossal glaciers, or the annual migration of wildlife along our shores and across the expansive northern tundra may give an impression of permanence or timelessness.
However, the landscapes, climate and ecosystems of today's Alaska are fairly new on the Big Clock of geologic time, and have changed dramatically over the vast sweep of time.
Perhaps the best way to begin our understanding of the natural history of Alaska is to first look at Earth as a large, complex, dynamic, interconnected system that began some four and a half billion years or so ago.
EXPLORE
Teachers' Domain
To help visualize Earth as a System, watch this brief TD video by the same name.
To help visualize Earth as a System, watch this brief TD video by the same name.
EXAMINE
- What are the different pathways for the flow of matter and energy on Earth?
- Which change slowly?
- Which change rapidly?
EXTEND
- How has our growing understanding of Earth as a System informed our view of the world and our place in it?
ENGAGE
Geology Rocks!
You don't have to be a rocket scientist or a rock scientist to appreciate the basics of plate tectonic and mountain building forces that have shaped Alaska since the break-up of Pangaea a couple hundred million or so years ago.Of the several discrete components that make up the complex natural systems of this planet, we will begin our exploration of Earth's lithosphere and the geological forces that have placed Alaska on the map, both literally and figuratively. We'll explore Earth's atmosphere, hydrosphere, and even its cryosphere, a little later in this module.
Landform Forces -Mountain Building
We all look up to mountains. But how did they get there? And why are they so tall? Not to say that all of Alaska has towering mountains. Far from it. There are also vast plains sweeping for hundreds of miles between Alaska's great mountain ranges. But why? How did the mountains and plains and all the rest of the myriad smaller feature of our landscapes come to be? What's their history?It’s easy enough to figure out how a volcanic mountain forms because its processes are visible and rapid on either the geologic or human time scale. But what about other features that form more slowly, like Denali (Mt. McKinley), or Sagarmatha (Mt. Everest), or Uluru (Ayer’s Rock)? Clearly, these mountains are not volcanic, so early geologists struggled to piece together the puzzle of how these mountains were formed and in turn are worn away.
Little did early geoscientists realize the answer to the mystery of mountains was directly related to other important questions, such as the curious puzzle-fitting shape of the Atlantic continents and the similar fossil record and geology on opposite shores across the ocean.
EXPLORE
Teachers' Domain
Let’s use these select TD resources to take a closer look at the geologically recent discovery of plate tectonics and how it explains the origins of Alaska's mountains, volcanoes and even how entire continents drift apart.
Volcanoes in the Infrared
Explore Alaska's VolcanoesEXAMINE
- What is the relationship between tectonic forces, mountains, volcanoes and earthquakes in Alaska?
- How active are geologic forces in Alaska? Where?
EXTEND
- What local geologic structures and/or processes are evident to your students?
- How may knowledge of such be important for you or your students?
- Teachers' Domain has many great non-video, interactive resources if you want to delve into the subject a little deeper, or if you are looking for teaching resources for your class.
EXPLORE SOME MORE....
Sometimes it seems like everything about Alaska is super-sized. The biggest mountains. The biggest earthquakes. The biggest tsunamis. Let's jump way ahead in our geologic timescale and take a look at the causes and effects of geologic upheaval in a few videos about some big geologic events and some bad days in recent human history.
1964 Alaska Earthquake
Alaska Tsunami EXAMINE
- How are tectonics forces responsible for earthquakes and tsunamis?
- Why are tsunami inevitable along the gulf coast of Alaska?
EXTEND
Surviving the World's Biggest Waves
Some of the most dramatic Alaska Tsunami stories in Alaska are the result of the seismically active Fairweather fault that runs hundreds of miles along the coast of southeast Alaska--right through the head of Lituya Bay south of Yakutat on the Gulf of Alaska.
Tlingit oral tradition tells of one such earthquake and resultant tsunami in 1853 or 1854 that devastated a village in Lituya Bay. The story, as told in Francis Caldwell's Land of the Ocean Mists, says that most of the men had left their village to hunt and returned later that same day to find their village was gone and only one young girl and her dog were spared because she had been on high ground picking berries.
Another tsunami visited the same bay in 1936, wiping out the garden and shed of the Bay's sole inhabitant, Jim Huscroft. He, and his little cabin on Cenotaph Island, just barely survived that wave.
But the most dramatic story in Lituya Bay tsunami history occurred late in the evening of July 9, 1958. Fishermen in their boats anchored in the sheltered waters of Lituya Bay for the night awoke to the terrible shaking and groaning of the earth. The result - a wave more than 1700 feet high.
Some fishermen lived to tell the story....
BBC Nature, MegaTsunami
Now, we're off to explore how water in its various forms works to wear it all back down in the next section Atmosphere, Hydrosphere, Cryosphere.
What's Next?
Well, that was quite the journey. From plate tectonics to giant tsunamis, we've explored the BIG picture of the forces and processes that created Alaska's lithosphere. Now, we're off to explore how water in its various forms works to wear it all back down in the next section Atmosphere, Hydrosphere, Cryosphere.
