Photo Credit: Frank Kovalchek

Exploring the Kenai Mountains-Turnagain Arm National Heritage Area: Convergence of Corridors

CONVERGENCE OF CORRIDORS

Location:    Ball Park just North of Moose Pass: Turn off toward Lakef17-1

Alternative Site: Trail Lake Fish Hatchery

Short Description: This is spot is an ideal overview to emphasize the connection between geology and transportation corridors.  At this site one can see the convergence of two wide valleys —zones of crustal weakness created when assembling the Chugach Terrane.

Required Equipment: Maps of Peninsula showing highways and rail routes.

Suggested Equipment: Binoculars

Safety Consideration: None

Other Info: Visuals will be limited in low clouds.  No bathroom facilities however great wide area for students to stretch legs and for lunch.

f17-2Inquiry Prompts:  What’s Going On Here?

Stand on the shore of the lake making sure to have a complete view of the valleys leading to the south (toward Seward) to the East (the Highway Route) and to the North (the railroad and Johnson Pass Trail).

Ask the students what makes this spot different. If you’ve gone to other sites, then they may be looking for something subtle. But really, there’s nothing subtle about this spot. Upper Trail Lake is the result of the assemblage of crustal packages which ultimately became the Chugach Terrane to be transported north by plate tectonics. Even the shape of Trail Lake points like 3 arrows pointing down these wide valleys.

You’ve come to the geologic essence of the Kenai Mountains-Turnagain Arm National Heritage Areas.

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But alas . . . the rest of the story.

Yet this is not just a story of geology. It is a story of how geology has affected human activity. Not only did the action of plate tectonic shove rock laced with ore-bearing veins into place; this same action provided the corridors for which to get to those ore deposits. It is these same transportation routes that have been exploited to this day.

At this point the railroad and the highway diverge. The railroad travels the corridor to the north while the highway trends westward before heading northward. They will stay separated for about 45 miles until they rejoin at Portage.

This in itself truly illustrates the connection between geology and human activity within the eastern Kenai. But perhaps a more compelling question is this: Why does the railroad and roadway diverge from the same route. It is the norm for railroads and roadways to parallel each other. Services don’t need to be duplicated and supply/construction of each can be complementary to the other. Why, in Alaska, does the railroad snake off in its own separate journey?

This is a compelling story that is worth chewing over. To help provide some discussion points the map to the right shows when certain “routes” were finished.

The discussion could cover such angles as:

  • Goal of the railroad when it was started in 1903 and why this didn’t include linking the Hope/Sunrise gold fields.
  • The population areas of the peninsula during the 30s and 40s.
  • Established routes and desired destinations throughout peninsula.

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