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Alaska Climate Variation

Aloha Peggy!

Boy do I love all your pictures! So will my students who's first day is Wednesday. I am looking forward to sharing your adventure with them for sure.

OK, now for the questions-

What evidence do you find in the cores of human settlements in the area? 

Are the mosquitos good/bad/ugly?

What is the most fantastic thing you have seen so far?

I wish you all the best and want you to know that I am warmly supporting you from about 2000 miles straight below you, longitudinaly ;)

Maggie 

Fri, 08/03/2007 - 10:17

Peggy Foletta

Hi, Maggie thanks for asking! Your school starts waaaay early! I'm glad a class is tuning in.
Caleb tells me that in the sediment cores there is no physical evidence of local humans as these areas were not known to be settled by humans, but they have found chemical evidence of radioactive Cesium, Plutonium, and Americium in the cores, which were chemicals released into the air elsewhere during Cold War nuclear weapons testing.
That testing began in 1954. It spread around the world's atmosphere eventually settling onto the earth's surface. Testing continued and peaked in 1963. Since there is no natural source of these of radioactive elements in the atomosphere, if these chemicals are found in a layer in the core it indicates that this layer was deposited in 1954 or after. Nuclear testing peaked in 1963. There was also a peak of these radioactive elements emitted by the Chernobyl nuclear power plant disaster in 1986.
Researchers at Northern Arizona University send small samples at half centimeter intervals from their sediment cores to a lab to search for this signature using a gamma ray spectrometer. This apparatus counts the number of gamma rays emitted from the sample, determining the decays per minute per gram per cm2. Decay value vs. depth gives a profile of the amount of the radioactivity in the sediment. Scientists look for peak levels that would correlate to the 1963 peak activity and the 1986 Chernobyl disaster. A few chemical signatures from Chernobyl have been found in Alaska cores. These signatures are used to determine dates in core layers.
Mosquitoes! Who ever heard of good mosquitoes? They aren't really bad, but I get a bite or two a day, and some areas are different than others. We have stayed at three locations so far. The campground at the lowest elevation was the worst, but the two subalpine lakes we have been flown to are not so bad.
The most fantastic thing I have seen so far are the incredible glaciers at Greyling Lake!! I'm working on my posting so hopefully you will see them soon. Thank you so much for your support.
I followed your whole expedition and it was awe-inspiring!
Peggy