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Alaska Climate Variation 09

Hi Barney

Sorry I did not make it out to WA or even send an email before you left... we ended up heading further south and I just got back from UT... we had good times in red-rock country.

I was surprised to see that you split the cores in the field. Are you studying the cores in the field or will the cores be taken back to a lab somewhere? Do you know what is the sedimentation rate for Cascade Lake? Can you see varves in this sediment? Besides the Plutonium and volcanic ash, how are you going to date the sediment samples?

Since you are playing with lake mud too, maybe we can work on some joint lesson plans when you get home!

Try and avoid becoming lunch for the bears!

Tim

Mon, 08/10/2009 - 08:47

Barney Peterson

Good morning Tim, sorry for the answer delay, but connecitons were sometimes less than good in the narrow space above us; even Iridium was challenged. 
Are you studying cores in the field or will they be taken back to a lab somewhere?  The cores are split and inspected in the field for first impressions: are they stratigraphically ordered and not messed up during the coring process?  Next they are carefully dried a bit and wrapped securely for shipment to the lab in Flagstaff, AZ, at Northern Arizona University.  in the lab they are further split and analyzed for a variety of proxies.
Do you know the sedimentation rate for Cascade Lake? The sedimentation rate for Cascade Lake is 2.97 mm per year at the mid-lake site where sediment is focused. 
Can you see the varves in Cascade Lake sediment? Cascade has remained a lake for study in this project after initial coring because the varves in the sediment are clearly visible.
Besides Plutonium and volcanic ash, how are you going to date the sediment samples? Besides Plutonium and tephra, varves are counted for the younger sediments; radiocarbon dating is used for older sediments, especially for organic material.
I hope those answers fill in some gaps for you.  Heidi sends greetings.  We are really having a great time together, even when the rain pours down, the wind whips up whitecaps on the lakes, and we are tent-bound for hours at a time wishing we were out there bobbing around in the Zodiac doing our science thing!  Heidi and Dr. Kaufman are great about answering my questions and making powerful suggestions.  Glad to learn the vacation was a success.  Maybe we can get together some other year.
Barney Peterson