Submitted by Anonymous on Mon, 12/06/2010 - 06:58
Forums
Glacial History in Antarctica

Hi Leslie: Wow what a great trip, I think after all this cold you will be ready for any item on the menu at Kickin Chicken, our treat of course. My question is how accurate is the cosmogenic nuclides method for dating rocks? Are you doing this dating on this expedition and if so have you found any rocks to date, and how old are they? What a great honor to be selected for this trip. Keep up the good work. Ed Elswood Rawlins High School Vocational Ed. Instructor

Wed, 12/15/2010 - 17:51

Lesley Urasky

Ed,We won't be doing any dating of the rocks while in the field. This is an incredibly complex technique that requires chemicals and an accelerator mass spectrometer (AMS)! If you refer back to the post on equipment, the AMS is explained here.
Dates obtained from the AMS vary in their accuracy. The older a sample is, the greater the accuracy capabilities. For these rocks, dates usually fall with +/- 1-2%. Meaning, if you take the determined date and multiply that value by 0.02 and then add that value to the date as well as subtract that value from the date, you'll find a range of ages that the sample most likely falls into.
John Stone has been collecting data for this problem for several years and has found the ages vary from about 12,000 years to around 3,500 years ago.

Wed, 12/15/2010 - 17:50

Lesley Urasky

Ed, I'll definitely be taking you up on that offer for lunch. While the food is good here in McMurdo, there aren't any wraps that compare to the Kickin' Chickens!