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Drumlin Formation in Iceland

Hey Jamie -- again my apologies for the weather. Kim, my researcher, is still at Kevo in Finland, and says their weather turned cold and wet as soon as I left. So, obviously, my bad!

Anyway, I was hoping you could explain the use of the word 'fabric' in relation to your samples. I could easily have missed a previous explanation of yours, but the word keeps conjuring up visions of curtains hanging in a window, not something made of glacial silt. Is it possible to explain or describe your scientific use of the word 'fabric,' or is it a term that just generally means a horizontal layer made up of magnetically oriented particles.....?

Kiitos (takk) and cheers -

Carol

Fri, 08/16/2013 - 14:20

Sarah Crowley

OH! Great question Carol! I have also heard Erin Pettit use this word to describe the work she does and that Yamini will be participating in. Can't wait to hear Jamie's response.

Sat, 08/17/2013 - 09:28

Jamie Esler

Carol,AWESOME question! I think I did post a bit about how the AMS samples
work back in an earlier journal, but this is a great opportunity to go a
little deeper.
The fabric is a network of orientations of microscopic magnetic
particles of till in the samples. Each sample contains these
microscopic magnetic particles of till (mostly from magnetite), and they
are arranged in the direction that they were pushed or forced during the
last surge of the glacier.
The AMS device back home at UW-Milwaukee will detect the orientations of
these magnetic particles by measuring the strength of the magnetic
fields of the particles in three different axes. The device gives a 3D
analysis of what directions the magnetic particles are arranged.
Stronger fabrics have more particles aligned in one direction, which
will show up in the AMS device as one individual stronger magnetic
signal along a particle axes. Weaker fabrics will have more of a mix of
orientations of the particles, which will show up in the AMS device as
many weaker magnetic signals.
Fabrics are not stratigraphic layers of till. They are a network of
these little magnetic particles of till, and in what direction they are
pointing due to stress from the glacier.
I hope this helps! Back in Reykjavik now... :) Sunny, warm (18 C!!),
and just finished up with a few hours at the hot pool!
Take Care Carol,
Jamie