552 Micrographs

LAS email 2/14/08
Subject: a couple of photos from 552

As you can see, there are many pores in the ice. Not all areas show as many as are displayed here, though. The final photo (552_3c_9) was taken after a fair bit of sublimation time. I think those are grain boundaries at the base of all the pits, but not 100% sure. They're very small.

Most of the photos here focus on the ice. One of them (2nd one) shows the ice surface after a quartz grain was plucked away.

		(click to enlarge)

First batch of sample 552. The "1" series. Best shot is the 2nd to last photo here. Compression same as always, NE-SW.

2nd to last photo on this page was taken after a fair bit of sublimation. It really shows off the distribution of the quartz. There's still plenty of ice inside the sample and near (but not right at) the surface to hold the grains in place. So when I later take the sample out of the SEM, it's still nicely intact, not just a pile of sand.

The best from the "section 3" series. These photos focus on the ice/qtz boundaries rather than overviews of the qtz grain distribution. As you can see, some sections of ice contain many more pores than other sections. Best shot is the final image. (Maybe this was one of the original 5 photos I sent last week?)

I assume that you can easily identify the ice from the quartz after looking through all the previous images, but one image is labeled here anyway

sample 552, sections 3a and b

Here, the sample underwent a fair amount of sublimation in an attempt to etch and identify grain boundaries in the ice, but to no avail. I'm mystified as to why I cant see grain boundaries at any given scale, either large or small, and there are certainly plenty images that are of high enough resolution and clarity to show the boundaries if they were to be seen. And I'm talking about all samples 546-552, not just 552.

If you recall, the fine-grained ice samples (such as sample 515, shown in the final photo here) showed excellent grain boundary etching after far less sublimation time.