Seen in the field: Some more mud cracks! This time, we've got younger, still wet mud cracks on top of older, dry mud cracks.
The newer mud on the right is from late April, 2010 (almost active at the time of the photo); the older, sandier deposit on the left is known to be post-2008, probably from sometime earlier this year. The somewhat irregular and thin, crackly-looking younger mud cracks cover and sink into nicely formed, almost perfectly hexagonal mud cracks. The only area in the two photos where the more recent, still-wet mud shows sub-hexagonal shapes is in the upper right of this last photo.Too bad I won't get to check out this muddy, crackly, alluvial area to see what develops next!
4 comments:
Mud cracks. I didn't have a clue. Once again, your blog prompted me to do some research, revealing the geological connections for this non-scientist. Probably old news to you, but there's an interesting paper on the web at http://www.lgoehring.com/Papers_files/SM2009_preprint.pdf which concludes that through repeated cycles of wetting & drying, the cracks in a clay layer evolve from creating rectilinear shapes toward hexagonal shapes with 120 degree angles. So cool.
Very nice paper! Thanks for the link, Tony.
Silver Fox: Thought you might enjoy the picture of salt flats in Bolivia that accompanied a travel article in yesterday's Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2010/05/06/AR2010050605640.html
Tony
Nice! Salt-flat cracks.
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