This week’s LotW is the star dune. Like yardangs, star dunes are large scale aeolian landforms, but they’re depositional rather than erosional, and they’re composed of sand rather than sedimentary rocks. This is not the best picture, but it’s open source (from Wiki Commons), which is a good thing.
I live in a very duney landscape (the east coast of Lake Michigan) but I didn’t realize how many different shapes and sizes of dunes existed until I took a class from a coastal dune specialist. Star dunes don’t form on coasts—they’re more common in giant sand seas like those found in Algeria or Namibia—but they are awesome.
Form: 3 or more sharp-edged ridges extending from a single high pointed peak.
Formation: formed in environments with low vegetation and lots of sand where the wind blows from multiple directions. They grow up rather than out and can be some of the largest dunes in existence.
I’m enjoying all of my classes this semester, but it seems that geomorphology has really captured my imagination. So much so that I’ve decided to start a landform of the week feature for the duration of the semester. Wednesday, colloquially known as ‘hump day’ as it is, seems like an appropriate day for a landform feature, and our inaugural landform—THE YARDANG!—does indeed resemble something of a hump. The below picture is from Wiki Commons and shows a yardang near Meadow, Texas.
A yardang is an aeolian landform (meaning that it’s formed by the wind), it’s fairly large scale, and it’s the result of erosion. Yardangs can usually be found in groups, because basically, you’ve got strong winds carrying abrasive sand chipping away at a surface of smaller, more cohesive sediment until the surface gradually erodes into distinct hills. They’re quite common in deserts and can actually take a variety of shapes. One of the more famous yardangs in America is Window Rock in Arizona, which has a hole worn through it. The Oxford English dictionary informs me that the name yardang (you know I’m going to use that in Scrabble) comes from the Turkish yar, meaning steep bank.
So there you go, I’m incorporating a bit of Turkish from my history thesis too.