Shitfint Sands

The shifting sands article was interesting and I learned a lot of new things I learned that I never knew. For example, the shifting of sand dunes help interprets past climatic changes. There are sand dunes in places I wouldn’t have imagined like Antarctica, which I thought was all ice. Antarctica is basically considered a huge cold dessert.

There are three things you need in order to create a sand dune. A source of sand, winds strong enough to move the sand, and a lack of vegetation. The process by which sand grains bounce downwind is called saltation. I always wondered why when you put sand on top of the pile it slips downward. This process is called a slip face. It pushes the bulk of the dune in the direction of the wind.

I also wondered how the different heights and shapes of the sand dunes are created. I learned it was because of the different strengths of the winds. From this, you can track past wind patterns, and weather patterns. Scientists thought that the Wahiba Sands’ sand is from before the ice age, which is more than 12,000 years ago! But then later they realized that some of the organisms give off carbonate minerals which may look like the sand and misguide them. The oldest layers of sand were only deposited about 5,600 years ago.

There are several factors that scientists need to be sure of. Vegetation can’t be totally diminished and there can’t be extended droughts. If any of this happens, past climatic records can be erased because the sand is remobilizing. Dunes are first created by ice, when the ice moves north; it leaves behind a lot of sand which is carried by the streams going south. Then this sediment dries out, and the wind carries it to form dunes in North America.