That is where the sand and the original silt and clay came from originally, weathering of rock, and the sahara is mostly exposed rock, with sand only making up a minority of its surface. Minimum volumes of mobile sand can be estimated for each region of the Sahara, such as the 26 meter average thickness of the Erg Oriental of Algeria. Sand migration model conclusions regarding such volumes of sand are that the current Saharan dune distribution and morphology took at least 1. Independent geological evidence indicates that cycles of wet and dry periods have occurred over the past 20 million years, corresponding respectively to semi-arid periods of erosion in the source areas , and to periods of hyper-arid redistribution of sand.
Aerial photographs of the Spirit Dunes , Manitoba, Canada show this can happen in decades:. The Sahara dunes were still there during fertile times - they were just grown over with grass. Un-watermarked version avaliable on www. Algeria and Morocco are m average, Chad and Egypt are about m, Lybia and Mauritania are about m. The sand and rock material was there all the time, it's just been changed and collected into dune zones. The quartz is stronger and lighter and it sorts itself to the top, and the dark mafic minerals are sorted by gravity.
The Sahara has had aridity troubles for the last 30 million years, the alps are only 35 million years old. They say it was all green, perhaps like India, Nevada and California and Texas.
It's probably changed from desert to savanna many times in the last millions of years due to ice ages. Perhaps there was a kind of biannual monsoon during ice ages, and the monsoon transitions to the current rain habit every time for the past 35 million years, which is when the alps started forming. All of you dont account sand from the bottom of the Mediterranean Proof to my claim is being unearthed above the Dead Sea where sulfer, among other things, from a meteorite exploding upon entering the atmosphere has been found.
An explosion of 10 megatons vaporized the Dead Sea region leaving the aftermath as told in the bible.
What makes you think another meteorite couldn't have done this? Throw a rock in a shallow puddle and see what happens to the sand where and around you made the impact Home Questions Tags Users Unanswered. Where did the sand in the Sahara come from?
Making the desert sand bloom - BBC News
Ask Question. BWhite BWhite 63 1 1 silver badge 4 4 bronze badges. That doesn't answer the question.
In another case, it was assumed that it was the sand that blew because there was no clay mixed in. In retrospect, wind isn't going to be able to separate sand mixed into clay, so that seems less credible.
For instance, the decomposed granite soils found in a lot of places around where I live. It's mixed with organic matter humus and held together by plant roots. If the plants die from lack of water, the organic matter eventually decays and leaves just sand. A research team announced that they had found it in The claim is disputed. Sand is made of tiny particles of rock and minerals ranging from 0. The composition of the sand will determine its colour.
For example, beaches in southern Europe are a deep yellow colour caused by the imperfections in the quartz. Tropical white sandy beaches are the result of eroded limestone and, sometimes, crushed coral and shellfish. Sand derived from volcanic rocks like obsidian are black. There is one such beach near my hometown. You know how hot sand burns your feet? Building sand castles is a popular beach activity. Pirates of the Caribbean sand sculpture — Photo Credit: Anthony Magic sand is ordinary sand coated with a hydrophobic water-repelling compound.
Which means that you can drop in in water, remove it and it will be totally dry!
Experiment May Transform Unusable Desert Sand Into Usable Construction Sand:
Have a look at the video below. Pingback: Bananas are all clones! And 6 more bananas! Was just watching Stargate over the holidays and was looking at the desert sand, remembered that the sand on the beaches of Florida was made of shells and sea creatures, and that there was once an ocean covering the Sahara where in the desert, they find whale bones!!
Its gotta be close to the same but much older, or?? Found out some cool stuff I didnt expect, but, anything else cool anyone knows will be cool to hear too! Desert sand has considerable amounts of iron because it is the mineral that paved the way for its granulation.
Of course, it has the many other minerals that is why there are variations in color. Dominant minerals display color of the sand. What made it turn into desert was the consummation of nitrogen element which obviously lacking, and is no longer arable. Acidic emissions from the ground burn the trees, and now houses too, consuming the deposits of nitrogen beneath. Such emissions are being induced by the entry of acidic sea water underground, which was a result of the melted polar ice. Hydrogen, even in presence of enough oxygen but in the absence of nitrogen cannot form clouds that support and suspend rain water.
In a few years, we shall see the transformation to desert land, as red iron oxide fills the environment from red oxide spewing Canlaon Volcano in the Philippines.
The Largest Desert
Home About Blog. Blog post How deep is the Sahara? How deep is the Sahara?