The shifting sand is a remarkable black dune, composed of volcanic ash from Oldoinyo Lengai, which is being blown slowly westwards across the plains, at the rate of about 17 meters per year. Some nine meters high and 100 meters long in its curve, it can be found to the north of Olduvai Gorge. There is little to no sand or ash in the surrounding areas and the shifting sands are moved by the strong winds that blow across the surrounding plains, a condition that sometimes creates a mini sand storm in the areas that surround it, making it difficult to see or visit the dunes. However; when it calms down it becomes possible to even climb to the top of the dune for photos or view the vast plains around it.
It’s near the Olduvai Gorge on the road to the Serengeti, are two crescent-shaped sand dunes. The sand is remarkably dark, especially in comparison with the soil surrounding the dunes. This is because it is highly magnetized volcanic ash, which explains why the particles tend to fall back on the dunes instead of being blown away by the wind.
In fact, it is possible to throw a handful of sand in the air and see how it clamps together and re-joins the dunes. However, when strong winds blow, these sand dunes, also known as barkan, begin to move. Slowly but surely, they travel through the desert, at an average of 55 feet (17 meters) a year. It’s estimated that these shifting sand dunes have been wandering the savannah for 3 million years.
Although this phenomenon is rare, it is not completely unique, and its origins have been ascertained. If volcanic ash is rich in iron, it can become magnetized, and when it is blown by the winds, it may start collecting around a rock. Given a sufficient amount of time, this little mound can become a dune.
The local Maasai people believe the shifting sand dunes have come from the nearby sacred mountain Oldoinyo Lengai, loosely translated as the Mountain of God (where God resides). As a consequence, these dunes are also considered sacred by the Maasai, who convene by the dunes in cases of prolonged drought. On these occasions, a goat is sacrificed to the gods so that rain may come soon. Understandably, climbing the sand dunes is inappropriate.
Note: The dunes are located near Olduvai Gorge within Ngorongoro Conservation Area, along the road to Serengeti National Park. The trails leading to the area where the shifting sand dunes roam require a 4×4 vehicle in the dry season and visiting the dunes shortly after rainfall is not recommended, as the trails can turn into impassable mud pits.