Answer:
They are called "loess".
Step-by-step explanation:
The loess (German word from Switzerland), are sedimentary clay deposits of wind origin. It is formed by silt deposits originated by the deposition of microscopic particles, which are transported by dust storms. They are yellowish. They are formed mainly by silicates, calcium carbonate and minerals from the clay group. It constitutes a very fertile and deep soil. The silt and clay are only visible through the microscope.
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