How do deserts form? Where are those sands coming from?
Deserts are fundamentally a barren area of the landscape. It is the variations in the temperature during the day and night, which has a huge role to play in forming them. A desert is formed when an area has received a very short amount of rain in a long time. Deserts can be divided into different types.
For instance, there are sand deserts known as an erg, rock deserts that are called hamada and pebble deserts are known as serir. We might think that the deserts we see today have been long-existing, but that is not the case. Many deserts between 8000 and 3000 BCE, such as the Sahara, had a climate that was comparatively milder and moister. Over time, several factors apart from climate change have jumped in to form the deserts as we see them today.
Mountains for instance, along with a number of other complex factors such as air pressure, cold air, and precipitation, contribute majorly to the formation of deserts. When air comes in contact with the mountains, it has to float and rise above them. During this, the moisture in the air precipitates on to the mountains, which creates snow on peaks. Therefore, as the air makes its way towards inland, it has little or no moisture left, which ultimately results in less rainfall and high temperatures.
The weathering process has a huge role to play in the formation of deserts. The huge variations in temperatures put the rocks under quite a bit of strain, which results in into breaking of the rock. Even though it is well-known that rains in such areas are scarce but when it falls on hard rocks, it causes them to shatter, and all that is left are the rubble-strewn and fragments on the floor of the desert.
Cold Deserts
Also known as temperate deserts, cold deserts are located at higher altitudes as compared to hot deserts, and it is the dryness of the air, which results in aridity here.
Semi-arid Deserts
A semi-arid desert as compared to regular deserts features much more vegetation, rainfall, and humidity. Temperatures in these deserts can greatly vary. Normally located in continental areas or on the edges of deserts, semi-arid deserts include or share some features/characteristics that are the same as of a true desert.
Coast Deserts
Deserts by Susan Heinrichs Gray
Desert Ecology by John B Sowell
Coastal Deserts are normally formed in areas that experience cool to warm moderate temperatures. The seasons here can variate, especially the winter season, that may be replaced by warm and long seasons of summer.
Deserts by Susan Heinrichs Gray is less of a book and more of an encyclopedia on deserts. It accurately mentions and describes how deserts are formed, and the prevailing desert conditions and climate found there. The writing style of the book and the structure of the information is such that it allows both kids and adults to become enthusiastic, particularly about something that is dry, lifeless, and hot.
John B Sowell, in his book Desert Ecology, has laid down every important information, especially about the ecology of deserts. Reviewers are off the view that the book is both instructive and informative when it comes to communicating about desert life along with the conditions. Perhaps the best feature of the book is that it includes a survey of desert conditions such as soil, water flow, and weather in addition to photos and tables for better understanding.