Water is a key component of life on earth. It covers slightly more than 705 of the earth surface. The hydrological cycle explains the behavior of water within the planet. Among the processes supported by water are: farming, construction, power, and human consumption. It is right to say that without water, human life would be impossible (The Hydrological Cycle1).It is through the hydrological cycle that the continued presence of this crucial commodity is maintained on the earth.
The hydrological cycle is made up a number of stages. These stages are evaporation, condensation, and precipitation. In between these three stages are small but equally crucial stages such as the formation of convectional currents and vapor cooling which comes just before condensation. Before the first process which is evaporation can take place, there must be water bodies. The seas, oceans and rivers have the water from which evaporation take place. The process of evaporation is followed by the condensation of the water vapor to form clouds which are then moved to some areas sometimes beyond the area above the water bodies. Jet stream is one of the mechanisms involved in cloud movement. After the movement of the condensed clouds, the heating up of the earth’s surface raises hot air that generates rain from the condensed clouds. The rain is what we call precipitation. The rain that falls on the earth’s surface creates runoff water while some of the water sinks to the ground to form ground water. The processes can occur all over again.
The hydrological cycle is significant in that it plays a major role in human activities such as farming. It also regulates climatic conditions; a phenomenon that helps eliminates extremes of weather.
Geological Features of Glacial Landscapes and Desert Landscapes Comparisons and Contrasts
With close to 33% of the earth’s surface being desert or semi desert, deserts are a significant part of the geological domain. They possess a number of geological features that are very significant. These include dunes, the loess, ventifacts, the mesa, blowouts, alluvial fan, pediment, and hoodoo. These desert features or landforms are formed through different processes. A dune is formed as a result of strong wind blowing desert sand and silt, which then accumulate over time at an angular position (Desert Usa 1). To form a significant sand dune, the winds must be strong and sufficient time is required. The Loess emanates from angular wind-blown silt that gets held together by calcitic cement.
The ventifact is a rock like landform that forms a flat top over a long time of wind action whereas a mesa normally forms as a result of either loss of material around it leaving a table-shaped hill or the long term accumulation of silt and sand. Then we have the depressions that are formed due to the erosion that takes place in deserts (Mangimeli 1). These depressions are what is referred to as blowouts. The other very important geologic landform that is very common in deserts is the alluvial fan that forms as a result of wind action on sand, silt and sometimes rocks leading to the formation of small cracks and holes. This normally occurs at the base of mountains (Mojave Desert Geology 1).
Glacial geological landscapes on the other hand are a product of ice. The best known forms of glaciers are sheets of ice. Glacial geological features include crevasses, eskers, fjords, rock flour, striations and piedmont glaciers (Glaciation 1). Piedmont glaciers are glaciers that flow out of areas of higher ground towards the slops, whereby they spread out into sheets. A fjord is usually formed as a result of the formation of a depression on ice under water in seas. The bottom of a fjord is usually flat. When a stream runs under a glacier, lengthy sediment is formed. This is what is called an esker. Eskers are also formed after the melting of ice sheets, an act that leaves behind debris that is in a nearly linear feature. A crevasse is a split of crack that is fairly deep and it is found at the upper part of a glacier ice.
The various geological landforms that are found in the desert and those found in glacial landscapes form a crucial part of the geological world. They both shape the face of the earth and influence man’s behavior. Most importantly, these landforms influence the climatic conditions that prevail in the environments where the features are found.
There are a number of differences between desert geological landforms and glacial geological landforms. Desert geological landforms mainly originate from the action of the strong desert winds on loose rocks, silt and sand. Glacial geologic landforms on the other hand originate from the movement of ice either on land, water or rocks. Also, the conditions under which they are formed are different. The desert climate in which desert geological features are formed is far much different from the climate in which glacial landforms are formed. Glacial geologic landforms are formed under wet, cold or humid conditions whereas the desert climate is windy and dry. Besides conditions of formation and mode of formation, most desert geological landforms are formed after a considerably long period of time. This is not the case with glacial geological landforms that take a shorter period.
References
Desert USA.Exploring desert Geologic Features. Web.
Glaciation. Web.
Mangimeli,J A Geology Of Sand dunes. Web.
Mojave Desert Geology. Web.
The Hydrological Cycle.Web.