Chemical Weathering
Chemical weathering in the mid-latitudes is the process where rocks are weakened and disintegrated by chemical reactions that occur in the soil. Some of the chemical reactions that cause chemical weathering are oxidation, carbonation, and hydrolysis. These processes are involved in either forming or destroying minerals and therefore altering the nature of the mineral composition of the rocks. The process of chemical weathering on rocks characterizes the second stage of rock disintegration. The first process occurs during physical weathering and it involves disintegrating rocks into small pieces which are further broken into smaller pieces by chemical weathering. The most common type of chemical weathering occurs due to acid reactions which form in the soil. For instance, acid reactions are formed when carbon dioxide in the atmosphere reacts with water to produce a weak carbonic acid. This carbonic acid possess the capability of attacking a lot rocks (Meybeck, 1987). For instance, when carbonic acid attacks limestone, it reacts with it to produce calcium bicarbonate which is soluble in water. Basically, limestone is one of the main rocks that are affected by chemical weathering due to its ease of reaction wit acids formed in the atmosphere. Because chemical weathering is the process whereby rocks are decomposed and loosened by chemical processes, there are a number of effects of this process. First, chemical weathering breaks the bonds that hold the rock together making them fall apart into pieces. This causes soil erosion because of the process of carrying the rock particles and depositing them in another place. There are ways of reducing chemical weathering. First, people should reduce all the processes that may increase the amount of carbon dioxide in the atmosphere. This means that pollution from industries and motor vehicles should be controlled (Meybeck, 1987).
Difference between Rivers with Deltas and those without
When a particular river streams into a lake or a sea, water starts to slow down and thus loses much power which it had earlier. Due to the lack of enough power, the river cannot carry the sediments into the sea or ocean. The sediments are therefore deposited at the mouth of the river. Some of the rivers deposit so much sediment in such a way that tides and waves cannot sweep away. The sediment therefore builds up and forms a layer referred as a delta. In some places in the world, big deltas have been formed up to the point where people can actually live in them. For instance, the Nile delta is an important farming area in Egypt. There are difference between rivers that have deltas and those that do not have. First, rivers with deltas lose the power of flow and flow into the seas or lake with less power. On the hand, rivers without deltas have the same speed and power they had before (Milliman, 1992). In fact, most rivers without deltas flow into the lake with much speed than they had earlier. Rivers with deltas are mostly found in desert regions where sediment that is carried by the river is much. Rivers without deltas are found in other places other than deserts because there is little sediment to carry. The existence of deltas has an impact on the human population because they are unique natural resources which possess natural and agricultural heritage. Deltas are also home to very fertile soil and large amount of vegetations sprout from them. Further, deltas can provide buffers to hurricanes and thus saving a lot of lives in the process. In addition, there are many species of rare and endangered animals that live in the deltas due to the good environment that offers a good atmosphere and food (Milliman, 1992).
The Interglacial Period
The ice age is an important period in the earth because it represents the time when temperatures of the earth’s surface reduced. The reduction in the temperature caused the expansion of the ice sheets, continental, and alpine glaciers. This period, which was long-term, was characterized by individual pulses of cold climate, and is referred as the “glacial period. The intermittent period, which is characterized by warm periods, is referred as the “interglacial.” The ice age period is characterized by the occurrence of ice sheets in both the northern and the southern hemisphere. Based on this definition, the current world is in the interglacial period. This period is also defined as the Holocene of the ice age; which began about 2.6 million years ago. The reason that we have arrived at the conclusion that we are at the interglacial period is because of the warmer climate that exists in the earth at the moment (Rohling, 2008). The second ice age, which is believed to have occurred about 850 million years ago, produced the second “snowball earth” whereby the earth iced over completely. This period is characterized by the melting of the sea and glacial ice due to the high temperatures. The high temperature is caused by global warming which results to the melting of the ice. Because of the melting of the sea and glacial ice, the global albedo of the earth is lowering, which means it is absorbing a lot of sun light and energy which results in the rise of temperature (global warming). Warming again encouraged the melting of the ice, and the cycle repeats. Many researches are arguing that global warming is not caused by high carbon dioxide in the atmosphere; instead, it is a natural occurring due to the ice age period in which the earth exists (Rohling, 2008).
References
Meybeck, M. (1987). Global chemical weathering of surficial rocks estimated from river dissolved loads. American Journal of Science, 287(5), 401-428.
Milliman, J. D., & Syvitski, J. P. (1992). Geomorphic/tectonic control of sediment discharge to the ocean: the importance of small mountainous rivers. The Journal of Geology, 525-544.
Rohling, E. J., Grant, K., Hemleben, C. H., Siddall, M., Hoogakker, B. A. A., Bolshaw, M., & Kucera, M. (2008). High rates of sea-level rise during the last interglacial period. Nature Geoscience, 1(1), 38-42.
