Chemical Weathering Research Paper

The Earth’s lithosphere and the rocks that it comprises of are constantly under attack from nature’s activities. Weathering, also known as clastaion or demorphism, as described by Encyclopaedia Brittanica, 2014, 1 is weathering the disintegration or alteration of rocks in situ at or near the Earth’s surface through physical, chemical, and biological processes induced or modified by wind, water, and climate. However, for the purpose of this essay we will be discussing chemical weathering and its effects on limestone, a sedimentary rock which is extremely susceptible to the effects of a particular type of chemical weathering called carbonation. Chemical weathering as defined by the McGraw-Hill Dictionary of Earth Sciences 1984, 133, is a

Of all the rocks found on the Earth’s surface limestone is the most suscpetible to chemical weathering. This is because of it’s carbonic nature which is easily broken down by carbonic acids such as rain water. Different factors affect the rate which chemical weathering takes place. Pearl, 1975, 97, mentioned that chemical weathering are affected by five (5) major factors: mineral/chemical compostion, temperature, moisture, altitude plant and animal life softer more soluable parts of the rock body decompose more easily that more resistant ones. Fragmented rocks are heavily dependant on the strength of their bonding material to determine their resistance to weathering.Soluable cements decompose reather quickly while firmly compacted rocks may hold together longermaking them more resistant to weathering. Warmer temperatures produce instability which cause convectional rainfall. Moisture and rainfall are extremely important to the chemical weathering process because most reaction take place in solution (e.g carbonation and hydrolosis). Even though all reactions do not take place in solution most have an element of water in them (e.g hydrogn ions are also exchanged during oxidation). Moreover, warmer temperatures means that minerals will not freeze preventing reactions from taking place. At higher altitudes there is more percipitation and snow melt to add to the moisture to facilitate reactions taking place. Plants grow their roots rough cracks in rocks causing to grow bigger and eventually brake away the rocks. Plants also creat chelting agents through their respiration that help to decomposing rocks. Not withstanding, burrowing animals so help to bring buried rocks