Radiometric dating is a scientific method geologist utilize to estimate the age of rocks. Rocks contain tiny amounts of radioactive materials. Over time the radioactive material breaks down into more stable substances in a process called radioactive decay. This process happens at a constant rate depending on the type of radioactive isotope. Radiometric dating uses radioactive materials present in rocks as a basis for estimating their age. Three requirements must be fulfilled in order to get an accurate radiometric date on granite batholith. First, the rate at which radioactive material in granite batholith must be reliably determined. This rate must also be constant. Second, the radioactive daughter elements must have been present when the rock solidified, and this amount must be determined. For instance, geologists can determine the original amount of lead present when the earth was formed (Wiens, 2002). Finally, geologists must take a sample that is in a closed system. A closed system shields granite batholith from external pressures such as heat which can change the original content. In estimating the radiometric date to granite batholith, geologists use methods such as the uranium-lead dating technique and Potassium-Argon dating technique (Wiens, 2002).
Unconformities are missing links in geologic records. The three types of unconformities include angular unconformities, disconformities and nonconformities. Angular unconformities happen when old sediments are removed by erosion then new sediments are deposited on the eroded surface. Angular nonconformities help to form sedimentary rocks. Disconformities occur when erosion takes place between two layers of sediments. Sediments are first deposited, an uplift of the rock surface follows, and then erosion occurs. Like angular unconformities, disconformities form sedimentary rocks. Finally, unconformities are formed after many years of erosion which is followed by deposition of sediments. They normally separate igneous rocks from sedimentary rocks. Unconformities provide a hint on the events that led to a gap in the rock record. The events include deposition of sediments, followed by erosion which removes old rocks then deposition of new sediments on the eroded surface. Erosion of old rocks creates a gap in the rock record (Andrew, 2017).
Radiometric dating has previously been used to estimate the age of the earth. It relies on the radioactivity of material such as uranium found in rocks. Radioactive materials are usually unstable but undergo decay to form stable elements like lead. Unconformities on their part inform geologists on missing links in rock records.
References
Andrew, A. (2017). Unconformities: Gaps in the Geological Record. ThoughtCo. Retrieved Feb. 28, 2017, from https://www.thoughtco.com/unconformities-gaps-in-the-record-1440771
Wiens, R. C. (2002). Radiometric dating: A Christian perspective. Science in Christian Perspective: The American Scientific Affiliation. Retrieved Feb. 28, 2017, from http://www.asa3.org/ASA/resources/Wiens.html
