Radiometric dating is a technique used to identify the age of a certain rock, fossil or artifact by measuring the radioactive decay of certain elements that they contain. The most common radioactive elements measured are Carbon-14, Potassium or Iron. According to Dr. Dennis Kent of the Columbia University, Carbon-14 measurements are only limited to samples of up to 50,000 years because of the short half-life of carbon. For older samples, Potassium and Iron are used to determine age in techniques known as tephrochronology and magnetostratigraphy, respectively (Ray, 2011).
The use of radiometric dating has been extensively used in archaeology. Specifically, it has been employed in providing detailed information about the timeline of Egypt’s Old, Middle and New Kingdoms (Bhanoo, 2010). Although the chronological order of the pharaohs who ruled ancient Egypt has been previously known, there has been no established and clear-cut timeline about when and for how long. Radiocarbon dating was used in this case to estimate the dates of the pharaoh’s reign.
In the study conducted by Dr. Christopher Ramsey and his colleagues at the University of Oxford, they made use of plant materials as samples because of their short life span. He explained that previous radiocarbon dating that made use of coal and wood samples were less precise because they were likely to be reused over the course of different reigns since these are in short supply. The team of Dr. Ramsey instead made use of seeds, fruits, plant stems and plant products such as baskets associated with a particular reign for a more precise estimation. They did this by dating 211 plant samples obtained from museums around the world. According to the results of their study, the era of King Tutankhamun and the Kings Rameses began between 1570 and 1544 B.C., as opposed to the previous estimate of 1550 or 1539 B.C. King Djoser of the Old Kingdom was estimated to start his reign between 2691 and 2625 B.C. whereas previous estimates suggested that his reign started in 2667 or 2592 B.C. The results of their study more or less agree with the previous estimates but are more precise because of the modifications in the method which they used.
There has been contention as to the accuracy of radiometric dating especially in the estimation of the age of artifacts with religious significance. This is because some of the findings from radiocarbon dating do not agree with established religious teachings. So how accurate is radiometric dating?
At present, radiometric dating is the scientific method and most precise way of determining the age of ancient artifacts. The results are expected to be reliable because measurements depend on stable radioactive decays. They are also verifiable because results of independent studies using dendrochronology and sediment layer analysis also often confirm the results of radiometric dating. Aside from this, there is a calibration method employed to minimize errors which results in standard calibration curves. In 2004, a calibration curve was prepared which extends back quite accurately to 26,000 Before Present (BP). In this curve, any errors do not contribute more than ±16 years to the measurement error during the historic and late pre-historic periods (0-6,000yrs BP) and no more than ±163 years over the entire 26,000 years of the curve (Reimer, et al., 2009). The accuracy of this calibration curve has been extended up to 50,000 years in 2009.
Works Cited
Bhanoo, Sindya. “Pharaohs Are Given an Update”. Science Times. The New York Times, 21 June 2010. Web. 09 June 2012.
Ray, C. “Dating Stone Tools”. Science Times. The New York Times, 12 Sept. 2011. Web. 09 June 2012.
Reimer, Paula. “IntCal09 and Marine09 Radiocarbon Age Calibration”. Radiocarbon 51.4 (2009): 1111-1150. Print.
