Relative and absolute dating methods in archaeology

Relative vs. Absolute Dating in Archaeology
Gaining insights into events of the past requires diligent research, meticulous observations and computing. In the field of human history known as archaeology, the importance of dating cannot be overemphasized. To this end, there are majorly two known and widely accepted dating method – relative and absolute methods of dating. The two dating techniques are different in terms of methods and age. Relative dating is an old founded method that has been in existence since 18th century while absolute dating came into being in the 20th century.
Relative dating is an old method of analyzing chronology of rock art and was based on nonscientific methods which use stylistic analysis of imagery to found one-way evolutionary schemes for many decades. It is limited to determining the relative chronological sequence of past events, without substantially giving their age. This method, due to its nonscientific approach has been known to be one of the most debated processes of dating that has been contested from various quarters, and it covers events from early stone age up until the present (Ruiz et al., 2012). Despite the controversies surrounding relative dating, it, however, remains relevant till date and has been proven useful to archaeologists in their endeavors to find answers to earth’s puzzles about the ages past, especially in the areas where absolute dating is entirely inapplicable.
Absolute dating, on the other hand, is the use of a scientific method which describes all schemes that give figures about the valid estimated age of archaeological entity or occupations. It usually “analyze physiochemical transformation phenomena whose rate are known or can be estimated relatively well” (Gagne, 2013). Its scientific way of analysis makes it more reliable and precise than relative method and is mostly accepted and used by most researchers in the field of human history as it reveal the exact age of the artifact or the site with the application of modern dating the method like carbon dating (Barry, 2015).
The relative dating method began as far back as the 18th century when people started taking a more in-depth look at the happenings of the ages past and thought there was a need to have an agreed way of finding and computing information about those events with the view to determine when they took place. First used by William Smith, an English geologist. Some of the methods used in relative dating include stratigraphy, biostratigraphy, and cross-dating.
The stratigraphy approach is based on the assumption that the lowest layer is the oldest and the topmost layer is the youngest layer. It applies the theory of the superposition which states that, in a sequence of undistributed soils, the upper horizons are newer than the lower ones (Gagne, 2013). Although, limited to some extents, it, however, remains very relevant till these days, and in some cases, the soil stratification is used to chronicles dating of some objects before the using the absolute for gain more accuracy. In other words, its relatively crude approach does not render it useless even with the advent of scientific technique. For instance, as Gagne, 2013 observes, “the oldest human remains known to date in Canada have been dated using soil stratification. The bones were buried under a layer of ash that resulted from volcanic eruption dating back to 7000 years BP (Before Present).” After the discovery was made using the relative method, the absolute method was later employed for more comprehensive and direct dating, which gives a date of 8250 BP. This shows the usefulness of the combination of the two dating methods. Stratigraphic also deals with the dating of pottery styles, certain stone tools and some other diagnostic artifacts that are discovered within the soil layers.
Typology is another method in relative dating. This method is based on the classification of certain objects in order to compare and determine the similarities and differences that exist therein, in order to trace their background and timing. It mostly employed whenever archaeologists find it impossible to make use of absolute dating method, and it gives insights to the particular time in the past to which a cultural site or object belongs. It elicits a specific order according to the aims of the investigator and on the phenomena so arranged, an order that limits how the data can be clarified (Typology, 2016).

Absolute dating, as Young, 2006 opines, became imperative due to geologists and archaeologists’ nonsatisfaction of the old (relative) methods that were not substantially formed. They wanted a more precise way and dating which will provide better and more satisfactory answers to the event of the past. That was what gave birth to absolute dating in the 20th century. First radiocarbon dating on a rock was done on a charcoal pictograph in South Africa in the late 1980s, and after that, in other places including Australia, USA, and Europe (Ruiz et al.). The absolute technique employs different methods of dating which include radiocarbon, dendrochronology, and thermoluminescence methods.

Relies majorly on natural phenomenum that is the fundamental of life on earth, radiocarbon is the most used dating method in the field of archaeology (Gagne, 2013). Radiocarbon dating method as explained by Young, (2006) is more useful when dating materials that are not more than hundreds of years or some tens of thousands of years old. To date an object using this method, the level carbon 14 left in the object up until when the dating is done, will be compared to a reference standard in this manner – ratio 14C/total carbon, 12C and 13C in figuring out the elapsed time since the event happened.
Dendrochronology is the dating method under absolute technique which studies the growth of tree rings. It is mainly on the belief that the disparity in the growth of trees from a particular year to another year is prompted by the intensity of soil type, sunshine, temperature, precipitations and other atmospheric states of the area. The principle states that, by this, it is possible to differentiate reference patterns. Developed in 1900 by an American Astronomer, A E Douglas from his keen interest in studying the climate, Douglas came up with the theory that that proxy date from tree rings could be used to extend climate study to back farther than it had been previously accepted and done. Though, he had made use of the method several times after his theory, it (dendrochronology), did not become popular until in the 1970s when archaeologists began to appreciate and employ the method in their field works (Manson).
Some of the fundamental principles of dendrochronology are Uniformity and limiting factors. The uniformity states that the history of a particular tree could be adjusted against the total of the existing history so as to arrange it in chronological order. The calibration should be able to reveal the accurate year which a particular ring was created. Limiting factors, on the other hand, states that a particular atmospheric condition can affect the growth of the tree ring in a season or year. It gives a more precise dating, sometimes to the nearest year. Gagne, (2013) points out that dendrochronology is mostly applied in developing “calibration curves used to correct data obtained from radiocarbon dating, a technique that remains imprecise due to fluctuations in the concentration of carbon 14 in the atmosphere over the centuries.”
Thermoluminescence (TL) is about the light emission of a mineral during a heating process. It is applied in modern dating to date objects that contain crystalline minerals to a certain heating event. Some of the archaeological items which thermoluminescence could be used to date include brick, hearths, ceramics, fire pits, kiln, heat treated flint, fire-cracked rocks, and slag. It requires a sophisticated operation in order to obtain a date for a single pottery sample as it is essential to carry out laboratory fraction of the clay mineral used to mold the pottery and arrange almost 75 sub-samples, some of which will be heated to release the degree of thermoluminescence, while others get radiation dose to ascertain how sensitive they are to radiation (Gagne, 2013).

The scientific technique of dating has largely shaped the general worldview about past events and nature. Prior to the application of absolute dating, the major beliefs of the world about the past were based on assumptions, religious and cultural beliefs, and feelings. For centuries, people held wrong perceptions about nature, and in some cases, were totally ignorant of the existence of some of the discoveries that have now been made. Even the renowned philosophers, opinion leaders and political leaders of then did not know better.
For instance, analyzing how opinions in the past were divided even along unfounded claims, Braterman, (2013) recollects that the great “Aristotle thought the earth had existed eternally”, another unfounded claim about the earth was also expressed by the Roman poet Lucretius, intellectual heir to the Greek atomists, who also believed that the earth’s “formation must have been relatively recent, given that there were no records going back beyond the Trojan War.” On their parts, “the Talmudic rabbis, Martin Luther and others” in the religious setting, “used the biblical account to extrapolate back from known history and came up with rather similar estimates for when the earth came into being.