Dating - Wikipedia
Fluorine dating definition, a method of determining the relative age of fossil bones found in the same excavation by comparing their fluorine content. See more. Relative dating fixes a time frame in relation to other strata or material and not in . The method cannot provide an absolute age because the amount of fluorine. Element Fluorine (F), Group 17, Atomic Number 9, p-block, Mass Discovery date, Discovered by, Henri Moissan. Origin of the name, The name is derived form the Latin 'fluere', meaning to flow .. or other tortious action, arising out of or in connection with the use of the material available from this Site.
Acid peat or bog deposit is ideal sources of animal pollen, but dry sites, and clays contain enough pollen to provide a sequence.
Pollens in soil underlying or overlying archaeological sites may be correlated with the already known regional pollen sequence and the age of the site thus can be dated. A very good example of application of pollen method is the archaeological site at Choukoutien in China.
Patination - There is no precise definition for the term patination though it generally means chemical alteration of rock surfaces exposed to atmospheric conditions. The amount of patina on the stone is an index of its age valuable for relative placement of the stone artefact in the technological development.
The chemical alterations of the stone are usually brought about by the action of iron oxides through time. The observation of the amount of patina on a stone may be used at sites where there is a long sequence and demonstrates that those tools which lie in the bottom level may have more patina than those in the upper levels. The different types of tools from the river gravels, terraces of rivers or lakes can be differentiated in the relative amounts of patina on the basis of which of the relative ages can be assigned on the artefacts.
Goodwin who worked extensively on the patination in lists many variables involved in patina formation as well as different type of patination. That can be used fruitfully for the tools from stratified deposits.
Carbon Dating - Radiocarbon dating is a chemical analysis used to determine the age of organic materials based on their content of the radioisotope of carbon The method was developed by Willard F.
Libby and a team of scientists at the University of Chicago. In Libby received the Nobel Prize for his method to use Carbon for age determinations in archaeology, geology, geophysics, and other branches of science.
It subsequently evolved into the most powerful method of dating and Holocene artefacts and geologic events up to about 50, years. By radiocarbon method one can date different types of organic or inorganic materials as long as they consist of carbon.
The method is actually devised to measure the amount of low level radioactivity of carbon remaining in ancient and dead material of organic origin. Radiocarbon 14C dating is the most widely accepted technique for studying the chronological relationships of archaeological complexes.
Using the radiocarbon method as a source of objective information, we are able to build Stone Age chronologies as well as establish the primary chrono-cultural boundaries. The earth's crust contains potassium of which isotope K40 decays to A40 at a known rate. The ratio of potassium to Argon may be measured to ascertain date of minerals and rocks in a deposit. This method is able to cover a wide range of time even far greater than C method because, the half life of the radioactive potassium is million years.
The method has proved quite useful in dating some hominid fossils as employed in the site of Olduvai Gorge in east Africa where the remains were as old as 1. The advantage of the method is that it works well in case of the sites which areyears old.
But the disadvantage of the method is that it can be applied to only to those rocks and minerals which are rich in potassium. Therefore the method is restricted to the areas where volcanic rocks rich in potassium are available. Aitken and co- workers. Initially designed to date archaeological ceramics, it was subsequently extended to other mineral materials, such as burnt flint. This is based on the fact that objects such as pottery that have been heated in the past can be dated by the measurement of their Thermoluminescence TL glow.
Thermoluminiscence TL is the emitted light in the pottery which can be measured. If the ground up pottery is reheated, it emits light. The phenomenon results from radio-active influence of the metallic elements like uranium and potassium present in the clay and surrounding soils. By the use of Thermoluminescence TL dating methods and the results obtained could make it possible to provide a new chronological framework for archaeological and anthropological knowledge.
For example, the new chronology based on Thermoluminescence TL dating enabled in revising some prior assumptions about the evolution of lithic industries and the nature of hominids present in the Near East at various stages of the Middle Palaeolithic. Dendrochronology - The age of wooden objects can be determined by means of Dendrochronology or tree ring analysis. It determines the calendar years of tree-ring formation and the felling dates of trees, which helps to determine the age of wooden objects with a great precision.
Dendrochronology has therefore become well established in the field of archaeology, art history and cultural heritage. The method depends on the fact that trees growing in temperate zones have clearly defined annual rings of growth. As these tree rings represent annual growth, merely by counting rings one can count the age of the tree and hence its association. This dating method with latest methodological advances helps us in defining the calendar year in which the tree-rings were formed and in interpreting such dating in terms of the age of a wooden object.
Despite many difficulties found for ESR dating of bones and carbonates, tooth enamel dated by Electron Spin Resonance ESR has been proven as a reliable method in its application to fossil teeth and quartz. Both of the latter materials have allowed dating of Early and Middle Pleistocene sites which are not datable using other methods.
In particular, recent discoveries of human remains in Western Europe have been proposed to be sites of the earliest arrival of humans there, and have been dated to the Early Pleistocene by Electron Spin Resonance ESR using quartz and tooth enamel. Electron Spin Resonance ESR method can be applied to different types of samples in various environments; its contribution to the elaboration of a chronostratigraphic frame is of a great importance for the understanding of the Homo erectus dispersals out of Africa and especially for the first settlements in Europe.
Palaeomagnetic Dating - It is an important means of crosschecking the dates based on the constantly shifting nature of the earth magnetic field, both in direction and intensity. The measurement of the earth's magnetic field in several places of the world for centuries has shown that it varies with time.
A number of studies have shown that a record of past magnetic field in the form of angles of declination and dip can be trapped in baked clay. When clay is heated to a certain degree, the magnetic elements of baked clay realign themselves along lines dictated by the intensity and character of the magnetic field of the earth at that time.
On cooling the magnetic elements are frozen and can be recorded as long as the clay is preserved. This is called remnant magnetism.
When records of past angles of declination and dip have been kept it is possible to compare the values of historic records and arrive at the date of archaeological specimens of fired clay. Fluxgate, Spinner magnetometer, Super-conduction magnetometer are the instruments used for measuring magnetic remenence. The method was used in Great Britain by Aitken in detail. It has also been used in Japan and Arizona. In India the method is applied in dating Karewa sediments in Kashmir.
The reliability of the application of the method depends on certain conditions such as The availability of good records of change of magnetic paths near the prehistoric sites, Occurrence of series of already dated baked clay in the area against which objects of unknown dates can be dated, Availability of archaeological samples which are found in their place of first occurrence.
Fire places and kiln thus provide best samples for dating. Varve analysis - Varve analysis, one of the oldest dating methods which demonstrate seasonal variation and also reflect the climatic conditions of ancient time. The word varve in Swedish means annual layers of sediments deposited at the bottom of the lakes by the runoff from melting glacial ice. The method is based on the relative thickness of the varves and their comparison to the new sections as in tree ring analysis.
Formation of varves depends on climatic variation. In summer when ice melts coarse sediments deposits at the bottom and in winter when the lake is frozen, the finer sediments deposit at the top. It is possible to measure the relative thickness of the varves and obtain a series to which one can compare and correlate new sections as they are discovered.
The application of varve dating is restricted by several factors. First, it is because varve accumulation occurs only to glacial areas of the world. Second, many of the Pleistocene glacial areas has receded nowadays and affecting the supply of sediments. Therefore outside Scandinavia it is difficult to find continuous sequence of varves reaching the present. The longest sequence known goes back only 17, years.
Third, the varves may form frequently rather than annually depending on the pattern of the melting. However, instead of the limitations, varve analysis can be used indirectly for archaeological dating.
In North America, Ernst Antevs has made several attempts to relate Pleistocene geological formations in the American Southwest to events that produced varves in the northern parts of North America. Fission Track Technique - This technique dates material ranging from 20 years to 1,, years before the present.
One example of reused wood from ancient tomb showed the wood to be far older than the construction of the tomb It was the case, and the method was not flawed, but the reliance on this method requires other aspects to be considered to ensure that we are not solely relying on absolute dating methods in isolation. One of the greatest problems that archaeologists have had to handle is the overlap and replacement of Neanderthal with anatomically modern humans in Central Europe Contamination by modern carbon sources suggests that the dates often thrown up at the greater end of the range of radiocarbon dating suggest that traditionally understood dates of the appearance of modern humans, disappearance of Neanderthals and the extent to which they overlap on the continent, suggests that dates acquired over the last 50 years may be too young in some instances.
Relative Dating Methods Relative dating methods do not seek to put an exact date on a layer, artefact or activity although it can within a reasonable amount of doubt. It seeks to explain each item in context of its relationship to everything else, placing it in a sequence. With relative dating, we can see that artefact A came after artefact B by examining its evolution in design or methods of production. We can also see and explain how one geological layer came after another.
Here are the most common methods. Useful in geography, anthropology and archaeology and environmental studies, this examines the principles of relationships of species relative to each other. It observes sedimentary rock layers for signs of fossilized organic material. This data is used to explain not evolution although it can - that's not its purposebut the sequence of succession for the lifeforms that occupied that particular landscape at a given time, and to examine when a layer was set down.
It does not give dates, but it does demonstrate landscape changes through the organic life that occupied it in that time frame. Pieced together, we can build a profile over larger areas Useful in Earth Sciences such as geology and geography, as well as archaeology and anthropology, there is surprisingly much to learn about the palaeomagnetic record the study of the magnetic field of the past.
It's contributed to the study of continental drift and plate tectonics in the former and dating pottery and brick firing in the latter In archaeology, the study has provided unequivocal and solid dates for the earliest occupation of humans in China and Western Europe, including several relative studies of the archaeological landscape.
This is the study of fungal spores and plant pollen during their sexual reproduction stage. Archaeologists and anthropologists can use surviving materials to build a chronology of changes to a landscape over time This can be used to build a landscape history, a profile of land occupation by humans, and tell us much about the local climate at any given time.
Often used in conjunction with absolute methods such as radiocarbon dating. Stratigraphy This is a broad area within geology, and in archaeology and anthropology, that examines layers of a landscape. It says nothing about the age of each layer, merely the sequence of deposition.
Fluorine absorption dating - Wikipedia
The principles mentioned below make up the theory of the science. Used in geology, this is one of the main defining principles of the science.
It's the process of examining relationships and interactions between geological layers to determine a sequence - usually to understand which are earlier. Through it, we come to understand and explain how disrupted layers are older than the actual layers It challenges the principle that a sublayer is always earlier though it is in most cases. Tectonic plates can push rock layers beneath others, creating mountain ranges This is a tool of stratigraphy rather than a method used in archaeological contexts, utilizing some of the three Principles listed below.
A Harris Matrix is a diagram similar to a flowchart that breaks complex stratigraphic layers into a most likely sequence. It does not state the age of the layers but sets down the most likely process by which the sequence came to be. Usually, they will use three labels: Like cross-cutting, the premise for this is that any anomalous clasts in geologic layers or inclusions found within an archaeological stratigraphic layer must be older than the layer itself, even if deposited later.
There are many reasons why we should never attempt to date inclusions as proof of the age of the layer; the anomalies that inclusions throw up is just one of them. It's important not to confuse the age of the item with the date of deposition Principle of Lateral Continuity: Mostly used in geology but with some stratigraphic use in landscape archaeology too, it defines that layers that have become separated or split but otherwise appear to share a relationship must have been deposited at the same time.
How this is used as a relative dating method is by examining the stratigraphic layer and looking at those elements of the landscape that cut through them Returning to the Grand Canyon as an example, The rock layers on both sides of the canyon were deposited at around the same time but were broken up by the cutting of the river through it. Principle or Law of Original Horizontality: This is a simple premise defining that even when stratigraphic layers are vertical or angled, they must have originally been set down horizontally - that later geological processes must have skewed the rock formation, altered the angle or distorted the present profile This can be used in conjunction with the other principles listed here - Superposition see below and Lateral Continuity see above.
Principle or Law of Superposition: It states that lower surface layers in a sequence must have been deposited first and are therefore the eldest.
This method for dating volcanic ash based on its inclusions such as glass particles and other chemical compounds. As it can travel potentially enormous distances and survive under the same conditions as palynology peat bogs and silt it can tell us a great deal about when the volcano erupted, its strength and power, and when examined in conjunction with other archaeological and geological evidence, to build a picture of the fall out This means it is also useful for climatology and paleoclimatology.
Typology This examines the evolutionary changes to any artificial item - be it functional or aesthetic artefacts, rock art, building construction and materials, it attempts to demonstrate through sequences or examining the methods and materials, its relationship to other items in its class or style.
Fluorine absorption dating
Used in archaeology and anthropology, the examination of artefact size, shape and form to define them into categories such as period, style, design and technological advance. This is used in conjunction with artefact typology see below which is a much more complex form of categorization which examines function as well as form and design 20 p Seriation is the placement of artefacts in chronological order, assuming a sequence of evolution usually by technological advance, complexity and method of manufacture It's most frequently and reliably used with stone tools, pottery and grave goods in prehistoric and historic contexts.
He developed the relative dating method during his studies in Egypt. This further refines Seriation by examining different styles of artefacts and categorizing into different archaeological time periods. Its fundamental to examining both artistic styles and technological advance, but also social and political change These archaeological concepts set a final and earliest possible date on something To use a simple example, a Roman grave containing coins from the reign of Emperor Nero could not possibly have been buried before his reign.
The earliest possible date then is the first year of his reign AD A Terminus Ante Quem would be discovering the above burial beneath a structure with a known date by documentary or other evidence such as Trajan's Column. This was constructed in AD Our hypothetical grave could not have been buried before AD54 or after AD Advantages and Problems of Relative Dating Methods Relative dating has proven useful for most of the existence of the sciences considered here.
Each, in their own way, has allowed researchers to determine sequences and relationships between artefacts development including methods, technology and artistic style, geological sequences and events, attempting to piece together a most likely series of phases of evolution and change. In archaeology, it typically shows us technological advance and artistic style change. In geology, it shows us long-term environmental change and events and effects of geological cataclysms.
But there are limitations to all these methods above, even when used in conjunction with each other. Most relative dating methods work best when used in conjunction with the absolute dating methods already discussed; when dates correlate, we can be confident of the methods. Together, they allow us to build a complete picture for dating and sequencing.
The first major drawback to all relative dating methods is that they rarely put specific dates on an artefact or process. We can only say that Event A came before or after Event B. It cannot tell us when either event took place. Only absolute dating can do that within reason and with a reasonable margin of error supplied.
The second major drawback and similarly, Relative Dating Methods rarely lend themselves well to demonstrating timescale. Even if we know that Artefact A was produced and used before Artefact B, on its own the relative dating method used to explain this cannot tell us how far apart they were produced or used, or how long they existed in the human record. It could be a year, or it could be millennia. To place five artefacts in a visual diagram sequence may, in isolation, suggest that each artefact type's style, method, or morphology have some sort of parity - either in terms of popularity, ubiquity or length of use.
This is especially the case with stone tool development of the Stone Age periods. In the Old World, the Paleolithic lasted 2. To adapt this problem for geology, relative dating methods cannot tell us how long a stratigraphic sequence took to accumulate - only explain those after which and before which it was set down.