But even in properly observed and recorded stratigraphic levels there is often doubt, and the question arises: are all the artifacts and human remains found in the same level contemporary? Is it possible that there could have been later intrusions that have been difficult to distinguish in the field? The analysis of the fluorine content of bones has been very helpful here. Recognized as a valuable technique by French scientists in the 19th century, it was developed in England by K.P. Oakley in the 1950s. If bones in apparently the same geological or archaeological level have markedly different fluorine content, then it is clear that there must be interference—for example, by a later burial, or by deliberate planting of faked remains, as happened in the case of the Piltdown “Man” hoax in England.
Absolute man-made chronology based on king lists and records in Egypt and Mesopotamia goes back only 5,000 years. For a long time archaeologists searched for an absolute chronology that went beyond this and could turn their relative chronologies into absolute dates. Clay-varve counting seemed to provide the first answer to this need for a nonhuman absolute chronology. Called geochronology by Baron Gerard De Geer, its Swedish inventor, this method was based on counting the thin layers of clay left behind by the melting glaciers when the European Ice Age came to an end. This gave a chronology of about 18,000 years—three times as long as the man-made chronology based on Egyptian and Mesopotamian king lists. Thus, absolute dates could be established for artifacts from the Late Paleolithic Period, the whole of the Mesolithic Period, or Middle Stone Age, and much of the Early Neolithic Period.
Dendrochronology, the dating of trees by counting their growth rings, was first developed for archaeological purposes by A.E. Douglass in the United States. The application of this method to archaeology depends, obviously, on the use in antiquity of old datable trees in the construction of houses and buildings. It has been possible by dendrochronology to date prehistoric American sites as far back as the 3rd and 4th centuries bce.
The greatest revolution in prehistoric archaeology occurred in 1948, when Willard F. Libby, at the University of Chicago, developed the process of radioactive carbon dating. In this method, the activity of radioactive carbon (carbon-14) present in bones, wood, or ash found in archaeological sites is measured. Because the rate at which this activity decreases in time is known, the approximate age of the material can be determined by comparing it to carbon-14 activity in presently living organic matter. There have been problems and uncertainties about the application of the radioactive carbon method, but, although it is less than perfect, it has given archaeology a new and absolute chronology that goes back 40,000 years.
Following the revolutionary discovery of radioactive carbon dating, other physical techniques of absolute dating were developed, among them potassium–argon dating and dating by thermoluminescence. Potassium–argon dating has made it possible to establish that the earliest remains of man and his artifacts in East Africa go back at least 2,000,000 years, and probably further. Historical judgments
The last and most important task of the archaeologist is to transmute his interpretation of the material remains he studies into historical judgments. When he is dealing with medieval and modern history he is often doing no more than adding to knowledge already available from documentary sources: but even so his contribution is often of great importance; for example, in relation to the growth and development of towns and the study of deserted medieval villages. When he is dealing with ancient history and prehistory, he is making a contribution of the greatest importance and often one that is more important than that of purely literary and epigraphical sources. For the prehistoric period, which now appears to stretch from 2,000,000 years ago to about 3000 bce, archaeological evidence is the only source of knowledge about human activities. But prehistoric remains have always been the most difficult to interpret, precisely because there are no written records to aid in the task. Now, with exact dating techniques at his disposal, the prehistorian is becoming more like the historical archaeologist and is concerned with the periodization and the historical contexts of his finds. Glyn Edmund Daniel
Citation Information
Article Title: Archaeology
Website Name: Encyclopaedia Britannica
Publisher: Encyclopaedia Britannica, Inc.
Date Published: 07 February 2019
URL: https://www.britannica.com/science/archaeology
Access Date: August 10, 2019
Additional Reading
Good general introductions to the aims and methods of archaeology are Leonard Woolley, Digging Up the Past (1930); Sir Mortimer Wheeler, Archaeology from the Earth (1954); and Grahame Clark, Archaeology and Society, 3rd rev. ed. (1957). For the history of archaeology and its relation to the development of anthropology, see C.W. Ceram, Götter, Gräber und Gelehrte (1949; Eng. trans., Gods, Graves and Scholars, 1951); G. Bibby, The Testimony of the Spade (1956); and Glyn Daniel, A Hundred and Fifty Years of Archaeology (1974). Anthologies of archaeological writings that relate both to the history of the subject and its present methods are many. The following are recommended: R.F. Heizer, The Archaeologist at Work (1959), and Man’s Discovery of his Past, 2nd ed. (1970); and Jacquetta Hawkes, The World of the Past (1963). For the development of American archaeology, see G. Willey and G. Sabloff, The History of American Archaeology (1973). Special aspects of the development of archaeology are dealt with in D. Brothwell and E. Higgs, Science in Archaeology, 2nd ed. (1969); George F. Bass, Archaeology Under Water (1967); W.F. Libby, Radiocarbon Dating, 2nd ed. (1955); Kenneth Hudson, A Social History of Archaeology (1981); Myra Shackley, Environmental Archaeology (1981); and M.G.L. Baillie, Tree-Ring Dating in Archaeology (1982).