CHAPTER 5: SCIENCE AND ARCHAEOLOGY
Note: this is part of an electronic companion that supplements Kevin Greene's book Archaeology: an introduction (1995); click on the title to start from the home page.

CHAPTER 5: SCIENCE AND ARCHAEOLOGY

COPYRIGHT STATEMENT
  1. IS ARCHAEOLOGY A SCIENCE?
  2. THE EXAMINATION OF OBJECTS AND RAW MATERIALS:
    2.1 Microscopic examination (petrology, metallography); 2.2 Analysis and characterisation (obsidian, Bronze Age metallurgy, Roman coins, isotopic analysis); 2.3 Provenance by date
  3. CONSERVATION
  4. THE ENVIRONMENT
  5. CLIMATE
  6. ROCKS AND SOILS
  7. PLANT REMAINS: 7.1 Pollen analysis; 7.2 Tree rings
  8. ANIMAL REMAINS: 8.1 Animal bones; 8.2 Fish bones; 8.3 Shells
  9. HUMAN REMAINS: 9.1 Genetics, 9.2 Coprolites
  10. STATISTICS: 10.1 Computers
  11. EXPERIMENTAL ARCHAEOLOGY: 11.1 Artefacts; 11.2 Sites and structures
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1 IS ARCHAEOLOGY A SCIENCE?

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'So much of the evidence left behind by past cultures has been destroyed that archaeologists have a duty to employ whatever methods are available to extract the maximum possible information from what still survives. ... In practice, there are few questions about the past that would not benefit from investigation with the help of the natural or biological sciences; indeed, many questions may only be answered with the assistance of scientific methods. One of the principal educational virtues of archaeology is that it is truly multi-disciplinary, and that it defies all attempts to pigeon-hole it either as a science or as one of the humanities.' (p. 130)

2 THE EXAMINATION OF OBJECTS AND RAW MATERIALS

2.1 Microscopic examination (petrology, metallography); 2.2 Analysis and characterisation (obsidian, Bronze Age metallurgy, Roman coins, isotopic analysis); 2.3 Provenance by date; Go back to chapter heading
'Scientific analysis offers many insights into ancient objects, but, as with dating methods, there must be full cooperation and communication between archaeologists and laboratory scientists to ensure that the most appropriate methods are applied to suitable samples. There is little point in conducting analyses without clear questions in mind, and those questions should be the result of archaeological research.' (p. 130)
2.1 Microscopic examination
'Not all questions of scientific analysis require complex analytical methods; traditional study by microscope allows many aspects of stone or metal artefacts to be examined. ... Archaeologists now use microscopes in use-wear analysis of artefacts, in particular tools, for patterns of wear or damage on working surfaces may suggest how a tool was used. ... Visual examination in use-wear studies is enhanced dramatically by a scanning electron microscope (SEM), which projects a magnified image onto a screen.' (p. 131)
Petrology
'Petrology involves the examination under a microscope of thin sections cut from samples of stone. Many minerals may be identified by eye, and distinctive rocks are recognisable without the help of spectrographic analysis to measure their elements.' (p. 131-2)
Metallography
'...it should become a rule that analysis and metallography (and hardness testing) should always be combined, since a full interpretation of one is impossible without the other.' (Peter Northover) (p. 132)
2.2 Analysis and characterisation
'The basic aim of the analysis of an artefact is to identify the materials from which it was made, and to measure accurately the relative quantities of its constituent minerals or chemicals. When this information is interpreted it may be possible to define the sources of the raw materials, to suggest a place of manufacture, and to deduce techniques involved in the manufacture of an object. Analysis is not restricted to objects, however; structures such as buildings offer many possibilities for the analysis of stone, bricks and mortar.' (p. 133)
Obsidian
'This volcanic glass occurs widely in both the New and Old Worlds... Like flint, it has excellent working properties for chipping, flaking and grinding into tools with sharp cutting edges. ... Most analyses have attempted to study patterns of prehistoric trade by identifying sources that supplied sites.' (p. 134)
Bronze Age metallurgy
'Bronze usually consists of copper alloyed with tin, and varying percentages of other metals. The composition of an artefact made of copper or bronze is usually examined by a technique known as atomic absorption spectrophotometry. ... The quantity of an element is indicated by the amount of light absorbed by atoms of that element in the sample, to an accuracy as precise as five parts per million if necessary; this allows trace elements to be measured along with the principal metals.' (p. 135)
Roman coins
'The use of information derived from the analysis of metals is not restricted to the prehistoric period. Roman metallurgy has been extensively studied through examinations of ores, ingots, coins and manufactured objects.' (p. 136)
Isotopic analysis
'Individual elements can be examined in more detail to establish which isotopes (elements with an abnormal number of electrons) are present, and in what proportions. ... Studies of stable isotopes now assist in the study of Greek and Roman architecture and sculpture.' (p. 136)
2.3 Provenance by date
'Like obsidian characterisation studies, accuracy depends on how many potential sources have been sampled and tested.' (p. 137)

3 CONSERVATION

3.1 Ancient objects; 3.2 Historic buildings and archaeological sites; Go back to chapter heading
'Although conservation is one of the most important aspects of archaeological science experienced by visitors to sites and museums, it is easily overlooked.' (p. 137)
3.1 Ancient objects
'Whenever an ancient object is removed from the ground during an excavation it is immediately placed at risk, for the stable environment that has protected it from total decay since its burial has been lost. ... It is essential that an exact identification of the composition and structure of an object is made before conservation begins.' (p. 137)
3.2 Historic buildings and archaeological sites
'Newly excavated structures soon suffer from exposure, and require permanent supervision if they are to be left on display. ... Buildings that have been visible for hundreds of years are increasingly vulnerable, for ancient stonework is easily damaged by air pollution in modern urban environments.' (p. 139)

4 THE ENVIRONMENT

4.1 The concept of 'sites'; 4.2 The survival of environmental evidence; Go back to chapter heading
'The tendency to treat environmental archaeology as a separate discipline obscures the diversity of specialist skills that it draws upon. For example an archaeologist engaged in studies of the early Stone Age requires a detailed knowledge of the plant and animal resources available to hunter/gatherers, an understanding of the prevailing climatic conditions, and information about human diet, diseases and life expectancy.' (p. 139)
4.1 The concept of 'sites'
'Few techniques used in environmental archaeology are restricted to individual 'sites' or excavations; humans are just as much part of a wider ecological system as other animals or plants. Broader aspects, such as climate and vegetation, provide a background setting for human activity, and the primary sources of evidence for these aspects do not come from excavations of habitation sites.' (p. 140)
4.2 The survival of environmental evidence
'Archaeology in the New World has always taken a close interest in environmental aspects of sites because of the many different ways that native American cultures developed in diverse settings, from tropical rain-forests to temperate woodlands, and from plains to deserts. The superb preservation of organic remains on settlement sites in arid desert conditions in the Southwest of the United States made the observation and examination of environmental evidence an obvious part of archaeology, in contrast to most European sites, where organic remains had disappeared through decay.' (p. 140)

5 CLIMATE

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'Long-term climatic change has been a fundamental factor in human development, seen at its most dramatic the during periods of extensive glaciation that have been known to geologists for more than 200 years. ... While long-term change is obviously important from an archaeological point of view, short-term fluctuations may have had an important impact on human life in the past - especially in farming communities.' (p. 141)

6 ROCKS AND SOILS

6.1 Soil science; Go back to chapter heading
'Geology and geomorphology are essential for understanding the present landscape and its past configurations, along with changes in sea level, erosion, and the deposition of new land by sedimentation or volcanic activity. This information not only influences our concepts about the environmental context of human activities in the past, but also provides vital insights into the likelihood of finding sites and artefacts.' (p. 141)
6.1 Soil science
'Surface deposits and outcrops of rock, combined with evidence for rivers and lakes, dictate the forms of vegetation and animal life available to hunter-gatherers or early farmers. An understanding of soils adds further detail, for soils with differing colours, textures and other characteristics are formed and changed both by natural and human activities.' (p. 141)

7 PLANT REMAINS

7.1 Pollen analysis; 7.2 Tree rings; Go back to chapter heading
'Nineteenth-century botanists concentrated on large fragments of plants, but the focus in the twentieth century moved to microscopic pollen grains. Large items such as seeds and pips remain important, however, for they not only reveal the existence of plant species but also give insights into the collection and processing of wild fruits or crops from domesticated plants. ... The prospects for future research are expanding now that methods for extracting ancient DNA from ancient seeds or cereal grains are beginning to succeed.' (p. 143)
7.1 Pollen analysis
'Since palynology is able to monitor general changes in climate and vegetation over long periods, it is of considerable interest to climatologists, ecologists, botanists and geographers as well as to archaeologists. Samples of pollen taken from cores bored from deep peat bogs or lake sediments are stratified, with the earliest part lying deepest. A deposit that has formed over thousands of years should reflect overall changes from tundra to forest or from forest to farmland, and indicate fluctuations in the prominence of individual plant species.' (p. 144)
7.2 Tree rings
'Besides their value for dating, tree-rings provide a continuous annual record of climate. The correlation between modern meteorological records of temperature and precipitation and the width of individual rings seems sufficiently close to allow them to be used to make estimates of conditions in the past before such records began, but caution is still advised. At the opposite end of the scale, the pattern of tree-rings in an individual trunk is influenced by the location of the tree.' (p. 146)

8 ANIMAL REMAINS

8.1 Animal bones; 8.2 Fish bones; 8.3 Shells; Go back to chapter heading
8.1 Animal bones
'The principal task of a zoologist confronted with a collection of ancient bones is to identify the species that are represented. ... Another important task is to estimate the number of animals involved. ... The approximate ages of individual animals may be ascertained by examining the state of ossification of particular bone structures, the eruption of teeth in jaw bones, and the amount of wear on teeth. Sex is more difficult to establish, but statistical studies of large samples of bone sizes may help to divide them into groups...' (p. 146-7)
Interpretation
'The most important aspect of the study of bones is that the nature of an excavated context must always be looked at very closely. Bones found on sites reflect living populations of hunted or domesticated animals in different ways, and a sample recovered from an excavation may not be representative of the whole site. ... Studies of DNA recovered from animal bones offer great potential for confirming difficult identifications of species or sex, and for studying the processes of domestication by examine the genetic links between wild and domesticated animals.' (p. 147-9)
8.2 Fish bones
'Sieving and flotation techniques have improved the recovery of bones from small mammals, birds, reptiles, amphibians and fish. Unlike all the others, fish bones appear on archaeological sites on dry land as a direct result of human activity.' (p. 150)
8.3 Shells
'Some were brought to settlements from the sea shore and discarded after their contents had been eaten, and are informative about diet and the exploitation of marine resources. Others belonged to land molluscs that lived on the site; many of these are extremely small and can only be separated from samples of soil under laboratory conditions, but they provide valuable insights into the local environment.' (p. 150)

9 HUMAN REMAINS

9.1 Genetics; 9.2 The study of coprolites; Go back to chapter heading
'Evidence for early prehistoric people is very fragmentary, especially the fossil bones from the geological deposits in East Africa that are so important for tracing the emergence of modern species. ... Where soil conditions allow, burials allow complete skeletons to be recovered for study, and this offers the possibility of establishing the cause of death, which demands the expertise of a pathologist. The study of well-preserved bodies is like an excavation itself, involving X-ray examination, dissection, and the study of all the materials encountered, whether fibres of clothing, skin tissues, or food remains.' (p. 152)
9.1 Genetics
'Work is progressing rapidly on the recovery of DNA and blood proteins from bones or (when preserved) other body tissues. At a basic level, DNA indicates the sex of a deceased individual - not always possible from skeletal remains. It also offers the possibility of studying whether bodies found in a cemetery come from related family groups. Like existing studies of blood groups, this information might prove useful on a broader scale in charting ethnic continuity or change over periods when artefacts seem to indicate the arrival of external influences.' (p. 154)
9.2 The study of coprolites
'...arid conditions ensure the preservation of fibrous matter that has passed through the human digestive system, including fragments of bone, skin, scales, hair, feathers and meat, as well as pieces of insects, parasites and their eggs. Plant fibres and seeds are also found, together with microscopic pollen and 'plant opals' (distinctively shaped silica crystals formed by some plants). Even soft tissues from plants and animals can be extracted and identified by careful processing and sieving of re-hydrated coprolites.' (p. 154)

10 STATISTICS

10.1 Computers; Go back to chapter heading
'Simple statistics are useful for checking almost any statements that involve comparisons, such as claims that the dimensions of a type of artefact change over time, or that settlement sites of a particular period tend to occupy one particular kind of soil. ... An awareness of probability and correlation also leads to a better understanding of sampling. ... Scientific analyses carried out for purposes such as the characterisation of obsidian or clay produce bewildering columns of figures that can only be clarified by means of statistical methods.' (p. 155)
10.1 Computers
'Besides their involvement in statistics, laboratory science and cartography, the principal function of computers in archaeology is to record, store and retrieve large quantities of information, such as excavation records or museum archives; this is a question of management rather than science. ... However, geographical information systems (GIS) are a rather more scientific application of computing that combines maps, environmental and archaeological data with statistical calculations to produce graphic visualisations of relationships between these categories of information. GIS promises to provide major advances in the analysis and interpretation of ancient landscapes.' (p. 156)

11 EXPERIMENTAL ARCHAEOLOGY

11.1 Artefacts; 11.2 Sites and structures; Go back to chapter heading
'One welcome by-product of a scientific approach to archaeology has been the increasingly frequent use of practical experiments to test hypotheses. ... The strict definition of an experiment employed in the scientific world is rarely fulfilled in an archaeological context, for many factors are difficult to control or measure, let alone replicate on another occasion. Even when they are demonstrations or simulations rather than true experiments, they may still produce valuable information.' (p. 156)
11.1 Artefacts
'Experimental archaeology is a useful companion to scientific analysis in the study of artefacts, for their composition and structure may suggest methods of manufacture. ... Besides experiments concerning manufacture, the functions and efficiency of tools have also been examined. Again, scientific analyses may provide relevant information, and experiments are frequently carried out in association with microscopic use-wear analysis.' (p. 156)
11.2 Sites and structures
'Large-scale structures such as ships, buildings or earthworks may also be subjected to experiments and simulation studies, normally by means of reconstructions based on evidence derived from excavations. ... The chief advantage of simulation studies is that they demand a much closer analysis of excavated traces than might otherwise be carried out.' (p. 157)

12 CONCLUSION

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'Archaeologists and historians ignore scientific evidence at their peril if they wish to understand the chronological framework of the past, or the material resources available to ancient societies, and the natural environments where they lived. The development of new techniques, and the inevitable errors that they will contain at the outset, provides an opportunity for interaction between science and archaeology when disagreements arise, for both must re-examine their own particular forms of data and analysis.' (p. 158)
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