The foundation for paleoenvironmental studies in archaeology was laid in the early nineteenth century by European geologists such as James Hutton, Ignaz Venetz, A. Bernhardi, Jean de Charpentier, and Louis Agassiz, who convinced the Western world of the evidence for massive glacial movement brought on by striking climatic changes in the past. By the 1860s the concept of a Pleistocene Ice Age was generally accepted, and other types of environmental evidence began to fall into place. Enigmatic fossil remains of cold-loving animals found in temperate climates were suddenly explainable by this new idea. Pollen analysis, first used to identify pollen grains, which could be used as temporal stratigraphic indicators, later became a powerful tool for reconstructing vegetational history in the light of climatic fluctuations, as well as for delineating the climatic changes themselves.
In 1863 T. F. Jamieson, also a geologist, suggested that even semiarid regions had experienced Pleistocene climatic change, and that those areas had once enjoyed climates that were markedly cooler and wetter than existing ones. Paleolimnologists working in the Near East and North Africa began to identify evidence for now extinct pluvial lakes in regions that are today desertic or semiarid. At this time a French archaeologist, Louis Lartet, recognized that the Lisan sediments surrounding the Dead Sea were in fact the remnants of a very much enlarged Pleistocene lake.
The archaeological community of the time soon acquired an awareness of the importance of environmental contexts. Pioneering researchers such as the Danish archaeologist J. J. A. Worsaae maintained In 1840 that environmental information was essential for understanding archaeological finds. In the 1920s and 1930s, these ideas were brought to Near Eastern archaeology and implemented in studies such as those conducted by Dorothy A. E. Garrod and Dorothea M. A. Bate for understanding the prehistory and animal exploitation at the Carmel cave sites in western Palestine, and Gertru de Caton-Thomson and E. Gardiner in studies of the prehistory and environment of the Egyptian Faiyum.
Concepts and Goals.
A major goal of paleoenvironmental reconstruction is to understand the social, economic, and spatial relationships between past human groups and the environment. This includes such lines of research as spatial patterns of settlement over a given landscape; ancient subsistence practices; human impact on the landscape; and the influence of climatic change on cultural systems. To achieve this end, techniques have been borrowed from the biological and earth sciences and adapted to address these and other archaeological questions.
In his book Archaeology as Human Ecology (1982), Karl W. Butzer outlined five important concepts and methods for approaching paleoenvironmental studies: space, scale, complexity, interaction, and state of equilibrium. The concern with space and spatial distribution applies to landforms and biological communities, as well as to human settlements. The spatial patterning of these three groups is often interrelated and provides insight into the interaction among them.
Paleoenvironmental studies in archaeology are carried out in the framework of three scales of research: macroscale, mesoscale, and microscale. These refer to the physical size of the land area being investigated, the extent of a given biotic zone, the size of a human community, and the magnitude of temporal units. In physical terms, the macroscale refers to major regions with distinctive life zones, or biomes, such as the eastern Mediterranean area or North Africa. Temporally, it can range from about 10,000 to 100,000 years.
The mesoscale is a much smaller unit of space, usually within the vicinity, or catchment, of an archaeological site. It may encompass a variety of different landforms—hills, valleys, dunes, lakes, and streams—each with distinctive groups of biota. Temporal changes at this scale could take place at a magnitude of about 100–10,000 years.
The microscale of investigation includes the site itself, the patterning of residences, and the location of activity areas. Temporally, it is concerned with periods of fewer than one hundred years. Although the three scales of investigation are interrelated, they all impart different information about environmental variability and the interaction between environments and past sociocultural and economic systems. Human perceptions of their natural surroundings also vary with respect to scale, and these perceptions govern the interaction between human groups and their natural milieu.
The concept of interaction refers to the interactive relationships of human communities with each other and their natural environment at varying scales and rates. The relationship between people and their environment is not a deterministic one—with climate, landscape, and biotic communities shaping human responses—or the opposite—with human groups completely manipulating their surroundings. Environmental changes can be viewed as positive or negative stimuli to a human system. The response to this stimuli will differ according to internal factors such as technological level, social organization, and cultural perception of the change.
The complexity factor maintains that environments and human communities are heterogeneous, and that researchers should therefore structure their investigations to account for spatial and temporal variability at different scales of analysis. Finally, the equilibrium state refers to the stability of a given system, either cultural, or environmental, and its vulnerability to changes of differing magnitudes created by stress from outside factors.
Methods of Reconstruction.
In reconstructing ancient landscapes and environments, methods have been borrowed from the earth sciences, botany, and zoology. Although the methods resemble those used in the natural sciences, objectives and research questions differ because they are related to archaeological goals and concerns. This has given rise to three basic environmentally oriented subdisciplines in archaeology: geoarchaeology, paleoethnobotany, and archaeozoology. Often, the goals and techniques of these three areas of research overlap.
Some of the major goals of geoarchaeology include reconstructing past climates and interpreting their role in a region's archaeological developments; reconstructing ancient landforms in the vicinity of a site (marshes, springs, floodplains, and streams), including their availability as resources or liabilities and their use in aiding site surveys; assisting in site surveys using methods of geophysical prospecting; identifying the sources of a site's mineral resources; determining the factors that formed an archaeological site; and analyzing areas of diverse activities within a site by chemical tests and microartifact analyses.
One of the cornerstones of paleoenvironmental reconstruction in geoarchaeology is the concept that weathering, transportation, and sediment deposition are controlled by environmental conditions. This life history of sediments is revealed by some of the characteristics of the deposit. Therefore, in describing the color, composition, grain-size distribution, shape, angularity, bedding form, and postdepositional changes of deposits, the geoarchaeologist can find substantial clues for reconstructing ancient land forms and the nature of past environments.
Identifying ancient landforms (abandoned stream or beach terraces, playa lakes, and ancient marshy areas) can aid in locating sites in a site survey, as well as in assessing an area's past agricultural, mineral, and water resource potential. Geophysical prospecting for archaeological sites is conducted by magnetometry, electrical resistivity, and ground-penetrating radar. The appropriate geophysical technique depends on the type of site being investigated, the kind of finds expected (e.g., brick walls, stone walls, or pits), and the nature of the sediment matrix.
Mineral resources at a site include building stone, clay used in ceramic manufacture, metal ores, obsidian and flint for tool production, metals, and precious or semiprecious stones for jewelry and utensils. Locating the sources of this material involves identifying distinctive minerals through heavy mineral, petrographic, and neutron activation analyses and having knowledge of the character of local and regional sources.
On the archaeological site the geoarchaeologist helps to identify the processes of stratigraphic development, factors of site disturbance, and the interface between natural and cultural sediments at the boundary of the archaeological deposits. He or she is concerned with reconstructing the site's formation history and the amount of postdepositional disturbance to artifacts.
The geoarchaeologist may also participate in delineating activity areas. Two procedures used are microartifact and chemical analyses. In microartifact studies, the researcher examines the artifacts, which range in size from about 3 cm down to 0.250 mm. These remains on and in a living surface, too small to be removed or swept away, would have been trampled into the floor or occupation surface. Microartifacts such as sherds, flint chips, charcoal, bone, eggshell, and beads provide a record of activities throughout the life of the living surface. This is one of the only archaeological techniques that allows direct comparisons of percentages of different artifact types.
Chemical analyses of living surfaces include determining pH and phosphate content of the sediments, with a low pH (indicating acid sediment) and high phosphate value indicative of high concentrations of decaying organic matter. These analyses can aid in identifying animal pens and stables. Along the same line of research is soil micromorphology, in which a small unit of sediment from an archaeological site is solidified and thin sections are taken for microscopic examination. This allows the researcher to examine the relationships between site formation and natural soil processes at a microscopic scale.
The techniques of paleoethnobotany vary with the kinds of research objectives. Some of the aims of paleoethnobotany are paleoenvironmental reconstruction, both at the macroscale of regional vegetation and at the mesoscale of local site environs; investigating ancient plant use for subsistence, fuel, building materials, medicines, and ritual practices; analyzing farming practices; determining the seasonality of site occupation; and understanding the interaction between ancient peoples and their environment. Two techniques commonly applied to the problem of paleoenvironmental reconstruction at the macro- and mesoscales of investigation are palynology and phytolith analysis.
Palynology is the study of pollen grains originating in flowering plants and dispersed primarily through the air. The microscopic (silt sized) pollen is identified according to the size, shape, and surface features of individual grains—which are distinctive to family, often to genus, and sometimes to plant species. At the macroscale of research, pollen samples are usually extracted from water-logged sediments in bog and lake cores and are used to reconstruct regional vegetation and general environmental conditions. This is accomplished by comparing suites of species from the past with modern ones and by identifying “indicator species” that point to a specific ecological situation.
One of the problems facing palynological studies of this kind includes the differential output of pollen by different types of vegetation. This precludes a simple comparison of pollen frequencies without taking into account the amount of pollen produced by each type of plant. Pollen sequences are dated by radiocarbon dates taken from pollen cores. This dating is sometimes problematic because the dated units are often meters apart and changing sedimentation rates can hinder the extrapolation of dates throughout the core. Although a large number of trees and shrubs are identifiable by pollen type, the pollen of grasses is usually indistinguishable.
Identifying grass families and other types of monocotyledons (rushes, sedges, and palms) can be accomplished by another microbotanical technique: phytolith analysis. Phytoliths are microscopic mineralized bodies, usually composed of amorphous silica (opal), that form within the epidermal tissue of living plants. They generally take on the shape of the plant epidermal cells and are seen as microfossils of individual cells or sections of epidermal tissue encompassing from two to hundreds of joined cells. Phytoliths are commonly identifiable to plant family and often to plant genus. Occasional identifications can be made at the species level. As basic research in this field progresses, the range of identifiable plants is rapidly increasing. Phytoliths are initially deposited in the location at which the host plant disintegrated and are generally not dispersed through the air, as is pollen. They are washed into lake sediments by streams in the vicinity.
The combination of pollen and phytolith analyses affords a more exacting method for reconstructing regional vegetation patterns at the macroscale, as well as local plant communities at the mesoscale. The analysis of charred woods from an archaeological site can also offer information about local plant communities, but caution is needed in interpreting this information because humans can transport woods from other ecological zones.
At the microscale of analysis, or site level, the most traditional paleobotanical technique is analyzing macrobotanical remains, usually charred seeds, wood, and sometimes fruit and nuts. The most useful method of retrieving this material is by a system of flotation whereby sediment is mixed with water or a chemical solution. The charred material floats to the top and is removed using a fine-mesh sieve. Macrobotanical remains give information about the types of plants used for subsistence, fuel, building materials, medicines, and ritual pursuits. They are also informative about farming practices, cropping strategies, and the seasonality of site occupation. On a more detailed level of significance, they contribute to what is known about the timing and location of the first cereal domestication.
Phytolith analysis is also an advantageous technique at this level of investigation. Phytoliths are resistant to decay and are commonly preserved where macrobotanical remains are not. Phytoliths have distinctive shapes in different parts of a given plant, which allows differentiation between its stem and its flower. They can therefore aid in identifying activity areas by distinguishing, for example, the remnants of straw, or reed mats, from the remains of cereal glumes. One drawback to this technique is the as yet relatively small corpus of plants with known identifiable forms; however, the list of plant types identifiable by their phytoliths is growing. To date, there are cereals (including maize, wheat, and barley), weed grasses, reeds, sedges, and palms that can be identified at the family and genus level with this technique. Phytoliths are usually extracted from sediment taken from the archaeological site and processed by a researcher specializing in this technique.
Some of the concerns of zooarchaeology, faunal studies of bones from archaeological deposits, include paleoenvironments at the macroscale, as well as the mesoscale, in the vicinity of a site; the season of site occupation; nutritional studies of protein intake from meat; hunting strategies, such as the types and sizes of animals hunted, and the energy expended in the hunt; animal domestication; pastoral strategies of animal species mixtures and patterns of transhumance; the use of secondary products such as milk, wool, and draft power; and how animals were raised for domestic use or market sale.
The most reliable method of bone collection at archaeological sites is the systematic sieving of most archaeological excavation units. This provides the faunal analyst with a large and mostly unbiased sample usable for statistical analyses. Because bones and botanical remains are not independently assignable to a specific period or archaeological level, much care must be taken to record proveniences and note the temporal homogeneity of the archaeological unit. If there are intrusive artifacts, there can also be intrusive bones and botanical remains.
With these considerations in mind, faunal analysts can reconstruct environments in a site's vicinity by the types of wild species present—and sometimes by the size of the species. Seasonality of site occupation is determined by fauna that is only present in the region during specific months in the year (e.g., migratory birds) or by the characteristics of the fauna that change with the seasons (antler growth or juvenile tooth development). Faunal analysts can also approximate the amount of meat consumed by weighing bones because there is a correlation between bone weight and meat. They can also identify butchery practices by the patterns of cut marks on the bones.
Animal husbandry and domestication are recognized by such features as a decrease in species size, signs of draft labor, wear marks from bits, and cultural factors (e.g., the deliberate burial of whole animals and calcium depletion in the bones from milking). The use of secondary products such as milk and wool and the raising of animals for domestic use or market sale are determined by the age profiles of a population of animals at the time of slaughter.
In reconstructing climates and paleoenvironments at the macroscale of research, each of the three approaches discussed above investigates different and independent data sets that are all environmental responses to climatic factors. In any reconstruction of climatic conditions, it is necessary to compare scenarios from several varied forms of information. Often, these data sets appear to have contradictory facts that, in essence, can be related to inconsistencies in dating the environmental indices. This can sometimes be reconciled by comparing patterns of trends indicating vacillations to wet or dry and cool or warm conditions that are similar to the trends specified by different methodologies.
In applying information about environmental and climatic change to explanations of human responses, it is essential to account for cultural, technological, economic, and settlement variability. All of these factors control the reaction of human groups to their environment, whether stable or changing. This is also true of the impact of the human group on its surroundings. Broadly speaking, hunter-gatherers, pastoralists, subsistence farmers, and cash-crop farmers will respond in different ways to an environmental stimulus such as drought. They will also impact their environments in different manners.
On the meso- and microscale of research, results from landscape reconstructions, combined with analyses of biological and mineral remains from an archaeological site, can assist in delineating site catchment areas or spheres of resource exploitation in the site vicinity. These types of studies are most successful when combined with other factors that influence settlement in a given region: political connections, cultic considerations, and access to resources through longdistance trade. The combination of paleoenvironmental reconstruction with settlement-pattern and catchment analyses provide a powerful body of information that can significantly contribute to our understanding of many aspects of political, social, and economic organizations.
- Butzer, Karl W. Environment and Archaeology: An Ecological Approach to Prehistory. 2d ed. Chicago, 1971. Essential introduction to environmental archaeology, outlining techniques and their applications to such significant processes as human evolution and the origins of agriculture.
- Butzer, Karl W. Archaeology as Human Ecology: Method and Theory for a Contextual Approach. Cambridge, 1982. Theoretical framework for integrating environmental studies with archaeological concerns, with a good introduction to geoarchaeology, archaeobotany, and zooarchaeology.
- Davis, Simon J. M. The Archaeology of Animals. New Haven, 1987. Good introduction to the techniques and concerns of zooarchaeology.
- Dincauze, Dena. “Strategies for Paleoenvironmental Reconstruction in Archaeology.” Advances in Archaeological Method and Theory 11 (1987): 255–336. Integrated approach to environmental studies in archaeology.
- Evans, John G. An Introduction to Environmental Archaeology. Ithaca, N.Y., 1978. Primarily concerned with technical methods.
- Hesse, Brian, and Paula Wapnish. Animal Bone Archaeology: From Objectives to Analysis. Washington, D.C., 1985. Good basic source on zooarchaeological techniques and applications to archaeological problems.
- Pearsall, Deborah M. Paleoethnobotany: A Handbook of Procedures. San Diego, 1989. Thorough survey of field and laboratory techniques, including pollen, phytoliths, and macrobotanical analyses.
- Piperno, Dolores R. Phytolith Analysis: An Archaeological and Geological Perspective. San Diego, 1988. Introduction to phytolith analysis and its broad applications.
- Roberts, Neil. The Holocene: An Environmental History. Oxford and New York, 1989. General survey of techniques for environmental reconstruction and an outline of environmental history for the last ten thousand years.
- Roper, Donna C. “The Method and Theory of Site Catchment Analysis: A Review.” Advances in Archaeological Method and Theory 2 (1979): 119–140. Introduction to site-catchment analysis and critical review of previous studies.
- Rosen, Arlene Miller. Cities of Clay: The Geoarchaeology of Tells. Chicago, 1986. Study of tell formation in a cultural, geomorphological, and environmental context.
- Schiffer, Michael B. Formation Processes of the Archaeological Record. Albuquerque, 1987. Detailed study of the factors responsible for the placement of artifacts and the formation and erosion of archaeological sites.
- Stein, Julie K., and William R. Farrand, eds. Archaeological Sediments in Context. Orono, Maine, 1985. Collection of articles on geoarchaeology covering a broad range of site contexts.
Arlene Miller Rosen