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Soil micromorphology in archaeology
Soil micromorphology in archaeology Richard I. Macphail, Marie-Agnks Courty, and Paul Goldberg Soil micromorphology has been a recognized technique in soil science for some 50 years and experience from pedogenic and palaeosol studies first permitted its use in the investigation of archaeologically buried soils. More recently, the science has expanded to encompass the characterisation of all archeological soils and sediments and has been successful in providing unique cultural and palaeoenvironmental information from a whole range of archaeological sites.
Soil micromorphology is the microscopic study of soils and soil-like materials, such as loose sediments. It is quite similar to petrography in the geological sciences, which employs thin sections and the polarizing microscope. The technique has been used in geology since the last century, and exploited in soil science for over 50 years. It was first applied to archaeology in the 1950sand 1960s but it is only during the last 10 to 15 years that a small number of workers [l] achieved results with far greater resolution than those arrived at from the application of standard archaeological and sedimentological approaches (for example phosphate, grain size, and mineralogical analyses) to investigations of ancient soils and sediments. This success has led to a sudden increase in the importance of soil micromorphology in archeology that has yet to be fully appreciated by universities and the academic services which provide scientific support for archaeological research. In this article the methodological and philosophical approach will be explained, followed by some examRichard
I. Macphail
BSc.,
MSc.,
Ph.D.
Has been research fellow in the Institute of Archaeology, University College London, since 1979. His research interests include ancient clearance and agriculture and their effects on soil landscapes. Marie-Agnes
Courty,
Doctorat
d’etat
After graduating in geology has engaged in research for the CNRS in Europe, North Africa, the Near East, and Central Asia. Her interests include experimental archaeology as applied to ancient agriculture and the formation of sediments produced by human and animal occupation. Paul Goldberg, B.A., M.Sc., Ph.D. Based at the Institute of Archaeology, Hebrew University of Jerusalem he has had world wide experience in studying geological aspects of archaeology. His research interests are particularly concerned with the effects of humans and biota on soils and sediments in both cave and open-air sites.
Endeavour, New Series, Volume 14, No. 4.1990 OlW-9327I90 93.00 + 0.90. Pergamon Press pk. Printed in Great Britain.
ral, environmental, and geological settings, the present authors can now begin to demonstrate how detailed information on the cultural and environmental aspects of an archaeogical site can be uniquely ascertained by soil micromorHistorical and philosophical phology. Archaeologists and palaeoperspective environmentalists have begun to ask For many years and, unfortunately, still, sediments have been regarded by much more vigorous questions of the archaeologists solely as a medium con- soil or sedimentary medium that forms taining cultural materials (pottery, their archaeological features (layers, flints, bones etc). It is generally thought hearths, pit and ditch fills, ramparts, that the sediment itself contains little floors) and contains their artefacts information relevant to cultural or environmental (zooarchaeological, archaeology, and only after extraction geoarchaeological, and archaeobotanicof the cultural material may a pedolog- al) indicator materials (for example ist or sedimentologist be requested to grain-size fractions, minerals, soil and carry out some standard analyses to sediment fragments, diatoms, pollen, characterize the sediment generally. If a molluscs, bones, seeds, charcoal). Through soil micromorphology it is buried soil is recognized, this stratum would be regarded as of little interest now possible to recognize, for example, and termed ‘sterile’ or ‘natural’ by the various types of habitation floors, animarchaeologist because it contains no al stabling layers, ash dumps, wild artefacts, and a soil scientist would be animal and bird occupation phases, expected only to attempt to classify the periglacial periods, arid epochs and soil type. Hence on many occasions irrigation, snow-covered boreal landneither the archaeologist nor associated scapes, woodland clearances, and agrisoil scientist or geologist, have been cultural impacts as recorded in soils and fully aware of the amount of detailed sediments. information that can be obtained from the soil or sedimentary makeup of a Methods site. For this reason inappropriate tech- The study of undisturbed soils in thin niques have often been applied. For section was commenced by W. L. example, grain-size analysis is a popular Kubiena [2]. In the 1950sIan Cornwall technique, but when applied to dumped of the Institute of Archaeology (now cutural material it will merely confirm part of University College London) that the deposit is unsorted, whereas made the first applications of the technigrass ash middens would be regarded as que to archaeology [3]. His aim was to silt-rich deposits, but only because they improve the understanding of past eninclude abundant silt-size phytoliths vironments, and this initiated the study (plant opal). Even in natural sediments, of human-related (anthropogenic) desuch as colluvium and alluvium, high posits, a field of investigation not again clay contents may not relate to low taken up until the 1970s [4]. energy deposition, but to the breakThin sections are usually prepared by down during sample preparation, of sampling an undisturbed, oriented transported soil clasts (redeposited block of soil or sediment [ 11,drying it in eroded soil fragments; see figure l), the laboratory for several days at which are common in Quaternary sedi- around 60°C and then impregnating it under vacuum with resin (epoxy or ments. Due to the inadequacies of such tech- polyester) [5]. The hardened block is niques, it was necessary to develop a sliced with a rock saw, and after smoonew approach to the study of archaeolo- thing is mounted on a glass slide and gical soils and sediments. After more ground down, to 20-30 pm, using a light than a decade of tackling archaeological lubricating oil. Over the last 20 years problems from sites of different cultu- important advances have been achieved ples of how, through soil micromorphology, debates on cultural and environmental aspects of archaeological sites have been advanced.
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Figure 1 The Middle Pleistocene cave of Westbury-sub-Mendip, Somerset, England: Unit 14, Grey Silty Breccia made up of sub-rounded yellowish phosphatised (highly fluorescent) cave soil fragments containing pieces of very strongly leached bone (centres of right and top soil fragments), reddish silt coatings, dark reddish iron stains and a cementing matrix of mosaic sparitic calcite. Original cave sediment formed through freezing and thawing causing the fracturing of limestone cave wall material (not illustrated) and its mixing with cave sediments and soils transported from outside. Partially digested bone fragments of small mammals rejected as pellets by predatory birds (eg. owls) became mixed with cave soil that was affected by phosphate-rich bird excrement. The formerly red cave soil eventually became iron depleted and phosphatized. Further freeze/thaw activity broke up the cave earth into rounded fragments, whereas later meltwater washed red silts into this layer, coating them. Eventually, the whole layer became cemented by secondary calcium carbonate. PPL, frame length is 3.35 mm.
in the preparation of thin sections. With the use of more efficient resins and specially designed machines, thin sections can now be as large 13 x 6 cm in size. This large format may be compared with the geological and ceramic thin-section size of 2.2 x 4 cm, which has limited value for studying such large-scale features as structure, archaeological layers, and the coarse microfabric heterogeneity that is typical of archeological sediments (figure 2). Similar advances have been made in the objective description and interpretation of thin sections. ‘Anthropogenic’ microfeatures and materials can now be successfully characterized using internationally recognised terminology [6]. Strategies in field sampling and analogue studies In field sampling the soil micromorphologist aims to obtain undisturbed soil/ sediment blocks from enough contexts to be representative of the site as a
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whole. The new large-format thin sections help this enormously. For example, a single column of undisturbed samples from one profile of the 28 cm thick buried Neolithic soil at Maiden Castle (Dorset, England) permitted 135 sq. ems to be examined, and at this site sequences and buried soils are often studied from a series of localities across a site. The main strategy for sample selection is to ensure that all features of interest are sampled, together with sufficient local ‘reference’ materials. The latter may include on-site and off-site soil profiles, local sediments that may have been imported on to the site, and examples of probable floors, ash layers, hearths, daub, ditch-fills, coprolites (figure 3), etc., that may help in the final interpretation of the site and its surroundings. Particular site problems may require experimentation. has The study of ancient cultivation been advanced by soil micromorphological experiments in ‘ancient’ agriculture at both modern soil experimental
plots (for example, Dept des Sols, Institut National Agronomique, Grignon, France), and at the ‘ancient’ farms of Butser Hill (Iron Age farm reconstruction, Hampshire, England) and Hambather Forst (Neolithic agricultural simulation, Elsdorf, Germany). These experiments, together with studies of inferred ancient cultivated soils (such as ploughmarks) and the wealth of soil science literature on soil micromorphology of modern agricultural soils [7, 8, 91, has allowed attempts the effects of ancient
to characterize
agriculture on a number of soil types [lo] (figures 4 and 5). The characterization of occupation features is being similarly aided by studies of such modern analogues as Bedouin
camps
and ‘prehistoric’
hearths,
buildings, and floors reconstructed by enthusiasts. Enigmatic ash layers from Mediterranean caves could be properly investigated only after a whole range of fresh and burned excrements from herbivores were characterized.
Figure 2 The cave of Arene Candide, Liguria, Italy: Early Middle Neolithic burned stable layers; (a) layer of ashed cow coprolites (i), comprising fine calcium carbonate and calcium oxalate crystals produced by the burning of dung of cattle foddered on a diet of branches and attached leaves; (b) cattle bedding and trampled fodder remains of twigs and branches, that stayed brown after combustion because they were probably stained with cattle urine; (c) partially compacted combusted ashed coprolite layer, containing wood charcoal (ii) and sheep/goat coprolite fragments (iii) that are yellowish because they retain charred undigested lignified remains typical of their diet of bark and other woody material. Plane polarized light (PPL), scale 0.5 cm.
Figure 3 Viking period human coprolite from York (human parasite egg analysis by Andrew Jones); legume (e.g. bean) testa, possible legume cells and phytolith lengths cemented in a phosphatic (highly fluorescent under ultra violent light illumination) matrix that contains bone fragments, indicate an omnivorous diet of meat and vegetables. PPL, frame length is 0.33 mm.
ity, will affect an unweathered sediment or an occupation floor, for example. Experience from soil science and One of the problems of studying buried palaeosol soil micromorphological stu- soils is that if they are not totally sealed, dies has shown that microfeatures have post-burial earthworm activity or roota temporal hierarchy: that is, the most ing can be seen to rework soil and recent features affect earlier ones. Thus anthropogenically formed fabrics dating a pedological process or processes to when the soil was buried. Anaerobassociated with human or animal activ- ism may also convert organic remains Observational interpretation
procedures
and
into iron and manganese pseudomorphs, or aquatic inundation may through iron and clay depletion - remove all evidence of earlier soil fabrics. All these processes make difficult the simple aims, on any archaeological site, which are to clarify what the site was like before occupation, how it was affected by human activity, and what happened afterwards on abandonment or burial. These interpretive problems can neither be overcome by examining the soil or sediment at a single scale, nor under a single lighting medium; rather, observations have to be carried out under a variety of lighting types and at all scales. Thus although photographs can illustrate a point they present only one aspect of a soil microfabric at one specific magnification or scale.
Figure 4 Beaker period ard-cultivated colluvium at Ashcombe Bottom, Sussex, England: tillage has caused the weakly structured silty loam soil to slake when water saturated, and separate into its components of silt and reddish clay; trapped air probably formed the vesicle or round soil void (bottom centre), typical of such a process, and as found in modern irrigated soils, for example. PPL, frame length is 3.35 mm.
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Figure 5 Ashcombe Bottom: dense silt loam cultivation colluvium, with parallelsided, straight-edged planar voids (shear planes) probably produced by tillage implement lard) impact. PPL, frame length is 5.56 mm.
Figure 6 Arene Candide: Early Middle Neolithic burned sheep/goat stabling layer contains fragments of interwoven non-cellular fibres. These are considered to be ashed pieces of knitted woolen textile. Note on combustion, organic remains are reduced by some 90 per cent. PPL, frame length is 0.33 mm.
Figure 7 Arene Candide: Early Middle Neolithic occupation layer, comprising a made floor of densely laminated fine charcoal and ash-rich mud, upon which probable straw mats, as indicated by the very long phytoliths, were layed. Phytoliths are very resistant silica (opal) strengthening of plant materials such as straw, and their in tact presence on well preserved floor layers suggests that this occupation horizon has been little disturbed. PPL, frame length is 5.56 mm.
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the end of the last century. The ashed organic fodder remains and coprolites also provided evidence of seasonality, as independently inferred from the animal bone data [14]. After every period of stabling it seems that the manure layers were burned, probably for cleaning. On each successive stabling episode the underlying ashed material was tramped and compressed, whereas the new stabling material and fodder also became tramped and probably soaked in cattle urine. Hence on burning, the bottom layers were only partially combusted and remain now as thin brown layers that separate the more totally ashed material. The underlying ash was also compacted. The evidence indicates an Early Middle Neolithic pastoral system involving the stabling of large numbers of herbivores for short episodes and their foddering on shredded tree material. DurFigure 8 As figure 6, but under crossed polarized light (XPL), showing the ing the Late Early Neolithic, there was laminated nature of the compacted floor and the presence of bright birefringent local and probably continuous grazing calcium carbonate ash; the phytoliths, that are the remains of probable mats, are of only a few cattle and sheep/goats. typically non-birefringent. These findings from Arene Candide are of major significance in studies of prehistoric pastoralism. Until now the only certain indication of pastoral activity has been the presence of animal In the laboratory, the resin impre- formation and function can be illus- bones, whereas studies of pollen and gnated blocks and large thin sections trated from the ways information re- land molluscs have only been able to are first viewed without magnification, lates to local, micro-environmental, and provide indicators of grassland and pastures. Moreover, the identification of for it is essential that there is no obser- regional scales. vational gap between the field and the ashed fragments of probable knitted microscale. Possible layers seen in the Local scale woollen textile (figure 6), is a unique One of the most important contribufield can be confirmed in the hand-held discovery of cultural material by soil thin section, and these layers can then tions soil micromorphologists can make micromorphology. be studied using the polarizing micro- to a site is the correct appraisal of how Armed with such findings, Neolithic scope at higher and higher magnifica- layers formed, because this affects not cultural material at Arene Candide can be reassessedon the basis that the site is tions (X5, X10, X50, X100, X200, only the taphonomy (post-depositional x400), perhaps using some of the block weathering, movement etc.) of all the now definitely identified as a stabling or unimpregnated undisturbed material environmental and cultural material site in a pastoral economy. Further, the for examination by scanning electron present, but can also provide most use- cultural material may reflect changes microscopy (SEM) (x2000). Some in- ful clues on the cultural history of a site. that occurred in this economy during terpretive problems can occur if field At the coastal cave of Arene Candide, the Late Early and Early Middle samples are studied immediately at the Finale, Liguria, Italy [ll], some of the .Neolithic periods. The functions of indiNeolithic cultural materials and associ- vidual areas (and layers) as stables, micron scale, because the relationship of materials can be best observed if ated domestic animal bones occur in 2.5 living space (figures 7 and 8), passagestudied at a whole range of scales (see metre-thick whitish sediments spanning ways, temporally abandoned ground, approximately 1000 radiocarbon years etc. - as reflected by their microfabrics figures 2, 6, 7 and 8). Using the optical microscope, thin sections are examined (cu 4th to 5th millennia BC). The Early also allows more accurate appraisal of under plane polarized light (PPL), cros- Middle Neolithic sediments, however, other analytical data from charcoal, bone, and phytolith analyses now being sed polarized light (XPL), oblique inci- contrast with the Late Early Neolithic dent light (OIL) and ultra violet light deposits by being thicker and more interpreted. (UV), permitting a whole range of whitish generally, except for the regular scale optical tests; the last especially for iden- presence of thin brown layers (see Micro-environmental tifying organic materials and phosphate figure 2). This deposit comprises ash At open-air archaeological sites the old and charred organic remains [12, 131. ground surface or occupation surface minerals. Thin sections are described in detail The ash material consists of densely may often be preserved by a monument packed cubic calcite crystals which form such as a barrow, or occur beneath following the guidelines and terminology of P. Bullock et al. [6], although pseudomorphic fabrics of twigs and colluvium or alluvium. The soil microsome materials - such as ash and herbi- branches and loosely packed burnt cal- morphological study of such surfaces vore, carnivore, and omnivore excre- cium oxalate crystals, the remains of can make possible the identification of ments (see figure 3) or mortar and mud cornbusted fresh leaves. Ashed herbi- lateral and vertical features of interest vore coprolites are also’abundant, parti- across a site: for example, features inbrick, for instance - were previously unstudied phenomena in soil science cularly those of cattle and sheep/goats dicating woodland clearance, cultivathat have been characterized by the fed primarily on a diet of cut branches, tion and human occupation (hearths, as opposed to grass. Such systems of floors, daub from mud-hut walls, midauthors [ 11. Results from the application of soil tree shredding for fodder were still com- dens, etc.) [l, 15, 161. Their temporal micromorphology to the study of site mon practices in the Mediterrean up to hierarchy may also be elucidated.
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unit 4b; in situ fragment of flint debitage (cetitre) from Lower Palaeolithic (Acheulian) flint reduction Figure 9 Boxgrove: layer (chipping floor), sealed in calcareous (chalky) laminated silt and clay deposited in a probable mud flat environment. XPL, frame length is 5.56 mm.
When humans occupied a site, woodland clearance often occurred. Soil micromorphological evidence of soil profiles probably disturbed by clearance activity can also be recognized in soils when particularly large field features, probably caused by human-induced tree-throw, are absent [17]. For example, the clearance of shallow rooting herbaceous plants ahead of Neolithic monument construction caused shallow soil turbation and the concentration of ash, fine charcoal, and phytoliths at the soil surface, because cleared vegetation was burned. Such instances have been recognized in Brittany, France, and in the adjacent Cornish peninsula, England. Such clearance practices could cause erosion, and in the Chalcolithic in the Western Apennines of Liguria, Italy, soil colluvium, including burned soil, was washed into shallow basins and aided peat initiation as drainage became impeded. According to the associated pollen stratigraphy, the contemporary large-scale fir forest cover began to diminish at the same time [l]. In addition, it is now possible to identify the variable effects of prehistoric cultivation at different times and on differing soil types. At the site of Hazleton, Gloucestershire, England, inferred Neolithic cultivation shifted across the
site [16]. Soil micromorphological studies of the buried soils show that areas cultivated earlier became vegetated, whereas an occupation area rich in charcoal and cultural material was later chosen for cultivation. One major finding in these studies of early cultivation is the inferred fragility of cultivated soils as a result of diminishing organic matter produced by subsistence agriculture [18]. This caused much of the soil to break down under cultivation implement impact (figure 4) fine soil being often washed down profile, a phenomenon also recorded in modern agricultural soils [7, 8, 91. Many soils were eroded, and these themselves later formed valley-bottom arable soils. For example, Beaker period ard-cultivated soils in the dry valley of Ashcombe Bottom, near Lewes, Sussex, England, seem to have microfabrics reflecting cultivation impact. Such features have been recognized from experiments in both ‘ancient’ and modern agriculture [lo]. For instance, natural coarse peds (soil structures) were broken up, allowing an open porosity to be worked by soil fauna. Finer peds were concentrated down profile, producing a compacted layer that developed shear planes probably due to ard impact (figure 5). The structural breakdown of
soils into their fine and coarse components by the effect of slaking on the Ashcombe cultivated soils has already been illustrated (figure 4). There is increasing evidence that ancient peoples recognized that lack of organic matter was an agronomic problem, and it has been inferred from included cultural materials that manuring was carried out. These additions of organic matter have been recognized in some Bronze Age, Iron Age, and Medieval soils from Europe, where acidity or waterlogging has preserved organic fine fabrics rich in phytoliths. Regional Palaeosols.
Soil micromorphology has always been a main tool in palaeosol studies [19] enabling workers to differentiate, for example, soil microfabrics produced under periglacial conditions as opposed to temperate ones. Past vegetations and water regimes have also been elucidated [20]. Under a boreal climate, coniferous forest and snow dark fulvic-acidmelt can produce stained clay coatings in the soil porosity. At the other extreme, plant and animal (bio-) turbation is greatly reduced under arid conditions, but various salts may precipitate. About 4000 years ago in north-west India, formerly arid soils
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slopes and causing soil erosion [21]. Thus soil micromorphology has proved one of the most important techniques in helping to decipher regional environmental, including climatic, changes in relation to human occupation at this site. Future prospects
Figure 10 Middle Pleistocene sediments, Boxgrove, West Sussex, England: Unit 4d; finely laminated silt and iron-replaced organic matter layers in pond-like deposits containing a probable bird bone; these deposits which also contain death assemblages of fish and amphibia, are probably contemporary with the main human activity (unit 4c) at Boxgrove (Roberts, personal communication). PPL, frame length is 5.56 mm.
high biological activity and strong resistance to wind erosion [ 11, as a result of Harappan cultivation.
developed
Caves. Until recently workers on cave sediments have tended to assume a direct link between sedimentary and post-sedimentary processesand climatic change. Our experience of the complexities of some cave sediments suggests that methodologies need first to recognize these complexities before adequate interpretations can be attempted (figure 1). Soil micromorphological studies of a number of caves in the Near East (for example, Kebara, Tabun, Hayonim), North Africa (Taforalt), France [ 11,England (Westbury-sub-Mendip) [21] and Gibraltar (Gorham’s), have shown that biogenic and anthropogenic depositional and post-depositional agents have been largely overlooked in earlier studies. Coprolites of various animals such as hyaena [22], egg-shell fragments (in the Palaeolithic levels at Arene Candide) [l], layers rich in organic matter [12], and non-descript fragments of vegetation and aggregated fabrics due to animal burrowing, all clearly indicate the influence of plants and animals. As a consequence, the inferred palaeoclimatic signal of the sediments may have been over-estimated in the past. In addition, the burrowing effects of macro and micro-fauna may’have influenced the integrity of the archaeological remains uncovered at the site, resulting in blurring of the archaeological record, and is an imposed constraint on our ability to infer past human activities and
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behaviour. The archaeological material may simply not be in the position in which it was left by former inhabitants of the site.
and directions
Soil micromorphology in archaeology can now be regarded not as a specialist technique of relevance to soil scientists alone, but one with tremendous potential for adding to our understanding of the cultural nature of an archaeological site. Great advances have also been made in improving our understanding of ancient environments and how these have been affected by human activities such as cultivation. These results are due to the fact that many physical, chemical, biological and human processes create microfeatures, which from our increasing experience, can be correctly recognized and interpreted from thin sections. This suggests that soil micromorphology is a technique capable of studying global effects because so many processescan be recorded microscopically in a soil or sediment. Moreover, the association with archaeology commonly permits the dating of past changes. It is thus strange that numbers of soil micromorphologists generally, as may be reckoned from attendances at regular international working-meetings, have not increased over the last decade. The authors would like to challenge micromorphologists in soil science by suggesting that it is in the application of soil micromorphology to archaeology that some workers are revealing the true potential of the technique over and above its understood role in soil science.
Sediments. The site of Boxgrove, West Sussex, England, is of exceptional interest. Here Middle Pleistocene fauna1 material (figures 9 and 10) is accompanied by the best preserved Lower Palaeolithic (Acheulian) flint working levels [23], possibly the finest yet excavated in the world. Soil micromorphological, sedimentological, and fauna1 evidence all indicate that human groups were Acknowledgments active towards the end of a temperate The authors wish to thank the many phase, possibly some 500000 years ago. funding agencies (including English Their occupation areas were affected Heritage, C.N.R.S., the French Ministhrough time by sea-level changes, try of Foreign Affairs, the Soprintenestuarine conditions, and by river distridenza Archeologica della Liguria, and butary migration. During an early the Natural History Museum, London) occupation, chipping floors were situ- and the long-term friendly cooperation ated on probable mud flats, and each of archaeologists and palaeosuccessive, probable tide-related, inun- environmentalists, too numerous to dation caused the micro-debitage mention by name, who make these in(figure 10) and associated butchered vestigations worthwhile. Stuart Laidlaw bone remains, to be sealed by cal- kindly provided expert photographic assistance, and Jill Cruise made useful careous silts and clays. Soil micromorphology has been essential in con- comments on the text. firming the in situ nature of this unique cultural material at this level, because higher up in the sedimentary sequence, References (11 Courty, M. A., Goldberg, P. and Maca drop in base level permitted a ripened phail, R. I. ‘Soils and Micromorphology soil to develop, and biological activity in Archaeology’, University Press, had a dramatic affect on the taphonomy Cambridge,1989, of the flint and bone. Sediments that [2] Kubiena, W. L. ‘Micropedology’, Coloccur above the occupation levels are legiate Press,Ames, Iowa, 1938. silty colluviums that may contain trans1. W. ‘Soils for the [3] Cornwall, ported soil clasts, an effect of the onset Archaeologist’, Phoenix House, London, 1958. of cold climate devegetating the local
[4] Romans, J. C. C. and Robertson, L. In ‘The Effect of Man on the Landscape: the Highland Zone’. J. G. Evans, S. Limbrey and H. Cleere (eds), pp. 37-9, CBA Research Reoort 11. 1975. [S] Murphy, C. P. Thin Section Preparation of Soils and Sediments’, A B Academic Publishers, Berkhamsted, 1986. [6] Bullock, P., Fedoroff, N., Jongerius, A., Stoops, G. and Tursina, T. ‘Handbook for Soil Thin Section Description’, Waine Research Publishers, Wolverhampton, 1985. [7] Jongerius, A. In ‘Soil Micromorphology’. P. Bullock and C. P. Murphy (eds), pp. 111-138, 1983. [8] Fedoroff, N., Bresson, L. M. and Courty, M. A. (eds) ‘Soil Micromorphology’, AFES, Plaisir, 1987. (91 Douglas, L. A. (ed.) ‘Soil Micromorphology’, Elsevier Press, Amsterdam, 1990. [lo] Macphail, R. I., Courty, M. A. and Gebhardt, A. In ‘Soils and Early Agriculture’. K. Thomas (ed.), World Archaeology, 22, 1, 53-69, 1990. [ll] Tine, S. In ‘Archeologia in Liguria’, pp.
149-156, Soprintendenza Archeologica della Liguria, Genoa, 1976. I121 Wattez. J.. Courtv. M. A. and Macphail, R. I.’ In Soi Micromorphology’. C. A. Douglas (ed.), pp. 431~440,199O. [13] Courty, M. A., Macphail, R. I. and Wattez, J. In ‘The Archaeology of Pastoralism in Southern Europe’. G. Barker, R. Maggi and R. Nisbet (eds), Rev&a di Studi Liguri, 55, 1-4, 1989 (in press). [14] Rowney-Conwy, P. In ‘The Archaeology of Pastoralism in Southern Europe’. G. Barker, R. Maggi and R. Nisbet (eds), Rev&a di Studi Liguri, 55, 1-4, 1989 (in press). 1151Macphail, R. I. In ‘Gli Scavi del Castellaro di Uscio nella Liguria di Levante (GE)‘. R. Maggi (ed.), Soprintendenza Archaologica della Liguria, Genoa, 1989 (in press). [16] Macphail, R. I. In ‘Hazleton North, Gloucestershire, 1979-82: the excavation of a Neolithic Long Cairn of the Cotswold-Severn Group’. A. Saville (ed.), English Heritage ‘Archaeological Report 13, pp. 223-227, London, 1990. [17] Macphail, R. I. and Goldberg, P. In
‘Soil Micromorphology’. L. A. Douglas (ed.), Elsevier, Amsterdam, pp. 441448, 1990. [18] Romans, J. C. C. and Robertson, L. In ‘The Impact of Aerial Reconnaissance on Archaeology’. G. S. Maxwell (ed.), pp. 136-141, CBA Research Report 4Y, 1983. [ 191 Miicher, H. J. and Morozova, T. D. In ‘Soil Micromorphology’. P. Bullock and C. P. Murphy (eds), pp. 151-194, A B Academic Publishers, Berkhamsted, 1983. [20] Fedoroff, N., Courty, M. A. and Thompson, M. L. In ‘Soil Micromorphology’. L. A. Douglas (ed.), pp. 65% 666, Elsevier, Amsterdam, 1990. [21] Goldberg, P. and Macphail, R. I. In ‘Soil Micromorphology’. L. A. Douglas (ed.), pp. 441-448, Elsevier, Amsterdam, 1990. [22] Horwitz, L. K. and Goldberg, P. Journal Archaeological Science, 16, 1989. [23] Roberts, M. B. Proc. prehist. Sot., 52, 215-245, 1986.
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Soil micromorphology is the microscopic study of soils and soil-like materials, such as loose sediments. It is quite similar to petrography in the geological sciences, which employs thin sections and the polarizing microscope. The technique has been used in geology since the last century, and exploited in soil science for over 50 years. It was first applied to archaeology in the 1950sand 1960s but it is only during the last 10 to 15 years that a small number of workers [l] achieved results with far greater resolution than those arrived at from the application of standard archaeological and sedimentological approaches (for example phosphate, grain size, and mineralogical analyses) to investigations of ancient soils and sediments. This success has led to a sudden increase in the importance of soil micromorphology in archeology that has yet to be fully appreciated by universities and the academic services which provide scientific support for archaeological research. In this article the methodological and philosophical approach will be explained, followed by some examRichard
I. Macphail
BSc.,
MSc.,
Ph.D.
Has been research fellow in the Institute of Archaeology, University College London, since 1979. His research interests include ancient clearance and agriculture and their effects on soil landscapes. Marie-Agnes
Courty,
Doctorat
d’etat
After graduating in geology has engaged in research for the CNRS in Europe, North Africa, the Near East, and Central Asia. Her interests include experimental archaeology as applied to ancient agriculture and the formation of sediments produced by human and animal occupation. Paul Goldberg, B.A., M.Sc., Ph.D. Based at the Institute of Archaeology, Hebrew University of Jerusalem he has had world wide experience in studying geological aspects of archaeology. His research interests are particularly concerned with the effects of humans and biota on soils and sediments in both cave and open-air sites.
Endeavour, New Series, Volume 14, No. 4.1990 OlW-9327I90 93.00 + 0.90. Pergamon Press pk. Printed in Great Britain.
ral, environmental, and geological settings, the present authors can now begin to demonstrate how detailed information on the cultural and environmental aspects of an archaeogical site can be uniquely ascertained by soil micromorHistorical and philosophical phology. Archaeologists and palaeoperspective environmentalists have begun to ask For many years and, unfortunately, still, sediments have been regarded by much more vigorous questions of the archaeologists solely as a medium con- soil or sedimentary medium that forms taining cultural materials (pottery, their archaeological features (layers, flints, bones etc). It is generally thought hearths, pit and ditch fills, ramparts, that the sediment itself contains little floors) and contains their artefacts information relevant to cultural or environmental (zooarchaeological, archaeology, and only after extraction geoarchaeological, and archaeobotanicof the cultural material may a pedolog- al) indicator materials (for example ist or sedimentologist be requested to grain-size fractions, minerals, soil and carry out some standard analyses to sediment fragments, diatoms, pollen, characterize the sediment generally. If a molluscs, bones, seeds, charcoal). Through soil micromorphology it is buried soil is recognized, this stratum would be regarded as of little interest now possible to recognize, for example, and termed ‘sterile’ or ‘natural’ by the various types of habitation floors, animarchaeologist because it contains no al stabling layers, ash dumps, wild artefacts, and a soil scientist would be animal and bird occupation phases, expected only to attempt to classify the periglacial periods, arid epochs and soil type. Hence on many occasions irrigation, snow-covered boreal landneither the archaeologist nor associated scapes, woodland clearances, and agrisoil scientist or geologist, have been cultural impacts as recorded in soils and fully aware of the amount of detailed sediments. information that can be obtained from the soil or sedimentary makeup of a Methods site. For this reason inappropriate tech- The study of undisturbed soils in thin niques have often been applied. For section was commenced by W. L. example, grain-size analysis is a popular Kubiena [2]. In the 1950sIan Cornwall technique, but when applied to dumped of the Institute of Archaeology (now cutural material it will merely confirm part of University College London) that the deposit is unsorted, whereas made the first applications of the technigrass ash middens would be regarded as que to archaeology [3]. His aim was to silt-rich deposits, but only because they improve the understanding of past eninclude abundant silt-size phytoliths vironments, and this initiated the study (plant opal). Even in natural sediments, of human-related (anthropogenic) desuch as colluvium and alluvium, high posits, a field of investigation not again clay contents may not relate to low taken up until the 1970s [4]. energy deposition, but to the breakThin sections are usually prepared by down during sample preparation, of sampling an undisturbed, oriented transported soil clasts (redeposited block of soil or sediment [ 11,drying it in eroded soil fragments; see figure l), the laboratory for several days at which are common in Quaternary sedi- around 60°C and then impregnating it under vacuum with resin (epoxy or ments. Due to the inadequacies of such tech- polyester) [5]. The hardened block is niques, it was necessary to develop a sliced with a rock saw, and after smoonew approach to the study of archaeolo- thing is mounted on a glass slide and gical soils and sediments. After more ground down, to 20-30 pm, using a light than a decade of tackling archaeological lubricating oil. Over the last 20 years problems from sites of different cultu- important advances have been achieved ples of how, through soil micromorphology, debates on cultural and environmental aspects of archaeological sites have been advanced.
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Figure 1 The Middle Pleistocene cave of Westbury-sub-Mendip, Somerset, England: Unit 14, Grey Silty Breccia made up of sub-rounded yellowish phosphatised (highly fluorescent) cave soil fragments containing pieces of very strongly leached bone (centres of right and top soil fragments), reddish silt coatings, dark reddish iron stains and a cementing matrix of mosaic sparitic calcite. Original cave sediment formed through freezing and thawing causing the fracturing of limestone cave wall material (not illustrated) and its mixing with cave sediments and soils transported from outside. Partially digested bone fragments of small mammals rejected as pellets by predatory birds (eg. owls) became mixed with cave soil that was affected by phosphate-rich bird excrement. The formerly red cave soil eventually became iron depleted and phosphatized. Further freeze/thaw activity broke up the cave earth into rounded fragments, whereas later meltwater washed red silts into this layer, coating them. Eventually, the whole layer became cemented by secondary calcium carbonate. PPL, frame length is 3.35 mm.
in the preparation of thin sections. With the use of more efficient resins and specially designed machines, thin sections can now be as large 13 x 6 cm in size. This large format may be compared with the geological and ceramic thin-section size of 2.2 x 4 cm, which has limited value for studying such large-scale features as structure, archaeological layers, and the coarse microfabric heterogeneity that is typical of archeological sediments (figure 2). Similar advances have been made in the objective description and interpretation of thin sections. ‘Anthropogenic’ microfeatures and materials can now be successfully characterized using internationally recognised terminology [6]. Strategies in field sampling and analogue studies In field sampling the soil micromorphologist aims to obtain undisturbed soil/ sediment blocks from enough contexts to be representative of the site as a
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whole. The new large-format thin sections help this enormously. For example, a single column of undisturbed samples from one profile of the 28 cm thick buried Neolithic soil at Maiden Castle (Dorset, England) permitted 135 sq. ems to be examined, and at this site sequences and buried soils are often studied from a series of localities across a site. The main strategy for sample selection is to ensure that all features of interest are sampled, together with sufficient local ‘reference’ materials. The latter may include on-site and off-site soil profiles, local sediments that may have been imported on to the site, and examples of probable floors, ash layers, hearths, daub, ditch-fills, coprolites (figure 3), etc., that may help in the final interpretation of the site and its surroundings. Particular site problems may require experimentation. has The study of ancient cultivation been advanced by soil micromorphological experiments in ‘ancient’ agriculture at both modern soil experimental
plots (for example, Dept des Sols, Institut National Agronomique, Grignon, France), and at the ‘ancient’ farms of Butser Hill (Iron Age farm reconstruction, Hampshire, England) and Hambather Forst (Neolithic agricultural simulation, Elsdorf, Germany). These experiments, together with studies of inferred ancient cultivated soils (such as ploughmarks) and the wealth of soil science literature on soil micromorphology of modern agricultural soils [7, 8, 91, has allowed attempts the effects of ancient
to characterize
agriculture on a number of soil types [lo] (figures 4 and 5). The characterization of occupation features is being similarly aided by studies of such modern analogues as Bedouin
camps
and ‘prehistoric’
hearths,
buildings, and floors reconstructed by enthusiasts. Enigmatic ash layers from Mediterranean caves could be properly investigated only after a whole range of fresh and burned excrements from herbivores were characterized.
Figure 2 The cave of Arene Candide, Liguria, Italy: Early Middle Neolithic burned stable layers; (a) layer of ashed cow coprolites (i), comprising fine calcium carbonate and calcium oxalate crystals produced by the burning of dung of cattle foddered on a diet of branches and attached leaves; (b) cattle bedding and trampled fodder remains of twigs and branches, that stayed brown after combustion because they were probably stained with cattle urine; (c) partially compacted combusted ashed coprolite layer, containing wood charcoal (ii) and sheep/goat coprolite fragments (iii) that are yellowish because they retain charred undigested lignified remains typical of their diet of bark and other woody material. Plane polarized light (PPL), scale 0.5 cm.
Figure 3 Viking period human coprolite from York (human parasite egg analysis by Andrew Jones); legume (e.g. bean) testa, possible legume cells and phytolith lengths cemented in a phosphatic (highly fluorescent under ultra violent light illumination) matrix that contains bone fragments, indicate an omnivorous diet of meat and vegetables. PPL, frame length is 0.33 mm.
ity, will affect an unweathered sediment or an occupation floor, for example. Experience from soil science and One of the problems of studying buried palaeosol soil micromorphological stu- soils is that if they are not totally sealed, dies has shown that microfeatures have post-burial earthworm activity or roota temporal hierarchy: that is, the most ing can be seen to rework soil and recent features affect earlier ones. Thus anthropogenically formed fabrics dating a pedological process or processes to when the soil was buried. Anaerobassociated with human or animal activ- ism may also convert organic remains Observational interpretation
procedures
and
into iron and manganese pseudomorphs, or aquatic inundation may through iron and clay depletion - remove all evidence of earlier soil fabrics. All these processes make difficult the simple aims, on any archaeological site, which are to clarify what the site was like before occupation, how it was affected by human activity, and what happened afterwards on abandonment or burial. These interpretive problems can neither be overcome by examining the soil or sediment at a single scale, nor under a single lighting medium; rather, observations have to be carried out under a variety of lighting types and at all scales. Thus although photographs can illustrate a point they present only one aspect of a soil microfabric at one specific magnification or scale.
Figure 4 Beaker period ard-cultivated colluvium at Ashcombe Bottom, Sussex, England: tillage has caused the weakly structured silty loam soil to slake when water saturated, and separate into its components of silt and reddish clay; trapped air probably formed the vesicle or round soil void (bottom centre), typical of such a process, and as found in modern irrigated soils, for example. PPL, frame length is 3.35 mm.
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Figure 5 Ashcombe Bottom: dense silt loam cultivation colluvium, with parallelsided, straight-edged planar voids (shear planes) probably produced by tillage implement lard) impact. PPL, frame length is 5.56 mm.
Figure 6 Arene Candide: Early Middle Neolithic burned sheep/goat stabling layer contains fragments of interwoven non-cellular fibres. These are considered to be ashed pieces of knitted woolen textile. Note on combustion, organic remains are reduced by some 90 per cent. PPL, frame length is 0.33 mm.
Figure 7 Arene Candide: Early Middle Neolithic occupation layer, comprising a made floor of densely laminated fine charcoal and ash-rich mud, upon which probable straw mats, as indicated by the very long phytoliths, were layed. Phytoliths are very resistant silica (opal) strengthening of plant materials such as straw, and their in tact presence on well preserved floor layers suggests that this occupation horizon has been little disturbed. PPL, frame length is 5.56 mm.
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the end of the last century. The ashed organic fodder remains and coprolites also provided evidence of seasonality, as independently inferred from the animal bone data [14]. After every period of stabling it seems that the manure layers were burned, probably for cleaning. On each successive stabling episode the underlying ashed material was tramped and compressed, whereas the new stabling material and fodder also became tramped and probably soaked in cattle urine. Hence on burning, the bottom layers were only partially combusted and remain now as thin brown layers that separate the more totally ashed material. The underlying ash was also compacted. The evidence indicates an Early Middle Neolithic pastoral system involving the stabling of large numbers of herbivores for short episodes and their foddering on shredded tree material. DurFigure 8 As figure 6, but under crossed polarized light (XPL), showing the ing the Late Early Neolithic, there was laminated nature of the compacted floor and the presence of bright birefringent local and probably continuous grazing calcium carbonate ash; the phytoliths, that are the remains of probable mats, are of only a few cattle and sheep/goats. typically non-birefringent. These findings from Arene Candide are of major significance in studies of prehistoric pastoralism. Until now the only certain indication of pastoral activity has been the presence of animal In the laboratory, the resin impre- formation and function can be illus- bones, whereas studies of pollen and gnated blocks and large thin sections trated from the ways information re- land molluscs have only been able to are first viewed without magnification, lates to local, micro-environmental, and provide indicators of grassland and pastures. Moreover, the identification of for it is essential that there is no obser- regional scales. vational gap between the field and the ashed fragments of probable knitted microscale. Possible layers seen in the Local scale woollen textile (figure 6), is a unique One of the most important contribufield can be confirmed in the hand-held discovery of cultural material by soil thin section, and these layers can then tions soil micromorphologists can make micromorphology. be studied using the polarizing micro- to a site is the correct appraisal of how Armed with such findings, Neolithic scope at higher and higher magnifica- layers formed, because this affects not cultural material at Arene Candide can be reassessedon the basis that the site is tions (X5, X10, X50, X100, X200, only the taphonomy (post-depositional x400), perhaps using some of the block weathering, movement etc.) of all the now definitely identified as a stabling or unimpregnated undisturbed material environmental and cultural material site in a pastoral economy. Further, the for examination by scanning electron present, but can also provide most use- cultural material may reflect changes microscopy (SEM) (x2000). Some in- ful clues on the cultural history of a site. that occurred in this economy during terpretive problems can occur if field At the coastal cave of Arene Candide, the Late Early and Early Middle samples are studied immediately at the Finale, Liguria, Italy [ll], some of the .Neolithic periods. The functions of indiNeolithic cultural materials and associ- vidual areas (and layers) as stables, micron scale, because the relationship of materials can be best observed if ated domestic animal bones occur in 2.5 living space (figures 7 and 8), passagestudied at a whole range of scales (see metre-thick whitish sediments spanning ways, temporally abandoned ground, approximately 1000 radiocarbon years etc. - as reflected by their microfabrics figures 2, 6, 7 and 8). Using the optical microscope, thin sections are examined (cu 4th to 5th millennia BC). The Early also allows more accurate appraisal of under plane polarized light (PPL), cros- Middle Neolithic sediments, however, other analytical data from charcoal, bone, and phytolith analyses now being sed polarized light (XPL), oblique inci- contrast with the Late Early Neolithic dent light (OIL) and ultra violet light deposits by being thicker and more interpreted. (UV), permitting a whole range of whitish generally, except for the regular scale optical tests; the last especially for iden- presence of thin brown layers (see Micro-environmental tifying organic materials and phosphate figure 2). This deposit comprises ash At open-air archaeological sites the old and charred organic remains [12, 131. ground surface or occupation surface minerals. Thin sections are described in detail The ash material consists of densely may often be preserved by a monument packed cubic calcite crystals which form such as a barrow, or occur beneath following the guidelines and terminology of P. Bullock et al. [6], although pseudomorphic fabrics of twigs and colluvium or alluvium. The soil microsome materials - such as ash and herbi- branches and loosely packed burnt cal- morphological study of such surfaces vore, carnivore, and omnivore excre- cium oxalate crystals, the remains of can make possible the identification of ments (see figure 3) or mortar and mud cornbusted fresh leaves. Ashed herbi- lateral and vertical features of interest vore coprolites are also’abundant, parti- across a site: for example, features inbrick, for instance - were previously unstudied phenomena in soil science cularly those of cattle and sheep/goats dicating woodland clearance, cultivathat have been characterized by the fed primarily on a diet of cut branches, tion and human occupation (hearths, as opposed to grass. Such systems of floors, daub from mud-hut walls, midauthors [ 11. Results from the application of soil tree shredding for fodder were still com- dens, etc.) [l, 15, 161. Their temporal micromorphology to the study of site mon practices in the Mediterrean up to hierarchy may also be elucidated.
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unit 4b; in situ fragment of flint debitage (cetitre) from Lower Palaeolithic (Acheulian) flint reduction Figure 9 Boxgrove: layer (chipping floor), sealed in calcareous (chalky) laminated silt and clay deposited in a probable mud flat environment. XPL, frame length is 5.56 mm.
When humans occupied a site, woodland clearance often occurred. Soil micromorphological evidence of soil profiles probably disturbed by clearance activity can also be recognized in soils when particularly large field features, probably caused by human-induced tree-throw, are absent [17]. For example, the clearance of shallow rooting herbaceous plants ahead of Neolithic monument construction caused shallow soil turbation and the concentration of ash, fine charcoal, and phytoliths at the soil surface, because cleared vegetation was burned. Such instances have been recognized in Brittany, France, and in the adjacent Cornish peninsula, England. Such clearance practices could cause erosion, and in the Chalcolithic in the Western Apennines of Liguria, Italy, soil colluvium, including burned soil, was washed into shallow basins and aided peat initiation as drainage became impeded. According to the associated pollen stratigraphy, the contemporary large-scale fir forest cover began to diminish at the same time [l]. In addition, it is now possible to identify the variable effects of prehistoric cultivation at different times and on differing soil types. At the site of Hazleton, Gloucestershire, England, inferred Neolithic cultivation shifted across the
site [16]. Soil micromorphological studies of the buried soils show that areas cultivated earlier became vegetated, whereas an occupation area rich in charcoal and cultural material was later chosen for cultivation. One major finding in these studies of early cultivation is the inferred fragility of cultivated soils as a result of diminishing organic matter produced by subsistence agriculture [18]. This caused much of the soil to break down under cultivation implement impact (figure 4) fine soil being often washed down profile, a phenomenon also recorded in modern agricultural soils [7, 8, 91. Many soils were eroded, and these themselves later formed valley-bottom arable soils. For example, Beaker period ard-cultivated soils in the dry valley of Ashcombe Bottom, near Lewes, Sussex, England, seem to have microfabrics reflecting cultivation impact. Such features have been recognized from experiments in both ‘ancient’ and modern agriculture [lo]. For instance, natural coarse peds (soil structures) were broken up, allowing an open porosity to be worked by soil fauna. Finer peds were concentrated down profile, producing a compacted layer that developed shear planes probably due to ard impact (figure 5). The structural breakdown of
soils into their fine and coarse components by the effect of slaking on the Ashcombe cultivated soils has already been illustrated (figure 4). There is increasing evidence that ancient peoples recognized that lack of organic matter was an agronomic problem, and it has been inferred from included cultural materials that manuring was carried out. These additions of organic matter have been recognized in some Bronze Age, Iron Age, and Medieval soils from Europe, where acidity or waterlogging has preserved organic fine fabrics rich in phytoliths. Regional Palaeosols.
Soil micromorphology has always been a main tool in palaeosol studies [19] enabling workers to differentiate, for example, soil microfabrics produced under periglacial conditions as opposed to temperate ones. Past vegetations and water regimes have also been elucidated [20]. Under a boreal climate, coniferous forest and snow dark fulvic-acidmelt can produce stained clay coatings in the soil porosity. At the other extreme, plant and animal (bio-) turbation is greatly reduced under arid conditions, but various salts may precipitate. About 4000 years ago in north-west India, formerly arid soils
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slopes and causing soil erosion [21]. Thus soil micromorphology has proved one of the most important techniques in helping to decipher regional environmental, including climatic, changes in relation to human occupation at this site. Future prospects
Figure 10 Middle Pleistocene sediments, Boxgrove, West Sussex, England: Unit 4d; finely laminated silt and iron-replaced organic matter layers in pond-like deposits containing a probable bird bone; these deposits which also contain death assemblages of fish and amphibia, are probably contemporary with the main human activity (unit 4c) at Boxgrove (Roberts, personal communication). PPL, frame length is 5.56 mm.
high biological activity and strong resistance to wind erosion [ 11, as a result of Harappan cultivation.
developed
Caves. Until recently workers on cave sediments have tended to assume a direct link between sedimentary and post-sedimentary processesand climatic change. Our experience of the complexities of some cave sediments suggests that methodologies need first to recognize these complexities before adequate interpretations can be attempted (figure 1). Soil micromorphological studies of a number of caves in the Near East (for example, Kebara, Tabun, Hayonim), North Africa (Taforalt), France [ 11,England (Westbury-sub-Mendip) [21] and Gibraltar (Gorham’s), have shown that biogenic and anthropogenic depositional and post-depositional agents have been largely overlooked in earlier studies. Coprolites of various animals such as hyaena [22], egg-shell fragments (in the Palaeolithic levels at Arene Candide) [l], layers rich in organic matter [12], and non-descript fragments of vegetation and aggregated fabrics due to animal burrowing, all clearly indicate the influence of plants and animals. As a consequence, the inferred palaeoclimatic signal of the sediments may have been over-estimated in the past. In addition, the burrowing effects of macro and micro-fauna may’have influenced the integrity of the archaeological remains uncovered at the site, resulting in blurring of the archaeological record, and is an imposed constraint on our ability to infer past human activities and
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behaviour. The archaeological material may simply not be in the position in which it was left by former inhabitants of the site.
and directions
Soil micromorphology in archaeology can now be regarded not as a specialist technique of relevance to soil scientists alone, but one with tremendous potential for adding to our understanding of the cultural nature of an archaeological site. Great advances have also been made in improving our understanding of ancient environments and how these have been affected by human activities such as cultivation. These results are due to the fact that many physical, chemical, biological and human processes create microfeatures, which from our increasing experience, can be correctly recognized and interpreted from thin sections. This suggests that soil micromorphology is a technique capable of studying global effects because so many processescan be recorded microscopically in a soil or sediment. Moreover, the association with archaeology commonly permits the dating of past changes. It is thus strange that numbers of soil micromorphologists generally, as may be reckoned from attendances at regular international working-meetings, have not increased over the last decade. The authors would like to challenge micromorphologists in soil science by suggesting that it is in the application of soil micromorphology to archaeology that some workers are revealing the true potential of the technique over and above its understood role in soil science.
Sediments. The site of Boxgrove, West Sussex, England, is of exceptional interest. Here Middle Pleistocene fauna1 material (figures 9 and 10) is accompanied by the best preserved Lower Palaeolithic (Acheulian) flint working levels [23], possibly the finest yet excavated in the world. Soil micromorphological, sedimentological, and fauna1 evidence all indicate that human groups were Acknowledgments active towards the end of a temperate The authors wish to thank the many phase, possibly some 500000 years ago. funding agencies (including English Their occupation areas were affected Heritage, C.N.R.S., the French Ministhrough time by sea-level changes, try of Foreign Affairs, the Soprintenestuarine conditions, and by river distridenza Archeologica della Liguria, and butary migration. During an early the Natural History Museum, London) occupation, chipping floors were situ- and the long-term friendly cooperation ated on probable mud flats, and each of archaeologists and palaeosuccessive, probable tide-related, inun- environmentalists, too numerous to dation caused the micro-debitage mention by name, who make these in(figure 10) and associated butchered vestigations worthwhile. Stuart Laidlaw bone remains, to be sealed by cal- kindly provided expert photographic assistance, and Jill Cruise made useful careous silts and clays. Soil micromorphology has been essential in con- comments on the text. firming the in situ nature of this unique cultural material at this level, because higher up in the sedimentary sequence, References (11 Courty, M. A., Goldberg, P. and Maca drop in base level permitted a ripened phail, R. I. ‘Soils and Micromorphology soil to develop, and biological activity in Archaeology’, University Press, had a dramatic affect on the taphonomy Cambridge,1989, of the flint and bone. Sediments that [2] Kubiena, W. L. ‘Micropedology’, Coloccur above the occupation levels are legiate Press,Ames, Iowa, 1938. silty colluviums that may contain trans1. W. ‘Soils for the [3] Cornwall, ported soil clasts, an effect of the onset Archaeologist’, Phoenix House, London, 1958. of cold climate devegetating the local
[4] Romans, J. C. C. and Robertson, L. In ‘The Effect of Man on the Landscape: the Highland Zone’. J. G. Evans, S. Limbrey and H. Cleere (eds), pp. 37-9, CBA Research Reoort 11. 1975. [S] Murphy, C. P. Thin Section Preparation of Soils and Sediments’, A B Academic Publishers, Berkhamsted, 1986. [6] Bullock, P., Fedoroff, N., Jongerius, A., Stoops, G. and Tursina, T. ‘Handbook for Soil Thin Section Description’, Waine Research Publishers, Wolverhampton, 1985. [7] Jongerius, A. In ‘Soil Micromorphology’. P. Bullock and C. P. Murphy (eds), pp. 111-138, 1983. [8] Fedoroff, N., Bresson, L. M. and Courty, M. A. (eds) ‘Soil Micromorphology’, AFES, Plaisir, 1987. (91 Douglas, L. A. (ed.) ‘Soil Micromorphology’, Elsevier Press, Amsterdam, 1990. [lo] Macphail, R. I., Courty, M. A. and Gebhardt, A. In ‘Soils and Early Agriculture’. K. Thomas (ed.), World Archaeology, 22, 1, 53-69, 1990. [ll] Tine, S. In ‘Archeologia in Liguria’, pp.
149-156, Soprintendenza Archeologica della Liguria, Genoa, 1976. I121 Wattez. J.. Courtv. M. A. and Macphail, R. I.’ In Soi Micromorphology’. C. A. Douglas (ed.), pp. 431~440,199O. [13] Courty, M. A., Macphail, R. I. and Wattez, J. In ‘The Archaeology of Pastoralism in Southern Europe’. G. Barker, R. Maggi and R. Nisbet (eds), Rev&a di Studi Liguri, 55, 1-4, 1989 (in press). [14] Rowney-Conwy, P. In ‘The Archaeology of Pastoralism in Southern Europe’. G. Barker, R. Maggi and R. Nisbet (eds), Rev&a di Studi Liguri, 55, 1-4, 1989 (in press). 1151Macphail, R. I. In ‘Gli Scavi del Castellaro di Uscio nella Liguria di Levante (GE)‘. R. Maggi (ed.), Soprintendenza Archaologica della Liguria, Genoa, 1989 (in press). [16] Macphail, R. I. In ‘Hazleton North, Gloucestershire, 1979-82: the excavation of a Neolithic Long Cairn of the Cotswold-Severn Group’. A. Saville (ed.), English Heritage ‘Archaeological Report 13, pp. 223-227, London, 1990. [17] Macphail, R. I. and Goldberg, P. In
‘Soil Micromorphology’. L. A. Douglas (ed.), Elsevier, Amsterdam, pp. 441448, 1990. [18] Romans, J. C. C. and Robertson, L. In ‘The Impact of Aerial Reconnaissance on Archaeology’. G. S. Maxwell (ed.), pp. 136-141, CBA Research Report 4Y, 1983. [ 191 Miicher, H. J. and Morozova, T. D. In ‘Soil Micromorphology’. P. Bullock and C. P. Murphy (eds), pp. 151-194, A B Academic Publishers, Berkhamsted, 1983. [20] Fedoroff, N., Courty, M. A. and Thompson, M. L. In ‘Soil Micromorphology’. L. A. Douglas (ed.), pp. 65% 666, Elsevier, Amsterdam, 1990. [21] Goldberg, P. and Macphail, R. I. In ‘Soil Micromorphology’. L. A. Douglas (ed.), pp. 441-448, Elsevier, Amsterdam, 1990. [22] Horwitz, L. K. and Goldberg, P. Journal Archaeological Science, 16, 1989. [23] Roberts, M. B. Proc. prehist. Sot., 52, 215-245, 1986.
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