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Goldberg Paul and Macphail Richard I, Formation Processes. In: Encyclopedia
of Archaeology, ed. by Deborah M. Pearsall. © 2008, Academic Press, New
York.
Nixon T (ed.) (2001) Preserving Archaeological Remains in situ.
Proceedings of the 2nd conference 12–14 September 2001.
London: Museum of London Archaeological Service.
Stanley Price N (1984) Conservation on Archaeological Sites with
Particular Reference to the Mediterranean Area. Rome:
ICCROM.
van Heeringen RM and Theunissen EM (2002) Desiccation of the
Archaeological Landscape at Voorne Putten. Amersfoort,
The Netherlands: Rijksdienst voor het Oudheidkundig Bode-
monderzoek (Nederlandse Archaeologische Rapporten 25).
http://www.english-heritage.org.uk/upload/pdf/MoRPHE-Project-
Managers-Guide.pdf.
Formation Processes
Paul Goldberg, Boston University, Boston, MA, USA
Richard I Macphail, University College London,
London, UK
ã2008 Elsevier Inc. All rights reserved.
Glossary
dark earth Dark-colored and pedologically modified
occupation deposits formed over decades and centuries. As a
consequence, the original stratigraphic integrity of pedogenesis
and time of the deposits is largely obscured.
diagenesis Chemical and physical changes in a sediment
occurring at surface conditions after deposition.
loess Wind blown silt deposits found worldwide.
pedogenesis Soil formation that results from factors of climate,
living organisms, parent material, topography, and time.
Quaternary Geological Period dating to about the last 2 Myr
and including the Pleistocene and Holocene (last 10 000 years)
Epochs.
Introduction
The concept of ‘site formation’ existed in scholars’
minds (e.g., F. E. Zeuner) for decades before it was
concisely articulated by archaeologist M. B. Schiffer
in his seminal work on the subject. A human and
physical geographical approach was advanced by
K. W. Butzer who considered the interplay of cultural
and natural processes that go into forming a site.
Even now, the notion that site formation develops
through a combination of natural and anthropogenic
agencies is still often overlooked.
Site-formation processes can be broadly divided into
those processes that occur before, during, and after
occupation. These include natural sedimentation,
anthropogenic deposition and modification, soil for-
mation (pedogenesis), and other postdepositional
effects. The occurrence of any of these processes is
quite variable at a given site, and depends upon
(among others) age, climate and location/setting of
the site, and type and complexity of occupation (hunter
and gatherers vs. complex societies).
Natural Sedimentation
Natural sedimentation follows most of the processes
found in modern geological environments (e.g., beach,
alluvial, aeolian, and lacustrine) and most sediments
reflect the available energy of deposition: higher ener-
gies are associated with beach and stream cobbles,
whereas lake basins are low-energy settings; the latter
may also be the locus of chemical sedimentation where
carbonates and other salts may accumulate.
For prehistoric sites typified by hunter and gatherer
occupations, natural sedimentation predominates at
most open-air and cave sites (see Caves and Rock-
shelters;Sites: Mounded and Unmounded). At sites
such as Lower Palaeolithic Boxgrove (UK), hominin
occupation appears to have had negligible effect on
estuarine and mudflat sedimentation, and periglacial
solifluction. In caves, detrital sedimentation of wind-
blown sand and silt, mud flows, and sheetwash are
commonly accompanied by organic-rich inputs of bird
guano, as well as chemical sedimentation of carbo-
nates (speleothems and flowstone/travertine) and
phosphates. In volcanic terrains meter-thick layers of
ash and lapilli can bury large settlements, such as
Pompeii and Cere
´n (El Salvador).
Anthropogenic Deposition/Activities
Archaeological deposits often have more compli-
cated site-formation histories than natural ones be-
cause they encompass a potentially infinite variety of
anthropogenic activities (see Figure 1). Thus, at a tell
or mound site, for example, we might observe combi-
nations of interdigitated features and constructions
(e.g., walls, plazas, and kilns); domestic occupation,
including combustion zones and pene-contemporane-
ous rake-out of ashes charcoal (see Figures 2 and 3),
and bone; and agricultural practices adjacent to the
site (e.g., plowing, manuring). Moreover, people can
rework and modify archaeologically contempora-
neous features and deposits, as in the case of pits (see
Figures 4 and 5), fills, and dumps. Furthermore, all
of these types of activities can often take place on
the same existing substrate, thus making it difficult
to isolate individual strata and associated events.
Anthropogenic deposition and alteration become
particularly noticeable from the Middle Palaeolithic
onwards (after c. 250 ka), ultimately encompassing
most Holocene sites in the Old World, and parti-
cularly Late Holocene mound sites in the New World.
Formation Processes 2013
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Pedogenesis and Other Postdepositional
Processes
Soils form on natural sediments, on anthropogenic
deposits, or on previously formed soils. Pedogenesis
brings about changes in color, texture, composition,
and structure of the material on which it develops.
The types and degrees of transformations and soils,
are well documented, and are a function of the com-
bined effects of climate, organisms (biota), relief (e.g.,
slope and altitude), parent material (geology or an-
thropogenic deposit), and time. Prime examples of
the effect of pedogenesis on anthropogenic deposits
are the formation of Roman and medieval urban dark
earth in European urban deposits and stratigraphy,
and the formation of black earths such as terra preta
on Mesoamerican occupation sites. On more regional
scales, the formation of soils on alluvial or aeolian
landscapes (e.g., loess deposits in Europe and Asia)
furnish detailed palaeoenvironmental information
that can be commonly linked with past occupations.
Moreover, when viewed over the span of the Quater-
nary, soils form relatively quickly and thus constitute
distinct temporal markers that can be traced over
large areas and thus permit the correlation of soils,
deposits, and sites.
In addition to ‘traditional’ pedogenesis, other post-
depositional processes can substantially alter the
integrity and nature of archaeological sites and de-
posits. Bioturbation, for example, is a well-known
process, but its effects are often under-appreciated;
original stratification can be effaced and artifacts
substantially moved from their original positions
(see Figure 1). Human activities, such as trampling
(Figures 2 and 3) and cleaning, can have similar
effects, along with activities involving reuse and dis-
card of artifacts and materials within dumps or offsite.
Finally, postdepositional chemical modifications
also act to contribute to the formation of sites. In
more classical situations, diagenesis can involve cemen-
tation of deposits by carbonate derived from ground-
water, or iron precipitation/dissolution resulting in
Figure 1 Field photo of an archaeological profile at Huizui, loess
plateau, Henan Province, China; Yangshao (Neolithic c. 5000–
3000 BC) construction of lime floors (LFs) over buried alluvium or
possible paddysols (soils); also visible are burned daub (Collapse),
the upper homogenized (Reworked) levels, and plastic downpiping
monoliths (Samples) for soil micromorphological investigations.
Collaboration with La Trobe University, Australia and Institute of
Archaeology, Chinese Academy of Social Sciences, Beijing.
Figure 2 Scan of thin section M500b (context 4907; period 9)
of typical room occupation deposits from the Medieval Canons’
Infirmary, Spitalfields Hospital, London, UK (Museum of London
Archaeological Services). The thin section shows an alternating
series of constructed ‘orange’ brickearth floors and ‘blackish’
laminated(trampled) beatenfloors. Width is 50 mm. Bulk analyses
of the brickearth constructed floors demonstrate generally low
amounts of organic matter (LOI) and heavy metals (Pb, Zn, and
Cu), with little enhancement of magnetic susceptibility, although
phosphate may be enriched because of floor-use contamination.
Average bulk analysis of constructed floors: (1) organic matter
(loss on ignition – LOI) ¼1.70%; (2) phosphate ¼2.05 mg g
1
;
(3) magnetic susceptibility¼31.2 10
8
SI w,4)2.50%w
conv
;
(4) 128 mgg
1
Pb, 36.3 mgg
1
, Zn, 34.2 mgg
1
Cu. Bulk data from
John Crowther, University of Wales, Lampeter, UK, unpublished
report by Macphail and Crowther to Museum of London Archaeo-
logical Service.
2014 Formation Processes
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yellow, brown, or reddish mottling as in gleyed hori-
zons. In more subtle instances, diagenesis – particularly
within cave settings – can be responsible for the com-
plete destruction of bone and organic matter, and
concomitant formation of secondary minerals that
include phosphates (Figures 4 and 5), carbonates,
sulfates, and nitrates.
Thus, postdepositional effects can result not only in
the wholesale removal of fundamental parts of the
archaeological record (e.g., bones) but also modify
textures, colors, and other aspects of the deposits
which in turn hinder recognition of the original depo-
sitional characteristics and associated stratigraphic
relationships (Figures 6 and 7) they can also render
difficult the excavation and retrieval of components
of the artifact record.
Investigative Methods
Methods of investigating site formation depend on
the nature and scale of the site and the types of
questions being asked. Nevertheless, site formation is
best understood first with a thorough understanding
of the geomorphological setting of the site, includ-
ing position in the landscape, types of bedrock and
Quaternary deposits, as well as knowledge of soils
and sediments near the site. Such investigations are
Figure 3 Photomicrograph and detail of thin section M500b,
illustrating three trampled layers, the middle one rich in charcoal,
ash, burned soil and kitchen waste such as burned bone; the
uppermost layer is characterized by brickearth soil trafficked in
from brickearth floors. Oblique incident light (OIL), frame width
is 4.3 mm. Bulk analyses by Crowther also found that charcoal-
rich layers contrast with the brickearth layers by being more
organic, more phosphate- and heavy metal-rich, and display an
enhanced magnetic susceptibility because of included burned
mineral material (e.g., from hearths). Bulk data: 2.83% LOI,
4.09 mg g
1
phosphate-P, 62.310
8
SI w, 5.37% w
conv
,
980 mgg
1
Pb, 52.4 mgg
1
Zn, 82.1 mgg
1
Cu.
Figure 4 Photomicrograph of thin section M80, from another
important Medieval context at Spitalfields – an enigmatic pit fill
(context 1485; period 9); this illustrates the presence of calcium
phosphate cemented human cess (latrine waste) within which are
embedded plant fragments (legume testa?) probably relict of the
ingestion of vegetables. The presence of cess was also identified
through independent palynological (pollen) and macrobotanical
studies. PPL, frame width is 5 mm. (The thin section also under-
went elemental mapping by microprobe, see Figure 5.)
Figure 5 Microprobe map of a part of thin section M80 (combi-
nations of the elements Ca, P, and Si). Two distinct materials are
present: probable mineralized human cess (Ca–P – pale blue) at
the base (and as fragments above) (see Figure 4); and silt-rich
layered, probable stabling waste (Si – red) intercalated with stable
crust phosphate (pale blue). Scale bar at bottom of photograph is
2 mm. Microprobe analysis of the cess layer confirmed the domi-
nant presence of calcium phosphate – probably as hydroxyapatite:
7.87% Ca, 3.44% P, 2.46% Si. Bulk analysis (by Crowther) also
found the deposit to be extremely organic and exceptionally rich in
phosphate, as well as containing anomalously high amounts
of zinc: 51.6% LOI, 72.4 mg g
1
phosphate-P, 0.388 10
8
SI w,
0.285% w
conv
, 266 mgg
1
Pb, 809 mgg
1
Zn, 172 mgg
1
Cu.
Formation Processes 2015
Encyclopedia of Archaeology (2008), vol. 3, pp. 2013-2017
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usually carried out with the aid of satellite and aerial
photography, maps (topographic, geological, soil sur-
vey), and geophysical techniques (e.g., magnetometry).
In the laboratory, grain size analysis has tradition-
ally been used to scrutinize these processes. Within the
past two decades this approach has been supplanted
by soil micromorphological techniques, including the
thin section analysis of undisturbed sediments and
Transform soils using the petrological microscope,
coupled with scanning electron microscopy (SEM),
X-ray analyses (e.g., microprobe and X-ray diffrac-
tion), and Fourier Transform infrared (FTIR) spec-
trometry, which are effective means to examine
microchemistry and mineralogy (Figures 4 and 5).
Bulk chemical (organic matter, phosphate, trace
elements) and physical (bulk density, magnetic sus-
ceptibility) analyses (Figures 2 and 3)arealsooften
utilized to determine, and/or corroborate indepen-
dently, depositional and postdepositional processes
(see Soils and Archaeology). For example, soil micro-
morphology of the high medieval deposits in the pre-
cincts of Magdeburg Cathedral, Germany, found
burned and ash-rich deposits formed under open-air
conditions, which included nonferrous metal frag-
ments. This was consistent with an enhanced mag-
netic susceptibility (induced by burning) and the
enriched copper content found in the associated bulk
sample. Complementary microprobe and archaeo-
metallic analyses on the thin section identified the
fragments as corroding bronze alloy fragments com-
posed of copper and tin, which contained the appro-
priate amount of lead required in bells. This supplied
an inferred link between these deposits containing
bronze casting droplets and supposed local medieval
bell manufacture for the Cathedral.
Conclusions
Two decades after the appearance of Schiffer’s vol-
ume, researchers are finally becoming more sensitive
to the concept of site-formation processes and the
variety of techniques that are currently being used to
reveal the type of natural and human processes/events
that together are responsible for the buildup that they
are excavating. Furthermore, they realize that without
such an understanding, their ability to comprehend
what they dig out of the ground is severely com-
promised and that studies of site formation should
constitute a fundamental aspect of any excavation.
See also: Caves and Rockshelters;Sites: Mounded and
Unmounded; Soils and Archaeology;Volcanism and
Archaeology.
Further Reading
Berna F, Behara A, Shahack-Gross R, et al. (2007) Sediments ex-
posed to high temperatures: reconstructing pyrotechnological
processes in Late Bronze and Iron Age Strata at Tel Dor (Israel).
Journal of Archaeological Science 34: 358–373.
Figure 7 Middle Palaeolithic anthropogenic deposits about
50 ka from the West wall of Kebara Cave, Mount Carmel, Israel.
The bulk of the deposits are intact combustion features comprised
of ashes and organic-rich layers. In this part of the cave, all of the
ashes have been diagenetically altered from their original carbon-
ate composition, and instead are composed of various phosphate
minerals; no bone occurs in these altered deposits. In the upper
part of the photograph the well-defined structures disappear and
the deposits are more homogeneous. Such homogenization is a
result of bioturbation, presumably by micromammals, and an
elliptical burrow is shown in the upper left part of the photograph
(b). Red line is 1 m.
Figure 6 Site of Wilson-Leonard, south central Texas showing
stratigraphic sequence of deposits that span from Early Palaeo-
indian at the base (c. 11300BP) up to Late Prehistoric at the top
(c. 1000 BP). The sequence here consists of fluvial gravels at the
base that are overlain by interfingering cienega, organic rich silty
clays (Icl) and overbank silts (Isi), stony colluvial and alluvial silts
(II) that become successively rich in organic matter and rocks
resulting from the use of anthropogenic rock ovens dating to
Archaic through Late Prehistoric Periods (IIIa, IIIc); a more geo-
genic, less anthropogenic silt (IIIb) separates these two oven-rich
layers.
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Butzer KW (1982) Archaeology as Human Ecology. Cambridge:
Cambridge University Press.
Courty M-A, Goldberg P, and Macphail RI (1989) Soils and
Micromorphology in Archaeology. Cambridge: Cambridge
University Press.
Duchaufour P (1982) Pedology. London: Allen and Unwin.
Goldberg P and Bar-Yosef O (1998) Site formation processes in
Kebara and Hayonim Caves and their significance in Levantine
prehistoric caves. In: Akazawa T, Aoki K, and Bar-Yosef O (eds.)
Neandertals and Modern Humans in Western Asia, pp. 107–125.
New York: Plenum.
Goldberg P and Macphail RI (2006) Practical and Theoretical
Geoarchaeology. Oxford: Blackwell Scientific.
Holliday VT (2004) Soils in Archaeological Research. New York:
Oxford University Press.
Karkanas P, Bar-Yosef O, Goldberg P, and Weiner S (2000) Diagen-
esis in prehistoric caves: The use of minerals that form in situ to
assess the completeness of the archaeological record. Journal of
Archaeological Science 27: 915–929.
Macphail RI (1994) The reworking of urban stratigraphy by human
and natural processes. In: Hall AR and Kenward HK (eds.)
Urban–Rural Connexions: Perspectives from Environmental
Archaeology, 47, pp. 13–43. Oxford: Oxbow.
Schiffer MB (1987) Formation Processes of the Archaeological
Record. Albuquerque: The University of New Mexico Press.
Stiner M, Kuhn SL, Surovell TA, et al. (2005) Bone, ash, and shell
preservation in Hayonim Cave. In: Stiner M (ed.) The Faunas of
Hayonim Cave, Israel, American School of Prehistoric Research
Bulletin, vol. 48, pp. 59–79. Cambridge: Peabody Museum of
Archaeology and Ethnology, Harvard University.
Sites/Frozen See: Frozen Sites and Bodies.
Mapping Methods
Ian Johnson, University of Sydney, Sydney, NSW,
Australia
ã2008 Elsevier Inc. All rights reserved.
Glossary
GIS (Geographical Information System) Software for
capturing, managing, analysing and presenting spatially
referenced data. Raster (cell-based) systems provide the
best analysis capabilities, whereas vector systems provide
the best mapping capabilites. Most modern systems are hybrid.
GPS (Global Positioning System) A worldwide system of
navigation satellites allowing a portable receiver to triangulate its
position on the earth’s surface to within a few meters.
Differential GPS (DGPS) uses one or more fixed base stations to
provide a correction signal, improving accuracy to submeter or
centimeter level with higher grade receivers.
remote sensing Non-invasive recording of site or landscape
features. The term is used to cover both high-altitude recording
(satellite and airborne sensor imagery, aerial photographs) and
sub-surface recording (magnetometry, resistivity and ground
penetrating radar).
total station A theodolite with electronic distance
measurement, digital readout and data logging.
What and Why Do We Map?
Introduction
Sites and maps The notion of the site, and the use
of maps to describe them, is based on an implicit
understanding that human behavior is inherently
spatial, and the identification of concentrations of
archaeological material which are equated with past
settlements or activities. Site maps – in many cases
more accurately referred to as plans, since they
generally use a local coordinate system and reference
plane – provide a concise method of recording the
limits and structure of the sites we define, the process-
es of sampling and excavation, and the extent and
spatial structure of archaeological material. Site maps
are frequently used to present interpretations of the
material recorded or excavated. As a result, they have
been a fundamental component of site recording since
the early eighteenth century.
The process of site mapping not only generates site
maps, but may also generate an underlying spatial
database susceptible to analysis and to alternative
modes of presentation (including web delivery, multi-
media, and 3D visualization).
Sites and scale Sites may range in size from a transi-
tory campsite, covering a few square meters, to im-
mense settlements such as Teotihuaca
´n in Mexico or
Angkor in Cambodia (Figure 1), extending to hundreds
or even thousands of square kilometers. These large
sites are palimpsests of many features occupied, re-
used, and adapted over time – temples, villages, work-
shops,stores,houses,wells,bridges,etc.–whichare
often treated as sites in their own right. Naturally,
different techniques are required for mapping across
such vastly different spatial and temporal scales, and
Mapping Methods 2017
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