Pollen and spores

Nature and occurence

Pollen (pollen grains) and spores are microscopic products of plants, measuring between 5 and 100µm. Some pollen grains, such as those of corn, are larger. The material is collected by taking soil samples in places where one expects to find this material. During the analysis phase, in addition to pollen and spores, the specialist distinguishes a wide variety of other microfossils, ranging from soil fungi to single-celled endoparasites. These microfossils, including pollen and spores, are called palynomorphs. Palynology is the science that deals with these particles. In addition to the group of microfossils taken with palynological research, diatoms (diatoms) are valuable for archaeological research in a number of cases. Diatoms can be determined on the basis of lime skeletons. Pollen and spores are also present everywhere and in abundance today: in the air, in water, on and in the ground. Pollen and spores are found in archaeological context mainly in an uncharred form. The material is preserved under low-oxygen conditions in permanently wet environments. In addition, pollen is preserved under special conditions, for example, in mineralized manure (coprolites) and microenvironments in which pollen remains preserved occur, particularly in dry, acidic soils. Translated into sediments, these remains are best preserved in peat, lake deposits (gyttja) and clay. In sandy soils, pollen is preserved only in soils. In archaeological contexts, pollen and traces are found particularly in all kinds of soil traces that extend below the permanent level of the groundwater, such as ditches, wells, pits, humus packages and field layers. This category of material is also preserved in, for example, ash decks - located above the groundwater table.

Research

Landscape and environment

Palynological research is eminently applicable for obtaining information about landscape and environment and their developments over time. It is recommended that palynological research be combined with physical geographic and soil research, so that a precise layout of the landscape in certain successive periods is possible. The sample locations for landscape and environmental research are preferably outside the settlement and thus often outside the excavation. Undisturbed soils and sediments are prerequisites for good results.

Agriculture

An example for this research topic is palynological research on ash decks. This research provides information about the crops grown and the organic fertilizers applied. Ash decks are generally well above groundwater. Yet the soil conditions are such that the pollen is preserved. Pollen and traces of the plants that once stood in the field may also have been preserved in honorary loft traces. However, the preservation conditions here are less favorable and the likelihood that the pollen has been preserved is greatest in places where the fields were in a moist environment; for example, plow marks on peat that have been covered by sand or plow marks on sand that have been covered by peat or clay. Coprolites and (mineralized) manure from cattle, goats, sheep, for example, contain a lot of pollen. Analysis of these remains provides information about the food of these animals and/or the pastures where they walked.

Food- and utilization plants

The examination of botanical macro remains (seeds, fruits, etc.) is ideally suited to obtain information on food and use plants. Palynological research can provide additional information, especially about plants from which no seeds or fruits were eaten, but leaves, for example. Increasingly, this facet of pollen research is being conducted as part of archaeobotanical research. Since pollen is only preserved in its uncharred form, archaeological traces that have been in permanent contact with groundwater, such as fills of cesspools, wells and deep pits, are particularly eligible.

Botanical macro remains

Nature and occurrence

Botanical macro remains are defined as:

• various parts of plants, such as seeds, fruits, stems, threshing residues, roots, tubers;
• Remains composed of plants, such as food remains (bread, porridge), caking in pots;
• imprints, particularly in pottery and hut clay. These are usually small remains (0.25 - 5 mm), which are hardly visible to the naked eye.

Not only the size of the remains, but also the fact that they are surrounded by soil, means that they are usually not seen during fieldwork. Only a concentration of botanical material or remains larger than 5 mm, for example cherry pits or shell parts of hazelnuts, are recognizable in the field. Because these botanical macro remains are generally so small, it is common to take soil samples. A wide range of plant remains can be found in soil samples. Seeds, fruits, and charcoal are the most common plant remains. The possibilities for charcoal research are discussed elsewhere. In addition to the seeds and fruits already mentioned, plant remains that cannot be identified at first glance are regularly found in soil samples. These may be plant fibers, (charred) food remains or remains of roots and tubers. With the aid of a microscope (sometimes an electron microscope is needed) these remains can usually be identified. Also in caked layers in pots or tubs recognizable plant remains may be present, which may give insight into the origin of the caking (food or some craft process). Especially in pottery and hut loam impressions of plant remains can be easily recognized. The plant remains themselves have often disappeared. The impressions generally contain sufficient features for determination. For this component, consultation between the pottery specialist and the botanical specialist is recommended. Botanical macro remains occur in charred, uncharred, or mineralized form. In archaeological contexts, plant remains may be charred only under the influence of fire. In charred form, the material can be preserved in all types of archaeological traces. Charred remains, however, are fragile. The temperature at which the remains carbonized as well as various (post)depositional processes influence the quality of the carbonized material. In uncharred form the remains will be preserved especially under extremely dry or under oxygen-poor, wet conditions. In archaeological context (in the Netherlands) we are almost exclusively dealing with the second situation. This means that in archaeological traces that have been permanently under the influence of groundwater, uncharred plant remains may occur, for example in wells, cesspools, pits, embankments. The quality of the uncharred material is good when the tracks in which they ended up have been wet from the beginning of deposition. A poorer preservation is always related to the drying of the soil in which the remains were found. Plant remains mineralize when they come into contact with phosphates. The mineralization process preserves plant remains even in dry environments. The quality of mineralized remains is generally moderate to poor. In archaeobotanical research these remains play, with a few exceptions, a subordinate role. Occasionally, plant remains are preserved in the vicinity of metal.

Research

Research on botanical macro remains provides valuable contributions about:

• food and use plants
• agriculture (arable and livestock farming)
• landscape and environment
• trade and industry

In addition, seeds and fruits in particular are ideally suited for 14C research because - unlike wood - this material was formed in a very short time, usually within one year.

Glass

Nature

Glass is created when a mixture of silicon with potassium or sodium or lead, and calcium is exposed to a high temperature. At about 1000 degrees Celsius in an open fire, a glassy crystallized substance, opaque but with a dense structure that, after grinding, is solidified by heat: faience. It is found mainly in the form of beads. They can vary in quality from solid to friable. In closed kilns with a higher temperature at which glass melts (<1200 degrees Celsius), it occurs both transparent and opaque (opaque), depending on the addition of coloring metal oxides and firing atmosphere. Glass is encountered in many different qualities in the soil. Often it was broken in the old days and dumped as waste. Glass (even the highest quality glass) has been fragmented by mechanical (pressure) force. Glass is sensitive to moisture. Glassware from Roman-early medieval graves can be found intact in many cases. Late and post-medieval utility glass is often of poor quality, making it extra sensitive to moisture. Impure composition of the (lower quality) raw materials, too short firing time of the mixture and/or too low firing temperature are to blame. The composition of the soil also affects the quality and conservation of the glass. 

Research

Glass offers many research opportunities in the socio-economic field, including the reconstruction of trade routes and relations and technological developments in the past. The high status that glassware enjoyed in many periods resulted in fashionable products, so that the various models succeeded each other rapidly. Glass objects generally have a relatively short lifespan due to their fragility. Glass objects are therefore very suitable for determining the dating of archaeological complexes. The glass examination determines qualitative (e.g. color, quality and function of the object) and quantitative characteristics (e.g. number of shards, weight, degree of fragmentation, and minimum number of specimens). For objects and, to a lesser extent, shards, relative dating can be determined by typo-chronology.

Metal

Nature

Metal is obtained from minerals under the addition of energy. As a result, it is an essentially unstable group of materials that is prone to decay back to its original state, that of ore. As a result of (electro)chemical processes, metals in the soil are subject to corrosion. The nature and extent of corrosion depends on a large number of variables in soil conditions and in the properties of the metal. The most important variables in the soil are: the acidity and moisture content of the soil, the amount and nature of ions present, the permeability of the soil and thus the rate of exchange of ions and gases. As for the object, the homogeneity of its composition, the surface roughness and the oxidation potential of the metal are the most important factors. The fastest decay occurs in a relatively dry, sandy and well permeable soil. Metal is best retained in a soil that is wet, compact and rich in organic constituents. In these environment types, aerobic and anaerobic corrosion patterns occur, respectively. For metal from the seafloor, the same is largely true as for finds from the land. Material located underwater beneath layers of organic material will exhibit corrosion patterns similar to those of an anaerobic environment, except that the maritime environment will exhibit more aggressive corrosion due to the high salt content (chlorine). Many products were made of metal in ancient times. During archaeological research, metal objects may be found as lost objects, waste, production residues, or in the form of burial gifts.

Iron

In an oxygen-rich environment, a thick layer of corrosion in the form of iron hydroxide forms on iron. The object is converted into corrosion material at a relatively high rate. After excavation, crystal conversion can occur through interaction with atmospheric moisture and chloride ions present in this layer. As the entire corrosion layer flakes off the iron core, great damage is done to the object. Aerobic corrosion can be recognized by its large volume and brown color. With timely conservation treatment, the corrosion material on the object can generally be reasonably preserved. - Iron from an anaerobic environment exhibits a thinner corrosion that is black in color due to the sulfides and oxides present in it. The danger of flaking is less present here. Usually a well detailed iron object is still present under the corrosion layer. - In cast iron, corrosion forms between the crystals of the material in almost every soil. Cast iron is therefore not easy to stabilize.

Cupperalloy

Copper is usually found as bronze (alloyed with tin) or brass (alloyed with zinc), but objects of pure copper also occur.

• In well-aerated soils, copper alloys develop an unstable corrosion pattern, especially if there is a lot of chlorine in the soil. Usually the corrosion consists of an even dark green layer of carbonates that is broken here and there by light blue-green pustules where copper chloride can be seen: pitting corrosion. With improper preservation and deposition this material can later develop the so-called bronze plague.
• In an anaerobic environment, mainly water-soluble corrosion products are formed on copper alloys. As a result, the object is found as bare metal. This form of decay is also called moor-patina. Eventually, the object may dissolve completely in the soil.

Lead and tin

Lead and tin are reasonably resistant to soil impacts.

• In an aerobic environment, a layer of gray corrosion consisting mainly of carbonates develops on both metals.
• In an anaerobic environment a very thin layer of black sulfides develops. Lead and tin often occur in alloy with each other.

Tin can be affected by tin plague. In this not yet fully understood decay pattern, the metallic tin is converted into a looser crystal structure that has little cohesion. Tinning plague only occurs at temperatures below 13 degrees Celsius, but observations of its occurrence at temperatures below freezing are unknown. Observations of the occurrence of plague in soil are very rare.

Silver

Although silver is a fairly noble metal, it tolerates a stay in the soil worse than, say, lead or tin.

• In airy soil a gray layer of silver chloride forms. This material is sensitive to light and therefore discolors to purple in a short time. Not infrequently the object is strongly corroded.
• In an anaerobic soil a layer of sulphide forms on silver that is relatively easy to remove and under which there is usually still a little tarnished object.

Silver is often alloyed with copper so a silver object may be covered with a green copper oxide and therefore initially be mistaken for copper.

Gold

Gold is not affected by staying in the soil. However, if the gold content is low, other components present in the alloy can cause a corrosion layer to form. A brown precipitate of iron salts often forms on gold, which is easy to remove. Metal is often found in association with other materials, which complicates further treatment. If necessary, the treatment of the most vulnerable material is given priority. Mineralized remnants of decayed organic materials, e.g. wood, textile or leather, are regularly observed on metal objects. As material is very informative, this should be handled with great care.

Research

In ancient times, metal was a material that was difficult to extract and therefore expensive. In a culture, objects are often made of metal that are characteristic of occupations, households and rituals. Once excavated, they can provide a lot of information about past social structures. They also provide insight into the development of the (manufacturing) technique. Often these objects are subject to a clear development of form, which makes their use as dating material possible. Coins in particular are a reliable and relatively easy to consult dating source. Because metal objects are found in large numbers in excavations, a selection must first be made. For each object it is determined whether it provides enough information to justify an individual course of research. This means that the object will be described and depicted during the research and that it must be possible to trace it afterwards for verification. Objects of high informational value are therefore given a unique find number and, if possible, preserved. Objects with a lower information value will not be treated individually during further research, but at most described, weighed or measured per trace as a group. The selection of the material is made by the field archaeologist, in collaboration with the material specialist and preferably also with the preservation expert. The information gathered during research forms the starting point for the social and economic interpretation of a context or site. A number of specific investigation techniques can also be mentioned with regard to the material category 'metal':

• X-ray examination. If cleaning and preservation are not possible, individual objects can be examined and depicted using X-rays.
• Microscopy. With optical or electron microscope, the surface is studied to gather information on processing and use traces and on mineralized organic residues.
• Metallic analysis. A polishing plate from a sample of the object is studied microscopically. Manufacturing technique, machining and corrosion leave characteristic traces.
• X-ray fluorescence and other elemental analysis techniques. The material composition of a metal sample is determined. Indications for material use and processing technique can be found here
• X-ray diffraction. By determining the crystal structure, information about corrosion processes can be obtained.
• Mass spectrometry. The ratio of the different isotopes of a metal is determined. This can be used to determine the origin of the material in some cases.

Prior to microscopic examination, the material to be studied may not be impregnated. The other analytical research techniques do not impose any requirements on the handling of the finds, because they assume a sample from the inside of the material.

Natural stone

Nature

In archaeology, the term natural stone is used to distinguish between stone and stony materials that are artificial, man-made, such as pottery and slag. Stone is a general name for rock ("rock"), which may be found as individual pieces, either cut or crushed, in archaeological contexts. Rocks are naturally occurring aggregates of one or more minerals. They can be broadly classified into three main groups:

1. Magmatic rocks: formed by solidification of magma, which is liquid rock material. Examples: granite, bazalt, tephrite.
2. Sedimentary rocks: formed by various processes (weathering, erosion, deposition and possibly charring) at (or close to) the earth's surface. Examples: sandstone, siltstone, limestone, flint, but also loose rocks such as clay and sand belong to this category.
3. Metamorphic rocks: rocks that have undergone a change in structure and/or mineralogical composition at increased temperature (and often also increased pressure). Examples: slate, marble, quartzite.

Archaeologists often refer to natural stone and flint as if they were two adjacent, distinct categories. This is nomenclaturally incorrect (cf. "animals and cows"). Since flint was the most important raw material in the Stone Age, a specialism of its own has developed, neglecting attention to other stone types. In these specialties much knowledge has been developed about typology, production techniques and traces of use, which could also be useful for objects made of other stone types used in the Stone Age. It is therefore recommended that the flint specialist extends his knowledge to these types of stone, or that he works very closely with the specialist for the other types of stone. For this reason, reference is made to the chapter on flint for the treatment of early stone material. Rocks have been used in the past for the production of various types of tools (grindstones, grinding stones, mortars, weights, etc.) building and sculpture, including sarcophagi. Rocks have also been mined for the production of pottery, glass and metals (ores are also rocks!). Also of interest are organogenic sediments, such as coal, amber, coral, and git. Ornamental stones may also be found, such as precious stones (topaz), semi-precious stones (garnet/almandine and various quartz varieties, etc.). In our country, many stones are found as boulders/rolling stones, while others are quarried from solid rock

Research

Natural stone occurs at virtually all archaeological sites, from the Paleolithic to the Modern Period and it is surprising that, with the exception of flint, it is a stepmotherly find category, by no means always determined and sometimes only partially collected. The absence of solid rock in the Netherlands is precisely why this find category is so rich in information. In addition to the typology of certain objects, it provides insight into the crafts carried out at the site, into areas of activity and the intensity thereof, for example milling, fishing, grinding (metalworking). It also provides insight into the technology of tool production. From the Roman period onwards, natural stone research contributes to the knowledge of building materials and techniques. Provenance determinations of stone contribute to knowledge of trade contacts and networks. In some cases, natural stone can also contribute to the dating of the site, this is especially true of Roman and (Early) Medieval material. The regular research includes the macroscopic determination of the stone type and the object that was made from it. This includes qualitative features (color, shape, stone type, machining/use traces, type of artifact, typo-chronology, post-depositional traces) and quantitative features (size, number, weight and degree of fragmentation). Specific research is used to quantify the above qualitative properties, such as gaining a better understanding of stone types and their areas of origin; nature of use/production traces; conservation status and degradation processes of the different stone types in different soil environments. The following techniques are commonly used:

• microscopic analyses (transmitted/striking light);
• X-ray diffraction (XRD), for mineralogical research.
• microprobe and scanning electron microscope (SEM) for in situ analyses in an object.

In addition, physicochemical analysis methods exist, such as neutron activation analysis (NAA), X-ray fluorescence (XRF), infrared spectrometry (IR) and many others to determine composition (major and/or trace elements). In some cases, it may be useful to determine physical properties such as specific gravity or breaking strength.

Unburned/burned bones

Nature (animal)

Animal remains may be found as individual skeletal elements or fragments thereof (slaughter, consumption and production waste), but may also be found in anatomical context and form part of a more or less complete skeleton. The animal may have been sacrificed or otherwise deliberately buried, or may have died a natural death. The skeletal elements may be undamaged, but may also show signs of foraging, cutting, felling, or other processing. Animal remains may also be used to make objects (artifacts) or be part of an object composed of multiple materials (e.g., bone handle of an iron knife).

Research (animal)

The importance of animal material for archaeology can hardly be underestimated. Among other things, the find group can contribute to the reconstruction of the landscape, to the knowledge of the development and health status of (domestic) animals in the past and to the interpretation of numerous socio-economic and religious aspects of past societies. These may include, for example, the food economy (whether there was, and if so, how hunting and animal husbandry were practiced), the relationship between meat consumption and social status, and craft production processes.

The archaeozoological survey establishes qualitative (e.g., animal species, skeletal component, dentition) and quantitative characteristics (e.g., number, weight, degree of fragmentation). These basic data form the starting point for the archaeozoological investigation of a context or site. Objects can sometimes be dated typochronologically. There are some specific research forms and techniques:

• dating: the absolute age of bone material (burned and unburned) can be determined by 14C dating;
• DNA analysis;
• Chemical analysis;
• Histological examination: small samples can be used to determine the difference between humans and animals, as well as the species. The state of preservation of the bone can also be determined;
• Micro-wear analysis

Micro-wear analysis can be used to determine the difference between humans and animals, as well as the animal species. The state of preservation of the bone can also be determined;

Nature (human)

Human skeletal material can be found in various forms. In inhumation graves, the skeleton usually lies in an anatomical position in a grave. The position in the grave can vary greatly. We distinguish between primary and secondary inhumation graves. Primary inhumation graves are those in which the intact skeleton is found, as it was deposited after death. Secondary inhumation graves are characterized by the fact that there is treatment of the body after death and before interment. In the case of a secondary burial, the parts of the skeleton are usually no longer in anatomical alignment. In addition to inhumation graves, cremation graves also occur. After burning, the cremation remains may have been left at the cremation site or placed in an urn or loose in a pit. Not all human skeletal remains are found in the context of an intentional burial. Bodies may have been abandoned or left behind without being formally buried. In addition, once deposited in the ground, skeletal elements may have been taken out of context by various processes and activities. Such skeletons are often incomplete, and recovered parts may show feeding marks, cut marks, bone fractures, and evidence of secondary burning.

Research (human)

From the skeleton, data on gender, age, height and pathology can be derived. As a result, skeletal material provides information about the demographics and health of past populations. Relationships to the food economy and lifestyle are important here. In conjunction with the archaeological context, such as tomb type and accessory items, traditions in the treatment of the dead are highlighted. Data on gender and age are important for the study of the social and cultural aspects of burial ritual within a population and/or between different populations in space and time. The study of human skeletal elements is part of physical anthropology. Physical anthropological research includes the inventory of skeletal parts present, the determination of gender, and the estimation of age and length. In addition, bone measurements, non-metric variation, and any pathological changes in the skeleton are documented. The description of cremation remains also includes data on weight, fragmentation, and degree of combustion. Skeletal material can also be utilized for specific research:

• 14C dating: for the determination of the absolute age of bone material (burned and unburned); if AMS immediately also carbon and nitrogen isotope research! * DNA analysis: for the determination of genetic relationship and pathological examination (sample collection by or in consultation with specialist).
• Chemical analysis: examination of stable isotopes and trace elements for the determination of paleo diet, toxic load and origin (arrange samples for biochemical examination with specialist).
• Entomological examination: for the study of insects from the burial context (sample collection by specialist).
• Microscopic examination: by means of histological examination it is also possible to determine the biological age of an individual. Here, the pipe bones and the teeth are used. Furthermore, histological examination can be used to further investigate pathological changes in the skeleton (samples do not need to be taken in the field).
• Palynological examination: regional/local origin of individual, e.g. from floral by-products in burial pit (sample taken by specialist).
• X-ray examination: to determine age at death and diagnose pathological changes in the skeleton. * Facial reconstruction: to reconstruct the face of individuals from the past on the basis of the skull.

Slags/sintels

Nature

This chapter deals with pyrotechnic process residues, or waste products released from exposure of material to fire. When first selected in the field, the following materials often end up in the slag category: iron slag, iron ore, burnt loam, and sintered material. A slag is a waste product of metal production, processing, and nonmetallurgical processes, such as lime burning, brick production, pottery production, and glass production and processing. Given its resistance to secondary degradation, the material will occur in virtually every site from the Bronze Age onward. An exception is burnt loam, which can in fact be very fragile.

Ironslag

Iron slag can come from several processes: production of iron, and the so-called reheating and forging of iron. Production, and reheating slag are found comparatively less often, much more often they are forging slag. Production slag can lie in situ (slag heap, in or next to a furnace, pit furnace slag in pit furnace). Reheating and forging slag are also found in situ (hammered slag in a forge, forging slag in a forge hearth), however, usually the larger specimens are found in a waste pit or scattered throughout the excavation. Production slag and forging slag can be roughly distinguished as follows: production slag often has a metallic surface and is not magnetic; forging slag often has a rusty appearance and is magnetic; reheating slag may have characteristics of both previous types of slag.

Iron ore

This may be found as ore at an iron production site or as building material in a foundation.

Burned or sintered clay

This is often found with the slag material. Burnt clay from crucibles or molds may occur along with slag, but it need not. The latter materials are used for melting and casting metals such as copper and bronze and not in early iron processing. Prior to an excavation, the results of field explorations should be discussed with specialists. In particular, from drilling results, predictions can be made about the location and nature of the material to be expected.

Research

Snail research provides insight into the technology and organization within a site and the socio-economic conditions within which a site functions both at the regional and supra-regional levels. In addition, snail research provides knowledge of the material culture and contributes to the overall picture of the site. Research questions and possibilities are strongly dependent on the period and soil conditions, therefore a breakdown is given below into specific points of interest per period and find conditions. In the Netherlands a distinction is made between a wet and a dry context. The primary elaboration of the study of snails includes determination, weighing, dating and determining the archaeological context. From this material a selection is then made for further investigation. After making a representative sample, the remaining material can be discarded. In addition to the snail research, all botanical samples are scanned for the presence of small snail material using an x-ray machine. In consultation with the botanical department the samples are processed further. There are a few specific research forms and techniques

• Chemical analysis (XRF, ICP_AES, XRD)
• Microscopic analysis (incident and transmitted light)
• Microprobe/SEM

Unburned wood

Nature

In principle, in northwestern Europe in all oxygen-poor and wet environments below the groundwater level wood can be found in an uncarbonized form, as (un)processed material from anthropogenic layers, or as trunks, root systems and twigs from natural layers. Stored under good conditions, the wood looks firm and solid immediately after uncovering, however, as soon as it is exposed to air, sun and wind, the quality deteriorates noticeably within a few hours. Oxygen, heat and light in particular promote the growth of maggots, fungi and bacteria. The wood shrinks, cracks and starts to disintegrate from the very first moment. In practice, wood is one of the most vulnerable material groups in an excavation. In addition, this material group often involves large structures and a large volume whose drawing and processing takes a lot of time. In an excavation where a lot of wood is to be expected, ample time should be planned for wood specialist research.

Research

Wood was one of the most widely used raw materials in the past and was used as a building material for houses, roads, bridges and revetments, but also for all kinds of different objects, from culverts to small household objects. Given the use of wood for a wide variety of purposes and its diverse forms, this find group provides insight into:

• material culture;
• socio-economic aspects such as trade, seasonal labor and degree of organization of a community;
• the development of technological ability through processing techniques; - the natural wood vegetation in the past;
• the use of this natural resource by man, for example, through management of local forest stands.

In addition, a very important aspect is the possibility of dating by means of:

• dendrochronological research;
• 14C dating;
• used processing techniques that in some cases can give a very rough dating.

If one assumes that a lot of wood will be found in various structures at a site, a wood specialist should be consulted during the formulation of the Program of Requirements and/or prior to the survey to ensure that the best possible information is obtained and that research questions are formulated that fit within, or complement, the general issues of the site to be surveyed. Sometimes the true potential of wood research for specific deposits becomes clear only during excavation.

Wood in burned or hardened state

Nature

Charcoal is created by slow and incomplete combustion of wood under low-oxygen conditions and at temperatures of 300-400 degrees Fahrenheit. It can be an unintentional by-product of an incomplete combustion process such as in cremations, in fireplaces or incidental burning of a house. For some industrial activities such as for metalworking, wood is intentionally converted to charcoal under controlled conditions. Wood in charred form is highly resistant to biological attack and therefore can be found in both wet and dry environments, but it is very sensitive to mechanical pressure. Wood is often found in mineralized form in cesspools, among objects composed of, for example, wood and metal (lance shafts, coffins and the like).

Research

The information from charred wood from archaeological contexts is in the area of:

• cultural information, such as wood choice (from functional, religious considerations and the like) and trade;
• vegetation reconstruction;
• dating 14C research.

The importance of charcoal research and its priority within the overall objectives of a site depends to a large extent on the other possibilities for obtaining the requested information on, for example, vegetation and to what extent charcoal provides additional or stand-alone information. There are sites where organic material has only been preserved in charred form and in that case information about vegetation cannot be obtained in any other way than from this charred material. Temporary hunting camps from the paleo and mesolithic periods in particular are often found only in the form of hearths.

Shells

Nature

Shells are the hard outer skeletal parts of the invertebrate mollusks or shellfish. This animal group is also called mollusks. In a further classification, we distinguish, among others, snails and bivalves (mussels). Cuttlefish also belong to the molluscs. Sometimes we can find the (internal) dorsal shields or jaws of cuttlefish during excavation. Shells have been used in many ways by humans for hundreds of thousands of years and their contents eaten. The science that deals with shells is called malacology. Shells consist largely of carbonated calcium (calcium carbonate). In many cases, the wall is composed of three layers: an inner layer of lime (pearl layer), a middle layer of lime (prism or porcelain layer), and an outer layer of conchioline (epidermis). The epidermis is usually brown or black and usually very thin. The material is horny and is similar in composition to chitin (as found in insects). Usually shells are firm and can be preserved in the soil for a long time and well. However, chemical processes in the soil can cause the shell to soften or dissolve completely due to acids. In an originally lime-free soil, shells are not to be expected. If the sediment is calcareous, however, large numbers of shells may be present in both natural and anthropogenic deposits. Soil movements (including excavation) may cause the larger, thin shells in particular to disintegrate. Shells or shell fragments can be found in all sorts of places. The animals may have lived there, shells may have washed ashore, they may be food remains of humans or animals (shell heaps) or remains of bait and furthermore they may have served as jewelry (grave finds), decorations (ornaments), inlays in other materials, beads, buttons, cameos, means of payment (cash cow), pearl suppliers, musical instrument, tools, container, tray, ritual/sacrifice, dyes (purple), road paving, building material e. d. In broken form, we find shells as magings in pottery, manure, medicine, grit for poultry etc.

Research

Shells in an archaeological context can provide important information. Especially in prehistoric coastal settlements, mollusks may have been an important component of the diet. In favorable cases even the season of collection can be determined with the help of grinding plates. Shells make a good contribution to the reconstruction of part of the environment. Questions such as what did a coastal area look like, did the water flow, did animal material change the salinity, did forests occur can be answered with them. Sometimes changes in the environment due to natural or human causes can be shown with the help of a mollusc diagram (development of species and numbers per layer). In a larger context, shells are suitable for reconstructing past coastlines or for determining climate. Species that do not belong in the study area can say something about trade. Rare shells in graves indicate status. Smaller specimens of a species over time sometimes indicate overexploitation. Examination of the shell aging of pottery can provide information about the origin of the pottery clay. Some species are characteristic of certain periods. Shell research first looks at the species present, their numbers, and in the case of eaten species, size classes and weight. Further investigation may include:

• Establishing the age by means of 14C dating, Uranium/Thorium and amino acid racemization (consult with specialist, for example in the case of amino acid racemization the material may not be heated).
• Composition of shell (chemical analysis).
• Period of dying (growth rings examination using grinding plates).
• Traces of use, traces of processing (do not wash with strong brushes, do not let it come into contact with metal, so do not sieve on metal either but on plastic sieves for example, do not number the shell but put all the shells in a separate bag with number, do not impregnate/conserve, drying is allowed).
• Changes in collection location, - intensity or environment (changes in size within species over time).
• Provenance by establishing the presence of remains or boreholes of other organisms on or in the shell (do not wash with hard brushes, etc.).
• Climate (O16/O18, C12/C13).
• Composition and origin of water (stable isotope research)
• Pollution and industrial activities (geochemical study).

Insects and mites

Nature

This chapter deals with chitinous remains. They are remains of the large group of arthropods (Arthropoda), which includes the crustaceans, centipedes and millipedes, mites and other arachnids and insects. In archaeology, insects and mites are primarily used. Edible crabs and other crustaceans are similar to bone material in terms of collection and processing due to their size. Chitin is a very strong substance that can be preserved for a very long time under the right conditions. Favorable conditions include wet anaerobic (oxygen-poor) conditions, but insect and mite remains can also be preserved well under extremely dry conditions. Strong fluctuations in humidity are disastrous for the quality of preservation, both before and after sampling. Only exceptionally will remains of mites or insects be visible to the naked eye during an excavation. These are usually concentrations of fly pupae (e.g. in graves or cesspools) or the wing-cases of large beetles. In any deposit, however, the microscopic remains of arthropods can be detected. Of course there are large differences in density, quality of preservation and thus usability of the faunas present. As a rule of thumb within Dutch archaeology, wetter, lower lying deposits are more likely to yield usable samples than higher, drier deposits. In some cases arthropod remains are carbonized or mineralized and can then still be reasonably identified. In addition to soil sampling, there are a number of more specific ways to collect arthropods within an archaeological context. For example, remains of (parasitic) insects can be found between the teeth of combs and in tufts of hair or textiles, and remains of all kinds of informative organisms can also be found on or in human remains.

Research

Research on arthropod remains has many possibilities. On the one hand, information can be obtained about climate and landscape, where with the help of winged insects relatively rapid changes in these can also be detected. On the other hand, mites, unwinged insects and insect larvae can provide information about conditions on a very small scale. Because there are very many species of arthropods and because they live under very different and often very specific conditions, the information can also relate to many things and also be very specific. For example: predatory mites in manure on its producer, stock insects on conditions of food storage, ectoparasites such as lice and fleas on their host, fly pupae and other insects on conditions during and prior to an inhumation (compare forensic entomology). In this way, the remains of arthropods can provide additional information on livestock and agricultural techniques and thus on the food economy, but also, for example, on material use and living conditions. Besides being used as indicators, mites and insects often played an important role in human life: as pests for their own health, in animal and plant production, in storage, and in used materials, but sometimes also as food or medicine. The regular survey normally leads for each sample to a species list, quantitative or otherwise, of one or more animal groups. In combination with other data, this is the basis for interpretations. Observations concerning, for example, conservation status or fragmentation patterns can be useful at a later stage in interpreting taphonomic processes. In practice it proves to be almost impracticable not to work with a two-step research strategy: first an appreciation study followed by an analysis phase of (a selection of) the material. The absolute age of chitinous remains can be determined by means of 14C dating, whereby as a rule it can be assumed that an object is dateable using the accelerator method as soon as it is visible to the naked eye. Furthermore, using the Mutual Climatic Range method, an attempt can be made to quantify the paleo-climatic data of larger find complexes.

Leather

Nature

Leather means an animal skin that has been treated in some way to prevent decay. In practice, archaeologists in northwestern Europe will only have to deal with vegetable tanned leather, since other methods are not water-resistant and thus rarely preserve it in our climate. In a few special situations (e.g., in crypts or under church floors) leather may have been preserved dry. In that case, the method of handling is similar to that of dry textiles. In principle, leather objects can be expected in all anaerobic, mainly water-rich environments (embankments, mounds, deep pits, canals, old river courses, embankments and urban expansions). When digging in such situations, the special requirements for cleaning, conservation and storage of organic materials (leather, wood, textiles) must be taken into account from the start, even on the excavation site itself. All these materials must be treated immediately, and cannot be put in a tub of water 'for the time being'. The project leader will have to have the processing route well in mind beforehand. In the financial planning for each research project in waterlogged conditions, a fixed percentage of the budget must be reserved in advance for the conservation, storage and study of organic materials. The experience in London shows that this reserve is in the order of 10-20%.

Research

Leather is the plastic of antiquity and was used for a variety of purposes. The highly varied objects - as well as production waste - provide insight into material culture, the nature of settlement, the organization of production and industry, prosperity and trade relations. The most common product is leather footwear, which can be dated well in both the Roman and Middle Ages and also provides information about population, health and status. In Roman times leather is used extensively for military purposes, such as tents, horse harnesses, saddles, shield covers and other military equipment. In the Middle Ages, belts, purses, sword and knife sheaths, cases for books, spectacles and the like are common in addition to footwear. Ritual deposits of footwear should be taken into account when emptying wells. Determination of animal species provides information on animal husbandry. Currently, the usefulness of chemical examination of leather is not proven for wet material. For dry leather, one should consult the specialist about research possibilities. Leather research focuses on object identification, quantitative analysis of large find groups, and interpretation within a cultural context.

Textile

Nature

Under special conditions, depending on the acidity and relative humidity in the soil, textiles can be preserved. Textilia, made of both plant (linen, cotton) and animal (wool and silk) fibers, can remain more or less intact under extremely dry conditions (digging, cavities in structures). In contrast, in the predominantly acidic and wet soils, only the animal fibers are preserved. Plant tissues are further preserved in the Netherlands only if they harden by mineralization in very calcareous environments (cesspools with mortar remains). In early medieval graves on sandy soils, textiles may be preserved (indirectly) in the oxidation layer of a metal object that was given to the deceased as an accessory. During centuries of residence in the soil, most textiles are affected by bacteria and fungi. In addition, textiles were often cut up into smaller pieces. Therefore only relatively small fragments are excavated. Large pieces such as recognizable garments are mainly found under wet conditions (moat, peat) or in dry graves in churches.

Research

Although clothing is one of man's basic needs next to food, because of the great impermanence of the material, very little is known about clothing in pre- and protohistory. In museums, one finds only clothing from the seventeenth century onward. These are the clothes of the higher classes or of historically famous people. Clothing of the common man is missing. This was then endlessly repaired and/or cut into smaller pieces usable for other clothing. Many textiles ended up as cleaning rags. Given the low probability of finding textiles, it is necessary that every fragment be examined, even the smallest shred. A lot of information can already be extracted from 1 cm2. The processed material of each textile find is examined. With luxury fabrics one can expect metal threads, whether or not oxidized. Furthermore, the technique of fabrication is investigated: felt-making, spinning, weaving, braiding, knitting, embroidering, sewing, etc. Thanks to the study of textiles through the ages, developments in applied materials and techniques can be investigated. In the case of larger pieces, one can reconstruct clothing. The occurrence of valuable fabrics provides information about trade and status. When starting an excavation in an area where a lot of organic material is expected, the (financial) planning has to take into account the conservation and study of textile finds since, textiles have to be treated soon after the excavation (e.g. fungal growth can occur within a few days/weeks). If one wants to apply specific research techniques then special measures have to be taken before cleaning.

Ceramics from Roman times, Middle Ages and New Times

Nature

Ceramics is a collective term for objects made of fired clay. The physical properties of ceramics vary widely, depending on the raw materials used, the clay preparation, the forming techniques, and the techniques of firing and possibly glazing. Archaeologists often make a not very clean distinction between "hand-formed" and "turned ceramics" with the former being made (almost) entirely without a turntable. In everyday practice, the designation "turned ceramics" (turntable pottery), although in fact entirely unjustified, is used not only for ceramics made with a turntable but also for ceramics molded in molds or even for objects, which were made in a combined hand-formed and turned technique (e.g., plates and frying pans of late medieval red earthenware). The end result of the raw material preparation and firing of the clay is referred to by the term "bake". Bakes are usually distinguished according to grain size distribution, type of magnesium, hardness, porosity, structure of the fracture surface and colors, sometimes also the surface treatment. Various types of clay may have been used as raw materials, possibly mixed with other types of clay or raw materials (for example, lime in post-medieval faience). Often the firing contains a sand fraction, with a grain size of between 0.1 and 1 mm, sometimes also other stone inclusions up to a grain size of a few millimeters ("pebbles", "gravel"), whereby the quantities can vary greatly. This sand fraction may have either been naturally present in the mined clay or may have been added subsequently during clay preparation. Although technically only the latter may be called "magering," in practice all grains visible to the naked eye are often referred to as "magering." A biscuit may also contain magering from organic material (shell grit, straw, usually only visible as cavities after the clay has been fired) or from pot grit (chamotte, sometimes difficult to distinguish from discolored spots from natural iron concentrations in the clay). Controlling higher temperatures can produce harder bricks. In an oven, the temperatures can be raised so far that the recrystallization point ("melting point") of a clay type is exceeded and the clay changes its crystal structure. In this process, the clay may become sintered and the biscuit becomes very hard and the porosity is reduced to a glass-like density. One then speaks of "stoneware" or "porcelain". In other cases, the biscuit is described as "pottery". Earthenware has varying degrees of hardness but there are no well-defined standards for this. Sometimes there is a big difference between the hardness of the surface and the hardness of the interior, "the fracture".

Research

Ceramics are collected for a variety of purposes:

• dating of ground tracks,
• socio-economic aspects of find complexes,
• research into the use of objects,

research into typochronology, production, trade and consumption of ceramics.
Numerous methods and techniques are in use in the study of ceramics. Because of the large scope of the period described here (various period specialties) this text is not the place to go into more detail on the identification of ceramic types, research into pottery technology, traces of use, production, trade and consumption of ceramics, not to mention the possible use of natural scientific means. The field archaeologist involved is also expected to have some specialist knowledge in this area. Some remarks can be made about quantification. Because there are many different methods, the comparability of research results is not promoted. After washing, most archaeologists fit as many shards as possible together, identify them and count the numbers. Unnoticed in the process, different methods are adhered to. Examples: making an inventory of only the rims and/or bases or also of the wall fragments, making an inventory of fragments without first fitting them or after fitting them, counting or not counting the remaining wall fragments that after fitting are not connected to rim or base fragments, or counting wall fragments of rare, or decorated, or specifically shaped ceramics but not counting those that are less easy to identify. How does one deal with wall fragments that most likely belong to certain edge or bottom fragments but do not fit. It is therefore advisable to record how the counts were made, because the methods are not nearly as universal as is sometimes thought. Meanwhile, other methods of quantification are also coming into use, such as measuring edge percentages or weighing find material.

Prehistoric pottery

Nature

This chapter covers prehistoric pottery, both crockery and objects made of fired clay. Dishware includes objects such as pots, bowls, platters, and other tableware. Crockery is made of clay. Depending on the raw materials mixed through the clay and the firing method, the pottery is hard or soft. The scatter may consist of pottery (chamotte/sherd grit), organic material (plant remains, straw), mineral maging (gravel, stone grit, crushed quartz, feldspars, granite). The objects were usually fired in an open fire where the temperature remained low and the pottery did not completely harden. Baked clay objects may have been used as weaving weights, net weights, or spinning weights. These objects are usually not fired hard and sometimes not fired at all. The objects are generally not scorched. Shards of pots may also have been reused as spinning wheels or weaving weights. This can be seen by the rounding of the fracture surfaces (beware of weathering of the material, as this gives almost the same result).

Research

Several research options exist with respect to prehistoric pottery: -Macroscopic examination for technological and morphological characteristics.

• Grinding research to determine the origin of the firing or the composition of the magma or to establish the method of manufacture.
• Dating research, typochronological or via 14C dating.
• Function determination of the pottery, possibly to determine the context of use.
• Chemical analysis (XRD, X-ray diffraction for mineralogical research of the magering).
• Diatom analysis : determination of fresh or salt water deposition of used clay

During the pottery analysis qualitative (such as for example magering, pot shape, firing method, decoration, edge and soil type, weathering, color, typology, periodization, secondary traces and post-depositional traces) and quantitative characteristics (such as number of sherds, weight, pot size (diameter, wall thickness), degree of fragmentation) are determined. These basic data form the starting point for a typo-chronological classification of the pottery complex.

Fishremains

Nature

In broad outlines, the treatment of fish remains is in line with what has been said about animal material. As far as the nature of the fish material is concerned, a distinction can be made between three categories. Firstly, there is a fundamental difference between fish with a predominantly cartilage skeleton and fish with a bone skeleton. Of the former category, one will generally find little or nothing, while the skeleton of bony fish is as resistant as that of birds and amphibians. The third category is the scales. Some scales are firm and compact, others clearly composed of segments. Scales of the latter type tend to fall apart when dried.

Research

Examination of fish material makes it possible to determine whether it originated in a freshwater, brackish or saltwater environment. Fish material also plays a role in reconstructing the food economy, whereby sometimes (in a historical context) status differences between social environments can be noted. In contrast to regular research on animal material, fish material is not weighed.

Flint

Nature

For prehistory, especially the Stone Age, flint is one of the most important sources of information. Flint does not decay and is found in large numbers. Processing flint finds in the field is not as complicated as with other material groups. This chapter deals exclusively with flint, including some common quartzite types that are processed in the same way as flint, and the various themes involved. The focus is on the most commonly encountered issues. Topics such as survey design and excavation methods and techniques are not covered here. Not all flint found at a site has been brought there by people. In the parts of the Netherlands that were covered by glaciers during the Saale glaciation and in the parts of South Limburg with flint-rich deposits, flint not worked by humans must also be taken into account. Humans used flint from secondary sources: glacial deposits, rivers and beaches and from primary occurrences: the limestone deposits in South Limburg. Thus, a large number of different raw material groups can be distinguished, each with its own specific characteristics. Quartzite types from only a few primary sources were also used, such as Wommersom in Belgium. The examination of raw materials provides much information on long-distance contacts. Flint is very resistant, yet weathering can occur. Various gloss and color changes are then visible on flint. In many cases this is also an indication that these are ancient, often Paleolithic, artifacts.

Research

Due to the large quantities of flint worked in the past, flint is ideally suited for locating sites. In an excavation of course the spatial information is of great importance. This is the basis for the recognition of activity areas and the demarcation of sites. The refitting research -in which an attempt is made to fit all flints back together again- also makes an important contribution here. The technical analysis of the processing of the flint, the research of the raw materials used, the tool typology and the traces of use, are the most important research methods to determine the age, cultural attribution, the degree of disturbance and the function of the site. These are all building blocks with which an attempt can ultimately be made to reconstruct what happened at the site in the past.

References

• Bisdom, E.B.A., Henstra, S., Jongerius, A. enThiel, F., 1975: Energy-dispersive xray analysis on thin sections and unimpregnated soil material. Neth. J. Agric. Sci., 23 (2), 113-125.
• Bisdom, E.B.A., en Schoonderbeek, D., 1983. The characterization of the shape of mineral grains in this sections of soils by Quantimet and BESI. Geoderma 30, 303 - 332.
• Courty, M.A., Goldberg, P. and Macphail, R., 1989: Soils and micromorphology in archaelogy. Cambridge. Jongerius, A., en Heintzberger, G., 1975: Methods in soil micromorphology; a technique for the preparation of large thin sections. (Soil Survey Papers 10). Wageningen. Kooistra, M.J., 1990: The future of soil micromorphology, in: L.A. Douglas (red.), Soil micromorphology. Amsterdam, 1990, 1-8.
• Kooistra, M.J., 1991: A micromorphological approach to the interactions between soil structure and soil biota, Agriculture, Ecosystems and Environment 34, 315-328.
• Mücher, H.J., Slotboom, R.T., en ten Veen, W.J., 1989: Een enkeerdgrond palynologisch ontsloten: toepassing van de palynologie bij de toetsing van en aanvulling op archvalische data. KNAG Geografisch Tijdschrift 23, 2: 109 -118.
• Murphy, C.P., 1986: Thin section preparation of soils and sediments. Berkhamsted