Archaeological Pottery Research Articles

Multi–mode Sample Introduction System (MSIS) as an interface in the hyphenated system 2 HPLC–MSIS–ICP–OES in simultaneous determination of metals and metalloids species

The paper presents a usage of a new hyphenated technique, wherein a Multi–mode Sample Introduction System (MSIS) was applied as an interface of two high pressure liquid chromatography units and inductively coupled plasma optical emission spectrometry (2 HPLC–MSIS–ICP–OES). Simultaneous separation and detection of non–hydride forming and hydride forming elements was possible due to the application of two different HPLC column, cation–exchange and anion–exchange respectively. The method was able to determine 15 elements quantitatively with a distinction of three arsenic and two iron species and it was validated obtaining acceptable LODs (2.67–28.7 μg L−1) and recoveries (80–120%). The method applicability was presented and confirmed on 5 varied sample matrix types i.e. post–glacial sediments, yerba mate (Ilex paraguariensis), soil samples located in the proximity of industry wastes disposal site, river sediments, and archaeological pottery. In addition to the above, unknown Cu, Fe, Mn and Zn species were detected in real samples (qualitative speciation analysis) and the identification was attempted according to the literature.

Microstructure and Damage Assessment of some Ptolemaic pottery objects at Tell Abu Yasin in Sharkia, Egypt: Case Study

Microstructure and Damage Assessment of some Ptolemaic pottery objects at Tell Abu Yasin in Sharkia, Egypt: Case StudyThe research has concluded some great importance results in identifying technological process and damage of pottery objects at tel Abu Yasin in Sharkia. Abu Yasin site is one of the most important archaeological sites in Sharkia governorate and east of it dates back to Ptolemaic time age. Many tests, examinations and analyzes were performed to diagnose damage manifestations of some archaeological pottery pieces. Examination and analysis methods were Polarized Microscope (PLM) , Scanning Electron Microscope with Energy Dispersive of X-Ray Unit SEM- EDX , X-ray diffraction analysis ( XRD) and thermal analysis ( DTA ),they have played an important role in identification of archaeological pottery technology, surface treatment, manufacture and its deterioration. The research has proved that the clay used in that our archaeological pottery is Nile Clay in tel Abu Yasin site, while tempers (additives materials) are sand quartz , grog pottery powder, limestone powder calcite , and burnt straw, the used shaping technology methods of our pottery objects are potter wheel for all three pottery objects, the surface treatment is slip layer in all pottery objects in our site Tell Abu Yasin site , burning atmosphere inside the kiln was reduced atmosphere for the first pottery pot and oxidized atmosphere to the second and third pottery pieces. All archaeological Pottery objects in our site suffer from factors of Physiochemical damage, our archaeological pottery pots and plate suffered from soil sediments due to burial in the soil, in addition to phenomenon of fracture, scaling, cracking, weakness, fragility, peeling, stains, poor physical structure and crystallization of chlorides, sulfates, carbonates and phosphates salts as a result of burial in saline clay soil in our site. The research recommends that restoration; treatment and maintenance of these archaeological pottery pieces should base on results of tests, examinations, analyzes and damage assessment that has been proved by the researcher. The research has concluded some great importance results in identifying technological process and damage of pottery objects at tel Abu Yasin in Sharkia. It had proved that used clay was Nile clay; additions were sand, burnt straw, grog and limestone powder. Surface treatment was slip layer in samples, burning atmosphere inside the kiln was reduced for the first pot and oxidized to the second and third piece, it also illustrated mechanical and physiochemical damage, whether from manufacture defects or effect of burial environment, it has proved presence of soil sediments, crystallization of salts carbonate, sulfates, chloride, cracking, peeling, stains and poor physical structure. The research recommends that it should be treated and maintained based on the results of the tests and analyzes that have been proven by the researcher.AcknowledgementI extend my sincere thanks and appreciation to Prof. Dr. Ibrahim Al-Qalla, Dean of faculty of Archeology,zagazig university in sharkia for his assistance and encouragement. I also offer my thanks and gratitude to antiquities inspectors in tell basta in Sharkia Government east of delta.

GIUSEPPE FOLGHERAITER: THE ITALIAN PIONEER OF ARCHAEOMAGNETISM

ABSTRACT The history of the science of archaeomagnetism conventionally starts in 1600 with the publication of William Gilbert's monumental work De Magnete, but the theoretical basis of this scientific field has to be positioned at the end of the nineteenth century. In Italy at that time, a number of scientists such as Giambattista Beccaria, Macedonio Melloni and Silvestro Gherardi, were working on magnetic field characteristics and their work variously contributed to the early study of Earth and rock magnetism. A major contribution to the birth of paleomagnetism as a science, and archaeomagnetism as a dating technique, was produced by Giuseppe Folgheraiter (1856–1913) by means of his research on the magnetic properties of volcanic deposits and his attempts to date ancient pottery of different epochs based on the magnetic properties of clay materials. Initially, Folgheraiter studied the rock magnetism of the volcanic rocks of Latium where he replicated the findings of Macedonio Melloni, who had studied Vesuvius lavas, and found that volcanic rocks are affected by a permanent magnetization. In addition, Folgheraiter verified the discovery by Filippo Keller of the Punti distinti. Folgheraiter also made the innovative proposal that lightning strongly influences the magnetic properties of lavas resulting in magnetic disorder. The main analytical effort of Folgheraiter at the end of the nineteenth century was dedicated to the study of the variations of magnetic inclination in different epochs as registered in archaeological pottery. He produced archaeomagnetic sets of analyses on 191 samples grouped into 10 epochs, that resulted in the first reconstruction of a geomagnetic secular variation curve (SVC). Even if nowadays the Folgheraiter analytical results have been replaced by more precise measurements, a great portion of the development of modern archaeomagnetic techniques originated with Folgheraiter’s experiments and intuitions. Many of those advances were improved upon only during the first half of the twentieth century by Emile Thellier (1904–1987). Actually, the well-known work by Thellier, resulting in the birth of the Saint Maur archaeomagnetic laboratory at the Institut de Physique du Globe de Paris, had as a starting point the theories and suggestions developed by Giuseppe Folgheraiter. Based on the studies by Thellier, the well-known secular variation curve for France was derived, later to be perfected by Ileana Bucur in 1994.

Definition of analytical cleaning procedures for archaeological pottery from underwater environments: The case study of samples from Baia (Naples, South Italy)

This work is focused on a multidisciplinary study of 13 pottery fragments collected in the submerged archaeological site of Baia (Naples, Italy). Founded by the Romans in the 1st century B.C., this archaeological area represents one of the greatest evidences of Roman architecture and it includes ancient ruins whose structures range from maritime villas and imperial buildings. Several diagnostic tests were carried out in order to characterize the archaeological materials, their structure and properties, as well as the alteration and degradation products. Degradation forms in seawater imply not only a variation in the physico-mechanical and chemical properties of the material but also an aesthetic damage, due to superficial deposits, which can lead to the illegibility of the artefacts. In this context, it is crucial to determine to what extent these decay factors, mainly attributable to biological growth, could affect the durability of pottery and what are the effects of cleaning procedures. The work offers further elements to obtain new insights into the underwater cultural heritage field and in the function of ceramic matter, especially related to several applications in technology and in the adoption of strategies for suitable conservation procedures.

Analysis of lead-based archaeological pottery glazes by laser induced breakdown spectroscopy

The aim of this study was to demonstrate the potential of Laser-Induced Breakdown Spectroscopy (LIBS) in the analysis of pottery shards, which are commonly the most abundant artefacts recovered at archaeological sites. The analytical capability of LIBS in identification of elements characteristic to inorganic pigments used for decoration was assessed. Based on the specific elements detected in the LIBS spectra of glazes, correlations between the elemental composition of the glaze and the colours of the glazed surface were established. The results were in accordance with the previously reported Energy Dispersive X-ray Fluorescence (EDXRF) and Raman analyses of some of the samples, and with the presently performed XRF analysis. Two important parameters for plasma characterization, temperature and electron number density, were estimated from the spectral data. A potential use of LIBS for depth profiling was also investigated by analysing the silicon to aluminium intensity ratio as a function of the number of laser shots applied. Profilometry analysis of the damages created on the glazed surfaces by laser shots was used to estimate the average ablation depth and ablated mass.

Effects of sample processing on XRF results from archeological pottery

ABSTRACT The aim of this paper is to present the results of XRF analysis of archeological samples in two different states of preservation: intact vessel surfaces and transformed into powder. To investigate the effect of sample processing for XRF analysis, a handheld spectrometer was used. In total, 41 pottery samples were measured. The samples were extracted from Late Bronze Age and Early Iron Age ceramic vessels of two different technological traditions: local (hand-made pottery) and exogenous (wheel-thrown pottery) from the archeological site of Setefilla (western Andalusia, Spain). Multiple statistical tests were used to examine the effect of sample processing on the semi-quantitative outcome of XRF analysis of pottery. The results obtained from intact samples are considerably different from the results obtained from pulverized samples. The analyses revealed that levels of Co, Sb, Sn, Al, Si, Ca, Fe, S, K, Sr and Nb were higher in the group of intact samples. This study underlines the need to evaluate sample preparation when designing archeometric research programs.

Analytical investigation of archaeological pottery fragments excavated from Porunthal, Tamil Nadu, India

Abstract Within the framework of a technological study of pottery production of Porunthal, Dindigul district of Tamil Nadu, India, the chemical composition and mineralogy of the 7 potteries of different varieties from that archaeological site were studied using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), and scanning electron microscopy coupled with energy dispersive spectrometer (SEM-EDS). The analytical data obtained from several analyses were used to determine the mineral transformations during firing, such as quartz, feldspar, and iron oxides (hematite and magnetite), firing temperature, and firing conditions. The results of all the techniques confirmed that all the samples were manufactured by the artisans locally with the same raw materials and also were fired at the same temperature.

Graph clustering and portable X-Ray Fluorescence: An application for in situ, fast and preliminary classification of transport amphoras

In the last decade, numerous papers have been delivered on the potential of portable X-Ray Fluorescence (XRF) in archaeological ceramics. Additionally, new chemometric methods have been proposed to manage chemical dataset and facilitate the use of geochemical discrimination for provenance classification of ancient ceramics. In this contribute, the potential of portable Energy Dispersive X-Ray Fluorescence (ED-XRF) analysis and chemical data processing by Graph Clustering is evaluated for provenance classification of archaeological potteries, discussing possible merits and limits of the employed routine. A ceramic assemblage represented by seventy-three transport amphorae classified by typological analysis have been used as testing materials; spectra have been collected on samples simulating in situ analysis conditions (e.g. on fresh cut surfaces without any preparation) and Graph Clustering method has been applied in chemical data processing; comparison with classical Cluster Analysis (CA) and Principal Component Analysis (PCA) is also evaluated. The obtained results favor the use of Graph Clustering for a preliminary classification of ceramics, which can be chemically analyzed in easy, fast and non-destructive way. With a 75.35% of correct attribution, the study shows the suitability of portable ED-XRF in rapid screening of a large number of ceramic samples usually recovered in the framework of archaeological excavation. Misclassifications have been mostly verified for samples exhibiting a coarse-grained clay paste, suggesting that the method is particularly suitable for fine-grained ceramic materials.

Living off the land: Terrestrial-based diet and dairying in the farming communities of the Neolithic Balkans.

The application of biomolecular techniques to archaeological materials from the Balkans is providing valuable new information on the prehistory of the region. This is especially relevant for the study of the neolithisation process in SE Europe, which gradually affected the rest of the continent. Here, to answer questions regarding diet and subsistence practices in early farming societies in the central Balkans, we combine organic residue analyses of archaeological pottery, taxonomic and isotopic study of domestic animal remains and biomolecular analyses of human dental calculus. The results from the analyses of the lipid residues from pottery suggest that milk was processed in ceramic vessels. Dairy products were shown to be part of the subsistence strategies of the earliest Neolithic communities in the region but were of varying importance in different areas of the Balkan. Conversely, milk proteins were not detected within the dental calculus. The molecular and isotopic identification of meat, dairy, plants and beeswax in the pottery lipids also provided insights into the diversity of diet in these early Neolithic communities, mainly based on terrestrial resources. We also present the first compound-specific radiocarbon dates for the region, obtained directly from absorbed organic residues extracted from pottery, identified as dairy lipids.

Micro‐Raman spectroscopy to investigate production techniques: A focus on fine ware potteries

AbstractThe study of manufacture technologies and provenance of raw materials in archaeological potteries are two fundamental aspects in providing information about sociocultural aspects on past societies. The most acknowledged technique in this field is represented by minero‐petrographic analysis, allowing to describe the compositional features of the artefacts and to link them to geological outcrops and technologic processes. In the case of fine‐grained potteries, minero‐petrographic analysis might sometime give back not clear results, requiring the use of high‐resolved methods. In this framework, information about raw materials and firing techniques might be provided by the support of micro‐Raman spectroscopy, able to supply information on mineral grains not detectable under a microscope and for which powders diffraction methods are not able to provide unique interpretations. In this work, particular attention was devoted to the phases formed during the ceramic body annealing, especially to newly formed feldspars, exhibiting a not natural occurring composition. Their correct identification, important for thermometric studies, is possible only with the use different techniques, due to the different investigated aspects (structure, composition and lattice dynamics).Fine‐grained potteries from the famous site of Volterra, Tuscany (Italy) have been characterized as case study during a comparative evaluation of the results obtained by different techniques (micro‐Raman analysis, optical microscopy [OM], X‐ray diffraction [XRD] and scanning electron microscope energy dispersive spectrometry [SEM‐EDS]) on the same mineral grains. The obtained results demonstrated how micro‐Raman spectroscopy might improve interpretation of data collected with different methods in several aspects, from provenance to firing temperature estimation.

Multi-technique study of He+ micro-irradiation effects on natural quartz crystals contained in archaeological pottery

The effect of α irradiation on natural quartz is commonly known in geology, resulting in the formation of luminescent halos around radioactive inclusions. In archaeological ceramics quartz grains are present and can be surrounded by radioisotopes contained in the clay. The aim of this study is a first attempt to detect similar halos on the outer rims of quartz grains isolated from archaeological pottery. Such identification could be of interest in luminescence dating and as an alternative method for ceramic artworks authentication. Isolated grains were characterized with cathodoluminescence imaging, SEM-EDX and Raman spectroscopy. Some of the crystals were irradiated for reference with a microbeam of He+ accelerated ions and investigated by means of real-time ionoluminescence. Obtained results seem to confirm that the natural effect on archaeological quartz might be too weak to be detected with these techniques and underline the importance of the multi-technique approach to avoid misinterpretations.

Mechanisms of lipid preservation in archaeological clay ceramics revealed by mass spectrometry imaging

Traces of lipids, absorbed and preserved for millennia within the inorganic matrix of ceramic vessels, act as molecular fossils and provide manifold information about past people's subsistence, diet, and rituals. It is widely assumed that lipids become preserved after adsorption into nano- to micrometer-sized pores, but to this day the distribution of these lipids in the ceramics was virtually unknown, which severely limits our understanding about the process of lipid preservation. Here we use secondary ion mass spectrometry (SIMS) imaging for direct in situ analysis of lipids absorbed in 700- to 2,000-y-old archaeological pottery. After sectioning from larger sherds, wall cross-sections of smaller fragments were used for SIMS analysis. Lipids were found in relatively large zones of 5- to 400-µm diameter, which does not support the notion of absorption only into individual nanometer-scale pores but indicates that more macroscopic structures in the ceramics are involved in lipid preservation as well. Furthermore, lipids were found concentrated on calcium carbonate inclusions in the ceramics, which suggests that precipitation of fatty acids as calcium salts is an important aspect of lipid preservation in archaeological samples. This has important implications for analytical methods based on extraction of lipids from archaeological ceramics and needs to be considered to maximize the yield and available information from each unique sample.

Pattern recognition techniques for provenance classification of archaeological ceramics using ultrasounds

This paper presents a novel application of pattern recognition to the provenance classification of archaeological ceramics. This is a challenging problem for archaeologists, which involves assigning a making location to a fragment of archaeological pottery that was found along with other fragments of pieces made in different distant locations from the find. The pieces look very similar to each other and, often, other contextual information about the use of the pieces cannot be used due to the small size of the fragments. Current standard methods to solve this problem are limited since they are time consuming, require costly equipment, and can lead to the destruction of a part of the pieces. The proposed method overcome those limitations using non-destructive ultrasonic testing and incorporates versatile data analysis through advanced pattern recognition techniques. Those techniques include the following: feature ranking, sample augmentation, semi-supervision based on active learning; and optimal fusion. This latter is based in the concept of alpha integration, which allows optimal fitting of the fusion model parameters. Different provenance classification problems are showcased: provenance classification of terra sigillata ceramic pieces from Aretina, Northern Italy and Sud-Gaul origins; and provenance classification of Iberian ceramic pieces from archaeological sites of Paterna, and Les Jovaes in Valencia, Spain. We demonstrate that the proposed fusion-based method achieves the best results, in terms of balanced classification accuracy and F1 score, compared with competitive methods like linear discriminant analysis, random forest, and support vector machine. Experiments for simulating small sample sizes and uncertainty in labeling of the pieces are included. In addition, the paper provides a design of a practical specialized device that could be used in different applications of archaeological ceramic classification.

Archaeological implications of ethnographically grounded functional study of pottery from Nyanga, Zimbabwe

The value of typological analyses of pottery in global archaeology is widely acknowledged. However, pottery typologies in southern Africa are frequently criticised for one-dimensionally revealing more about decorations on pots and not their function and meaning to people that made and used them. This motivated an experiment to combine functional and stylistic variables of pottery from modern-day Nyanga district, in north-eastern Zimbabwe to develop alternative ways of approaching archaeological pottery. With the alertness that the present and the past are different, even in contexts of strong cultural continuity, we applied the results of the experiment to a collection of archaeological pottery from Nyanga tradition (CE 1300–1900) sites. For the recent past, the study indicated that vessel shapes strongly correlated with names and functions of pottery across the mundane, ritual and symbolic worlds. Comparisons with the archaeological picture identified a similarity of shapes between the past and the present. This stimulated reflections on a wide array of quotidian roles and functions that pottery fulfilled for Nyanga populations in the deep past. The conclusion to the paper is that functional classifications, particularly when combined with style, are a strong alternative to dominant classification schemes which enlighten more on people and not the vessels. However, the robustness of such an approach must be firmed up with the application of approaches from the material, chemical, and molecular approaches to develop a holistic view of pottery and its role in everyday practice at individual, community and societal levels.

Accurate compound-specific 14C dating of archaeological pottery vessels.

Pottery is one of the most commonly recovered artefacts from archaeological sites. Despite more than a century of relative dating based on typology and seriation1, accurate dating of pottery using the radiocarbon dating method has proven extremely challenging owing to the limited survival of organic temper and unreliability of visible residues2-4. Here we report a method to directly date archaeological pottery based on accelerator mass spectrometry analysis of 14C in absorbed food residues using palmitic (C16:0) and stearic (C18:0) fatty acids purified by preparative gas chromatography5-8. We present accurate compound-specific radiocarbon determinations of lipids extracted from pottery vessels, which were rigorously evaluated by comparison with dendrochronological dates9,10 and inclusion in site and regional chronologies that contained previously determined radiocarbon dates on other materials11-15. Notably, the compound-specific dates from each of the C16:0 and C18:0 fatty acids in pottery vessels provide an internal quality control of the results6 and are entirely compatible with dates for other commonly dated materials. Accurate radiocarbon dating of pottery vessels can reveal: (1) the period of use of pottery; (2) the antiquity of organic residues, including when specific foodstuffs were exploited; (3) the chronology of sites in the absence of traditionally datable materials; and (4) direct verification of pottery typochronologies. Here we used the method to date the exploitation of dairy and carcass products in Neolithic vessels from Britain, Anatolia, central and western Europe, and Saharan Africa.

FeIII in pottery: Identifying firing temperature and ambiguity

Firing parameters for archaeological pottery were estimated from the coincidence between iron concentration (FeIII) in the pottery and in a clay specimen, both chemically and mineralogically identical, fired under controlled conditions. Most pottery specimens analysed here were produced in a reducing environment, and one of them has been used as a pan. For reference clays, heating causes FeIII signal intensification, followed by reduction at high temperatures in reducing atmosphere. This behaviour differs from the model to identify firing parameters (Mangueira et al., 2013, 2016, 2018) and results in ambiguity to identify the firing temperature for the archaeological pottery. Pure hematite (Fe2O3) shows the same behaviour in reducing environment and indicates that the iron oxide in the clays is responsible for this kind of variation. The ambiguity of the firing temperature of some ceramics could not be clarified neither by producing the ceramics in the laboratory nor by X-ray diffraction and infrared spectroscopy techniques. However, electron paramagnetic resonance provided the firing atmosphere and the possible firing temperatures.

Geochemical and petrographic assessment of clay outcrops and archaeological ceramics from the pre-hispanic site of Aguas Buenas (cal 400–1250 CE), Central Nicaragua

This research characterizes and reconstructs clay procurement and production practices through the integration of in-situ portable XRF and petrographic analysis on ancient ceramics and clay materials recovered from the Mayales river subbasin (central Nicaragua). A particular choice for this study was the largest and arguably most significant archaeological site in the area, Aguas Buenas (cal 400–1250 CE), a pre-Hispanic indigenous agglomeration consisting of 371 human-made mounds of various shapes arranged in geometric patterns. Microanalytical approaches were applied to reconstruct the use of raw mineral resources in the production of ubiquitous pottery materials found at this site and in its immediate surroundings. The resulting compositional analysis produced geochemical and mineralogical data allowing for the characterisation of distinct, geologically-based compositional groups throughout the valley, improving on the limited geological data resolution previously available. The integrated microscopic and compositional analysis (through p-XRF) of archaeological pottery materials and raw clay samples, generates a number of hypotheses and insights about the nature of the Aguas Buenas site, and its role as a shared space amongst groups living in the Mayales river Subbasin. Additionally, this study provides a solid research framework of investigation that can be employed for more detailed and extensive future studies on pre-Hispanic human occupation in this research area or elsewhere.

Compositional study of slips and paintings in San José and Santa María pottery (Yocavil valley, Northwest Argentina): an approach by non-destructive and complementary techniques

From a multidisciplinary perspective, we propose a first comparative study on the pigments of archeological pottery San Jose and Santa Maria of Yocavil valley, Province of Catamarca, Northwest Argentina (ca. S XI–XVI AD). Both stylistic sets share a color palette in which the black, red and cream tones are structured. Considering that we are handling objects of cultural heritage, an analysis strategy was developed that combines non-destructive techniques (XRFp and XRD) and minimally destructive sampling methods with other techniques (EDS and micro-Raman spectroscopy) for the characterization of elements and crystalline phases in pigments. The results show not only some shared features—as hematite in red paints and cream slips resulting from a low-iron clay base preparation—but also some diversity in the composition of the pigments—as presence of rutile in some red paints and pyrolusite or series of solid solutions in the system manganese–iron oxides in black pigments.

Comparative and Experimental Studies for Evaluation of Paraloid B-72 in Traditional and Nano Forms for Joining of Pottery Samples

Many of the excavated pottery artifacts are suffering from different deterioration aspects. The pressure of burial environment is considered the most deteriorative agent for pottery in soil, which leads to damage of the artifact. Therefore, it is necessary to join these damaged parts to be suitable for museum display. The adhesive materials play a significant role in the joining processes of these artifacts. In this study, Paraloid B-72 in its traditional and nano form was prepared (50% in acetone) as adhesive for pottery artifacts. Twelve pottery tiles (14 ×4×1 cm) were prepared and then were adhered together with the adhesive in traditional and nano forms. The pottery samples were exposed to artificial aging as follows; accelerated heat-humid aging (temperature 100°C and 60% relative humidity) and light aging by U.V lamp for 100 hours. Visual assessment and several analytical techniques were used for the evaluation of the selected adhesive. The analytical techniques are transmission electron microscope (TEM), scanning electron microscope (SEM), color change and tensile strength. The results obtained from transmission electron microscope showed that grain size of nano paraloid was ranging from 33 to 51 nm where the particle size of the traditional paraloid was in the range between 103 to 150 nm. Visual assessment proved that nano paraloid had some simple changes in appearance. Scanning electron microscope revealed that the nano paraloid was more resistance for aging than traditional form. Color change revealed that nano paraloid gave the lowest level of total color differences (ΔE) after light, heat-humid and light-heat aging with 2.31, 3.26 and 4.60 respectively. The tensile strength revealed that nano paraloid gave highest tensile strength (81.3 N/mm2). According to these results, we recommend the use of nano paraloid in joining of archaeological pottery artifacts.

Exploratory research about the selective cleaning of calcium sulfate sediments on archaeological potteries

A novel cleaning method for the selective removal of calcium sulfate sediments on archaeological potteries was studied.