"dig" (Developing International geoarchaeology)

Geoarchaeological investigations of the Danish Celtic fields at Øster Lem Hede, Western Jutland, Denmark

Nina Helt Nielsen

Department of Archaeology, Aarhus University, Denmark; Søren Much Kristiansen, Department of Geoscience, Aarhus University, Denmark; Kristian Dalsgaard, Department of Geoscience, Aarhus University, Denmark.

Celtic fields are the most widespread and well-known type of prehistoric field systems in North-West Europe. However, after about 100 years of research, many questions still remain to be answered regarding their age, the formation history of the banks and lynchets demarcating the fields, and the land use of these Bronze/Iron Age field systems. Furthermore, the dynamics within the field systems deserve more attention – the numerous maps of Celtic fields give a very static impression of the field systems that is somewhat misleading.

In a geoarchaeological investigation of the almost 1 km² large Celtic fields at the protected heathland Øster Lem Hede, Denmark, four trenches were dug through six selected banks/lynchets and samples were taken for geochemical, grain size, thin section, pollen and archaeobotanical analyses in addition to optical stimulated luminescence (OSL) dating.

OSL-dates from two banks show that these were created before c. 600±140 BC, i.e. in the Late Bronze Age/Early Iron Age, but evidence of cultivation, e.g. ard marks, predating the regular field system is also present beneath some banks.

Grain size and multi-element analyses by inductively coupled plasma mass spectroscopy (ICP-MS) suggest that the soil in the banks came from the fields (no significant difference between the soil in the banks and in the fields), and it appears to have accumulated gradually in the banks/lynchets over the years. The formation of the banks cannot be explained by aeolian processes alone (as it has sometimes been suggested), but must primarily be due to tillage erosion and deposition of soil directly by humans. Stones were also rare in the investigated banks – they appear primarily to have been deposited in clearance cairns.

Dynamic alterations of the layout and the field boundaries in the form of added banks and temporarily discontinued boundaries, which were ploughed over and incorporated into the neighboring fields, were identified. This shows that even very regular systems, such as the Celtic fields of Øster Lem Hede, were somewhat temporal dynamic in their structure and use.

ICP-MS analysis showed that among the 42 analysed elements, 11 were significantly (P < 0.01) enhanced in the fields relative to a reference outfield soil, still from within the protected heathland. The enhanced elements were: Na, P, K, Ca, Mn and Sr and the rare earth elements (REE’s), Nd, Sm, Eu, Gd and Dy. Enhanced P levels show that manuring was practiced, while elevated concentrations of Sr indicate that not only animal manure but also bones/domestic waste was added. Ceramics, charred material, and exotic soil particles in thin sections further confirmed that manuring was practiced. Moreover, the enhancement pattern of some major and minor elements indicates that unweathered subsoil was incorporated into the topsoil, probably through tillage erosion.

Thus, the geoarchaeological investigations of Øster Lem Hede provide new insight into the date, formation and use of Celtic fields – insight that cannot be revealed through analyses of the layout of field systems alone.

A Geoarchaeological Contribution to the Study of Archaeological Agricultural Resilience in Eastern Africa

Carol Lang and Daryl Stump

Department of Archaeology, University of York
The AAREA project (Archaeology of Agricultural Resilience in Eastern Africa) is a multi-disciplinary research project that brings together complimentary analytical techniques to retrieve the maximum amount of information from two historic terraced and irrigated landscapes: Engaruka in north west Tanzania and Konso in south east Ethiopia. The earliest occupation of Engaruka has been radiocarbon dated to the 14^thcenturyand was abandoned prior to the first European accounts of the area in the late 19^th. In contrast, genealogical evidence from Konso suggests that irrigation and terraces have been used in this area for over 500 years, leading some to regard it the system highly sustainable.

The overarching aim of the project is to answer one key question: ‘can archaeological investigations contribute to assessments of long-term sustainability, thereby informing future policies that can be applied to agricultural systems of the future?’ The research will allow us to understand adaptations that had occurred through increasing agricultural intensification, whilst gathering an extensive archaeological archive that will enable us to comprehend the resilience of the historic agronomic systems. The data obtained from the archaeological information may provide a resource base of environmental evidence that could be employed by development programmes and policies maker at a scale they require.

This presentation aims to focus on the highly visible agricultural archaeology of stone circles, habitations platforms, terraces, fields and irrigation systems at the abandoned site of Engaruka, Tanzania. It will explore the hypothesis that soils and sediments associated with past habitation and cultivation, across the site, can provide a record of past land utilisation, manipulation of alluvial deposits and soil amendment processes that were occurring during its period of occupation. Soil micromorphological investigation techniques were employed to analyse strategically collected undisturbed soil samples, from across a small area of the 2000 hectare site, to aid the understanding of the pedogenic processes and elemental composition associated with intensive agricultural.

The samples collected in 2010 and 2014 were from various locations that encompassed visible stone structures, alluvial deposition and gullies. Significant uniformity of soil texture and mineralogy was observed in the post-abandonment aeolian sediments from across the site. In contrast, fragments of burned bone were discovered in the upper archaeological context of a stone circle (one of approximately 50 such features interpreted by some researchers as former cattle enclosures), whilst there was a clear differentiation in the soil development between stratigraphic layers, suggesting there had been differential factors affecting the deposition and development of the sediment; the lower, older sediments displaying a high frequency of organic matter inclusions compared with the younger, overlying soil/sediments and, further up the stratigraphy, the abandonment layer.

Calcitic pendant hypo-coatings, observed in the samples collected from behind the revetment walls were in preferential positions and might relate to irrigation processes. The variation in the soil texture between the stratigraphic contexts may in addition indicate differences in the methods of alluviation and ultimately the irrigation processes employed. The micromorphological analysis provided a comprehensive inventory of information and confirms the delineation of land use, whilst providing a spatial analysis of diagnostic soil features.

These results and the data generated, through the utilisation of soil micromorphology, may potentially provide a wider understanding of the measures taken to attain long-term agricultural resilience and will provide information on the construction methods, maintenance, landscape utilisation and later abandonment of Engaruka, thus informing future decisions concerning sustainable agricultural policy.

‘Geoarchaeological perspectives on societal change in the landscape in medieval Europe’

Rowena Y Banerjea¹*, Alex Brown¹, Guillermo García-Contreras Ruiz^1,2, Aleks Pluskowski¹

¹ Department of Archaeology, School of Archaeology, Geography and Environmental Science, University of Reading, RG6 6AB, UK

² Departamento de Historia Medieval y Ciencias y Técnicas Historiográficas, Universidad de Granada, 18071, Spain

The medieval period in Europe sees shifting geographical boundaries and frontiers as a result of multiple waves of conquest and colonisation, as well as areas where different religious communities co-existed in the landscape; these processes have played an integral role in the shaping of present day European society. Frontiers remain largely perceived as zones of cultural polarisation, and our understanding of how multiculturalism was defined and sustained within the annexed territories remains problematic.

This paper draws together the results from sites in the eastern Baltic region from areas that were formerly Prussia and Livonia within the Ordensland, the former territories of the Teutonic Order (present day northern Poland, Latvia and Estonia), and presents the geoarchaeological research framework that has been developed and adapted to examine frontier landscapes in context of the Reconquista in the Iberian Peninsula. Castles and their hinterlands (commanderies) within Prussia and Livonia were compared to examine the longue durée development of occupation as a result of conquest and colonisation processes, and the scale of the impact of the crusades on existing communities. Geoarchaeological techniques enabled diachronic examination of the development of occupation, the use of settlements, and their hinterlands, through high resolution, multi-scalar analysis to understand the range of on-site and off-site activities, and the geochemical traces of sites in their hinterlands, specifically within lake sediments in conjunction with palynological approaches.

Sites at Święta Góra, Prussia, and Riekstu Hill, C?sis, and R?ga, Livonia provided opportunities to examine the nature of activities and settlement use before the Crusading period. Święta Góra, Prussia, is an indigenous Prussian settlement in the tribal territory of Galindia that was incorporated into the Teutonic Order’s territory during the crusades, where the occupation during the transition from the period of ‘Roman Influences’ to the Migration period was investigated. The stronghold at Riekstu Hill, occupied by the pagan ‘Wends’ and also used the ‘Sword Brothers’ from the early 13^th Century shortly before the construction of the castle, has been examined using thin-section micromorphology to understand the destruction of timber fortifications and the periodicity of the formation of occupation deposits. Multi-proxy analysis of occupation deposits from buildings and streets in the area of the ‘Liv’ village, R?ga, has provided insights into life within the indigenous quarter, which was later incorporated into the medieval town by the end of the 13th century with the construction of the outermost town walls.

In order to examine how occupation developed with the arrival of the Teutonic Order, a multi-proxy geoarchaeological approach was applied at Biała Góra, Prussia, to examine the nature of occupation at this rural colony. The examination of the occupation within the outer bailey at the castle in Elbląg, Prussia, and within the high castle at Karksi, Livonia, has presented a unique opportunity to study the early colonising activities, particularly the animal husbandry practices of the Teutonic Order in these key administrative centres.

There is a requirement for consistency in settlement and context sampling to produce good comparative data. Therefore, it is important to strategically select case study sites by considering issues such as multiple phases of use, changes in occupiers, the type of settlement, and the proximity of geochemical catchments such as lakes and bogs to settlements. In the Iberian Peninsula, issues relating to the occupation within frontiers can be examined in different geographical regions and landscape formations, and to examine different agricultural practices such as terracing and irrigation, which are being investigated through two geoarchaeological pilot studies at the fortified complex of Molina de Aragón, Guadalajara, and a 16^th century Carthusian monastery with previous Islamic phase in Granada.

Geoarchaeological analyses of construction materials from the

Neolithic site of Aşkl Höyük, Turkey

Melis Uzdurum¹,Susan M. Mentzer², Jay Quade³, Mihriban Özbaşaran¹

1 Istanbul University, 2 University of Tubingen; 3 University of Arizona

Aşkl Höyük is the oldest Aceramic Neolithic tell in the Cappadocia region of Central Anatolia. The site spans five major levels composed of the degraded remains of earthen structures and occupation debris. Excavations reveal that the morphology and general composition of architectural elements changed at the site over time. The earliest structures excavated to date are subterranean and round, with outer covering of wattle and daub. Later round structures were constructed from kerpiç (mudbrick) and mortar, with plaster floors and walls. Over time, the shape of the structures shifted from round to rectangular, and buildings were clustered into “neighborhoods.” Finally, the village was divided into broad residential and “special purpose” sectors. We sampled construction materials from all major areas of the site and occupation levels in order to document changes over time in the production of kerpiç, mortar and plaster. As part of a preliminary geoarchaeological study, we analyzed a subset of the loose sediment samples for texture, organic material, carbonate content and source, and stable isotopes of carbon and oxygen. In addition, we conducted micromorphological analyses of a subset of samples. Our results indicate that construction materials vary in composition, particularly in the presence or absence of carbonate and its source, and the use of different tempering elements. There are also several trends in construction material production over time, including a shift in source material for mortar production. In addition, we confirm using stable isotopes and FTIR that lime plaster was used in the production of plasters at the site. Future work will expand upon these pilot analyses.

Chemistry applied to Archaeology - “The informative potential of the invisible”

Marco Milanese,^a Maria Antonietta Zoroddu,^b Massimiliano Peana,^b Serenella Medici,^b Martina Zipoli^a

^aDepartment of History, Human Sciences and Education, University of Sassari, 07100 Sassari, Italy

(Methodology of Archaeological Researches, Medieval and Post-Medieval Archaeology)

^bDepartment of Chemistry and Pharmacy, University of Sassari, Via Vienna 2, Sassari, Italy

Within the archaeological excavation campaigns carried out at the sites of Mesumundu (Siligo) and S. Antioco di Bisarcio (Ozieri) (SS), the group of Medieval and Post-medieval Archaeology started a collaboration with the Inorganic and Bioinorganic Chemistry group of the University of Sassari (Dept. of Chemistry and Pharmacy) with the aim of clarifying some specific issues emerging from the archaeological research in progress. Departing from the analytical perspective of chemical studies, it was sought to offer solutions and interpretative integration of archaeometric data.

Any human activity leaves its traces, both visible and “invisible”. The latter can be chemical traces. Indeed, every surface can absorb inorganic and organic compounds and retain them for centuries, even millennia. Starting from this consideration and looking towards the informative potential of all the archaeological contexts, investigative strategies were oriented along two main research topics:

- chemical analysis of archaeological sediments for the characterization of activity surfaces;

- chemical analysis of compounds absorbed by artifacts and vessels for the determination of their use.

For the analysis of sediments, the excavation units were mapped according to a series of chemical markers in order to establish the anthropic activities that characterized life in the times when the sediments formed, or to infer the use of specific structures in cases where the functional determination from an archaeological point of view was questionable or uncertain (for example, a drainage system identified at S. Antioco di Bisarcio). Two chemical methodologies were applied: a quick-response set of spot tests that makes it possible to rapidly determine the presence of some classes of organic and inorganic compounds; the application of gas-chromatography coupled to mass spectroscopy (GC-MS) analysis, a method capable of separating and identifying different molecules present in the substrate.

The same techniques were also applied to the study of ceramic artifacts in order to identify which substances they once contained.

Keywords:

Chemical analyses, sediments, sampling, spot test, GC-MS, informative potential

Water draining and regimentation in the site of Mesumundu (Siligo, SS)

Marco Milanese, Martina Zipoli .

Department of History, Human Sciences and Education, University of Sassari, 07100 Sassari, Italy; (Methodology of Archaeological Researches, Medieval and Post-Medieval Archaeology), Municipality of Siligo (Sassari)

Within the archaeological campaigns carried out in the sites of S. Vincenzo di Ferrer and Mesumundu (Siligo, SS), in the years 2011-2014, both natural and artificial paleoriverbeds, and contemporary rural buried canalizations have been localized, targeted to drain waters. Thanks to the local oral sources they can be brought back to a typology locally known as the cora covaccada.

This contribute is aimed at presenting the results collected in area 2700 (2014 excavation campaign) of the site of Mesumundu, where a contemporary buried cora covaccada was found. It was dug within the middle of the XX century and built with limestone slabs partially wrought, whose course retraces that of a more ancient paleoriverbed. The stratigraphic excavation of the whole context allowed highlighting interesting technical-constructive features of the canalization and of the sediments found inside the structure, relative to the use activity and subsequent obliteration of the cora covaccada, whose task was to direct water drained from the soil towards a close by stream.

The excavation also evidenced that the rural canalization insisted onto a paleoriverbed, fully buried, of a small watercourse: the stratification presented an interesting sequence of slime-clay sediments with variable shades of colours, due to a natural formation process caused by a recurring seasonal variation of the water saturation level in the sediments, until a very superficial aquifer was reached.

Keywords:

Water draining, canalizations, paleoriverbed, sediment saturation, cora covaccada

Climatic changes and human impact on coastal evolution: the Mistras-Cabras barrier-lagoon system (Oristano Gulf, Central-Western Sardinia)

V. Pascucci¹, C. Del Vais², S. Andreucci³, G. De Falco⁴, A. Depalmas⁵, A.C. Fariselli⁶, R.T. Melis³, G. Pisanu⁷, I. Sanna⁸

¹ Università degli Studi di Sassari, Dipartimentodi Architettura, Design, Urbanistica ([e-mail]); ² Università degli Studi di Cagliari, Dipartimento di Storia, Beni Culturali e Territorio ([e-mail]); ³ Università degli Studi di Cagliari, Dipartimento di Scienze Chimiche e Geologiche; ⁴ Istituto per l’Ambiente Marino IAMC-CNR; ⁵ Università degli Studi di Sassari, Dipartimento di Storia, Scienze dell’Uomo e della Formazione; ⁶ Università di Bologna, Dipartimento di Beni Culturali; ⁷ Soprintendenza per i Beni Archeologici per le province di Cagliari e Oristano

The current interglacial differs from past ones particularly because of the human presence. Coastal areas are the most affected by environmental modifications induced by climate fluctuations, small eustatic changes and anthropogenic impact.

In this context, Sardinia is a key area for the definition of interactions between man and climate during the last 6-4000 years. The sparse population of the coast up to modern times is an advantage for distinguishing between anthropogenic and climate signals. Integrated archaeological and geological studies conducted in the coastal barrier-lagoon Mistras-Cabras system (Oristano Gulf) showed that the lagoon developed as transgressive during the final stages of the Holocene sea level rise (about 6000 years BP) and become regressive (prograding) from about 2600 years BP.

The regression of the coast , however, was not continuous but rather characterized by three distinct phases associated to precise climatic fluctuations. The first phase lasted about 400 years between 2600 and 1900BP. It was associated with 250 m coastal progradation that lasted until 1900 BP. This time interval, known as Greek-Roman Warm, coincided with the beginning of the Punic and Roman attendance of the Mistras-Cabras area. At that time, the area, close to the ancient city of Tharros, hosted a landing and perhaps the port of the city, probably in front of the trading centre located at short distance from the shoreline. Recent archaeological excavations have proved the presence of pottery and organic material dating back to Phoenician and Punic periods in marine sediments. Punic wood and boulders breakwaters dated at 2300 BP are well-documented around the innermost Mistras present-day lagoon.

The second phase lasted about 440 years, between 1140 and 700 years BP, during a new warm period - the Medieval. During this phase, the progradation of shorelines was very wide and fast (about 4 m/y). This anomaly could be explained considering the little or none land use of the coastal area during Medieval times. The harbour was no more active and large sandy dunes developed and nourished the shore favouring progradation of the coast with no human influence. An intense exploitation of the coast, instead, occurred during Punic and Roman time. The break-water construction modified the natural evolution of the beach. This developed as a sand spit nourished by offshore sediment carried in to the gulf by a long shore current from NW between 2500 and 2300 BP. The beach evolved from 2300 to 1900 BP into a barrier-lagoon system. This new beach system was induced by the construction of break-water artefact that isolated an open sea embayment creating a lagoon.

The third stage is the current one and begun about 164 years ago (after 1850 AD) i.e. after the end of the ‘Little Ice’ Age.

Geological and archaeological data of the Mistras-Cabras system revealed that little human activities on the coast could influence its natural behaviour. In addition the study showed that even small climatic changes (both positive and negative), could induce significant progradation or erosion of the system.

Micromorphological analyses of an open-air stone structure at the Magdalenian site of Peyre Blanque, France
Rachel Kulick
Recent studies of structural remains at Magdalenian open-air sites have afforded valuable insights into patterns of occupational and intra-site spatial organization and have enhanced understandings of the Magdalenian cultural landscape. However, identifying more detailed use-of-space within the Magdalenian structures has been challenging due to modifications by natural and anthropogenic post-depositional processes and difficulties in amalgamating structural data from recent studies with those of previous excavations (e.g., at Oelknitz and Gönnersdorf). Current excavations at the site of Peyre Blanque, Fabas, Ariège, have revealed a possible Magdalenian stone structure, and spatial analyses of the associated archaeological finds and structural remains have been implemented. Geoarchaeological analyses of the potential structure have been conducted to better understand the use-of-space within the structure and the post-depositional and soil formation processes that have affected the structure and overall site. The preliminary results of the soil micromorphological analyses demonstrate dynamic geological processes and complex taphonomic processes at play and indicate overall stratigraphic stability since the site’s Magdalenian occupation.