Site Formation Processes Field School

I recently had the chance to attend a field school in Site Formation Processes of the Athenian Agora in Athens, Greece. It was organized by Takis Karkanas and Paul Goldberg through the Americal School of Classical Studies and the Wiener Lab

It was an amazing experience and gave the participants the chance to deepen our knowledge in aspects of geoarchaeology concerning formation processes of an urban archaeological site. Different scales of the site were discussed: the regional scale, the site scale, as well as the microstratigraphic scale.

 

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Looking at the broader picture: Geological section of fluvial deposits and palaeosoils in Boeotia, Greece

 

The field school combines both field (geomorphology, stratigraphy, sampling strategies) and laboratory (micromorphology, FTIR) training.

 

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Discussing the profiles within the Athenian Agora

In addition to the skillset acquired, the field school was a lot of fun and gave the opportunity to meet people interested in the same research field. It is organized annually (applications due ~April) and I would highly recommend it!

Sedimentology Lab visit

The Leiden GeoArch group organised a visit to the sedimentology laboratory at Leiden University College, Den Haag. The lab is led by physical geographer Peter Houben and fluvial geomorphologist Paul Hudson. There, they conduct various sedimentological analyses like grain-size analysis and pH measurements.

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Our visit started with an introductory session where Paul and Peter presented their work and research. We then moved on to the sedimentology lab where they showed us their facilities and talked about future plans for expanding the lab.

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Finally, we discussed the potential for collaboration in research and teaching.

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We hope that our visit will provide foundations for the development of a geoarchaeological connection between the Faculty of Archaeology (Leiden University) and Leiden University College.

Soil geochemistry on an early Swahili daub house, Zanzibar

I came across an interesting paper by Frederica Sulas and others (2019) who conducted a geoarchaeological study on an early Swahili (medieval) daub house at Unguja Ukuu, Zanzibaar (7th-14th c. AD). The study integrated geochemical, artefact distribution, and phytolith analyses. For the geochemical study pH, Loss on Ignition, and multi-element (ICP-MS) analyses were conducted on bulk sediment samples. The samples were derived from both the archaeological site (indoor and outdoor of the daub house structure) and the surrounding landscape. The main objective of the research was to investigate spatial organisation and activities within the house and test high-resolution systematic sampling strategies in this type of contexts.

 

View of the excavation trench and the 50 cm interval sampling grid (Sulas et al. 2019)

 

The use of multi-proxy geoarchaeological techniques helps to further explore the microarchaeological record that would otherwise not be visible with the naked eye. Various anthropogenic everyday activities leave microscopic and elemental traces that can be present even in seemingly homogeneous archaeological deposits. For example, this paper considers the use of Rare Earth Elements (REEs) as indicators of human remains (e.g. nails, skin, hair), seaweed, shell, sand, and animal manures (as ref. by Sulas et al. 2019, 34).

 

Distribution of Sm, V, Na, and K chemical concentrations (Sulas et al. 2019)

 

The REEs in this study reveal significant concentration patterning, and when combined with the other results can provide insight into the way people lived on the site, their subsistence strategies, and their spatial organisation. All in all, this paper showcases another example of how integrating various geoarchaeological techniques can develop a deeper understanding of various aspects of archaeological sites. 

 

Reference

Sulas, Kristiansen, and Wynne-Jones. “Soil Geochemistry, Phytoliths and Artefacts from an Early Swahili Daub House, Unguja Ukuu, Zanzibar.” Journal of Archaeological Science 103 (2019): 32-45.

Leiden GeoArch: New geoarchaeology group

Exciting news for the Faculty of Archaeology, Universiteit Leiden: a newly founded group, Leiden GeoArch, that plans to promote and discuss matters concerning geoarchaeology!

The first event will have the format of a lunch-lecture where Victor Klinkenberg will present his work on micromorphology of Mycenaean chamber tombs (March 4th/ 12h/ Van Steenis, Leiden).

What a wonderful opportunity to get inspired by various applications of geoarchaeological techniques to answer archaeological questions!

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Leiden GeoArch: Micromorphology of Mycenean Chamber Tombs poster

Various lectures and activities are on the schedule for the near future including my talk “Micromorphology for dummies” coming up May 6!

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Spring agenda 2019 for the LeidenGeoarch group: Faculty of Archaeology, Universiteit Leiden

 

Stay tuned!

Umhlatuzana 2018: Micromorphology Sampling

The micromorphological sampling of the Umhlatuzana archaeological site started after completing the excavation in mid-August 2018. In addition, bulk sediment samples associated with the micromorphological monoliths were collected. These are going to be processed for sedimentological, geochemical, and mineralogical characterization through various analyses like pH, Magnetic Susceptibility, grain size, Loss on Ignition, and Carbonate presence.

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Bulk sediment sampling

 

The size of the profile was approximately 1.5 m x 2.2 m. Only the west profile of the excavation was sampled; the remaining profiles were unstable and collapsing due to vandalizing incidents that happened in the past.

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Defining the location of the samples within the profile

 

The majority of the samples were collected using plaster bandages because of the high concentration of rocks in the sediments.

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Micromorphology sampling using plaster

 

Sampling with Kubiena tins was possible only on the upper, Holocene deposits. Six samples were collected using this method.  

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Micromorphology sampling using Kubiena tins

 

A total of 31 micromorphology samples were derived mostly focusing on layer boundaries and on what was assumed to be Pleistocene deposits.

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Umhlatuzana 2018 micromorphology samples

Umhlatuzana Rock Shelter Excavation 2018

My Ph.D. research within the “Finding resolution for the Middle to Later Stone Age transition in South Africa” project discusses scientific debates about the South African archaeology during the Pleistocene. The project is reexamining two archaeological sites located in KwaZulu-Natal (eastern South Africa), the Shongweni and Umhlatuzana rock shelters, both of which demonstrate occupational deposits during the Middle Stone Age to Later Stone Age transition. By determining the site formation processes, the geoarchaeological study aims to answer questions raised in relation to the archaeological contexts of the individual sites.

This blog entry shortly describes the fieldwork strategies we followed during the Umhlatuzana excavation (June-August 2018). A second blog post will follow describing the micromorphological sampling process.

Feedback, comments, and thoughts are highly welcomed.

strategies

The fieldwork strategies:

Step 1: Initial profile description

The first step was to identify and describe stratigraphic layers on the profile of the previous excavation. After producing an archaeological drawing, we compared our observations to the stratigraphic descriptions of the original excavation (Kaplan, 1990). We identified the units that were not clearly defined and established site-specific research questions.

Step 2: Excavation

The second step was to start excavating the stratigraphic layers (Single Context Excavation System) while keeping track of sediment changes. We excavated in 25×25 cm squares using ~2cm spits and documenting the relative location of finds larger than 2cm using a Robotic Total Station.

Step 3: Profile description

After the excavation, we re-identified the stratigraphic layers and units. This revised stratigraphic description was based both on the initial profile and the observations made along the excavation. Archaeological drawings of the new sections were produced.  

Step 4: Sampling Strategy

Based on the stratigraphic description we established the sampling strategies for chronological (OSL, radiocarbon), micromorphological, phytolith, and geochemical analyses. We focused on sampling specific sections that addressed our research questions. These sections included the MSA-LSA transitional deposits, poorly understood stratigraphic layers, and features with anthropogenic (hearths) or biological (bioturbation) input.

Reference

Kaplan, J. The Umhlatuzana Rock Shelter sequence: 100 000 years of Stone Age history. Southern African Humanities. 2, (1), 1-94.

Reconstructing Archaeological Sites: Understanding the Geoarchaeological Matrix

A new geoarchaeological book entitled Reconstructing Archaeological Sites: Understanding the Geoarchaeological Matrix was released today by Dr. Panagiotis Karkanas and Dr. Paul Goldberg. The book explores the various aspects of archaeological site formation and depositional processes providing both a theoretical background and practical approaches to the subject.

Chapter 1 examines the principles of site formation processes presenting the type of events that can affect an archaeological site before during and after its occupation like soil formation procedures and post-depositional events. Chapter 2 studies natural sedimental processes in sites (structures, mass movements, bioturbation etc.) while Chapter 3 focuses on various types of anthropogenic sediments (burnt and organic remains, construction material etc.). Chapter 4 examines the principles and importance of site stratigraphy by analyzing and defining stratigraphic units and their context. The next two chapters are studying the different types of archaeological sites, with Chapter 5 focusing on non-architectural sites (open air vs cave sites) and Chapter 6 on architectural sites (roofed and unroofed, streets, house pits). Finally, Chapter 7 provides more practical information on field techniques like drawings, photography, sampling strategies, number and size of samples as well as micromorphological and microarchaeological sampling.

The book is addressed to both geoarchaeologists and archaeologists who want to study archaeological site stratigraphy. It provides a complete guide for understanding the geoarchaeological matrix and how deposits can be organized in time and space.

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