Underwater Archaeological Excavations Research Articles

DESALINATION OF UNDERWATER CERAMIC CULTURAL HERITAGE: THE EXAMPLE OF KERPE UNDERWATER EXCAVATION

Salinity, which is one of the chemical properties of the marine environment, is mixed into seawater due to the dynamic exchange processes between the atmosphere and the hydrosphere and the dissolution of the shells of marine organisms on the seabed. The amount of soluble salts is measured in parts per million (ppm), but in this article, it is measured in parts per thousand (ppt). When soluble salts are not removed by appropriate conservation methods, they crystalize in the pores of artefacts that constitute underwater cultural heritage. These crystals cause physical deterioration in ceramics, which are porous cultural heritage, such as fragmentation from the surface and microscopic cracks. For this reason, the first step in repairing cultural remains recovered from underwater archaeological excavations is to determine the physical properties of the artefacts, such as porosity and salt absorption capacity, as well as the type and amount of salt accumulated in their pores. Thus, the appropriate desalination method can be selected, and estimates can be made on how long the desalination process will take. This paper studied ceramic sherds of Roman and Byzantine amphorae and cooking vessels recovered during underwater excavations in the ancient harbor of Kerpe Bay in Kocaeli, Turkey, in 2022. The aim of the study was to make a preliminary examination for further studies, including instrumental analyses, and to determine the types and amounts of salt deposited on the samples. The samples were desalinated for one month in 200 ml containers with weekly changes of deionized water, and the desalination water was tested to measure salinity and determine the dissolved salt species. Spot tests were used to determine dissolved salts. Sulphate, chloride and carbonate were found in the samples due to these tests. The porosity of the samples was determined by the water absorption method.

Wood identification and tree-ring chronology building of oak pillars excavated from submerged prehistoric settlement (3000 BC), Ropotamo River estuary, Black Sea

Eighty one well-preserved wooden pillars were found аs a result of underwater archaeological excavations of a submerged prehistoric settlement in the estuary of Ropotamo River, Black Sea. That provokes a scientific interest to identify wood materials.  The longest tree-ring chronologies have been used to build floating dendrochronology series. Anatomical features of xylem showed that 34 out of the 81 studied wooden pillars belong to genus Quercus. The remaining 47 pillars belong to a species of the genera Fraxinus, Acer, Ulmus and Platanus.  It has been found that 8 out of 34 oak pillars have a length of tree-ring series over 30 years. This was the reason to select them for dendrochronological studies. The length of the built floating master chronology for the oaks is 84 years. The lack of strong coherent signal between 34 single oak dendrochronological series can be explained with three different types of oak forest ecosystems, in the area of the Ropotamo River estuary. These forest ecosystems are as follows: oak high stand forests in Strandzha Mountain, oak coppice forests on the Black Sea coast plains and riparian ‘Longoz’ forests of Ropotamo River. The tree-ring series of these forest types have different tree-ring signatures. Based on the tree-ring analysis it can be assumed that the timber of the above-mentioned three types of oak ecosystems was used in the construction of the prehistoric settlement.  

Between water and land: Connecting and comparing underwater, terrestrial and airborne remote-sensing techniques

Ostrów Lednicki is one of the most important early medieval sites in Poland. Land and underwater archaeological excavations have been carried out there for many decades. This has allowed for a significant reconnaisance of the Lednica settlement complex. However, further research, especially that carried out underwater and in the shore-zone, has required the use of modern methods involving a multibeam echosounder (MBES), sub-bottom profiler (SBP), caesium magnetometer and LiDAR scans. The primary platform used for combining the underwater and aerial survey data was a Geographic Information System (GIS) environment. This software made it possible to compare and correlate acoustic, magnetic, seismic and laser data. As a result, new important archaeological features were discovered, including two previously unknown bridges and extensive shore-zone fortifications.

When Time Is of the Essence—Recording an Underwater Excavation at 110 m

Underwater archaeological excavations present unique challenges, particularly when conducted at significant depths where divers face limited time on the archaeological site. Traditional methods of recording excavation progress, such as manual documentation and drawings, are too time-consuming when the time on the site totals no more than 12 min. To address these limitations, this paper introduces an innovative approach for daily recording and observation of underwater archaeological excavations using 3D photogrammetric models and point of view (PoV) cameras developed specifically for the excavation of a shipwreck situated at a depth of 110 m. The proposed system leverages advancements in photogrammetry and 3D modelling techniques to capture and analyse detailed visual data of the excavation site on a daily basis. Three-dimensional photogrammetric models offer a comprehensive and easily accessible representation of the excavation site, enabling the team to record and analyse excavation levels and features in a highly precise and detailed manner. By comparing the 3D models captured on consecutive days, researchers can precisely measure changes in the excavation area, identify new artifacts or structures, and record the progress of the excavation. The PoV cameras contribute to the planning of daily tasks required on the site. Overall, this paper showcases innovative methods for underwater archaeological excavations at significant depths, employing 3D photogrammetric models for daily recording as well as PoV cameras for observation. The proposed system represents a substantial advancement in the field of underwater archaeology, offering a more accurate, efficient, and reliable approach to documenting and analysing excavation progress, whilst also producing results that can be subsequently adapted and applied to other deep water archaeological sites.

Underwater Excavation at the Basilica Church in İznik Lake – 2019

The remains of the basilical church lie approximately in 2 or 3 meters of depth, and 50 m from the shore of the lake, outside the city walls that surround the ancient city of Nicaea. The underwater archaeological excavations at the basilica remain are being launched under the auspices of the Iznik Archaeology Museum with the permission of the Ministry of Culture and Tourism in 2015. In 2019, excavation was carried out in the atrium where we thought a water well was situated. This is because the British pilgrim, Willibald, pointed out that the site of the 1st Council had a rectangular open-roofed courtyard with a sacred source of oil in the middle. Although we went down 60 cm deeper than the foundation walls, we could not find the bottom of the well. However, a large number of ceramics, glass bracelets, or Scyphate coins (cup-shaped coins) were found indicating the 13th century. It was also found that the well was filled with stone. Therefore, we think that the structure was definitely abandoned in the approximately 12th century and then sank into the lake waters.

Served on a Plate: A Late Medieval Ceramic Vessel with Sgraffito Decoration of a Sailing Ship from the Ropotamo Underwater Excavations, Black Sea, Bulgaria

We report on the interpretation of a late medieval Eastern Mediterranean glazed ceramic vessel with sgraffito decoration depicting a sailing ship. The artefact represents a chance find that was recovered outside the excavation area of the Ropotamo underwater archaeological excavations on the Southern Bulgarian Black Sea Coast in 2017. Fragments of late medieval sgraffito-decorated ceramics with depictions of sailing ships are rare. Complete examples can be considered exceptional. The Ropotamo artefact is of particular interest due to the freehand execution of its decoration, which suggests some understanding of contemporary ship proportions and seafaring practices on behalf of the artisan. The specimen is analyzed against similar artefacts and discussed in the context of maritime graffiti from the Black Sea and Eastern Mediterranean regions. The aim is to establish its potential for studying archaeological ceramics and evaluate the extent to which the decoration reflects aspects of Eastern Mediterranean maritime culture of the late Byzantine and early post-Byzantine periods. More research is required to appreciate the full potential of the Ropotamo artefact. A hypothesis for origin, dating and significance has been proposed. However, due to a shortage of published parallels, it may be subject to further refinements in the future in case more stratified similis are identified.

Study on Distortion Compensation of Underwater Archaeological Images Acquired through a Fisheye Lens and Practical Suggestions for Underwater Photography - A Case of Taean Mado Shipwreck No. 1 and No. 2 -

Underwater archaeology relies heavily on photography and video image recording during surveillances and excavations like ordinary archaeological studies on land. All underwater images suffer poor image quality and distortions due to poor visibility, low contrast and blur, caused by differences in refractive indices of water and air, properties of selected lenses and shapes of viewports. In the Yellow Sea (between mainland China and the Korean peninsula), the visibility underwater is far less than 1 m, typically in the range of 30 cm to 50 cm, on even a clear day, due to very high turbidity. For photographing 1 m x 1 m grids underwater, a very wide view angle (180o) fisheye lens with an 8 mm focal length is intentionally used despite unwanted severe barrel-shaped image distortion, even with a dome port camera housing. It is very difficult to map wide underwater archaeological excavation sites by combining severely distorted images. Development of practical compensation methods for distorted underwater images acquired through the fisheye lens is strongly desired. In this study, the source of image distortion in underwater photography is investigated. We have identified the source of image distortion as the mismatching, in optical axis and focal points, between dome port housing and fisheye lens. A practical image distortion compensation method, using customized image processing software, was explored and verified using archived underwater excavation images for effectiveness in underwater archaeological applications. To minimize unusable area due to severe distortion after distortion compensation, practical underwater photography guidelines are suggested.

Foraminifera—A new find in the microtaphonomical characterization of bones from marine archaeological excavations

AbstractForaminifera are marine single‐celled organisms, ubiquitous in marine environments, present in brackish waters and absent in terrestrial locations. Their presence has been associated with archaeological and forensic studies only rarely and just once and superficially with bones of terrestrial mammals. In this study, a new association is presented between foraminifera enclosed in the dissolving trabecular spaces of terrestrial mammalian bones, recovered in underwater archaeological excavations between 1968 and 1980.Research on the new association aims to detail the micro‐characterization of bone in underwater environments, leading to a better understanding of bone taphonomic trajectories, the chronological sequences of changes occurring between death and the incorporation of the remains of an organism within the depositional environment. The analysis of taphonomic trajectories is known to hold relevance in distinct disciplines, such as archaeology, paleontology, and forensic sciences.Different foraminiferal taxa are linked to different marine environments, characterized by specific ranges of water depth, amount of light and oxygen, temperature, and composition of sediment. The association between foraminifera and terrestrial mammalian bones indicates deposition in a marine or brackish environment; thus, the analysis of the specific ecology of the identified foraminiferal taxa can point to a specific environment, adding information to paleontological, archaeological, or forensics casework.

Technique of Temporary Undisturbed Reinforcement Extraction of Fragile Lacquerware from Shipwrecks

A subject of continuous discussion in the field of underwater archaeology is how to safely extract fragile waterlogged artifacts while maintaining their best condition. In this study, lacquerware with fragile wooden body was simulated and extracted, using a triple-package reinforcement technique. Using veratraldehyde as a temporary consolidant, SH-MWCNTs@PU sponge/epoxy resin composite materials as free-form reinforced layers, and double-sided self-adhesive bandages wrapped around the outer layer, the safe underwater extraction and the layer-by-layer removal of the simulated artifacts were studied. The method maximized the preservation of the artifacts’ state and information and minimized their damage during removal and transport. This method can be used as a technique for the extraction of fragile artifacts from underwater archaeological excavation sites.

Reply to the comment by E. Kolaiti and N. Mourtzas on “Coastal subsidence, destruction layers and earthquakes from an underwater archaeological excavation: Kenchreai, eastern harbour of Roman Corinth, Greece” by S.C. Stiros. Mediterranean Geoscience Reviews

Reply to the comment by E. Kolaiti and N. Mourtzas on “Coastal subsidence, destruction layers and earthquakes from an underwater archaeological excavation: Kenchreai, eastern harbour of Roman Corinth, Greece” by S.C. Stiros. Mediterranean Geoscience Reviews

Comment on “Coastal subsidence, destruction layers and earthquakes from an underwater archaeological excavation: Kenchreai, eastern harbour of Roman Corinth, Greece” by S. C. Stiros. Mediterranean Geoscience Reviews, https://doi.org/10.1007/s42990-020-00019-4

Comment on “Coastal subsidence, destruction layers and earthquakes from an underwater archaeological excavation: Kenchreai, eastern harbour of Roman Corinth, Greece” by S. C. Stiros. Mediterranean Geoscience Reviews, https://doi.org/10.1007/s42990-020-00019-4

Coastal subsidence, destruction layers and earthquakes from an underwater archaeological excavation: Kenchreai, eastern harbour of Roman Corinth, Greece

One of the first underwater coastal archaeological excavations was made in the 1960 in Kenchreai (Cenchreae), eastern harbour of Roman Corinth, Greece, near the Isthmus (Corinth) Canal. This excavation brought to light an Isis temple with a destruction layer containing amongst others, packs of more than 100 precious glass panels of opus sectile, testifying to a hitherto unknown mosaic-type wall decorative technique. Above this destruction layer, indicating a violently disrupted renovation of the temple in circa AD 400, thereafter abandoned, an apsidal Christian chapel was constructed, currently also found quasi-submerged. The excavators, inspired by subsidence of piscinae (fishtanks) and theories for earthquake destruction and decline of Roman Corinth, a prosperous town controlling marine routes and commerce between Eastern Mediterranean and Italy, have explained the environmental and occupation history of Kenchreai in terms of three earthquakes with 2.3 m cumulative subsidence. This theory, however, has been challenged on different grounds. New evidence about the glass panels and detailed evaluation of historical, seismological, archaeological and coastal data revealed an about 1 m seismic subsidence of Kenchreai, most of which occurred during a destructive earthquake in circa AD 400, undoubtedly with serious impacts to Corinth. Identification of the causative fault is not easy because of unfavourable lithology and because Kenchreai is in a tectonically complex environment: at the east edges of the uplifting Corinthian coast (marked by a Roman harbour 4 m above water) and of the Isthmus of Corinth, a Plio–Quaternary uplifted horst, inside an active tectonic graben. Kenchreai represents one of the very few cases of seismic coastal subsidence deriving from archaeological data.

4D modelling of low visibility Underwater Archaeological excavations using multi-source photogrammetry in the Bulgarian Black Sea

This paper introduces the applicability of underwater photogrammetric survey within challenging conditions as the main tool to enhance and enrich the process of documenting archaeological excavation through the creation of 4D models. Photogrammetry was being attempted on underwater archaeological sites at least as early as the 1970s’ and today the production of traditional 3D models is becoming a common practice within the discipline. Photogrammetry underwater is more often implemented to record exposed underwater archaeological remains and less so as a dynamic interpretative tool.Therefore, it tends to be applied in bright environments and when underwater visibility is > 1 m, reducing its implementation on most submerged archaeological sites in more turbid conditions. Recent years have seen significant development of better digital photographic sensors and the improvement of optical technology, ideal for darker environments. Such developments, in tandem with powerful processing computing systems, have allowed underwater photogrammetry to be used by this research as a standard recording and interpretative tool. Using multi-source photogrammetry (5, GoPro5 Hero Black cameras) this paper presents the accumulation of daily (4D) underwater surveys carried out in the Early Bronze Age (3300 BCE) to Late Ottoman (17th Century AD) archaeological site of Ropotamo in the Bulgarian Black Sea under challenging conditions (< 0.5 m visibility). It proves that underwater photogrammetry can and should be used as one of the main recording methods even in low light and poor underwater conditions as a way to better understand the complexity of the underwater archaeological record.

4D Modelling of Low Visibility Underwater Archaeological Excavations Using Multi-Source Photogrammetry in the Bulgarian Black Sea

4D Modelling of Low Visibility Underwater Archaeological Excavations Using Multi-Source Photogrammetry in the Bulgarian Black Sea

Aportaciones de la arqueología subacuática al patrimonio organológico

El presente artículo se centra en el estudio de los restos de instrumentos musicales hallados en excavaciones arqueológicas subacuáticas en diferentes partes del mundo. Esos restos no han sido objeto de estudio hasta la fecha, exceptuando alguna investigación parcial.&#x0D; En primer lugar se catalogan, posibilitando así que el musicólogo tenga acceso a estos documentos que tienen la ventaja de no haber sufrido modificaciones de épocas posteriores como sucede en muchos casos en los instrumentos conservados en tierra. Se establece así una vía de comunicación efectiva entre el trabajo de los arqueólogos subacuáticos y los musicólogos. &#x0D; En segundo lugar, se expone el estudio de uno de los instrumentos catalogados que por su importancia histórica es digno de destacar entre los hallados. Dicho estudio consiste en un análisis de los restos y un estudio musicológico sobre el instrumento.

Raman spectroscopic analysis of archaeological specimens from the wreck of HMS Swift, 1770.

Specimens from underwater archaeological excavations have rarely been analysed by Raman spectroscopy probably due to the problems associated with the presence of water and the use of alternative techniques. The discovery of the remains of the Royal Navy warship HMS Swift off the coast of Patagonia, South America, which was wrecked in 1770 while undertaking a survey from its base in the Falkland/Malvinas Islands, has afforded the opportunity for a first-pass Raman spectroscopic study of the contents of several glass jars from a wooden chest, some of which had suffered deterioration of their contents owing to leakage through their stoppers. From the Raman spectroscopic data, it was possible to identify organic compounds such as anthraquinone and copal resin, which were empirically used as materia medica in the eighteenth century to treat shipboard diseases; it seems very likely, therefore, that the wooden chest belonged to the barber-surgeon on the ship. Spectra were obtained from the wet and desiccated samples, but several samples from containers that had leaked were found to contain only minerals, such as aragonite and sediment.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.

A staged geogenetic approach to underwater archaeological prospection in the Port of Rotterdam (Yangtzehaven, Maasvlakte, The Netherlands): A geological and palaeoenvironmental case study for local mapping of Mesolithic lowland landscapes

This study presents the geogenetic approach to detect presently drowned archaeological sites in the transgressive palaeoenvironment of the Holocene Rhine-Meuse delta. A staged and practical approach is advocated in which subsurface archaeological predictions are based on geological mapping and palaeoenvironmental reconstruction of the underwater location. The study area is located in the Maasvlakte harbour extension of the Port of Rotterdam, formerly a part of the southern North Sea. Prior to construction works, it was suggested that dredging of the new harbour (Yangtzehaven) would disturb the subsurface stratigraphy to around −21 m below present mean sea level, a zone which is known to contain archaeological remains. The staged approach makes use of geological data starting from a conceptual model that indicates the depths of layers that could be rich in Upper Palaeolithic/early Mesolithic artefacts. This initial model is used to determine the strategy of the subsequent phases of investigation, such as whether to proceed with dredging as part of the engineering work, down to 17 m water depth, to remove the upper (younger) sands and thereby improve the opportunities for underwater survey of fluvio-deltaic layers of Mesolithic age. Following the development of the initial site model, a full-area investigation was carried out using geophysics and coring, the latter providing material for palaeoenvironmental analysis. This allowed the reconstruction of the long-drowned former landscape, which included inland dune areas and local drainage systems and provided the physiographic context for the geoprospection of Mesolithic archeology. This predictive modeling identified two areas in the harbour for detailed investigation, again employing geophysics and coring at higher resolutions, allowing fine tuning of the palaeolandscape models at the localities of presumed highest archeological potential. Cores from one of the selected areas, an inland dune area within the Early Holocene wetland region, yielded in-situ evidence of Mesolithic occupation of this site in what is now the southern North Sea. These finds and the palaeolandscape context created with the data from the prospection phases were critical in the decision to undertake an underwater archaeological excavation using a large, boat-mounted grab sampling system. This paper provides an account of the geological and palaeoenvironmental work undertaken in the prospective phases leading up to the discovery of the site, highlighting the importance of the staged geogenetic approach for informing sampling strategies and securing high-quality information on landscape contexts, which in turn, informed archaeological decision-making and geoprospection strategies. Such an approach has wider generic application for palaeolandscape reconstruction and mapping at regional scales.

Reburial and Analyses of Archaeological Remains in the Marine Environment — Investigations into the Effects on Metals

The treatment and long-term storage of recovered cultural material from underwater heritage sites is becoming less cost effective, and reburial of archaeological sites and the associated artefacts in the marine environment is becoming increasingly common practice in managing the submerged cultural resource. Following recent large-scale underwater archaeological excavations in Marstrand harbour, Sweden, the majority of recovered finds were reburied in defined trenches in the harbour sediment. Subsequently, the Studio of the Western Sweden Conservators in conjunction with the Bohus County Museum initiated a fifty-year research project to evaluate reburial as an appropriate method of preserving waterlogged archaeological artefacts in the long term. The research project, entitled ‘Reburial and Analyses of Archaeological Remains’, was launched in 2002 and consists of six sub-projects. The main aims of these sub-projects are to analyse the extent of deterioration of the most common material types found on underwater archaeological sites, assess the stability of packing and marking materials used in archaeological documentation, and monitor the reburial environment.The aim of the metals sub-project is to investigate the short- to long-term corrosion behaviour of metals buried in the marine environment by examining the deterioration of reburied and exposed modern metal coupons and eventually compare these results to the analysis of actual shipwreck artefacts. The environmental monitoring sub-project is designed to complement the other sub-projects by assessing the physico-chemical changes occurring in the reburial environment over time and the effect on the deterioration of the different reburied material types. In comparing the results obtained over the past seven years from both the metals and monitoring sub-projects, it should be possible to more accurately evaluate the effectiveness of reburial as a long-term in situ preservation strategy for metallic archaeological remains.

Ranosrednjovjekovni nalazi iz hrvatskog podmorja

U članku će se uz nove nalaze kasnobizantskih amfora X. do XII. stoljeća ponovno obraditi pojedini raniji nalazi, posebno amfore iz neistraženog brodoloma na otoku Mljetu, kao i ranije publiciran nalaz željeznog alata iz ninskog podmorja. Datirajući ovaj željezni alat u X. ili XII. stoljeće, pokušati će se razjasniti njegovo podrijetlo, način dospijeća pod more te njegova pripadnost.

Multi‐proxy geoarchaeological study redefines understanding of the paleocoastlines and ancient harbours of Liman Tepe (Iskele, Turkey)

AbstractDetermining the position of Liman Tepe's (ancient `Clazomenae') archaeological features relative to the coastline is important for understanding their intended function and reconstructing the character of Aegean maritime activities and sea‐based trade. Previous attempts at reconstructing harbour locations at Liman Tepe relied on extrapolating paleoenvironments based on modern surface topography. In light of this, samples from a sediment coring survey and terrestrial and underwater archaeological excavations were analysed using multi‐proxy geoarchaeological methods to determine paleoenvironmental facies. Micropaleontological (foraminifera), sedimentological (grain‐size analysis) and geochemical (δ13C/δ18O) analyses resulted in the reconstruction of the coastal paleogeomorphology, including the presence and absence of ancient harbouring areas. Neither of the previous coastal reconstructions was supported by the new results. Instead, two separate harbouring areas were recognized, one coincident with the Early Bronze Age (4800–3900 years bp) and a second during the archaic and classical periods (c. 2800–2400 years bp). These results emphasize the necessity for multi‐proxy geoarchaeological studies when approaching coastal archaeological sites as a means to reconstruct paleocoastal geomorphology and understand ancient maritime development better.