12.2 Excavation techniques for Viking settlements

Overview of Viking settlements

Viking settlements span a wide geographic range, from Scandinavia to the British Isles to the North Atlantic islands. Excavating these sites reveals how Norse communities organized trade, structured their societies, and adapted technologies across different environments. The techniques used to dig these sites have changed dramatically over the past few decades, and understanding those methods is just as important as understanding the finds themselves.

Types of Viking settlements

Not all Viking sites look the same, and the type of settlement shapes how you approach excavation.

• Urban centers like Birka (Sweden) and Hedeby (northern Germany) had dense populations, dedicated craft production zones, and connections to international trade routes. These sites tend to have deep, complex stratigraphy with many overlapping occupation phases.
• Rural farmsteads are the most common site type, typically featuring longhouses, outbuildings, and evidence of agricultural activity such as animal enclosures and field systems.
• Coastal trading posts like Kaupang (Norway) functioned as hubs for maritime commerce and cultural exchange. They often have rich assemblages of imported goods.
• Temporary camps and overwintering sites were used during expeditions and explorations. These tend to leave lighter archaeological footprints and can be harder to identify.

Importance of excavation techniques

Why does technique matter so much for Viking sites specifically? A few reasons stand out:

• Viking settlements frequently contain delicate organic materials (wood, textiles, leather) that survive only under specific conditions, especially waterlogging. Clumsy excavation destroys them.
• Proper contextual recording preserves the spatial relationships between finds, which is how you reconstruct what activities happened where.
• Systematic, standardized methods make it possible to compare sites across regions, from Iceland to Novgorod.
• Techniques tailored to Viking architecture help reconstruct settlement layouts, including the distinctive longhouse forms and their surrounding structures.

Site selection and survey

Before anyone puts a trowel in the ground, the team needs to find and evaluate the site. This stage involves archaeologists, historians, and geologists working together, combining historical records, landscape analysis, and modern technology to pinpoint where Viking-age deposits are likely to survive.

Preliminary surveys determine the extent of a site, its preservation state, and its research potential. This information drives decisions about whether and how to excavate.

Remote sensing methods

Remote sensing lets you gather data about what's underground without digging. Four key technologies are used on Viking sites:

• LiDAR (Light Detection and Ranging) uses laser pulses from aircraft to map subtle topographic features. It's especially useful for detecting buried structures under vegetation or in forested areas.
• Aerial photography reveals crop marks and soil discolorations that indicate subsurface features. Crops grow differently over buried walls versus filled-in ditches, creating visible patterns from above.
• Magnetometry detects magnetic anomalies in the soil caused by burning or metalworking. Buried hearths, kilns, and smithing areas show up clearly because heating permanently changes the magnetic properties of soil and clay.
• Ground-penetrating radar (GPR) sends radio waves into the ground and records reflections from buried surfaces. It produces cross-sectional images of subsurface features without any disturbance to the site.

Ground-based prospection techniques

These methods involve physically walking and sampling the site surface and shallow subsurface:

• Systematic field walking collects surface artifacts along a grid, helping identify concentrations of Viking-age material.
• Geochemical sampling tests soil for elevated phosphate levels, which indicate prolonged human or animal occupation. Viking farmsteads often show distinct phosphate signatures around byres and middens.
• Electrical resistivity measures how easily electrical current passes through the ground. Stone walls and packed floors resist current differently than surrounding soil, revealing buried features.
• Microtopographic surveys map subtle surface undulations that may correspond to collapsed structures or filled-in ditches.

Test pitting strategies

Test pits are small, controlled excavations used to assess a site before committing to full-scale work. There are several approaches:

• Standard test pits (typically 1×1m or 2×2m) are placed strategically to check stratigraphy and artifact density at specific locations.
• Transect sampling places test pits along predetermined lines across the site, helping define its boundaries and internal variation.
• Judgmental test pitting targets areas that look promising based on surface finds or geophysical results.
• Systematic random sampling distributes pits across the site in an unbiased pattern, ensuring you don't just dig where you expect to find things.

Excavation planning

Viking settlement excavations are complex, multi-year projects. Careful planning at the outset saves time, money, and irreplaceable archaeological information down the line.

Research design development

Every excavation starts with a research design that lays out what you're trying to learn and how you'll go about it:

1. Formulate clear research questions targeting specific aspects of Viking settlement life (e.g., craft production, diet, trade connections).
2. Integrate multiple disciplines into the plan from the start, including environmental science, history, and materials analysis.
3. Develop sampling strategies for artifacts, ecofacts (animal bones, plant remains), and environmental data.
4. Incorporate non-invasive techniques where possible to minimize destruction of the site while still collecting meaningful data.

Permit acquisition process

You can't just start digging. The administrative side involves:

• Consulting with local heritage authorities to secure excavation permits
• Complying with national and international regulations governing archaeological work
• Negotiating land access agreements with property owners or local communities
• Preparing detailed project proposals that outline methods, timelines, and expected outcomes

Resource allocation

Viking sites often demand specialized resources that a typical excavation might not need:

• Equipment budgets must account for water pumps (for waterlogged sites), freeze-drying facilities, and conservation supplies.
• Personnel should include excavators experienced in Norse archaeology, since recognizing Viking-age features in the ground takes familiarity with the material.
• On-site lab facilities allow for immediate processing and preliminary analysis of finds, which is critical for fragile organic materials.
• Post-excavation funds are often the largest budget item. Analysis, conservation, and long-term curation of artifacts can take years.

Stratigraphic excavation methods

Stratigraphy is the backbone of archaeological excavation. By carefully removing and recording soil layers in sequence, you reconstruct the chronology of a site: what happened first, what came later, and how the settlement changed over time.

Viking sites require adaptation of standard methods to deal with specific conditions like waterlogging, thin occupation layers, and the organic-rich deposits typical of Norse settlements.

Single context recording

This is the standard recording method used on most Viking excavations:

1. Each distinct layer or deposit (called a context) is excavated and documented individually.
2. Soil characteristics, inclusions, and the relationships between contexts are recorded in detail.
3. Every context receives a unique number, which links it to all associated finds and samples.
4. Relationships between contexts are visualized using a Harris Matrix, a diagram that shows which layers are above, below, or cut into other layers.

Open area excavation

Open area excavation strips back large portions of a site to expose the full layout of structures and activity areas. This approach is especially valuable for Viking settlements because:

• It reveals spatial relationships between buildings, pathways, fences, and work areas.
• It allows you to identify how the settlement was organized and how that organization changed over time (phasing).
• It requires careful planning to manage large volumes of soil removal while maintaining stratigraphic control across the entire exposed area.

Quadrant method vs. baulk method

These are two strategies for excavating individual features (pits, postholes, sunken buildings):

• The quadrant method divides a feature into four quarters. You excavate two opposite quarters first, which gives you two cross-section profiles through the feature. This is often preferred for Viking pit features and sunken-featured buildings (grubenhäuser).
• The baulk method leaves standing sections of unexcavated soil between excavated areas, preserving visible stratigraphic profiles. This works well for maintaining spatial control in large open area excavations.

The choice between them depends on the feature type and what information you need most.

Artifact recovery techniques

Viking settlements produce a wide range of material, from iron nails to tiny fish bones. Recovery techniques need to balance thoroughness with efficiency, and specialized methods are essential for the fragile organic materials that Viking sites often preserve.

Dry sieving vs. wet sieving

• Dry sieving passes excavated soil through mesh screens to catch small artifacts missed during troweling. It's the standard approach for general soil processing on Viking sites.
• Wet sieving uses water to wash soil through sieves, which is much more effective at recovering small, delicate items. It's essential for catching small bone fragments, plant remains, and metalworking debris like hammerscale.

On most Viking excavations, dry sieving handles the bulk of the soil, while wet sieving is reserved for contexts with high potential for small finds.

Flotation for organic remains

Flotation is a technique that separates light organic materials from heavier sediment by agitating soil samples in water. Light materials (seeds, charcoal, insect remains) float to the surface and are collected in fine mesh.

This method is crucial for Viking sites because it recovers:

• Botanical evidence of diet, agriculture, and local environmental conditions
• Imported plant species that document long-distance trade networks
• Small fish bones and scales that reveal fishing practices, a major component of Viking subsistence

Metal detection protocols

Metal detecting is standard practice on Viking excavations, since Norse sites frequently yield metalwork (brooches, coins, tools, weapons fragments):

1. Systematic metal detecting surveys are conducted over the site before and during excavation.
2. All finds are carefully recorded with precise spatial coordinates to preserve their contextual information.
3. Discriminating detectors can be tuned to focus on non-ferrous metals (copper alloy, silver, gold), which are often associated with high-status Viking artifacts.
4. Metal detection data is integrated with other excavation records to help interpret activity areas within the settlement.

Documentation and recording

Every piece of information lost during excavation is lost permanently, since digging is a destructive process. Comprehensive documentation ensures that future researchers can revisit and reinterpret the evidence.

Modern Viking excavations typically combine digital recording methods with traditional paper-based systems as a backup.

Site grid systems

• A site-wide coordinate system is established at the start, providing a spatial framework for all recording.
• Total stations or Differential GPS (DGPS) are used for accurate three-dimensional mapping of features and finds.
• Local site grids are tied into national coordinate systems so the data can be integrated with broader geographic datasets.
• Detailed site plans show the spatial relationships between structures, features, and activity areas.

Context sheets and matrices

• Context sheets are standardized recording forms used to document each stratigraphic unit. They include descriptions, measurements, soil characteristics, and the excavator's interpretation.
• A Harris Matrix is constructed from context sheet data to visualize the stratigraphic sequence of the entire site.
• Digital database systems manage context information efficiently and allow for rapid querying and cross-referencing during analysis.

Photogrammetry and 3D modeling

Photogrammetry has become a standard tool on Viking excavations. The process works like this:

1. Overlapping photographs are taken of a structure, feature, or artifact from multiple angles.
2. Structure-from-motion (SfM) software processes these images to generate a detailed 3D model.
3. The resulting models are integrated with GIS data for spatial analysis and visualization.
4. Virtual reconstructions of Viking buildings can be built on top of the archaeological evidence, aiding both research and public engagement.

Environmental sampling

Environmental data fills in the picture that artifacts alone can't provide. Sampling tells you what people ate, what the landscape looked like, what fuel they burned, and how they managed their resources.

Systematic sampling strategies ensure that different site areas and context types are all represented, avoiding bias toward the most artifact-rich deposits.

Soil sampling techniques

• Bulk soil samples are collected from key contexts for multi-proxy analysis (pollen, seeds, insects, chemical signatures).
• Monolith tins extract intact columns of soil for micromorphological study, which examines thin sections of sediment under a microscope to identify formation processes.
• Grid-based sampling maps spatial variations in soil chemistry across the settlement, revealing activity zones.
• Specialized protocols apply to waterlogged deposits, which are common at Viking coastal and riverine sites and require careful handling to prevent drying.

Pollen and macrofossil analysis

• Off-site pollen analysis uses sediment cores from nearby lakes or bogs to reconstruct the regional vegetation and land-use history during Viking occupation.
• On-site sampling collects pollen and macrofossil remains directly from archaeological contexts, giving a more localized picture.
• Pollen assemblages reveal what plants grew nearby and how the landscape was managed (forest clearance, grazing, crop cultivation).
• Macrofossils (seeds, plant fragments, wood charcoal) provide direct evidence of what was eaten, grown, or burned at the site.

Radiocarbon dating methods

Radiocarbon dating is the primary absolute dating method for Viking-age sites. Getting reliable dates requires careful sample selection and analysis:

• Short-lived materials (seeds, twigs, annual plant parts) are preferred over long-lived wood, which can give dates hundreds of years too old due to the "old wood effect."
• Accelerator Mass Spectrometry (AMS) allows dating of very small samples, which is important when material is scarce or precious.
• Bayesian modeling combines multiple radiocarbon dates with stratigraphic information to produce refined chronologies for settlement phases.
• Radiocarbon dates are integrated with artifact typologies and historical records (such as dendrochronological dates from timber) for the most robust chronological framework.

Preservation of structures

When Viking structures survive in the ground, decisions about preservation versus excavation become critical. The goal is to balance research needs with long-term conservation.

In situ preservation techniques

Sometimes the best option is to leave structures buried and protected:

• Reburial uses carefully selected backfill materials to cover excavated features.
• Geotextile membranes are placed over buried structures to shield them from root damage and chemical changes in the soil.
• Water table management systems maintain the waterlogged conditions that preserve organic materials at sites like Bryggen in Bergen.
• Sacrificial layers protect original Viking surfaces in areas that are opened for public viewing, so visitors can see the remains without damaging them.

Removal of fragile features

When features must be removed from the site, the process follows a careful sequence:

1. Thorough documentation (photography, photogrammetry, measured drawings) before any removal.
2. Block-lifting extracts complex features like hearths or decorated floor surfaces as a single unit, supported by rigid frames.
3. Consolidants are applied to stabilize fragile materials before they're moved.
4. Molds or 3D scans preserve the spatial information of features that can't survive removal intact.

Conservation of wooden remains

Wood is one of the most important and most challenging materials from Viking sites. Waterlogged wood survives beautifully underground but will crack and collapse if allowed to dry uncontrolled.

• Waterlogged wood must be treated immediately after excavation to prevent cellular collapse.
• Polyethylene Glycol (PEG) impregnation is the standard method for stabilizing large timber structures. PEG gradually replaces the water in the wood cells. The Vasa warship and Oseberg ship both underwent PEG treatment.
• Freeze-drying works well for smaller wooden artifacts, removing moisture under vacuum without the shrinkage that air-drying causes.
• Conserved wood requires ongoing environmental monitoring in storage and display to prevent deterioration.

Post-excavation analysis

Excavation generates raw data. Post-excavation analysis is where that data becomes knowledge. This phase often takes longer than the dig itself and requires collaboration across many specialisms.

Artifact cataloging and storage

• Standardized typologies for Viking artifacts (brooches, weapons, tools, pottery) allow consistent classification across sites.
• Detailed catalogs record measurements, material composition, condition, and contextual information for every find.
• Storage solutions are tailored to material type: metals need stable humidity, organics need controlled temperature, and iron often requires desiccated environments.
• Database management systems make collections accessible for research and ensure long-term curation.

Data interpretation methods

• Statistical analyses identify patterns in artifact distribution and assemblage composition, revealing activity zones and social distinctions.
• GIS analysis maps spatial relationships between features and finds, showing how space was used within the settlement.
• Scientific analyses such as isotope studies (tracing origins of people and animals) and residue analysis (identifying what was stored or cooked in vessels) add layers of information that traditional methods can't access.
• Comparative analysis with other Viking sites identifies regional patterns, trade connections, and cultural variations.

Publication and dissemination

• Comprehensive site reports document all aspects of excavation and analysis, forming the permanent record.
• Specialist studies are published in peer-reviewed journals to share significant findings with the academic community.
• Online databases and digital archives increase data accessibility for researchers worldwide.
• Popular publications and media content engage the public with Viking archaeology, which also helps build support for future work.

Ethical considerations

Viking archaeology operates within a framework of ethical responsibilities to communities, descendant populations, and the sites themselves.

Stakeholder engagement

• Local communities and descendant populations are consulted throughout the excavation process, not just informed after the fact.
• Traditional knowledge and oral histories can provide valuable context for interpreting Viking settlement sites.
• Collaborative research partnerships with Scandinavian institutions ensure that expertise and perspectives from source countries are represented.
• Public outreach programs share results and involve communities in heritage preservation.

Cultural heritage protection

• Site security measures prevent looting and vandalism, which remain serious threats to Viking sites, particularly those with visible metal-rich deposits.
• Management plans address long-term protection of both excavated and unexcavated areas.
• Advocacy for stronger legal protections operates at national and international levels.
• The tension between research access and preservation for future generations requires ongoing negotiation, since every excavation destroys part of what it studies.

Repatriation of artifacts

• International agreements and ethical guidelines govern the movement of cultural property, and Viking artifacts are no exception.
• Repatriation requests for significant Viking artifacts to their countries of origin are considered on a case-by-case basis.
• Loan agreements facilitate international study and exhibition while respecting ownership.
• Digital repatriation initiatives use 3D scanning and online databases to increase access to Viking collections for source communities, even when physical return isn't feasible.

Challenges in Viking site excavation

Viking sites present distinctive challenges that require creative solutions and adapted methodologies.

Waterlogged site management

Waterlogged conditions preserve organic materials beautifully but make excavation extremely difficult:

• Dewatering systems (pumps, well points) lower the water table temporarily to allow excavation of submerged structures.
• Cofferdams create dry working environments at coastal Viking sites by holding back water with temporary barriers.
• Anaerobic excavation methods keep organic materials wet during excavation to prevent the rapid deterioration that occurs when waterlogged deposits are exposed to air.
• Specialized recording techniques are needed for underwater or inter-tidal sites, where standard paper recording isn't practical.

Urban vs. rural site differences

Urban and rural Viking sites demand different approaches:

• Urban sites (like York's Coppergate or Dublin's Wood Quay) typically have deep, complex stratigraphy with many overlapping occupation phases. Excavation is often driven by development pressure, meaning tight timelines and budgets.
• Rural sites tend to be more dispersed, requiring extensive survey to locate and define settlement boundaries. The challenge is characterizing large landscapes efficiently with limited resources.
• Sampling strategies differ significantly: urban sites may require near-total excavation of a small area, while rural sites benefit from targeted sampling across a wider zone.

Dealing with later disturbances

Viking-age deposits are often disturbed by centuries of subsequent activity:

• Careful stratigraphic analysis distinguishes original Viking layers from later intrusions (medieval plowing, modern construction, earlier archaeological trenches).
• Scientific dating methods help resolve ambiguous sequences where stratigraphy alone isn't clear.
• Targeted excavation strategies focus on pockets of undisturbed Viking-age deposits when much of the site has been compromised.
• Historical records and old maps can explain post-Viking impacts on the site, helping you anticipate where disturbance is likely and where intact deposits may survive.