Hidden in the soil: Can ancient soils reveal how water sustained life along the Silk Road?

Protocol 1 – Archaeological and Geoarchaeological Field Survey

Objective

To systematically document the archaeological landscape of Ravat, including settlements, irrigation canals, agricultural fields and associated metallurgical remains.

Procedure

The archaeological landscape will be surveyed on foot using handheld GPS units and drone imagery. All archaeological features, including canals, field boundaries, furnaces and sampling locations, will be photographed, described and georeferenced. Drone-based photogrammetry will be used to produce high-resolution orthophotos and digital elevation models that will be integrated into a GIS database.

The survey data will guide the selection of sampling locations and provide the spatial framework for subsequent laboratory analyses.

Protocol 2 – Geoarchaeological Soil Sampling

Objective

To collect representative archaeological soil samples from ancient agricultural fields, irrigation features and iron-smelting contexts while preserving their original sedimentary structure.

Procedure

Sampling locations will be selected on the basis of archaeological observations and drone mapping. Each location will be recorded using GPS, photographed and documented in the field.

Undisturbed sediment blocks will be collected using Kubiena tins for soil micromorphology. Additional bulk sediment samples will be collected from the same contexts for geochemical analyses. All samples will receive a unique identification number linked to their archaeological context and geographic position before being transported to the laboratory under controlled conditions.

Protocol 3 – Laboratory Analysis and Data Integration

Objective

To reconstruct ancient agricultural practices by integrating micromorphological, geochemical and spatial datasets.

Procedure

Undisturbed samples will be impregnated with resin and prepared as thin sections for micromorphological analysis following internationally accepted procedures. Thin sections will be examined under plane- and cross-polarised light to identify evidence of irrigation, cultivation, sediment accumulation, burning and other anthropogenic processes.

Bulk sediment samples will undergo geochemical analyses to characterise nutrient enrichment, fertilisation and other human-induced changes. The laboratory results will then be integrated with archaeological observations, drone mapping and GIS data to reconstruct the organisation and functioning of the Ravat agricultural landscape.

Protocol 4 – Archaeometallurgical Sampling and Landscape Integration

Objective

To investigate the relationship between iron production and agricultural activities within the Ravat archaeological landscape by documenting and sampling recently identified iron-smelting furnaces and their surrounding sediments.

Procedure

The iron-smelting furnaces located on the edge of the modern village will first be documented using archaeological recording, GPS positioning, photography and drone imagery. Their spatial relationship to the ancient settlement, irrigation canals and agricultural fields will be integrated into the project's GIS database.

Samples will be collected from furnace fills, associated slag deposits and surrounding sediments using standard archaeological and geoarchaeological sampling procedures. Where appropriate, undisturbed sediment blocks will be taken for micromorphological analysis to identify combustion features, post-depositional processes and possible evidence of workshop activities. Bulk samples will also be collected for geochemical analyses to characterise anthropogenic enrichment associated with iron production.The analytical results will be compared with those obtained from the agricultural soils in order to evaluate whether iron production formed an integral part of the same economic landscape. Rather than studying agriculture and metallurgy as separate activities, the project aims to reconstruct how food production, water management and craft production functioned together within a single, integrated settlement system.

All sampling locations, metadata and analytical results will be archived to ensure that the study is transparent, reproducible and available for future comparative research.