This thesis reviewed evidence from Neolithic and Bronze Age settlements in the Scottish North Atlantic to better understand the formation and uses of "midden" sediments. Several contexts for these anthropic sediments were identified, including interior floors, hearths, exterior surfaces, and materials for construction and agriculture. Geoarchaeological research showed that past communities exploited midden as a valuable resource. Excavations at Links of Noltland provided an opportunity to test a new model of sediment formation pathways within a human ecodynamics framework. Results demonstrated anthropic materials were incorporated into all excavated contexts and showed discrete burning activities, gradual accumulation of outdoor sediments, and animal penning.

1. Abstract
Traditionally archaeology has referred to the anthropic sediments accumulated around prehistoric
settlements with the blanket term ‘midden’. This is now recognised as an inadequate term to
describe the complex formation processes and functions represented in these sediments. This thesis
reviewed the body of evidence accumulated over the past century of research into Neolithic and
Bronze Age settlements on the islands of the Scottish North Atlantic seaboard and extrapolated the
many occurrences of ‘midden’. Several contexts emerged for these sediments including interior
floors, hearths, exterior occupational surfaces, dumped deposits, building construction materials and
abandonment infill. In addition, ‘midden’ is described added to cultivated soils to form fertile
anthrosols. The way in which prehistoric communities exploited this material for agriculture and
construction has been described through geoarchaeological research which implied that to past
communities ‘midden’ was a valuable resource. This led to the formation of a model based upon a
human ecodynamics framework to hypothesise sediment formation pathways. Rescue excavation at
the Links of Noltland, Westray provided an opportunity to conduct a holistic landscape and fine
resolution based study of Neolithic and Bronze Age settlement to test this model. The research
incorporated auger survey, archaeological and geoarchaeological excavation, thin section
micromorphology and SEM EDX analyses. Sediments identified in literature review and recovered
from the field site were described using this toolkit and set within a cultural and environmental
context. Results demonstrate that anthropic materials were incorporated into all contexts examined.
Discrete burning and maintenance activities were found to have taken place during the gradual
accumulation of open-air anthropic sediments whilst incorporation of fuel residues and hearth waste
into floors lead to the gradual formation of ‘living floors’ inside structures. An unexpected discovery
was evidence of animal penning within late Neolithic/Early Bronze Age settlement and the in situ
burning of stabling waste. Three types of land management strategy which relied upon the input of
anthropic sediments were evidenced and the range and extent of anthropic inclusions in the
landscape recorded. Spatial interpolation of auger survey data utilised a new sub-surface modelling
technique being developed by the British Geological Survey to explore soil stratigraphic relationships
in 3D. SEM EDX analysis supported micromorphological analysis providing chemical data for discrete
inclusions and assisting in the identification of herbivore dun ash and the Orcadian funerary product
‘cramp’. SEM EDX analysis was also applied to fine organo-mineral material for statistical testing of
nutrient loadings across context groups. It was found that anthropic sediments were enriched in
macro and intermediate plant nutrients Mg, P, K, S and Ca compared to geological controls, and the
application of anthropic material to cultivated soils improved soil fertility for the three observed land
management practices.
The versatility of anthropic sediments was explored through discussion of context groups based
upon the results of this research and the potential significance of this material to prehistoric
communities is explored.