Abstract. On the mainland of northwest Europe generally only remnants of
former peat landscapes subsist. Due to the poor preservation of these
landscapes, alternative approaches to reconstruct peat initiation and
lateral expansion are needed compared to regions with intact peat cover.
Here we aim (1) to find explanatory variables within a digital soil mapping
approach that allow us to reconstruct the pattern of peat initiation and
lateral expansion within (and potentially beyond) peat remnants, and (2) to
reconstruct peat initiation ages and lateral expansion for one of the
largest bog remnants of the northwest European mainland,
Fochteloërveen. Basal radiocarbon dates were obtained from the peat
remnant, which formed the basis for subsequent analyses. We investigated the
relationship between peat initiation age and three potential covariates: (1) total thickness of organic deposits, (2) elevation of the Pleistocene
mineral surface that underlies the organic deposits, and (3) a constructed
variable representing groundwater-fed wetness based on elevation of the
mineral surface and current hydraulic head. Significant relationships were
found with covariates (1) and (3), which were then used for subsequent
modelling. Our results indicate simultaneous peat initiation at several loci
in Fochteloërveen during the Early Holocene and continuous lateral
expansion until 900 cal BP. Lateral expansion accelerated between 5500–3500 cal BP. Our approach is spatially explicit (i.e. results in a map
of peat initiation ages), and it allows for a quantitative evaluation of the
prediction using the standard deviation and comparison of predictions with
validation points. The applied method based on covariate (1) is only useful
where remnant peat survived, whereas covariate (3) may ultimately be applied
to reconstruct peat initiation ages and lateral peatland expansion beyond
the limits of peat remnants.