This paper evaluates four different methods that have been proposed for the
estimation of the detachment depth beneath detachment folds. Guidelines ar
e presented in order to use the most suitable method in a particular region
deformed by detachment folds. These guidelines are constructed considering
the assumptions of each method, the influence of different parameters on t
he estimation of the detachment depth (folding mechanisms, cross-sectional
area variations, position and orientation of the regional datum, number of
stratigraphic horizons, bed length and thickness, dip and position of the b
ounding lines, initial thickness of the ductile unit, single anticlines or
fold trains) and the available data (ductile unit thickness, regional datum
, detachment depth). Moreover, a new, simple method based on two previous m
ethods is presented. The advantages of this new method are that the calcula
tions are extremely simple and it uses information from more than one strat
igraphic horizon; therefore, it does not depend strongly on the accuracy of
the data at one level. The precision of the proposed methods is tested by
their application to a number of natural and experimental single anticlines
and fold trains. It appears that better predictions are obtained when anal
ysing a complete detachment fold train than when dealing with a single deta
chment anticline. The reason might be that ductile material flow beneath th
e folds along the cross-sectional plane is taken into account when dealing
with a long-enough cross section. We also suggest some hypotheses concernin
g what the shape and dimensions of the detachment folds indicate about the
detachment depth in those cases where insufficient data are available to ap
ply the methods proposed.