The Early Jurassic dinosaur site of Toundoute which yielded the basal
sauropod Tazoudasaurus naimi is examined in the light of its
stratigraphic, sedimentological and palaeoenvironmental context. A thin
succession of Early Liassic marine carbonates (probably
Hettangian-Sinemurian in age) is continuously overlain by continental
beds with dinosaurs. These latter are assumed to be of Middle to Late
Liassic age. The continental deposits include a large part of
volcanoclastics, different from the Triassic basalts. The Jurassic
volcanoclastics originated from an unknown but obviously close eruption
centre. The continental sediments (channels and flood plain) were
deposited under tropical climate conditions with alternating humid and
dry episodes. The bones occur as isolated or partly articulated elements
(parts of carcasses). The two bone-beds are related to typical
mud-flows. This type of transport protected the bones from erosion, and
favoured their burying and fossilization.