only until the chamber was emptied that we could understand the precise
way the platform was built.
a first step, the builders dug a square pit with flat bottom,
approximately 2.5 x 2.5 m in dimension. In the northern part of the
digging surface, they excavated up to 65 cm below surface; in the
southern part, almost no excavation was needed, since the natural slope
was almost at the same altitude than the deepest dugout (see also Fig. 20). The flanks of the
pit were initially meant to be sub-vertical.
this stage, the builders arranged flat stone slabs vertically against
the northern, eastern and western pit flanks. Then they started to build
the platform itself around the pit by progressively placing new layers
of irregular stones over the first layer. From layer to layer, low
quantities of gravel and sediment were added between the stones. Once
the eastern and western platform flanks were almost at full height in
their center, the builders added more stones toward the southern edge in
order to correct the initial sloping.
next stage of construction consisted in adding two last layers of flat
stones over the platform flanks. The platform was then finished, but the
chamber was still empty and uncovered.