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5 Conceptual geological model

The conceptual geological model of the Favignana calcarenite is an attempt to combine all interpreted
sedimentary facies and their vertical and lateral distribution by placing them in a specific sedimentary
environment. First, the sediment supply mechanism will be discussed, followed by the transport mechanism
and finally the sedimentation processes. The aim is to present an overall schematic model of where,
how and in what geometry the calcarenite is deposited. This will be used to as the basis to build a
three-dimensional sedimentary model of eastern Favignana.

5.1 Sediment supply

The sedimentary structures show a predominant transport direction of southeast to south-southwest —
corresponding to the 140 to 210 compass degrees. Structures in both directions indicate that flow was
reversed from time to time. Given the amount of fragmentation of the bioclastic material, it is clear that
it must be either transported from the place it was generated, or reworked extensively.
Assuming that the sediment is generated somewhere north of Favignana, a location must have been
present where vast amounts of living material could develop. Other studies indicate that similar deposits
are cool-water biocalcarenites (Massari & Chiocci, 2006; Hansen, 1999). The investigation of thin
sections — described earlier in this report — points in the direction of cool-water carbonates as well (X.
Marquez, personal communication). These carbonates were able to flourish in the relatively temperate
Mediterranean of the Pleistocene, however the dependence of sunlight limits the water depth in which
they can develop. Figure 5.1 shows the Aegadian archipelago and the location with respect to the Sicilian
mainland. The present-day shelf edge is marked with the dashed line. According to Cohen & Gibbard
(2010) the Lower Pleistocene sea level was relatively high, and started to fall without large disruptions.
Therefore the location of the shelf edge is assumed to be not too far from the present day situation.
The production platforms of cool water carbonates probably have been located on the continental shelf.
Figure 5.1 indicates some possible locations of the platform that provided a breeding place for living
material. Geological investigation showed earlier that the limestones that form Monte Santa Caterina and
the two islands of Levanzo and Marettimo have a Triassic to Miocene age, and the deformation process

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