Island and Coastal Aquifers - Hydrogeology: Objectives, Methods, Applications - page 76

m 3 ·s -1 of spring water (Cova & Durozoy, 1980). One is therefore forced to
admit that a large part of Basse Provence has a water defi cit of approximately
4 L·s -1 ·km -2 . It is then tempting to imagine that half of the infi ltrated water
in the region feeds the excess discharge at Port Miou.
Keeping an average infi ltration modulus of 4 L·s -1 ·km -2 , a basin of
around 1500 km 2 would be necessary to feed Port Miou (Figure 43). Such a
basin could be drawn in a zone going up to the north, in the Arc basin, up to
Sainte Victoire and extending to the east towards Brignoles. The discharge
at Port Miou therefore lead one to imagine a gigantic deep karst system
draining the entirety of Basse Provence. The spatial organisation of such a
system imposes the imagination of a paleogeography very different from
that of the present day.
Figure 43 Hypothetical drainage basin for the Port Miou spring (from Blavoux et al. , 2004).
1-major crustal faults; 2-major overthrusts (A, B and C - erosion front of the principal nappes);
3-other faults; 4-normal contacts; 5-Quaternary; 6-continental Mio-Pliocene; 7-marine Miocene
and lacustrine Oligocene; 8-Cretaceous and Jurassic limestones; 9-Triassic (limestone and
evaporites); 10-Permian (sandstone and pelites); 11-Carboniferous and Variscan; 12- north-
south subalpine chains; 13-supposed drainage basin.