Abstract

From Atlantic to Pacific the Alpine System may be characterized by mobile belts surrounded by the more or less broken up pieces of a mosaic belonging to cratons which either presently exist or may have disappeared by fragmentation of former large cratonic blocks and ocean spreading. The first Tethyan furrows appeared in the Upper Carboniferous, often on the edge of poorly cratonised Hercynian highs. The main Alpine tectonic features are:

– Large nappes and overthrusts of two types:

– Internal nappes involving basement slides, often strongly metamorphosed.

– External nappes due mainly to gravity gliding, with little or no metamorphism.

– Ophiolites are unequally distributed along the system.

– Magamatism, especially the acidic type, exists in some places near the main collision areas, but it is much less important than in the Hercynian ranges or the peri-pacific cordilleras.

– The shape of the belts is characterized by complicated girdles and arcs: Gibraltar, Sicily, Western Alps, Carpathians, Aegean arc, Makran, Pakistan Ranges, Indonesia and especially Sulawesi etc...

The surrounding unstable platforms, often with thick marine sedimentary prisms, were folded into intetmediate chains with a "plis de couverture" style, often with sliding on salt series (Jura, Provence, Eastern Spain, Saharan Atlas and Tunisian Atlas, Zagros, Pakistan Ranges, Chittagong Hilss, New Guinea foot hills etc...). Vertical movements have often been neglected in the past but they are now becoming recognized as the principal factor controlling the sedimentation in the three types of Alpine basins. In the Mediterranean Sea, as in the Caribbean or in Indonesian marginal basins, relatively recent downwarps have played an essential role since Miocene time and have formed the deep basins which exist today.