A new model of orogenic evolution

Abstract

Many clues – already described in preceding papers (SCALERA, 2005a, 2005b, 2006a, 2006b, 2007a, 2007b) –, coming from a number of different fields, lead to an unitary interpretation for the involved phenomena and to a new interpretation of the orogenic processes and fold belt building. The unexpected inhomogeneous ‘filamentous’ distribution of the deep hypocentres on the Italian, Mediterranean and global Wadati-Benioff zones, the high velocity anomalies revealed by the seismic tomographies under the orogenic belt, the geochemical analysis of gas emissions and volcanic rocks, paleogeographic reconstructions and paleontologic fossils finding, all have called for a common schemata (SCALERA, 2005a, 2005b, 2006a, 2006b, 2007a, 2007b). The aforementioned clues, can certainly be considered each separated from the other, with the obvious result of finding non-unitary explanations, but if they are scrutinized all together, the whole set points to vertical displacements of materials as the main process responsible of earthquakes, orogenesis and volcanic phenomena. Then a model of the evolution of an idealised fold belt, without using the subduction concept, in a non-collisional view, should be searched for. In the following rows a proposal of model is presented (fig. 1 and fig. 2). In this initial formulation the orogen evolution sketch is a mono-vergence and its phases of evolution are analogous to the different phases that can be distinguished from south to north on Apennines and Alps, and on the Himalayas at a more mature stage.