<Li> lack of nappes </Li> <P> The advent of plate tectonics has explained the vast majority of orogenic belts and their features . The cooling earth theory (principally advanced by Descartes) is dispensed with, and tephrotectonic style vertical movements have been explained primarily by the process of isostasy . </P> <P> Some oddities exist, where simple collisional tectonics are modified in a transform plate boundary, such as in New Zealand, or where island arc orogenies, for instance in New Guinea occur away from a continental backstop . Further complications such as Proterozoic continent - continent collisional orogens, explicitly the Musgrave Block in Australia, previously inexplicable are being brought to light with the advent of seismic imaging techniques which can resolve the deep crust structure of orogenic belts . </P>

Of the following orogenic belts which is still forming and growing today