| Popis: |
One of the early triumphs of global comparative tectonics was the recognition of a fairly irregular radial migration of orogenic deformation away from stable continental interiors. Suess interpreted this as continental growth. The theory of continental drift, moulded by Argand's genius into a form capable of answering the demands of continental tectonics, provided the first satisfactory explanation of peripheral continental growth and why it was somewhat haphazard. The composite nature of continents found a ready explanation in the theory of plate tectonics, but suture zones were early stereotyped into Salomon-Calvi's suture lines (his Synaphie), although many orogenic belts do not possess a readily recognisable Indus-type clean suture line. In many mountain belts, zones of continental collision are marked by wide belts of accreted sedimentary rocks, commonly with steep structures, forming trapped accretionary complexes. In his subductionless view of continental drift Argand recognised the importance of accretionary material that he thought had been skimmed off the ocean floor by floating sialic rafts. He portrayed broad, accretionary material-filled suture zones in maps and in sections and contrasted them implicitly with narrow suture lines devoid of such accretionary cushions. |
