Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/88

masses of sial, which become depressed to great depths by the folds, must be melted there and spread out beneath the adjacent parts of the blocks, which therefore become elevated. If in this connection we confine ourselves to the highest region of the Asiatic block, lying on an average about 4000 m. above the level of the sea, measuring 1000 km. in the direction of thrust, and if, in spite of the much greater elevation, we take only a similar shortening to that of the Alps (namely, to a fourth of its original length), we obtain a displacement of India of about 3000 km. India must therefore have lain near Madagascar before the thrusting began. No room remains for a submerged Lemuria, in the older sense. The traces of this gigantic thrusting together are recognizable right and left of the rather narrow thrust-zone. The breaking away of Madagascar from Africa, the whole system of recent rift-valleys in East Africa, to which the Red Sea and the Jordan valley also belong, form part of this phenomenon. The Somaliland peninsula may have been somewhat dragged round to the north, and thus be connected with the forcing up of the Abyssinian mountain system; the masses of sial, submerged beneath the melting point isotherms flowed beneath the block towards the north-east in order to spurt out in the angle between Abyssinia and the Somaliland peninsula. Arabia also felt the stress towards the north-east, and drove the outlines of the Akdar mountains, penetrating like a spur, into the Persian mountain chains. The fan-shaped grouping of the ranges of the Hindu Kush and Sulaiman mountains denotes that there the western limit of the compression is reached; its replica also occurs on the eastern margin, where the chains of hills of Burma are dragged round from a direction cutting Annam, Malacca and Sumatra to a north-south direction. The whole of the east of Asia was certainly concerned in this