. Discovery. Science. riGS. 4 .«VD 5.—KOBER'S ILLUSTRATING THE PRESSING UP OF THE OROGENE TROUGH INTO ISLANDS AND ISLAND CHAINS. arcs [Aleutian, Japanese (East Asian), Carpathian, Dinaric, Tauric arcs]. Concretion of Continental Masses Though stiff and unyielding, the Old Blocks do not come off unscathed. Comparatively free from the volcanic and seismic travail which marks the birth and death of mountains, they yet buckle, crack, tilt, and sag under the tremendous strain. Every block is ringed round by an orogenic zone, and exerts and suffers pressure from all sides. Doubtless the in
. Discovery. Science. riGS. 4 .«VD 5.—KOBER'S ILLUSTRATING THE PRESSING UP OF THE OROGENE TROUGH INTO ISLANDS AND ISLAND CHAINS. arcs [Aleutian, Japanese (East Asian), Carpathian, Dinaric, Tauric arcs]. Concretion of Continental Masses Though stiff and unyielding, the Old Blocks do not come off unscathed. Comparatively free from the volcanic and seismic travail which marks the birth and death of mountains, they yet buckle, crack, tilt, and sag under the tremendous strain. Every block is ringed round by an orogenic zone, and exerts and suffers pressure from all sides. Doubtless the incidence of the pressure is unequal both in place and time, and mountain zones—or even single mountain chains— must not be thought of as rising or sinking simultane- ously and evenly always and all over the globe. Never- theless, the great tectonic disturbance lines of the continents—the lines of new, old, rejuvenated moun- tains, of scarps and fracture-valleys—are ranged concentrically around the continental blocks, the most violent around the edges and fading away gradually, like ripples, inwards so that the hearts of the conti- nents remain almost unmovtd. Such dominant lines, by their insistence and their compromises, clearly. Fig. 6.—KOBER'S diagram SHOWING (i) THE FORMATION OP A TYPICAL OROGENTJ MOUNTAIN SYSTEM; (2) THE PUSHING UP OF THE EDGE OF THE CONTINENTAL BLOCK UNDER PRESSURE (COLORADO PLATEAU). ' Kober points out that in the great Mid-World (Mediter- ranean) Orogene System these intermont blocks sink steadily, along with the sinking of the whole mountain system, as we go westwards from its highest part in Central Asia. Thus Thibetan Plateau: average elevation c. 12,000 ft. (cf. Roof of the World); Persian Plateau : c. 6,000 ft. ; Asia Minor Plateau; c. 3,000 ft.; Hungarian Plain: c. 300 ft.; West Mediterranean Basin : below sea level. Still, in spite of temporary flooding and submerg- ences, whole or partial, the blocks are permanent elements in' the ea
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