CHAPTER XVI 

 DIASTROPHISM AS THE ULTIMATE BASIS OF CORRELATION 



THOMAS CHROWDER CHAMBERLIN 

 The University of Chicago 



There are many and diverse views relative to the nature and the 

 causes of diastrophic movements. To keep as largely as may be 

 on common ground, most of these divergencies of view may be set 

 aside as immaterial to our present purpose. We may all agree that 

 the fundamental factors of the case are a lithosphere with a deformable 

 surface, a liquid, covering part of this surface and determining 

 erosion and sedimentation, and a gaseous envelope. We may easily 

 agree that the outer part of the lithosphere is solid and has a sufiEicient 

 measure of rigidity to maintain the surface inequalities. I do not 

 see that we need to agree as to the causes of deformation. In some 

 sense, I do not see that we need even to agree as to just what the 

 absolute movements were, i. e., I do not see that it is material for 

 us here to know whether the deformative movements were shrink- 

 ages, or expansions, or lateral shifts, provided we agree as to the 

 general nature of their effects on the agencies at work on the surface 

 of the lithosphere. We do not need to entertain the same conception 

 of the nature of the earth's interior, if we are at one as to the working 

 conditions which have prevailed on its surface. 



No doubt we can easily agree on the present great working factors: 

 (i) abysmal basins occupying about two- thirds of the earth's surface, 

 bordered by terrace faces rising at angles of 2° to 5° for say 12,000 

 feet to a quite definite terrace-angle about 100 fathoms below the 

 sea-level; (2) continental platforms whose upper faces slope gently 

 up from this angle to the coast-line and thence ascend into the various 

 reliefs of the land. If we thus agree that the upper face of the conti- 

 nental platform is bounded by the edge of the continental shelf, 

 and that this edge is equally the boundary of the abysmal basins, 

 whether the waters overlap the edge or not, we may also agree that 



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