BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 32, pp. 197-210 June 30, 1921 



GEOUNDWOEK OF THE EAETH'S DIASTEOPHISM ^ 



BY T. C. CHAMBEKLIN 



{Read before the Society December 29, 1920) 



CONTENTS 



Page 



lutroductioii 197 



Two basal hypotheses 198 



The collapsing type 198 



The nou-collap.siiig type 199 



The wasteful type 199 



The conservative type 200 



The long series of successive deformations 201 



The early and persistent development of surface differentiation 201 



The persistent effects of the deeper diastrophism 202 



The penetration of this basal diastrophism 202 



The total value of the self-compression 203 



The cause of the basal diastrophism 204 



The time of the most effective diastrophic action 206 



Bearings of the plauetesimal view on vulcanism 207 



Bearings of this view on igneous petrology 208 



Bearings on the problem of isostasy 209 



Introduction" 



Eecent studies have been fruitful in bringing to light new evidences 

 of diastrophism. The older terranes have been found to be more and 

 more intricately deformed, as inquiry proceeds. The later terranes have 

 disclosed overthrusts of unexpected extent and frequency. Troughs of 

 graben type have been found to form chains of almost continental length. 

 The recognition of unconformities has been multiplying to an embarrass- 

 ing degree. Moreover, as inquiry passes from local and regional fields to 

 the greater features of the earth, the continents and the oceanic basins it 

 discloses evidences of a profoimd order of diastrophism whose significance 

 has been only meagerly recognized m the past. In the light of these reve- 

 lations, it is important to workers in this difficult field to know whether 



1 Manuscript receivrd by the Secretary of the Society February 3, 1921. • 



XIV — Bull. Oeol. Soc. A.m., Vol. .",2, 1020 (197) 



