VOLUME XXVI NUMBER 3 
THE 
IOURNG@ OF GEOLOGY 
APRIL-MAY 1978 
DIASTROPHISM AND THE FORMATIVE 
PROCESSES. IX* 
A SPECIFIC MODE OF SELF-PROMOTION OF PERIODIC 
DIASTROPHISM 
T. C. CHAMBERLIN 
University of Chicago 
In the opinion of many students of diastrophism, world-wide 
deformative movements tend toward periodicity in the very nature 
of the case; more or less oscillation between relatively active and 
quiescent stages would arise without any special aid from accessory 
agencies. But in the natural order of things secondary movements 
often spring from the primary actions and abet them. It is the 
purpose of this note to call attention to a specific form of secondary 
action by which the oscillations between the active phases of 
deformation and the intervening quiescent stages are accentuated 
and the periodicity of major diastrophism emphasized. 
When world-wide diastrophism follows a period of general 
base-leveling and wide sea-transgression the diastrophic movement 
is logically regarded as springing from accumulated earth-stresses 
of such a nature as to give rise to relative downward movements 
of the sub-oceanic segments and relative upward movements in 
the continents in spite of whatever burden of epicontinental waters 
™For previous article (Part VIII) of this series see the Journal of Geology for 
July-August, to14. 
193 
