Variation of mean continental elevation with continent and time
Abstract
What factors determine the mean elevation and thickness of an individual continent? Given total continental crust volume, what determines the mean thickness (and hence total area) of all continents? Could mean continental thickness have doubled and continental area have halved in the geologic past? I present a firstorder model assuming that continental mean height is the steady state height controlled by uplift and erosion. The model predicts that it is more difficult to erode a larger continent. Hence mean continental height increases as continental area increases. This prediction is consistent with the general trend between presentday continental elevation and area (except for Antarctica), and can fit the trend well. This is the first time the relation between continental area and mean elevation is quantitatively explained. The model is applied to investigate variations of mean thickness of continental crust over the last 600 Myr over which the continental crust mass is assumed to be constant. Because a change in the number of continents leads to change in the area of continents, it is predicted that the mean continental thickness increases as the number of continents decreases. Nevertheless, the thickness variation is small, amounts to about 10% from one continent to six continents. Change in the number of continents leads to a sea level fluctuation of about 0.3 km, with the lowest sea level coinciding with times of Pangeas. This prediction is consistent with relative sea level curves. It is concluded that the number of continents played a major role in Phanerozoic sea level changes.
 Publication:

AGU Spring Meeting Abstracts
 Pub Date:
 May 2004
 Bibcode:
 2004AGUSM.T51A..05Z
 Keywords:

 8100 TECTONOPHYSICS;
 8110 Continental tectonics: general (0905)