%X We have conducted an extensive survey of the Magellan data to reassess the population of coronae. We identify a new type of coronae, here referred to as 'Type 2 coronae', having the same basic morphology as previously identified coronae (Type 1), but lacking a significant (> 50%) annulus of closely spaced fractures. 106 Type 2 coronae are included in the new database giving a total of 515 coronae on Venus. The characteristics of the expanded population of Type I coronae are similar to those of the previously described population, but the Type 2 coronae are smaller, tend to have relatively flat interiors surrounded by a topographic rim, and are more likely to be found isolated from other features. Our observations, in particular the morphology and setting of the Type 2 coronae, may provide supporting evidence for the existence of a depleted mantle layer under the venusian plains.
%I AMER GEOPHYSICAL UNION
%P 4267 - 4270
%D 2001
%O Copyright 2001 by the American Geophysical Union
%J Geophysical Research Letters
%N 22
%V 28
%L discovery113429
%T Preliminary analysis of an expanded corona database for Venus
%K Tectonics, Evolution, Features, Hotspots, Models, Origin
%A ER Stofan
%A SE Smrekar
%A SW Tapper
%A JE Guest
%A PM Grindrod