Selection of Illustrations
The computer code used to create the images in this publication uses 75 input parameters to describe bedform morphology and behavior. To illustrate three values for each variable, in combination with three of every other variable, would require more than 1035 images; and the effect of varying some of the parameters would still be insufficiently illustrated. The computer images in this publication are not a random sample of the structures of such a thorough set of images. Some images were selected to illustrate the kinds of detailed cross-bedding interpretations that are possible; some illustrate useful interpretive techniques such as distinguishing transverse, oblique, and longitudinal bedforms; some demonstrate that grossly different structures are indistinguishable in some outcrop planes; some simulate existing structures and demonstrate that the behavior of bedforms must be different from what is commonly expected; some demonstrate the use of computer graphics as a research tool (by showing the results of repeated trial-and-error computer experiments that duplicate real examples of cross-bedding). Computer images that illustrate more complicated and random bedform behavior and morphology were generally not included in this compilation, because such images are so complicated that they are nearly as incomprehensible as the bedding that they simulate.
In most of the computer simulations the angle of climb was adjusted so that the upper half of each bedform was eroded and the lower half was preserved. This angle of climb is probably higher than usual for most depositional situations and higher than is even possible in many situations (Rubin and Hunter, 1982).
Figures & Tables
The computer modeling that forms the basis for this publication was undertaken to relate the geometry of cross-bedding to the morphology and behavior of bedforms. Using computers for this purpose is necessary only because sedimentologists cannot adequately visualize the geometry arising when complex, changing surfaces move through space. Images range from the complicated, which will be of interest to sedimentologists who have had experience interpreting cross-bedding or studying the behavior of bedforms, to simpler illustrations the can convey an understanding of the origin of cross-bedding geometry even to those not experienced in the field.