Application of Results
The images and interpretive techniques in this publication can be used for several purposes: visualizing how migrating bedforms deposit complicated cross-stratified beds, predicting the internal structure of bedforms that have a known morphology and behavior, interpreting the behavior of bedforms from their morphology and internal structure, or reconstructing the morphology and behavior of bedforms that deposited cross-stratified beds that are observed in the field (either to learn about the bedforms that produced a specific deposit or to learn about how bedforms behave in general). For convenience all of the computer-generated depositional situations are cross-referenced in Appendix C.
Unfortunately for the field geologist, interpreting cross-bedding is often more complicated than matching illustrations and outcrops, because the curvature and orientation of outcrops can cause radical variations in the appearance of a single structure. Moreover, different bedform assemblages can produce structures that are so similar in single vertical sections that the structures are virtually indistinguishable. A more powerful investigative technique is to measure cross-bed strikes and dips and make a three-dimensional map of the beds that are being studied. These observations can then be compared with the computer-generated examples. Observed structures also can be interpreted by trial-and-error.
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.