I am pursuing a small project examining the relationship of deformation in reduction spots and deformation present in clutches of eggs to gain some insight to the taphonomic history of the samples. Many of the eggs exhibit “compression” ridges, which I am referring to as a feature that is preserved generally along the prolate or the long axis of the eggs. Reduction spots are spherical areas exhibiting a different, usually lighter color in a rock that have the same physical properties as the host, and thus measure the bulk strain of the rock. They are common within continental red beds in the geological record and have been used as strain indicators by structural geologists. Most dinosaur eggs are preserved in this type of deposit so this type of study may be helpful in other fossil studies. If the compression ridges line up or correspond with the changes in the shapes of the reduction spots then some overall interpretation as to the direction and percent of stress applied to both the egg and the spots might be inferred. The analysis may give some indication of a change in shape related to the percent strain associated with the rocks as interpreted by the amount of strain indicated by deformed reduction spots. The overall direction of maximum/minimum stress may help support the up and down determination of the egg or show the direction of a stress event which has influenced the shape of the preserved egg. The overall shape of a fossilized egg is a result of the taphonomic history of the egg.
Blog post by Anita Moore-Nall