October 12, 2009
The crosscutting relationships of graben and channels observed in this THEMIS image can be used to determine relative timing of events. Several upper left / lower right trending fractures are observed to crosscut upper left/ lower right formations. Crosscutting relationships are used by geologists to give relative ages / timing for the occurrance of one feature verses another. As an example, the graben located at the top central portion of this thumbnail, lets call this graben A, is crosscut by a separate graben, graben B, which trends from the upper left to the right. Using crosscutting relationships, graben A is thus relatively older than graben B.