Dictionary:Difference section, difference map, difference volume
The result of subtracting one section, map, or volume from another. 1. Where two maps/sections/volumes were acquired at different times, the difference (time-lapse map/section) shows the changes that have occurred. 2. Where the two maps are of different horizons, the difference (isotime or isopach map) represents the thickness of the intervening interval. Thickness changes may suggest changes in deposition or removal subsequent to deposition.