Definition - What does Valley Line mean?
A Valley Line is a contour line representing a valley which can be drawn on an isopach map. Isopachs are contour lines with equal thickness over a particular area. These maps are used in stratigraphy, structural geology, volcanology, petroleum geology and sedimentology. This type of mapping is used to predetermine the drilling depths of wells and locate the structures buried in the regions in which the formations commonly become thinner over certain structural crests.
Petropedia explains Valley Line
Valley lines are usually one of the characteristics of contour lines and generally appear in V-shaped contours. The sharper the “V” shape of the contouring lines, the more pronounced is the valley. If the contour lines are “U” shaped, they represent “Ridges”. In the “V” shaped contour, the point of the V line represents the elevation or upstream. In order to move toward the highest point in the valley, one needs to move toward the joints of the contour valley lines where they meet and make a “V”. The contour lines are generally represented on an isopach map which helps in understanding structural geology and sedimentology.