Main Page | See live article | Alphabetical index Stratigraphy is that branch of geology concerned with understanding the geometrical relationships between sedimentary rocks. Key elements of stratigraphy are understanding how certain geometries arise and what these geometries mean in terms of depositional environment. The study of stratigraphic sequences has led to some important results, such as the Vail curve, which attempts to define a global historical sea-level curve according to inferences from world-wide stratigraphic patterns. Stratigraphy is also commonly used to delineate the nature and extent of hydrocarbon-bearing reservoir rocks, seals and traps (see petroleum geology). This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.