The Stratigraphy Machine

There is a significant difference between the average sedimentation rate of a lengthy stratigraphic section spanning many millions of years, and the rate that can be calculated from any short segment within such a section, such segments typically yielding rates several orders of magnitude more rapid than the overall rate. Stratigraphic successions contain numerous surfaces of nondeposition and erosion representing time spans from minutes to many millions of years, which collectively may account for as much as 90% of the total elapsed time that the succession represents. The stratigraphic record is constructed by a range of geological processes that operate over all time scales from seconds to billions of years, and at rates that vary by ten orders of magnitude. The generation of the stratigraphic record can be conceptualized in the form of a mechanical device, which we term the ``Stratigraphy Machine.''