SCALE INDEPENDENT SCALE DEPENDENCY IN STRATIGRAPHIC ARCHITECTURE; AN EXPERIMENTAL PERSPECTIVE

The fascinating order in the scales associated with the sedimentary record can be characterised in two ways: 1) Architecture of environmental flows and the resulting sedimentary bodies is virtually scale-free, with similarities occurring over up to 7 orders of magnitude [on scales ranging from centimetres to hundreds of kilometres ]. 2) The architecture of sedimentary bodies is highly scale dependent, and the temporal and spatial scales of interest determine the architectural style of sedimentary bodies. Changing the scales at which a system is regarded invariably leads to a change in recognised architectural style. This poster presents a range of data and concepts from experimental studies that express this nature of “scale independent scale dependency”. Firstly, the experiments are compared with real world examples, where the focus is on presenting comparisons of architectural dimensions between experiment and prototype. Secondly, seven stratigraphic-hierarchy scale levels are loosely defined: Sediment grain scale; bedform scale; element scale; complex scale; parasequence scale; sequence scale; and shelf system scale. When moving upwards through this hierarchy, processes under investigation change from multiphase physics to process sedimentology to autogenig morphodynamic processes to external forcing by climate, tectonics and sea level. It is evident that some degree of crosstalk necessitates considerations of processes in adjoining hierarchical levels, yet the degree to which the system needs to be accounted for in a holistic way is limited: a grain-eddy interaction is essential to understand a bedform, but can be left unaccounted for when concerned with the parasequence stacking pattern in a sequence. Here, the focus is on the transition from autogenic to external forcings and the differences between the architecture of parasequences, sequences, and shelf systems. The differences in architecture are linked to vertical and horizontal characteristic scales and to corresponding characteristic temporal dimensions involved in their formation.