A New Process-based Model for Wreck Site Formation

Abstract In order for a model of wreck disintegration to have some predictive ability, it is advantageous that such a model should be process-orientated, scale independent (i.e., be applicable to the wreck as a whole and to individual wreck components) and/or spatially and temporally independent. Existing models and flowcharts for wreck site formation focus on the products rather than the processes of wreck disintegration. The major classes of environmental processes affecting wreck site formation are physical, biological and chemical, which are each closely linked to the depositional environment. Here a modified flow chart for wreck evolution is presented in which the major variables influencing wreck site formation are the wreck itself, sediment supply and the hydrodynamic environment. The rate of wreck disintegration (dD/dt) may be given by the sum of the rates of disintegration due to physical, biological and chemical processes (|gSdP/dt, dB/dt, dC/dt). A model is developed where wreck disintegration may be plotted against the relative sedimentation rate (dS/dt), which is a first-order control on the forces of degradation. The model possesses the advantageous features noted above, and acts to illustrate the characteristics of a wreck site and provide a framework in which to begin prediction of the nature of the material preserved. Although its application to marine wreck is outlined, the model is applicable to both terrestrial and marine wreck site formation.