Deposits of marginal marine depositional systems make up significant hydrocarbon reservoirs in the rock record. These systems are deposited by a complex interaction between competing depositional processes which can result in heterogeneous and compartmentalized reservoirs. Shallow marine systems are described using a ternary classification describing the relative importance of wave, tide and fluvial processes at the coastline. With the advent of freely available remote sensing data, modern systems are being increasingly used as analogues for the ancient, however to date, there has been no systematic quantification of global modern paralic systems. The aim of the present study has been to map and classify all the world's shorelines by ternary process and to consider the distribution and controls on different shoreline types.
The semi-automated classification of marginal marine clastic shorelines has been achieved by combining data from a series of proxies for the ternary processes. Combined with coastline morphology, an algorithm predicts shoreline classification with an 85% success rate when compared to manual interpretation. Using this algorithm, the global shoreline has been subdivided into 246,777, 5 km segments and the distribution and proportions of these analyzed.
The first order classification subdivides 28% of the world's coastlines as depositional. Within the depositional coastlines 62% are Wave-dominated, 35% Tide-dominated and 3% Fluvial-dominated. Analysis of shoreline type distribution suggests a complex network of inter-related controlling factors. Of these, climate and tectonic setting are reasonably well constrained in the ancient and can be used to predict the probability of a specific shoreline type. In addition to shedding insight into the controls on the distribution of different shoreline types, the results of this study can also be used to identify suitable modern analogues for ancient systems, which in turn can be used to extract data for better reservoir characterization.