GEOLOGIC PROBABILISTIC ASSESSMENT OF SAND VOLUMES ON THE ATLANTIC CONTINENTAL SHELF: APPROACH, DISTRIBUTION MODELS, AND PRODUCTS

The mineral resource assessment method used is one developed for onshore mineral deposits types, but modified for use in marine environments (http://pubs.usgs.gov/bul/b2209-m/). The method uses the distribution of deposits sizes and other geologic characteristics of known cape-and ridge-associated marine sand deposits. In this study, distribution models of volumes and proportion of sand-dominated facies were developed for cape-and ridge-associated marine sand deposits on the U.S. Atlantic continental shelf. Spatial models were also developed in well explored areas and were used to guide in estimating the number of undiscovered deposits within three tracts offshore of NY and NJ. The Monte Carlo Simulation method used combines sand volume model and facies model with estimates of the number of undiscovered deposits providing a probabilistic estimate of marine sand resources within the three tracts. An estimated volume of 3.9 billion m³ of marine sand resources is predicted in cape-and ridge-associated marine sand deposits in the three assessment tracts (http://pubs.usgs.gov/bul/b2209-n/). An important caveat, however, is that only a portion of these potential sand resources may ultimately be available for production because of geographic, economic, preemptive use, environmental, geologic, and political factors not considered in this assessment. This MCS modeling approach is being applied to other U.S. Atlantic shelf regions and may be applicable to continental shelves worldwide where cape- and ridge-associated marine deposits are permissive.