MODEL OF THE VARIABILITY OF FERROMANGANESE NODULES AS A FUNCTION OF SAMPLE SIZE

Abstract

We analyzed underwater photographs on areas of 20 × 20 km obtained in the Clarion-Clipperton province. We found the dependence of the standard deviation of the nodule bed density (weight per unit area) determined from samples with areas of less than 0.9 m2 as function of the bed density in an area of 0.9 m2. Each nodule in the photograph was enclosed in a circle whose area was equal to the visible projection of the nodule. Next, the coordinates of the center of the circle and its diameter were determined; a total of about 10,000 nodules were measured. All of the subsequent calculations were performed by computer, using algorithms and programs developed by the authors. The data indicate that the bed density of nodules and their chemical composition are highly consistent for areas of a few square kilometers.