ABSTRACT

Stereo-seabed photographs of Co-rich manganese deposits on a mid-Pacific seamount, were analyzed using an image analysis software for coverage estimation and size classification of nodules, and a photogrammetric software for calculation of height differences in the microtopography of seafloor. The preliminary results of these analyses show that many locations have high crust coverage (> 90%), as well as large nodule populations (60–70 % coverage). Nodule sizes range from <1 to> 10 cm, and their distribution vanes from uniform to inhomogeneous The local microtopography of the seafloor is influenced by the variation m coverage and sizes of the crusts and nodules as well as their surface features. These data are important inputs for resource estimation of these mineral deposits.

INTRODUCTION

Many studies on Co-rich manganese deposits have been earned out, due to their resource potential for metals such as cobalt, nickel and platinum and also availability at lesser depths. An important consideration in evaluating these deposits is the estimation of their thickness as well as the coverage on the seabed (Cronan et aI, 1991, YamazakI et ai, 1992a). Some methods have been proposed for ore-grade evaluation of Co-rich manganese crusts using a "cut out" model from photogrammetric analysis (Yamazaki et ai, 1992b) and calculation of resource potential using crust coverage, average thickness and dry density (Clark et ai, 1985). This study is an attempt to develop new methods for quantification of these deposits by image analysis as well as photogrammetric techniques on stereo-photographs to evaluate the distribution of these deposits ill x, y, and z dimensions on the seafloor. The results of these analyses on the distribution of the deposits with respect to the seafloor morphology, microtopography, coverage etc forms valuable data for the resource evaluation and delineation of potential areas. The important factors influencing resource evaluation of these deposits have also been discussed.

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