Marine Manganese Deposits

Marine Manganese Deposits

This handbook summarizes the main advances in our understanding of marine minerals and concentrates on the deposits of proven economic potential. In cases where our knowledge may be too limited to allow defining of their economic potential, those minerals are covered regionally or by deposit type. Handbook of Marine Mineral Deposits is divided into three sections; Marine placers, manganese nodules and crusts, and deep-sea hydrothermal mineralization. All of these mineral deposits have great potential importance to economic geologists and marine mines. Edited by an acknowledged expert in the field, this handbook includes work by internationally renowned contributors. The new United Nations Law of the Sea, ratified by over 100 countries within the past two years, provides a framework and guidelines for deep-sea mineral exploration that increases international interest in this book. The Handbook serves as a platform from which to launch the more detailed evaluation studies that will need to take place in the 21st century before recovery can continue or commence. Handbook of Marine Mineral Deposits is useful to mineralogists, economic geologists, marine geologists, marine miners, and conservationists. Features

Deep-sea manganese nodules, once an obscure scientific curios ity, have, in the brief span of two decades, become a potential mineral resource of major importance. Nodules that cover the sea floor of the tropical North Pacific may represent a vast ore de posit of manganese, nickel, cobalt, and copper. Modern technology has apparently surmounted the incredible problem of recovering nodules in water depths of 5000 meters and the extraction of metals from the complex chemical nodule matrix is a reality. Both the recovery and the extraction appear to be economically feasible. Exploitation of this resource is, however, hindered more by the lack of an international legal structure allowing for recognition of mining sites and exploitation rights, than by any other factor. Often, when a mineral deposit becomes identified as an ex ploitable resource, scientific study burgeons. Interest in the nature and genesis of the deposit increases and much is learned from large scale exploration. The case is self evident for petrol eum and ore deposits on land. The study of manganese nodules is just now entering this phase. What was the esoteric field of a few scientists has become the subject of active exploration and research by most of the industrialized nations. Unfortunately for our general understanding of manganese nodules, exploration results remain largely proprietary. However, scientific study has greatly increased and the results are becoming widely available.

The past 20 years have seen extensive marine exploration work by the major industrialized countries. Studies have, in part, been concentrated on Pacific manganese nodule occurrences and on massive sulfides on mid-oceanic ridges. An international jurisdictional framework of the sea-bed mineral resources was negotiated by the United Nations Conference on the Law of the Sea (UNCLOS III). A most important outcome of this conference was the establishment of an Exclusive Economic Zone (EEZ) of at least 200 nautical miles for all coastal states and the recognition of a deep-sea regime. Mineral deposits in EEZ areas are fairly unknown; many areas need detailed mapping and mineral exploration, and the majority of coastal or island states with large EEZ areas have little experience in exploration for marine hard minerals. This book describes the systematic steps in marine mineral exploration. Such exploration requires knowledge of mineral deposits and models of their formation, of geophysical and geochemical exploration methods, and of data evaluation and interpretation methods. These topics are described in detail by an international group of authors. A short description is also given of marine research vessels, evaluation of marine exploration examples; and an overview is provided of the jurisdictional situation after UNCLOS III.

Manganese mineralization is diverse in occurence, origin, mineralogy and geochemistry. This volume includes a review of the range of terrestrial Mn deposits and their relative abundance through geological time. Experimental and modelling approaches to Mn geochemistry and mineralogy can further aid our understanding of the formational and depositational processes involved and thereby our interpretation of deposit metallogenesis.