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The chemical composition of the nodules varies with the type of manganese minerals and the size and characteristics of their nucleus, but those who have an economic interest have the following composition: Mn 29%, Fe 6% Si 5%, Al 3%, Ni 1.4%, Cu 1.3%, Co 0.25%, Na 1.5%, Ca 1.5%, Mg 0.5%, K 0.5%, Ti 0.2 0.2% and Ba 0.2% (Morgan, 2000; ISA, 2002). The Pacific Rim is an area of abundant occurrence of polymetallic nodules (Glasby et al., 1980; Morgan, 2000). According to these authors, the Pacific sea floor of the Clarion-Clipperton Zone (CCZ) is one of the most interesting areas in regard to the genesis of polymetallic nodules. Their abundance in the ocean floor is very variable, as there are places where they cover more than 70% of the ocean floor. The nodules can be found at any depth, but the highest concentrations are between 4000 and 6000m (Morgan et al., 1993). In studies conducted in the EEZ of the Mexican Pacific are those made within the project "Research on the origin, process and distribution of minerals in the Pacific ocean floor in the Exclusive Economic Zone of Mexico". Within this project Rosales (1989) conducted studies on the origin, process and distribution of polymetallic nodules, finding that a number of processes give origin to nodules, being diagenesis one of the main mechanisms of elements that contribute to the nodules. Besides hydrothermal processes that are carried near the East Pacific Rise at 21° N, inputs are contributing to the nodules metallic elements and sediments, especially in regions close to the dorsal, as a greater influence hydrogenetic processes occurs westward (Rosales and Carranza, 1990). In 1993, after cruise MIMAR II, Carranza and Rosales refer that metals such as Cu, Co, Ni, Sn, Fe, Mg, Pb, Zn and Ba may have a relationship with the East Pacific hydrothermal activity and sea currents carry these metals in solution to the Clarion-Clipperton fracture area, where there are hydrogenic metals sources (Al, Fe and Mn). As result of chemical analysis of Mn, Cu, Ni and Co, polymetallic nodules observed in part of the EEZ of Mexico are possible of potential economic interest (Rosales and Carranza, 1990, 2001; Carranza and Rosales, 2003).

Sep 14, 2011

By Raymond A. Binns

Exploration for high-value massive sulfide deposits on the ocean floor typically commences with a search for chimney fields in appropriate geological settings, followed by collection and assaying of standing chimneys. Individual chimney fields are generally too small in aggregate volume to constitute viable resources in their own right. Unless numerous small fields occur in reasonably close proximity, presence of plentiful sub-seafloor mineralization with acceptable metal tenor is the more likely requirement for potential exploitation. Expensive drilling is required to prove up mounds of collapsed chimneys, or dilatory sheets and veins or replacements of massive/semimassive sulfide (?stockworks? or ?manto?-like bodies) in underlying host rock. Where multiple targets have been defined, as many parameters as possible are desirable to help rank them for drilling.

Jan 1, 2011

By NA UMC

Abstract Booklet

Dec 1, 2022

By NA UMC

Abstract Booklet

Dec 2, 2023

By Peter B. Hale

Canada has a long history of marine-related industry and onshore mining. Even so, commercial interest in marine mining, excluding seawater mineral extraction and offshore extensions of hardrock deposits such as iron and coal, has been sporadic; despite the fact that shelf mineral deposits supply a significant proportion of the national market requirements for many countries. Several factors have accounted for this including: a relative abundance of onland mineral desposits; the fact that onland deposits can be mined using conventional technology; and, a general lack of knowledge and public awareness as to Canadian offshore non-fuel mineral resource potential. In the mid-1970s the Department of Energy, Mines & Resources formed the Departmental Coordinating Committee on Ocean Mining. The Committee addressed the question of shelf non-fuel mineral resource potential and concluded that, while several reports had raised the possibilty of this alternative source, there had not been a systematic evaluation of the resource base. This led to the formation of a Shelf Working Group, whose task it was to outline and implement a departmental program to advance our knowledge of shelf resource potential. A methodology was devised that utilized existing geoscientific and hydrographic

Jan 1, 1985

By James C. Barker

Alaska's expansive continental shelf represents future opportunities for marine mineral development. Although today's metal prices and subsidized foreign mineral production continue to discourage industry investment in marine exploration worldwide, the longer term outlook is one of increasing costs on-shore with a dwindling land-base available on which to search for and extract minerals. Likely, the generations of the 21st century will increasingly recover their minerals from the sea-floor. Though largely unexplored, Alaska potentially represents a major port ion of the U.S. marine resources. Several factors demonstrate this. First, the Alaskan OCS is huge; 74% of the entire United States' continental shelf lies off of Alaska, and 54% of the U.S. coastline is Alaskan. Combined with the jurisdiction waters of the Soviet Far East, the Bering-Chukchi shelf is one of the world's largest tracts of shallow water. Second, Alaska is situated at the northwestern terminus of the mineral-rich American cordillera. From Chile to Alaska, major on-shore deposits of precious and base metals, ferroalloys, and industrial minerals are found in the tectonically disturbed belts of the cordillera. In 1988, the western U.S. cordilleran states produced 70% of this country's mineral output (excluding construction materials). Throughout the cordillera's entire 10,000 mile length, the rock units strike largely parallel to the coastline, but in Alaska they extend directly offshore and onto the continental shelf. Consequently, the mineral-rich terranes off of Alaska have a much more complex interaction with coastal and lit-

Jan 1, 1991