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By Kris van Nijen

IHC Merwede, a Dutch supplier of ships and equipment for dredging and mining activities, and DEME, a Belgian dredging and environmental services group, will enter into a joint venture for deep-sea mining activities. Under their cooperative agreement, IHC Merwede will be responsible for the development and construction of technical solutions, while DEME will be responsible for operations. Together the companies will offer a unique pioneering total solution. The joint venture will be known as OceanflORE.

Jan 1, 2011

By S. Jeffress Williams

The topic area for this paper covers the United States portion of the northern Gulf of Mexico, extending from the Rio Grande delta east to the Florida peninsula. Declaration of an Exclusive Economic Zone in 1983 expanded Federal economic jurisdiction on the continental margins from 12 to 200 nautical miles seaward from the coast. The nation-wide area of the EEZ totals 3 million square nautical miles, with approximately 186 thousand square nautical miles in the Gulf of Mexico. In the Gulf, the continental shelf has an area of 81 thousand square nautical miles, extending to a depth of 600 ft. and having widths of 6 to 120 nautical miles. Specific areas on the shelf offer the greatest potential for containing aggregate and other hard mineral resources. The primary geomorphic features along the Gulf coast include: barrier islands, chenier plains, tidal inlets, bays and lagoons, estuaries, and deltaic headlands. These features are composed of terrigenous siliclastic sediments, except for the west Florida coast, south of 29°N latitude, which is dominated by carbonate sediments. On the shelf, the primary features are linear sand shoals and associated sand sheets, relict delta lobes and channels, and banks related to salt diapirs and coral reefs. The composition and distribution of sediments in these coastal and shelf features are determined by numerous geologic factors including: seabed topography; riverine sediment discharge; sediment dispersal patterns due to currents, waves, storms and tides; tectonics and subsidence; and repeated fluctuations in sea level.

Jan 1, 1986

By Ivo Dreiseitl

Bottom sediment sampling by means of a box corer, as a direct method of deep seabed exploration for polymetallic nodules, is the most comprehensive way to obtain various types of geological information on points forming a network of stations. However, direct information is lacking from areas separating those stations and has to be approximated by interpolation or extrapolation, which leads to uncertainties. Sediment sampling with a gravity or piston corer can provide information on the superficial, up to 4 m thick, part of the sedimentary cover. As opposed to box coring, gravity or piston coring provides no information on nodule abundance. Information for unsampled areas can be gained by application of remote techniques of exploration. The techniques of choice in visualising nodule-rich fields, nodule-free areas, hard rock outcrops and other obstacles for seafloor mining involve using sonar and continuous deep sea (CDS) camera. Seafloor mapping can be rendered with two major sonar types: the side scan sonar used to obtain seafloor imagery and multibeam sonar for bathymetric data; the two types are usually combined and work with an intermediate frequency profiler. Photo-profiling by means of a deep sea towed camera provides a series of seafloor photographs, each supplemented with information on the area covered by each frame, including the nodule abundance. Remote techniques have been quite frequently applied by the Interoceanmetal Joint Organization (IOM) in nodule field exploration. Recently, geoacoustic techniques (side scan sonar + profiler) and CDS were applied for exploration of IOM?s first prime area H11 (5372 km2) on 6 transects. During the IOM-2009 cruise, a total of 295 km of geoacoustic transects and 344 km of photo-transects were surveyed. The data obtained were processed with the aid of earlier information produced by multibeam sonar surveys. The aim of this paper is to demonstrate the advantages of remote techniques, particularly with regard to application of the towfish device, for geological and geotechnical applications in exploration for polymetallic nodules.

Sep 14, 2011

By Marlene Olivares Cruz

The particles that make up the deep-sea sediments have two main sources: 1) those that are created in situ from dissolved components and 2) those that are washed into the ocean in solid phases from the continents, atmosphere, space and interior of the Earth. Many particles as they sink through the water column reaches the seabed and are known as pelagic sediments with terrigenous, biogenic, authigenic, and cosmogenic components. Among the minerals found in the terrigenous fraction of pelagic sediments are quartz, clay minerals, feldspar, micas, ferromagnesians, and the biogenic fraction with remains of siliceous organisms, such as, radiolarian and diatoms. The chemical nature of marine sediments is controlled by the contribution of particulate matter derived from various sources with varying compositions for the fixing of elements during deposition and the compositional changes carried out within the sediments during diagenesis. In the last decade there have been several studies on the mineralogical composition of seabed sediments, suspended particulate materials and cores, together with paleontological and geochemical data are used for paleoclimatic and paleoenvironmental reconstructions, analyze changes in sea level, stratigraphic correlations and identify past and present sources of sediment and terrigenous input pathways and to describe the current ocean mass (Martins et al., 2001, Oliveira et al., 1998). There is also a scientific and economic interest in the authigenic fraction of pelagic sediments formed from other materials for polymetallic nodules. The study of sediments associated with polymetallic nodules helps to know the genesis, evolution and occurrence of these deposits (De Koven et al., 2003, Dubinin et al., 2008).

Jan 1, 2011

By James R. Hein

Manganese nodules from the Cook Islands (CI) Exclusive Economic Zone (EEZ) are compositionally different from other nodule fields. CI nodules have relatively high cobalt concentrations and low nickel, copper, and manganese concentrations (e.g. Hein and Petersen, 2013). This reflects the predominantly hydrogenetic (seawater source) origin for metals in the CI nodules versus dual seawater-pore water sources for most other nodules. The concentrations of many critical and strategic metals have not been previously analyzed for CI nodules, so comparisons with other nodule fields have been limited. To address this, we analyzed a set of nodules distributed throughout the CI EEZ for a complete set of 67 elements, including all of the metals that may be of economic interest, such as the rare earth elements (REEs), yttrium, tellurium, niobium, zirconium, tungsten, titanium, and others (see selected elements in Table 1). In addition, we recalculated the tonnages of nodules and contained metals from nodule abundance areas (in square kilometers) determined by GIS ArcMap calculations based on JICA/MMAJ (2001) nodule distributions. The nodule tonnage calculated and summed from each abundance sector yields a total inferred resource estimate of 9.66 billion tonnes of nodules covering an area of 1.21 million square kilometers; using a cut-off of 6 kilograms of nodules per square meter, yields a median tonnage of 8.59 billion tonnes of nodules covering 687,647 square kilometers (Table 2).

Sep 14, 2011

By Mayumy Amparo Cabrera-Ramírez

Polymetallic nodules are a widespread resource in the Pacific Ocean, particularly in the areas of Clarion-Clipperton (Cronan, 2000). The most abundant mineral phases are forme d by iron and manganese oxides, with minor elements such as nickel, copper, cobalt, molybdenum and rare earths elements (Cronan, 1977; Cronan and Moorby, 1981; Iyer and Sharma, 1990; Mangini et al. 1990; Banerjee et al. 1991). In the Clarion-Clipperton Zone (CCZ), several authors mention that there are three main mineral species of manganese oxides, which have been recognized and which are associated with different processes of formation: todorokita (Mn2+, Ca, Mg) Mn3 4+ O7. H2), vernadite dMnO and birnessite enriched in Fe and (Na, Ca) 0.5 (Mn4+, Mn3+) 2O4. 1.5 H2O. In nodules of hydrothermal origin have been found todorokite, birnessite, vernadite, goethite and pyrolusite. Although there are many oxides and hydroxides of manganese and iron in amorphous and microcrystalline phases that make up the bulk of the nodule (Frondel et al. 1960; Cronan 1977; Dymond 1981; Calvert and Piper, 1984; Aplin and Cronan, 1985; Martin and Lallier, 1993; Achurra et al. 2009), identifying specific mineral phases is difficult due to the intergrowth of different phases and associated detrital material.

Sep 14, 2011

By Tao Chunhui

The seabed deposits type and distribution are very complex at the hydrothermal field. In this paper, we provided an approach to study the seabed deposits classification at the Precious Stone Mountain hydrothermal field (PSMHF) using MultiBeam sonar data . The PSMHF was found in the Galapogas microplate at the Leg 3 of the Chinese COMRA 21st Cruise. Using this approach, the seabed deposits at the PSMHF are mainly classified into three types, which are rock, breccia and sediment, respectively. We can find the distribution of the three types of seabed deposits according to the sonar backscatter data. The rocks are mostly distributed around the hydrothermal vent. The breccia are located at the foot of the vent. Most sediments are distributed at the southwest to the vent due to bottom current. Combining with seabed video, TV-Grab sample and the backscatter data, we draw the map of the seabed deposits distribution at the PSMHF.

Sep 14, 2011

By Peter A. Rona

Hydrothermal mineralization along slow-spreading oceanic ridges and rift -zones that comprise more than half the global length of the seafloor spreading center system is related to anomalous physical and chemical conditions acting within the geologic settings that characterize early and advanced stages of opening of an ocean basin. Mineralization in the early stage of opening is represented by the Atlantis II Deep of the Red Sea. There, hypersaline hydrothermal solutions discharging as density stratified brines into an axial basin, have formed the largest massive sulfide deposit (70 x 106 metric tons) known at a spreading center. Mineralization at the advanced stage of opening is represented by two types of sites: (1) oceanic crust on the wall of a rift valley; and (2) oceanic crust exposed on the wall of a transform fault zone. The first type of site is the TAG Hydrothermal Field, located on a wall of the rift valley of the Mid-Atlantic Ridge at the top of the basaltic layer of oceanic crust. Evidence is presented for multi-stage, high- and low-temperature hydrothermal activity that produces Cu, Fe, and Zn enrichments within the thin sediment column and stratiform interlayered deposits of manganese oxides, iron oxides, hydroxides and silicates, on the seafloor. The second type of site occurs along walls of transform fault zones of the equatorial Mid-Atlantic Ridge and Carlsberg Ridge, which exhibit stockwork-type Cu-Fe sulfide mineralization

Jan 1, 1985

By W. D. Siapno

Marine mineral resources have been reviewed in great detail on numerous occasions over the past few years. A summary of these efforts would indicate there is little new on the horizon as far as economic programs are concerned. Deep ocean minerals, though not forgotten, hold little promise for development in the immediate future, i. e., manganese nodules, cobalt crusts, polymetallic sulfides, etc. Nearer to shore, within the EEZ, and particularly within waters under state control greater industrial interest is expressed. Interest in sand and gravel not only persists but is growing, dependent largely upon the construction industry. Precious metals demonstrate the greatest growth potential.

Jan 1, 1988

By Irina Melekestseva

The Cu-Zn massive sulfides from the basalt-hosted Semenov-2 hydrothermal field (13°31.13´ N, 44°59.03´ W, MAR) are enriched in Au (22?188 ppm) and Ag (127?1787 ppm) [Ivanov et al., 2008] and elevated contents (ppm) of Se (269?289), Sn (123?125), and Sb (72?75). These may indicate heterogeneous substrate rocks and possible ultramafic rocks. Based on phase analysis, 70% of the gold in the massive sulfides is free. LA-ICPMS analysis has shown that the main carrier of the invisible gold is covellite (22.51? 226.64 ppm). Covellite is also characterized by elevated contents of Se, Mo, Sn, Te, Au, Bi, As, Ag, Sb, Tl, and Pb relative to the primary sulfides.

Sep 14, 2011

By V. K. Banakar, R. P. Rajani, A. R. Chodankar

The Afanasiy-Nikitin Seamounts (ANS) in Eastern Equatorial Indian Ocean (Figure 1) are shown to be the exposed part of the presently buried 85°E Ridge system under the Bengal Fan sediment and were emplacement around 75-80 m.y. ago (Krishna, 2003). The first recovery of ferromanganese crusts from the ANS was made during 1994, and the samples (Figure 2) provided important clues on the evolution of this seamount (Banakar et al., 1997).

By Irina A. Pulyaeva

Hydrogenetic Fe-Mn crusts are ubiquitous in the ocean basins and play an important role in marine mineral-deposit research because of their widespread occurrence and high concentrations of valuable and rare metals. Directed research, which started in the last quarter of the 20th century, has provided significant results, with substantial amounts of data produced on Fe-Mn crusts structure, composition, and distribution in the global ocean. Detailed study of several seamounts has given confidence about the scale of Fe-Mn crust development and their characteristics. Now, commercial interests gain more and more attention. However, at the same time some theoretical questions related to Fe-Mn crust history including controls on metal sources and concentrations have not yet been answered. Here, we present the overview of age, composition, distribution, and geological setting of hydrogenetic Fe-Mn crusts from Pacific and Atlantic seamounts and discuss the geological evolution and conditions that led to the formation of potentially economic concentrations of metals. The age, composition, and distribution of Fe-Mn crusts in the Atlantic and Pacific oceans were determined by using a Fe-Mn deposits database compiled from our original data, published papers, published databases, and other international sources. Comparative analysis of Fe-Mn deposits from the Atlantic and Pacific oceans shows that there are similarities in basic characteristics of crust formation in both oceans. Simultaneously, there are significant differences in the scale of Fe-Mn crust distribution and composition that can be explained by differences in geological settings and characteristics of the deposition environment.

Jan 1, 2011

By Ian J. Graham

Brothers volcano, in the southern Kermadec Arc, is host to two hydrothermal vent fields with very different geology, permeability, vent fluid compositions and mineralogy (see de Ronde et al. and Ditchburn et al. this volume). The NW caldera site contains mineral deposits (sulfide chimneys and crusts), which are either Cu-rich (?magmatic?) or, more commonly, Zn-rich (?epithermal?). The lower cone site, in contrast, is characterized by native sulfur mounds and spires. It has been proposed (see de Ronde et al. this volume) that the metals, especially Cu and possibly also Au, enter the hydrothermal system via injection and degassing of magma and/or the dissolution of metal-rich glasses. They are then transported rapidly upwards via magmatic volatiles along long (c. 2.5 km), narrow (c. 300 m diameter) pipes, consistent with evidence of vent fluids forming at higher than hydrostatic pressures, at relatively shallow depths. The NW caldera and cone sites may represent stages along a continuum between magmatic-hydrothermal and water/rock-dominated end-members. In this context, investigation of melt inclusions in conjunction with other geochemical and petrological research was carried out to ascertain the metal transporting conditions that may have led to mineral deposition and ore formation. Sixteen melt inclusions in plagioclase were analyzed for their chemical compositions from a typical cone dacite sample using LA-ICPMS at the University of Tasmania. The inclusions are typically glassy and commonly occur with other inclusions such as apatite, clinopyroxene, zircon, magnetite, sulfides and/or low-density fluids (Fig. 1). Major (XRF) and trace element (ICPMS) analyses were performed on whole rock samples collected during the 2005 Shinkai 6500 expedition. Haase et al., (2006) has also reported EPMA glass analyses from cone dacites, which may be used for comparison (Table 1). [ ]

Jan 1, 2010

By James R. Hein

Ferromanganese oxyhydroxide crusts (Fe-Mn crusts) precipitate out of cold ambient seawater onto hard-rock surfaces at water depths of about 600-4000 m throughout the ocean basins. Fe-Mn crusts concentrate most elements in the Periodic Table above their mean concentration in the earth's crust (continental plus oceanic crust), except for the major rock-forming oxides and also notably gold and palladium. Tellurium is concentrated greater than any other element relative to its earth's crust mean (about 1 ppb). For example, mean contents of the elements heretofore known to be most enriched in crusts, Mo, Tl, Sb, Co, Mn, Bi, As, Se, and Pb are enriched 100 to 1000 times over their earth's crust mean, whereas the mean Te content in Fe-Mn crusts is enriched about 50,000 times. However, the distribution of Te in the earth is poorly known. Estimates of the mean Te content of the earth's crust range from 0.36 to 10 ppb, with 1 ppb being the most commonly cited mean content (compilations in Levinson, 1974 and Govett, 1983). If we took the highest estimate of 10 ppb, then Te would be enriched in Fe-Mn crusts five times more than the next most enriched element, or 5000 times the estimated maximum mean earth's crust.

Jan 1, 2000

By Art Wright, Steinar L. Ellefmo, Kurt Aasly, Mike Williamson, Fredrik Søreide, Martin Ludvigsen, Michael Zylstra

Exploring for minerals on the seabed is challenging and expensive – and the ability to collect representative sub surface samples is essential. The research project MarMine led by NTNU has together with Seattle based Williamson and Associates developed and tested an ROV-based drill rig for mineral (seafloor massive sulfides and crusts) and rock sampling. The ROCS system is a single stroke drill and is simple, robust and possible to use from various larger ROVs. For the vehicle to provide a stable platform, the vertical bollard pull of the ROV and the vehicle mass are important variables. The developed drill uses a thin wall drill bit and barrel and operates at high RPM to reduce the required down weight and drilling moments. The system also contains an emergency release to be used if the core barrel is stuck. The drill is hydraulically powered with cylinders operating the tower and a rotation unit. It can rapidly be modified to provide samples from softer samples like unconsolidated material. At the Arctic Mid Ocean Ridge, a work class ROV was deployed with the drill mounted for testing at 2700 m depth in basalt rock. The recovery from the system was above 80%. Such core samples can be used for chemical analyses of metal and mineral grades, mineralogy and rock mechanical testing. The system provides a probing tool for marine mineral exploration, with low cost, low operational complexity and low risk. Proper resource estimation requires drilling deeper into the deposit, but the short core samples provided by the ROCS provide valuable a priori information planning for more extensive drilling campaigns.

Jan 1, 2017

By Arturo Carranza Edwards

Sedimento II oceanographic cruise, on board of the B/O El Puma, shows a new high anomaly or phosphate associated with shelf sediments from the south Mexican Pacific. Recently, were found two anomalies in the Gulf of Tehuantepec, that are located to the east of this new anomaly, that is related to muddy sands and rock fragment debris. The latter shows values of 17% P205. The phosphate occurrence is probably associated with red tides locations that usually are found in sites where sediments are phosphates enriched. These findings suggest that south Mexican Pacific is of potential interest for P205, in waters with high nutrients values. The possibility of a more regional occurrence of phosphate, from California to Chile is suggested.

Jan 1, 2000

By Leticia Rosales Hoz

A chemical and geological study of beach samples from the Mexican North Pacific was undertaken in order to evaluate the chemical composition of the beach sediments and it s association to lithology, climate, topography and weathering. The North Pacific Mexican littoral is characterized by arid weather with wide coastal plains and three geological provinces. The sands from the area are mainly finer, well sorted and show high maturity because of the high wave regime and the high energy conditions produced by the California Current in the coastline. The provenance index reflects that the region has a source of deep seated rocks, now exposed and dissected. Factor analysis made using the chemical composition showed the samples can be differentiated by five factors: 1) SiO2, 2) Al2O3; 3) Cu; 4) Sr and P2O2 and 5) Na content. Samples located in the northof the study area showed the highest values of Fe2O3 (17.72%), TiO2 (2.43%), V (576 ppm) and Zn (141 ppm) associated to methamorphic rocks present in the area.

Jan 1, 2000

By Burrows D. R.

Metal-rich sediments precipitating from hot saline brine pools were first discovered in 1965 in the Red Sea.1-2 The subsequent discovery of high temperature black smokers and associated massive sulphides in 1977 at latitude 21oN on the East Pacific Rise3 came more as a confirmation than a revelation. Formation of massive sulphides through precipitation from circulating sea-water had been predicted by Oftedahl in 19584, and the mechanisms well evaluated in basaltic-hosted Cyprus-type 5 and in Kuroko-type deposits.6,7 Sea-floor exploration from 1977 through the 1980?s in sediment-starved mid-oceanic ridge (MOR) settings had little impact on land-based exploration. This is primarily because: a) MOR spreading centres were recognized as poor analogies to even Cyprus-type basalt-hosted deposits; b) their preservation potential was limited due to rapid oxidation and c) the metallic deposits studied were small and therefore not directly comparable to the far larger ore bodies on land. More recently underwater mineral deposit research has focused in a variety of back-arc environments associated with felsic submarine volcanism, environments more similar to those predicted for the formation of Kuroko-type deposits (e.g. Okinawa Trough, 8 Lau Basin, 9 Manus Basin, 10 Aeolian arc, 11). Most studies, while scientifically interesting, were hampered, in general, by a lack of good descriptive data, a reliance on isolated grab samples, and a lack of sub-surface observations. This research has therefore had only limited direct impact on exploration strategies with the possible exception of research conducted in areas where faulting provided enhanced vertical exposures. 12

Jan 1, 2011

By Mark Vardy, Kasia-Leigh Chidlow, Tim Minshull, Jeorg Bialas, Sven Peterson, Bramley Murton, Alba Gil

Since the discovery of the first black smoker on the East Pacific Rise in 1977 (Francheteau, et al., 1979), the hydrothermal vents, now called seafloor massive sulphides (SMS) deposits, have generated great interest in the geological community, especially regarding their formation and composition. SMS deposits are areas of hard substratum, with high base metal and sulphides content, that form through hydrothermal circulation and are commonly found at hydrothermal vent sites. The high base metal (Fe, Cu, Zn, Pb), sulphur-rich mineral content has interested mining companies, due to their potentially high economic value. Currently, the known SMS deposits do not have the same dimensions as the massive sulphides (MS) found on land (covering just 10s to 100s m2) and pose significant mining challenges (being located in water depths between 800 m and 6000 m), meaning that they do not appear to be economically exploitable at present. However, these deep-sea mineral resources could be important targets in the near future, particularly with our ever-increasing demand for base metals. A key aim of the European Union-funded Blue Mining project is to develop techniques to robustly quantify SMS deposits dimensions (both surface expression and subsurface extent) and therefore assessing the suitability of SMS deposits for future economically viable and environmentally clean deep-sea mining operations.

Jan 1, 2017

By Gale L. Hubred

Kennecott?s Ledgemont Laboratory developed the Cuprion Process to recover metal values from manganese nodules in the early 1970s. A reducing leach of monovalent cuprous ion attacks the manganese oxide matrix, converting the manganese dioxide to manganese carbonate and releasing the copper, nickel, cobalt, and zinc as ammine complexes. Cuprous ion is generated by contacting leach liquor with carbon monoxide. Copper, and nickel, are recovered by solvent extraction and electrowinning. Cobalt is precipitated as cobalt sulfide and recovered as cobalt powder. Manganese, molybdenum, and zinc can be recovered optionally but have not been included in this process. Kennecott authors have described aspects of the process, but the Cuprion process has not been revealed except in patents. Tables are included for capital and operating costs and revenue. Even though economic recovery of nodules is not anticipated in the foreseeable future, some of the process steps may have application in other places. The Ledgemont Laboratory was a unique operation we think worth documenting. The report is based upon work done up until the mid 1970s. The report represents the work of the entire Kennecott nodule team. It is this author?s intention to save this result and credit the work of that nodule team. The paper is dedicated to the memory of Dr. Herbert Barner, a key member of the team who died in 2003.

Jan 1, 2005