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By Alexander Malahoff

Six active Kermadec Arc submarine volcanoes located between 34°S and 36°30?S were mapped and sampled by an interdisciplinary inter-institutional research team between April and July 2005 using submersibles Pisces V and Pisces IV aboard the mother ship the RV Kai?mikai-O-Kanaloa. The purpose of the expedition was to study the relationship between hydrothermal activity, formation of hydrothermal mineral deposits and the biodiversity of life associated with the hydrothermal vents. Of the volcanoes examined, all showed evidence of hydrothermal activity, plume production and helium anomalies. Only two of the volcanoes, namely Brothers and Clark, showed chimneys and surficial poly-metallic sulphide deposition. Hydrothermal venting at a water depth of 1700 meters within the base of the northern wall of the summit caldera of Brothers Volcano has produced a field of chimneys, some of them 5 metres high with black smokers venting. Temperatures of 300°C were measured within the active vents. Clark Volcano has a double cone summit at a water depth of 875 metres. The shallowest cone has a near-summit hydrothermal vent field with 5-meter high venting chimneys and smaller structures around the periphery. Water temperatures of 200°C. Geochemical and petrological analysis of the massive poly-metallic sulphide samples taken from Brothers and Clark show a diversity of mineralogy. This diversity is clearly a function of hydrothermal water temperature. Chimneys sampled from Brothers are pyrite and sphalerite dominant with lesser chalcopyrite. Sulphides from Clark Volcano tend to be barite rich with lesser sphalerite and pyrite. Sulphides from Brothers Volcano have a range in gold composition of 4 to 58 ppb with silver composition of up to 38 ppb. A mineral formation model for the volcanoes suggests hydrothermal fluid boiling within the volcanic edifice for those volcanoes with shallow summits and massive sulphide deposition with the edifice as well. Surficial deposits include native sulphur and lower temperature oxides. Only the deeper water Brothers Volcano shows massive sulphide deposition along the marginal faults of the caldera floor.

Jan 1, 2005

By Alister C. Skinner

The Marine Operations and Engineering section of the British Geological Survey based in Edinburgh, Scotland have, over the last 30 years, developed and operate a series of remotely operated, and powered, seabed coring systems. These systems were initially developed to provide a cost-effective solution to ground truth seismic reflection data for regional geological mapping, where the only solution that existed was conventional and expensive drill-ships. Since the early 1990?s these tools have been used for many other applications in industry and science. Currently the systems can operate in up to 2000 m water depth for 5m seabed penetration and up to 4500m water depth for a specialised oriented core drill which collects a scribed core to 0.8m below seabed. Scientific applications focus on determining the geology of an area and follows pre-determined geophysical interpretations. It usually also follows other coring attempts with non-powered coring equipment which is invariably unsuccessful if the strata is over-consolidated sediments or hard rock. Commercial applications include cable and pipeline route surveys, diamond, gold and base metal exploration, beach reclamation and aggregate materials evaluation. In many cases there is a blend of science and commercial investigation typified by coring in hydrothermal vent areas or carrying out geological coring in a frontier oilfield province. The versatility of the drills allows cost effective and rapid operations in remote and hostile areas where a rapid investigation may be the only one possible in a short weather window. The deepwater operational capability also allows science and commercial assay to be obtained ahead of potential exploitation and allows formulation of scientific theories or commercial project plans based on sound core data. Being mobile and compact these corers may be used from suitable (Dynamically Positioned or Anchored) vessels of convenience and thus provide a cost effective platform for sampling different types of seabed geology on an international basis.

Jan 1, 2004

By Peter E. Halbach, Andreas Jahn

"Co-rich ferromanganese crust deposits exist on slopes, summits and platforms of seamounts and guyots throughout the global oceans, where deep-sea currents have kept the seafloor structures more or less free of sediment for millions of years. They form by direct precipitation from cold seawater under more or less oxic conditions and consist of thin layers (2 up to 25 cm thick) covering hard substrate rocks in water depths of 800 to 5000m (Halbach and Marbler, 2009; Hein et al., 2000). Besides Mn these crusts contain interesting concentrations of minor elements (Co, Ni, Ti and Cu) and trace elements (Mo, W, Te, Ga, Pt and REEs), thus they represent significant metal deposits and promise potentially valuable additions to the world’s metal resources.The prospects for mining of this marine type of metal deposits largely depend on the grades and the scale of the potential ore resources. However, only a few percent of existing seamounts and guyots have been mapped and sampled in detail, most of them in the Pacific Ocean. Therefore, a model to estimate the geological resources based on the global seamount catalogue of Wessel (2001; revised: Wessel et al., 2009) and the empirical parameters which control the metal composition and distribution was developed."

Jan 1, 2017

By Ning Yang, Sup Hong

INTRODUCTION Metal components contained in deep-seabed mineral resources are being highlighted as “energy metals”, which are widely utilized in the entire fields of energy: harvesting and generation, storage and transportation, and saving. Those are mostly trace and rare metals, and rare earth elements as well: manganese, nickel, cobalt, copper, molybdenum, tellurium, selenium, platinum, etc. Toward low carbon society, for global sustainability, the role of metals and minerals is growing up in industries of energy and transportation [1]. In this context, the production and supply of energy metals from deep seafloor have to be approached also based on sustainable development. In deep-seabed mining activity, the sustainability is focused on potential impacts on ecosystems in benthic area and water column. The environmental impacts in deep-seabed mining are caused basically by intervention in benthic zones and transportation of materials. Those are, in particular, removal of benthic habitats, generation and dispersion of sediment plumes, surface transportation of seawater and sediment, tailing from mining vessel, sound and light noises, and chemical leakage, etc. This paper is aiming at fundamental guidance towards sustainable mining of polymetallic nodules.

Jan 1, 2018

By Dennis Sánchez Mora, John Jamieson

INTRODUCTION Work by Humphris et al., (2002); Ondréas et al., (2009); Barreyre et al., (2012); and Escartín et al., (2015) has identified active and inactive hydrothermal sites along the Lucky Strike segment. The sites that contain the largest accumulation of known sulfides are located between the north and the southern zones (Figure 1), a vent site area that is referred to as the Main Lucky Strike hydrothermal field (Escartín et al., 2015). Hydrothermal fluid outflow has been linked to a shallow fault network (Barreyre et al., 2012). However, specific constraints on fault geometries have not been determined. Other off-axis sites at Lucky Strike, such as Capelinhos (high temperature vent), and Grunnus (inactive?), as well as a low temperature vent field (on-axis), Ewan, have been described by (Escartín et al., 2015). Given the spatial relationship between the Main Lucky Strike hydrothermal field (MLSHF), and the intersection of northern rift faults with the southern rift faults, a structural analysis of this area can provide insight into the fault controls on fluid flow that leads to hydrothermal venting and sulfide precipitation. METHODOLOGY Structural data (dip direction and dip) was determined using Leapfrog Geo 4.0 software. Bathymetric data was obtained from Escartín et al., (2015) and references therein. The bathymetry was imported into Leapfrog Geo (in UTM format) and, using the structural modelling tool, individual measurements with dip direction and dip data were collected with a focus on the northern volcanic rift and the southern central volcano (Figure 2a). All measurements were taken from what the authors consider as normal faults, and to aid the determination of individual measurements a “face dip” map was constructed, where the bathymetry is colored by slope angle (Figure 2b). All measurements are simultaneously plotted on a stereonet generated by the Leapfrog Geo Software. Data were divided into northern and southern, and western and eastern zones to determine the relationship between hydrothermal venting and the structural geometries at Lucky Strike (Figure 2c). Slip measurements for individual faults were determined along the dip of the fault with a measuring tool. Net slip, heave (horizontal displacement), and throw (vertical displacement) was calculated for each of the zones.

Jan 1, 2018

By William D. Siapno

Approximately a century lapsed between the time nodules were discovered and the beginning of commercial exploration in the early 1960's. A period of rapid development of exploration and mining technology ensued over most of the next two decades. In recent years advancement has been sharply curtailed. This paper discusses the constraints inhibiting nodule mining and some developments that could aid in overcoming certain difficulties. Specifically, the greatest single constraint is economic. With few exceptions mineral markets are badly depressed. Present projections for development of nodules are for the late 1990's or beyond. However, the U.S. awarded exploration licenses in mid-1984 and more recently boundaries of license areas have been released. These conditions promote cooperation among organizations engaged in deep ocean mining. Survey data, and where appropriate some data products, have been exchanged between various consortia. The present hiatus in at-sea activities provides an excellent opportunity to investigate the best means to proceed. This period of quiescence offers a rare moment to distill the meaningful values of an era of hectic activity to permit more efficient development in the future.

Jan 1, 1985

By Brian D. Bornhold

A comprehensive multi-disciplinary marine geological survey of northwestern Graham Island, Queen Charlotte Islands, British Columbia, Canada was conducted by Offshore Survey and Positioning Services Ltd. of Vancouver, B.C. on behalf of the Geological Survey of Canada; Energy, Mines & Resources Canada, Pacific Geoscience Centre, Sidney, B.C. Canada during October 1984 and July 1985. The aim of the survey was to map both the surficial geology and geomorphology in order to identify and evaluate the nature of the nearshore sedimentation and recent tectonics including stability (slumps and scarps) seafloor faults (frequency and displacements) and both the classification and consistency of soil type boundaries and properties. Data was acquired by utilizing conventional indirect applied marine geophysical techniques including side scan sonar, precision echo sounding and complimentary soil sampling. During October 1984 a total of 320 line kilometres of data including 180 soil samples were acquired. During July 1985 a total of 300 line kilometres of data were acquired including 150 soil samples.

Jan 1, 1985

By D. S. Cronan

Mineral exploration problems in the S.W. Pacific are not unique to that region, but a combination of favourable circumstances render it an ideal area to attempt to solve such problems. The land area of the S.W. Pacific island nations is only a fraction of the total sea area they can claim under current International Law. Hence, they have a great need to explore and evaluate their offshore areas. For the past ten years the focus of this work has been CCOP/SOPAC which has individually and jointly with other groups initiated and maintained far reaching marine mineral exploration programmes. In association with CCOP/SOPAC the writer has obtained and analysed approximately 650 sediment samples from the S.W. Pacific region for seventeen elements. Multivariate statistical techniques have been applied to the data set. The aim has been to identify chemically anomalous sediments reflecting either sea floor mineralisation and/or mineralisation on adjacent land areas.

Jan 1, 1985

By James C. Barker

Concern over the availability of domestic critical and strategic mineral supplies has led the Bureau of Mines to evaluate the reserve development potential of alternative sources in Alaska. Near the village of Platinum, on the southwest Alaska coast, the Red Mountain concentrically zoned ultramafic complex is a source of onshore alluvial placers containing platinum-group-metals (PGM). It has long been suggested that valuable placers may also underlie the shallow coastal waters of the Bering Sea. A direct correlation of placer PGM and chromium to ultramafic rocks in the area was studied by the Bureau and the extent of the complex was mapped. Magnetometer and gravity data and geological studies suggest the complex is a large lensoidal body trending several kilometers offshore to the southwest with a probable steep southeasterly dip. Multiple Pleistocene glaciations and marine transgressions have eroded the western and southwestern portion of the complex. Sediments containing PGM, chromium, and associated gold (largely derived from glacial till) have been transported northward along the advancing coastline by littoral currents. Beyond the breaker zone, these sediments are generally buried by recently winnowed sand and gravel transported by strong longshore tidal currents. There is also evidence that paleoplacer channels underlie the marine sediments.

Jan 1, 1986

By C. H. Hobbs

A recently completed series of projects funded by the Commonwealth of Virginia and the U.S. Minerals Management Service was designed to assess the distribution of heavy minerals on the inner continental shelf adjacent to Virginia. These projects indicate that a suite of minerals of both strategic and economic interest is present. Analysis of several hundred grab and core samples shows that zircon, monazite, and titanium minerals (ilmenite, rutile, and leucoxene) occur in quantities that probably warrant further study by the mineral industry. Furthermore, side-scan sonography and shallow seismic profiles have provided information on the thickness and areal extent of the mineral-bearing sands. Possible development of the resource is enhanced by a potential use of offshore sand for beach nourishment. The results of the preliminary studies have been presented in open-file publications and oral reports in order that the mineral industry might have an up to date basis upon which to consider more exploratory work. Much of the effort south of the mouth of Chesapeake Bay was made in cooperation with and enhanced by an independent study of sand resources for beach nourishment and other needs. Preliminary review of the quantitative analyses of the heavy-mineral content of several hundred samples demonstrates that the distribution of high concentrations is non-uniform. From core data, the greatest abundances of some economic heavy minerals (ilmenite, rutile, leucoxene, monazite, and

Jan 1, 1988

By S. W. McCandless

Since the mid 1970's, the science of remote sensing has invented and demonstrated sensors that hold unique promise for users that operate in the marine environment. Earlier, visible and infrared sensors provided images and temperature maps of surface conditions, but the 1970's introduced active (radars) and passive (radiometers) microwave sensors capable of penetrating clouds and operating day or night over the world's oceans. Space-based observation satellites permit these systems to span the globe many times each day, providing a view of the world's oceans and Arctic areas consistent with daily and, sometimes, hourly changes in the marine environment. Experimental satellites launched by NASA proved that such systems had great scientific merit, but, even more importantly, they could produce information valuable to marine transportation, fishing, and resource exploration and extraction. This latter subject includes the off-shore search and production of petroleum and natural gas resources and ocean mining as well. A few early satellites, such as GEOS-3, Nimbus-7, and most notably Seasat established that global wind fields, all weather sea surface temperature, ocean topography and sea state, and fine scale images of wave patterns, surfactants,

Jan 1, 1986

By M. F. Dibble

The technology available for mining of underwater mineral resources such as placers and phosphorite, typically occurring with variable amounts of overburden, has remained largely unchanged for decades. The traditional bucket ladder dredge with maximum digging depth of 48 m and monthly capacities about 500,000 m3 still reins as the only heavy duty mining system capable of working the tough materials characteristic of heavy metal placers. Attempts at adapting the bucket wheel cutter-suction dredge to these severe conditions have not yet been successful except in moving small volumes from shallow depths. High capital cost (20-30 million U.S. dollars), high cost of overburden removable, and turbidity generation for the bucket ladder are often significant negative factors in mining operations where this system remains the only viable alternative. The Japanese continue to advance the technology of their submersible dredge pump system powered by specially adapted, direct drive electric motors. Present systems are designed primarily for working surficial deposits of aggregate to depths as great as 90 meters, the pump suspended by cable from a surface vessel with an eductor pipe leading from the pump to the vessel. Such a system may prove adaptable to a variety of surficial deposits including phosphorite, shell and heavy minerals in addition to aggregate. However promising for the exploitation of surficial deposits, little advantage can be expected for the deeper buried and more difficult deposits.

Jan 1, 1986

By Charles L. Morgan

For the past twenty years or so the oceans of the world have been transformed in the minds of most Americans from the ultimate and nearly infinite receptacles for sewage and other wastes to an almost sacrosanct and threatened last refuge of Mother Nature from man on Earth. While this general movement has helped somewhat to moderate the flows of pollutants into the oceans, it has had severe and sometimes devastating impacts upon various attempts to develop seabed mineral resources. Marine mining proposals have been easy targets for attack. In most cases, they have short or no histories and involve prototype or first-generation methods. They commonly lack major financial backing, and do not command significant public support. Their constituents are limited. Opposition movements to such proposals have been able to evoke strong support by appealing to this "last refuge" image and depicting mining operations as the final assault. In mounting these public appeals, the movements obtain visibility and support. Because of the small and sometimes tentative status of the constituencies which support particular proposal s, the potential liabilities for opposition movements are minimal.

Jan 1, 1989

By Alexander Malahoff

Accumulation of cobalt -rich ferromanganese crusts on Pacific seamounts located off-ridge in the Hawaiian EEZ, represents a complex process that involves geologic aging of the seamounts, geographic transportation- of the seamounts on the Pacific plate during the past 80 million years, and geochemical history of the oceans for that period. A comparative study of the building and erosion processes of the young Loihi Submarine Volcano, located south of the Island of Hawaii , and the 80 million year old Cross Seamount, located west of Hawaii , shows that both edifices show wide armchair-shaped talus chutes and intervening ridges of exposed dikes. The similarity between the observed mass wasting process on Loihi and Cross suggests that the slopes of submarine volcanoes are geologically unstable from the time of their origin on the seafloor through their entire geological history. The slopes of Cross are covered by coalesced ferromanganese crust covered talus, steep exposed dike faces, and crust covered dike ridges. A study of the stratigraphy of the crusts shows a range of thicknesses and number of unconformities present. The thickest crusts, up to 8 centimeters, are found preserved within the larger coalesced slabs along the shallower slopes of the talus chutes and along the crests of the ridges between water depths of 400 and 1800 meters. The platinum content was used in stratigraphic correlation between the crusts in the coalesced slabs and those collected from ridges with the PISCES V submersible. In the samples studied, the highest platinum content of 0.7 ppm

Jan 1, 1991

By Bonnie A. McGregor

The U. S. Geological Survey in cooperation with the Institute of Oceanographic Sciences (IOS), U.K., conducted a sidescan sonar survey of the U. S. Exclusive Economic Zone in the Gulf of Mexico from August 7 to October 22, 1985. A reconnaissance-scale view of 120,000 square nautical miles of sea floor seaward of the shelf-edge was obtained by using the GLORIA (Geologic Long-Range Inclined Asdic) sidescan sonar system. After these data were merged with GLORIA data from an earlier survey (1982) of the northwestern Gulf, a preliminary mosaic was constructed at a scale of 1:375,000. From this mosaic, we can identify morphologic features and interpret sea-floor processes. The extensive deformation of the continental slope seaward of Texas and Louisiana by salt tectonics has resulted in a complex pattern of basins and salt dome highs. One continuous meandering channel was identified in this portion of the Gulf, extending from the shelf edge to the Sigsbee Abyssal Plain. Bottom currents have reworked the sediments in this channel's levees seaward of the Sigsbee Escarpment, the seaward edge of the salt front, suggesting that this channel may no longer be actively transporting sediment. Talus appears to lie along the base of the Sigsbee Escarpment, suggesting that erosion and deposition is occur- ring along this front. Three other discontinuous channel systems can be identified on the mosaic and appear to have contributed sediments to the deep Gulf.

Jan 1, 1986

By Patrick J. C. Ryall

Remotely control led drills capable of being lowered to the sea-floor from ordinary research vessels have been developed over the past two decades. These drills are currently being used in geological survey programmes on the continental shelves (Canada, Japan, Norway, United Kingdom) and for studies of mid-ocean ridges. Generally the drills fall into two categories: 1) those which are powered from the surface and controlled by an operator, and 2) those which are battery powered and follow an automatic programme. Some drills have a television camera mounted on them sending a picture to the surface as an aid to site selection and geological interpretation. Typically the drills are capable of drilling a core 2.5 - 5 cm diameter up to 10 m long. While most of these drills are designed for <1000 m depth, some can drill in water depths of as much as 3500 m.

Jan 1, 1985

By Michael J. Cruickshank

The University of Hawaii, Ocean Basins Division (OBD) shares, equally with the University of Mississippi, Continental Shelf Division (CSD), congressional funding for the Marine Minerals Technology Center, a Generic Minerals Center under the U.S. Department of the Interior&apos;s Mineral Institutes Program. The State of Hawaii supports the program by the provision of salaries for the Executive and Technical Directors and by the provision of fiscal, administrative, and facilities support through the Hawaii Natural Energy Institute, the Research Corporation of the University of Hawaii, and the School of Ocean and Earth Science and Technology. The Center&apos;s program of research, technology development and education is multi-disciplinary and international in scope. Activities since the MMTC/OBD was established in June 1988 have included: Research projects * Development of a Free-Fall Seafloor Hard Substrate Corer. * The Microtopography of Manganese Crust deposits. * Evaluation of the Cobalt Crust Continuum on Seamounts in the Hawaiian Exclusive Economic Zone. * Graphite Furnace Atomic Absorption Spectrometer. * Computer Aided Design Methodology for Power, Communication and Strength Umbilicals. * Characterization and Environmental Impact Assessment of Tropical * Reef-derived sands for Beach Replenishment.

Jan 1, 1991

By Charles L. Morgan

In a commercial effort to characterize deep seabed manganese deposits in the Clarion-Clipperton region of the northeastern tropical Pacific, Ocean Mineral s Company carried out 16 expeditions to the region between -1978 and 1981. During these cruises OMCO collected substantial data. Activities included acoustic profiling, video and photographic imaging of the seabed, and sampling of the deposits with dredges, box cores and free-fall grab samplers. In 1990 the samples, photographs, technical reports and computer data bases which resulted from this work were archived at the Marine Minerals Technology Center at the University of Hawaii. This preliminary examination of the collection focuses on the biological observations made from almost 10,000 photographs of the seabed and the manganese nodule size distributions and compositional data from the free-fall grab recoveries. Regional trends are evident in all three data types. The biological examinations of the seabed photographs show significant geographical trends, with greater abundances of organisms being noted in the northeastern extreme of the region, decreasing toward the southwest (11.4 to 2.7 observations per 100 m2; 460 to 190 g per 100 m2). The nodule size distributions suggest that the ratio of the nodule burial rates to growth rates systematically decreases over the same range (0.65 to 0.36 nodules buried per 1 cm of growth). Preliminary geostatistical analysis of the ore grade data show that, in addition to high local variability, some deposit

Jan 1, 1991

By Robert M. Owen

Geochemical exploration for marine placers involves the acquisition, processing, and interpretation of geochemical data. Recent technological advances such as in-situ analysis systems and microcomputers have greatly improved our ability to acquire and process data, but their full benefits cannot be realized until we also develop improved methods for reducing and interpreting large amounts of raw geochemical data. Toward this end, our research has sought to identify existing and/or develop new geostatistical techniques for use in marine placer exploration. Each technique has been tested by evaluating its performance in the analysis of existing data sets. The data sets typically include the results of chemical analyses of suites of sediment samples collected from areas of known or suspected platinum and gold placers along the Bering Sea coast of Alaska. Results to date indicate that three geostatistical methods (subpopulation partitioning analysis, comparative factor analysis, and end-member compositional factor analysis) are useful in identifying elemental groups which can serve as "pathfinders" in the search for marine placers, and are also helpful in discerning the generic geochemical basis under lying observed statistical correlations between pathfinder elements and placer minerals. Existing methods of modelling sediment dispersal patterns have been examined with a view toward adapting them to the specific problem of understanding placer formation in

Jan 1, 1986

By David A. Larson

The future exploitation of crust deposits will require a dependable characterization system. The U.S. Department of the Interior, Bureau of Mines (Bureau) initiated research to develop a new sampling dredge by conducting a series of cutting and physical property tests on previously collected cobalt-rich manganese crust and substrate samples. Using the engineering parameters derived from these tests, a large, heavy dredge was designed and tested. This heavy dredge was capable of fragmenting and collecting in situ crust, but it created handling problems for the research vessel, thus an aggressive cutting, light-weight dredge was conceived and fabricated. The light-weight dredge is capable of fragmenting and collecting crust and some talus. This dredge can be used on flat or rough seabed terrains. It can be easily retrieved from hang ups and reset to sample again.

Jan 1, 1991