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By Benjamin W. Haynes

The Federal government has a lengthy history in supporting and conducting research in the ocean mining and minerals field. The Federal effort has been and is currently focused primarily in four agencies: the National Oceanic and Atmospheric Administration (NOAA) within the Department of Commerce, and the Geological Survey (USGS), the Bureau of Mines (BuMines), and more recently the Minerals Management Service (MMS) within the Department of the Interior. While NOAA and the USGS have played dominant roles in mapping and geologic studies, and the MMS has recently provided funding for several task force studies within the Exclusive Economic Zone (EEZ) , the Bureau of Mines has conducted research in mining technology, minerals processing, resource definition, and economic evaluation of minerals from the seabed for over 20 years. These studies have yielded considerable minerals information regarding manganese nodules and crusts, placers, mineral sands, phosphorites, and sulfides. This paper reviews the past achievements in ocean mining and minerals programs starting in the late 1960's, describes current research and information efforts, and presents an outlook for Bureau of Mines research and information gathering efforts. Specific topics

Jan 1, 1989

By Valery M. Yubko

"The conceptual basis of the developed model is based on the ideas that evolution of geological-geomorphological structure of the CCZ is controlled by four types of geologic factors: geodynamic, sedimentary, volcano-tectonic and erosion-lithodynamic. In terms of time span two factors (geodynamic and sedimentary) can be considered as permanent and the other two as sporadic.The geodynamic factor is responsible for two interrelated geological processes. One is going under conditions of the axial zones of spreading centers and results in formation of the CCZ basement. Historically this process is considered as a starting point for each of the heterochronous fragments of the CCZ. The second one controls gradual shifting towards the Pacific Plate (Hawaiian direction) and subsidence to greater depths of the neogenic fragments (basement). Thus, those processes control basic topography, geomorphology and the seabed depth within the CCZ.Volcanogenic-hydrothermal activity of the EPR is one of the main sources of the ore components, which finally compose manganese nodules as a result of complicated processes of their dissemination and transportation to the bottom in dissolved and organically bound forms.The role of the other constant factor (sedimentary) is displayed in two ways. Firstly, initial relief is smoothed under the influence of this factor, which, subsequently, makes favorable conditions for manganese nodules formation. Secondly, it favors transportation of the majority of the ore components, participating in manganese nodules formation into zones of active nodules formation."

Jan 1, 2017

By B. J. Bluck

Diamond mega-placers, in order to rank amongst the primary diamond deposits, are defined as => 70 m carats at =>95% gem quality. There is only one mega-placer known and that is found along the coast of southwestern Africa fringing the Kaapvaal craton. Placers are classified as residual when they are left on the craton, transient when being eroded into the exit drainage and terminal. Terminal placers, in being the final depositories of diamonds off the craton, have the greatest probability of being a mega-placer and such is the case in the placer deposits near the Orange River mouth, southwestern Africa. There are four main groups of conditions leading to the development of a mega-placer: the craton, the drainage, the nature of the environment at the terminus and the timing. The craton, in its role as the producer of diamonds is significant in respect to its size, diamond-fertility, the degree to which diamonds from successive kimberlite intrusions have been retained there and their availability to the final drainage yielding the mega-placer. Cratons in being buoyant have a tendency to leak diamonds into surrounding basins but in being incompressible often have orogens converge onto them resulting in lost sediment being returned as foreland basin fills. In order to concentrate a bulk of diamonds the drainage basin has to be large with a high proportion of it on the craton. The drainage yielding the mega-placer should ideally not have been preceded by older drainage and other systems that may have robbed the craton of earlier diamonds. The exits of diamonds from the craton need to be few in order to focus on their supply and the drainage network needs to be efficient in order to remove the maximum volume of diamonds off the craton. This efficiency and the focused termination is best achieved by the rejuvenation of a pre-existing drainage network. The drainage should be young enough to yield host sediments friable enough to allow brittle diamonds to be recovered from them.

Jan 1, 2004

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 Marco Figoni

The increased interest on deep water minerals resources is a challenge for both mining and oil industry. The exploration and production of oceans minerals require a synergy between of different technologies. While mining industry is leading the dredging and processing part of the system, oil industry is contributing through development of ore lifting technology based on existing subsea knowledge. The paper presents an overview, based on published projects around the world, of different approaches to marine mining. Several exploration techniques and offshore production systems were already designed and assessed, all of them with apparently positive results. Exploration phase is well advanced and in continuous expansion allowing the discovery of increasing resources around the world of different nature but production can be considered to be in an early stage. Different from onshore mining, subsea operations require a closer cooperation with international and local authorities to preserve as much as possible the environment. There are still many uncertainties at respect and all the exploration process must be carefully evaluated to allow subsea mining to develop in a sustainable manner. Technically, mining at seabed was already demonstrated and the process is based on three main components, namely seafloor mining tools, riser and lifting system and production vessel support. This layout is based on the concept that ore must be disaggregated at seafloor first, transported to surface in form of slurry that must be dewatered before loading to be transported to processing plants onshore. The challenges are rising because the environment and safety must be taken into consideration as a priority when evaluating the efficiency of the system. The most critical challenges regarding the production operations, especially in deep water are the deep-sea excavation process, the transport of large slurry volumes, the slurry abrasivity, the power supply management and the subsea

Sep 14, 2011

By Hunsoo Choi

Internal textures of manganese nodules from Clarion-Clipperton zone of northeastern Pacific Ocean are classified into five textural zones: columnar-textured layered zone, cuspate-textured layered zone, cuspate-textured massive zone, cuspate-textured porous zone and massive- textured massive zone. Vernadite is the main constituent mineral in the columnar- and cuspate-textured layered zone. Buserite sometimes occurs in the cuspate-textured layered zone. The cuspate-textured massive zone is mainly composed of buserite. Todorokite is also associated with buserite in the massive-textured porous zone, where cuspates and globes are partially replaced by massive texture. In the massive-textured massive zone, todorokite, buserite and birnessite occur together. The analyzed elements of all zones are also classified into four elemental groups by the cluster analysis of correlation coefficients: Mn group, Cu-Ni-Mg group, Fe group and Si group. Mn group consists of Mn and K. Cu-Ni-Mg group consists of Cu, Ni, Zn, Mg and/or Ca, Na. Fe group consists of Fe, Co, Ti and/or Ca, P. Si group consists of Si and Al. Each textural zone is composed of three or four elemental groups. These four elemental groups are correlated with mineral composition, such as, Mn group with todorokite, Cu-Ni-Mg group with buserite, Fe group with Co-bearing iron-oxyhydroxide minerals, and Si group with silicates.

Jan 1, 2002

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. Cronan

Both the S.W. Pacific and Caribbean island arcs are host to submarine hydrothermal mineral deposits, the former more so than the latter. In the S.W. Pacific, the whole gamut of such deposits occurs on the sea floor, sulphides, silicates, Fe and Mn oxides, whereas during the limited studies to date in the Caribbean only hydrothermal Mn oxides have been found to occur on the sea floor there in any abundance. Comparisons between the respective Mn oxides are thus the most fruitful at the present limited stage of our knowledge of Caribbean submarine hydrothermalism. Southwest Pacific hydrothermal ferromanganese oxides and their possible relationships to underlying sulphide mineralisation or bedrock anomalies (the geochemical window concept) has been a fruitful field of research in recent years. Certain element enrichments in crusts may be indicative of underlying mineralisation (Rogers et al. 2001). However, more recent studies on buried hydrothermal crusts in the S.W. Pacific (Cronan et al. 2002) have shown there to have been postdepositional diagenetic uptake of elements in them, and thus these elements cannot be used with any confidence in geochemical exploration for buried sulphide deposits unless sediment involvement can be eliminated.

Jan 1, 2002

By Steve Potter

"REVIEW OF ISA's DRAFT EXPLOITATION REGULATIONS – HAVE KEY STAKEHOLDERS' CONCERNS BEEN ADDRESSED ADEQUATELY?In early August 2017, the ISA published a revised draft of the exploitation regulations. My presentation will focus on the extent to which key State and Contractor issues raised in formal submissions in November 2016 have been addressed in the revised draft and any additional key issues in the revised draft which are likely to cause significant concern for Contractors.ABSTRACTFollowing the ISA's call for submissions in response to draft zero of the exploitation regulations in July 2016, 43 responses from stakeholders were received by the ISA in November 2016. My presentation will start by briefly looking at how the ISA has continued to engage with stakeholders following the publication of draft zero of the exploitation regulations, including at payment regime workshops in London (November 2016) and Singapore (April 2017) and at the environmental workshop held in Berlin in March 2017. It will also touch on the publication in February 2017 of what was in effect a very preliminary draft of the environmental regulations before moving on to consider in detail the extent to which key State and Contractor issues have been addressed in the ISA revised draft exploitation regulations which were published in August 2017. My review of the formal submissions will include, amongst other things, commentary on:(i) the level of Stakeholder response (State Parties to UNCLOS, Sponsoring States, Privately owned Contractors, State Owned Contractors and NGOs);(ii) the quality of the submissions (particularly by States and Contractors); (iii) the key concerns raised by State and Contractor stakeholders and how those issues have been addressed in the revised draft exploitation regulations; and(iv) how all stakeholders need to further engage with the ISA to ensure that the exploitation code adequately addresses the legitimate and reasonable concerns of each Stakeholder group (e.g. Contractors, Sponsoring States, Developing States and NGOs)."

Jan 1, 2017

By Bjørn Eske Sørensen, Kristian Drivenes, Przemyslaw Kowalczuk, Kurt Aasly, Gavyn Rollinson, Ben Snook

Efficient and successful mineral processing is dependent on detailed knowledge of the materials and minerals that are to be separated and concentrated. Common bulk methodologies such as XRD and XRF are fast and easy, and can provide an overview of the mineralogy and bulk chemistry of the material. However, they will not provide any textural information. Knowledge of the often intricate interaction between minerals in seafloor massive sulfide deposits is crucial in plant design for mineral processing. Samples from the Loki’s Castle hydrothermal vent have been characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), optical microscopy, Scanning Electron Microscopy (SEM), QEMSCAN, Electron probe microanalyzer (EPMA), and Electron Backscatter Diffraction (EBSD). Processing experiments used froth flotation and leaching techniques. The typical line of operation in ore characterization is shown in Figure 1. Mineral processing may be commenced after any stage of ore characterization. However, it is ideal to have completed as many steps in the ore characterization as possible in order to have the most information of the initial feed material. The main economic minerals in the samples are isocubanite (CuFe2S3), chalcopyrite (CuFeS2), and sphalerite (ZnS), with minor galena (PbS) and trace amounts of Au and Ag. The minerals show complex intergrowth textures down to the nanometer scale. These samples exemplify the need for advanced microtextural analyses to adequately characterize ore material prior to processing. The complex textures hamper the use of flotation as an efficient technique, due to the inability to sufficiently liberate the different minerals and problems with selectively floating isocubanite. Thus, leaching was the preferred method for extracting metals.

Jan 1, 2018

By Winston Rocher Anda

Traditionally, mining activities have been developed in firm land, but technological advances and human needs have opened in the last year?s new opportunities in the maritime field. This has happened not only in the oil or hydrocarbons industries, but also in relation to the exploration or exploitation of other minerals, metallic and non-metallic. This has forced several countries to complement or create legal rules that make possible its own development and the International Law, through the United Nations Convention on the Law of the Sea, to regulate this activity in the space of its own, the calling area. Chile, as country with a long experience in mining and great advances in large deposits exploitation, possesses a special juridical frame that regulates this economic activity according if it is the geographical or territorial area in which is realizes, and it has been complemented lately with the international normative.

Jan 1, 2011

By Yannick C. Beaudoin

Southern Explorer Ridge (SER) is an anomalously shallow, intermediate-rate spreading ridge located 200 kilometers off the west coast of Vancouver Island, Canada. It ranges in depth between 2600 m (deepest basins) and 1760 m (bathymetric minimum). At least 60 sulfide deposits are known to be associated with hydrothermal vent fields along the ridge. For the first time geological data, including deposit locations, collected from 15 marine expeditions to SER since 1983 have been assembled in a GIS format. GIS processing techniques were employed to plot the distribution of base metal concentrations for recovered sulfide samples. The highest base metal concentrations are found in the vicinity of the Magic Mountain site (main active vent field), and also proximal to a side scan sonar anomaly referred to as AGOR 171. Individual samples near these locations have yielded values as high as 29.3 wt\% Cu, 34.3 wt\% zinc, 0.97 wt\% Pb, 2.0 ppm gold, and 664 ppm silver. Sample paucity is the key limiting factor that prevents adequate assessment of the areas economic potential.

Jan 1, 2001

By Philomene Verlaan

This study examines the possible relationships between compositional variability in non-hydrothermal manganese nodules and large-scale environmental parameters. In the central SW Pacific (145-180° W and 20-O° S) the level of primary productivity, the rates and proportions of carbonate, silica and organic matter supply to the sediments, and the position of the seafloor relative to the Calcium Carbonate Compensation Depth (CCD) appear to directly influence nodule composition. Four zones of nodule composition are apparent. These zones correlate fairly well with the level of primary productivity in surface waters, as estimated by satellite-based measurement of chlorophyll content. The observed correlations between surface productivity and nodule composition are consistent with the contention that the dominant source of several transition metals in these deposits (i.e , Mn, Ni, Cu. and Zn) is provided by removal of fine-grained particulate matter from the water column by biological means. Subsequent decay of organic matter in sediments augments the content of these metals in the nodules through oxic and sub-oxic diagenesis. The opposite behavior of Fe and Co content may in part result from mineralogical and dilution effects.

Jan 1, 2000

By Øystein Sture, Kurt Aasly, Ben Snook, Sigurd A. Sørum

INTRODUCTION Efficient exploration methodologies for base metal deposits have huge benefits for future deep sea mining endeavours, and underwater hyperspectral imaging (UHI) has been variably demonstrated to have applications in the identification and characterisation of mineralisation on the seafloor for both nodules and seafloor massive sulphides (SMS) (Dumke et al., 2018 and 2017 respectively). Due to growing resource requirements (Singer, 2017), SMS deposits are considered to be increasingly significant sources of copper and zinc, as well as silver and gold. This style of mineralisation is currently occurring at active hydrothermal vents (black and white smokers) but now-inactive sites also have the potential to be large mineral deposits. As such, the development of novel methodologies to detect both on-going and extinct mineralisations are of high importance. Geological setting During the MarMine cruise (Ludvigsen et al., 2016), non-mineralised host rock, low grade ore and high grade ore grab samples (Snook et al., 2018) was collected by ROV from the Loki’s Castle deposit (Pedersen et al., 2010), located on the Mohn’s/Knipovich junction on the ultra-slow spreading Arctic Mid-Ocean Ridge (AMOR), at a depth of approximately 2300 m. This material has been characterised as part of the MarMine project (e.g. Snook et al., 2017), and, by imaging compositionally constrained material, the measured hyperspectral responses can be used to generate a library for identification of deposits on the ocean floor. UHI technology Remote sensing with hyperspectral and multispectral technologies has seen wide use in prospecting for ores and hydrocarbons on land (Van der Meer et al., 2012). Iron oxides and sulphides have low blue reflectance and high red reflectance in the visible spectrum. The ratio between these two pairs has been used in exploration for terrestrial deposits of hydrothermal origin (Sabins, 1999). This discrimination typically also includes wavelengths exceeding the visible spectrum (1.5µm – 2.5µm). These wavelengths are typically not utilised underwater because infrared wavelengths and higher are rapidly attenuated in water. However, discrimination based on the full shape of the spectral response in the visible light (350nm – 800nm) may still be possible (Bolin and Moon, 2003). Resolving the endmembers from the spectral responses requires prior knowledge about the optical properties of the materials, i.e. their reflectance. These reflectances can be obtained in a controlled environment, where the spectra of the lamps, wavelength- dependent attenuation in water and scattering of light can be accounted for (Johnsen, 2013).

Jan 1, 2018

By Seung-Kyu Son

This study was investigated about physico-chemical parameter such as water temperature, salinity, inorganic nutrients and total organic carbon (TOC). CTD (Model: Sea-Bird 911 Plus) castings were carried out on two transects in the northeast equatorial Pacific Ocean. As a part of the Korea Deep-sea Environment Study (KODES), inorganic nutrients and TOC were determined at 41 stations located from 131° to 136°W along 10.5°N and from 17° to 5°N along 131.5°W (Fig. 1). We particularly chose KODES Long-term Monitoring Station (St. KOMO) to observe for the annually environmental baseline study in the contract area. [ ]

Jan 1, 2005

By J. C. Wiltshire

Both ferromanganese crusts and nodules present potential processors with enormous volumes of tailings of dubious environmental character: most processing scenarios fail to utilize the uneconomic manganese itself, leaving a total waste volume on the order of 96% of the incoming ore. Each current disposal proposal seems flawed: (1) backhauling to the initial mine site is costly and might run afoul of EPA or UN marine dumping*regulations, (2) subsea disposal near a coastal processing site means almost inevitable community opposition, (3) agricultural soil amendment for improving barren lava or coral rubble appears to require prohibitive amounts of supplementary phosphate, and (4) the slag resulting from an energy intensive pyrometallurgical processing may have potential as road ballast, but few processors will opt for smelting in all but those locales where energy is very cheap. This unfortunately rules out a smelting operation in almost any Pacific Island environment. We envision at least one other scenario which could result in both the removal of tailings from a processing plant and an increase in the supply of useful building materials at little or no cost to either the processing or construction industries--transforming a tenacious waste into a novel resource. Ongoing experiments have demonstrated considerable potential for turning acid leach tailings into dark composite facing stone, fancy black tile, novelty ceramics or concrete aggregate. The tailings are commonly very fine grained and may also serve as an additive in drilling mud. Applications as an additive to asphalt also need to be explored. The metal scavenging nature of ferromanganese minerals should be considered as a radioactive waste disposal matrix. There is no doubt that the greatest challenge will be

Jan 1, 1991

By W. H. Pelton

Polymetallic sulphide (PMS) deposits have recently been discovered associated with hydrothermal vents on the sea floor off Vancouver Island, B.C. Visual estimates indicate reserves in excess of 1 million tons. Reliable reserve estimates have not yet been made, however, due to the extreme difficulty of drilling cores in 2 km of water. Few geophysical techniques can aid in the exploration of these deposits. There is little or no difference in radioactivity, magnetic susceptibility or electrical resistivity between the deposits and the surrounding sea floor sediments. This precludes radiometric, magnetic, electromagnetic and resistivity methods. There is a density contrast, but the logistics of gravity surveys at such depths are formidable. The physical property which shows the most contrast with the sea floor sediments, and which is perhaps one of the easiest to measure (with modern equipment) is polarizability. The induced polarization (IP) method is one of the major electrical geophysical techniques for exploring for PMS deposits on land.

Jan 1, 1985

By Alexander Malahoff

With its new continental shelf beyond the exclusive economic zone, New Zealand is a country with just 4% of its territory above water. The other 96% is submerged. New Zealand's marine territory covers an area about three-quarters the size of Australia. This territory includes large portions of the Gondwana continent from which NZ separated more than 80 million years ago. This underwater land mass extends from the shores of New Zealand to a water depth of more than 5,000 m, is largely unexplored and is almost certainly the site of many large, untapped oil, gas and mineral deposits. Underwater oil and gas drilling is now a universal activity. Underwater mining is in its infancy and will become a major activity in the future, contributing greatly to the New Zealand economy. New hydrocarbon deposits will undoubtedly be discovered under the ocean floor in regions such as the Great South Basin located off Canterbury and Otago. Mineral deposits are also undoubtedly located within the oceanic crust of this underwater NZ continent. These are as yet unknown and unexplored. The oceanic crust north of the North Island is currently being extended through the subduction of the Pacific plate into the Tonga Kermadec trench and through the growth of a line of submarine volcanoes extending north to Tonga. Active submarine volcanism has led to the growth of ocean floor mineral deposits consisting of polymetallic sulphides with iron, copper, zinc and lesser gold, silver and other metals.

Jan 1, 2011

By Tracy Shimmield

Deep sea tailings placement (DSTP) techniques have been pioneered in Papua New Guinea (PNG): a mining reliant economy in a seismically active region, facing major environmental challenges in the safe handling and storage of mine tailings on land. Scientists at SAMS have researched impacts of DSTP on the marine environment specifically to inform and develop guidelines for the use of DSTP to reduce environmental impact, thereby lowering risk and increasing private sector investment. Guidelines have been established as regulation by the PNG Government providing reassurance to private investors, facilitating an increase in mining exports to 60% of total export. Researchers investigated the effects of DSTP at 2 PNG mines: Lihir Gold Mine which has been actively discharging tailings since 1996 and Misima Mine, closed in 2004 after discharging tailings for 15 years, allowing an assessment of the recovery of the marine environment after tailings placement. Research involved investigating ocean currents and mixing, the behaviour of metals and the effect of tailings on benthic communities including the risk of elevated metal contents entering the food chain. The research established a metal ?fingerprint? of tailings compared to natural sediments, which enabled the transport of fine tailings within the deep ocean to be ascertained.

Sep 14, 2011

By Makoto Yuasa, Akira Usui, Shipboard Scientists of SIP Cruises, Atsushi Suzuki, Shingo Kato, Kyoko Yamaoka, Akira Nishimura, Kiyo Kisimoto, Katsuhiko Suzuki

"We report here on current topics of our project, based on the results of recent cruises and laboratory analysis, about the diversity of compositions and configurations of the hydrogenetic ferromanganese deposits in several Northwestern Pacific Seamounts. This recent research has discovered important aspects of these deposits regarding the mode of variation with water depth, topography and substrate geology, possible bacterial mediation, temporal variation with age in mineralogy, and major and minor element chemistry. All cruises and analysis have been supported by the facilities and staff of the Japan Agency of Marine-Earth Science and Technology (JAMSTEC), Japan Oil, Gas, and Metal resources Corporation (JOGMEC), Geological Survey of Japan, and Kochi Core Center (KCC) using a remotely operated vehicle (ROV), a monitored rock drilling system, dredges, and manned-submersibles in the NW Pacific seamounts,The results indicate that most of the rock outcrops on the slopes, shoulders, and much of flat tops are covered with maximum 10-cm thick crusts, but the thickness, metal content, and microstructural properties are not always uniform over the seamounts, but variable in space and time. The micro-stratigraphic description of whole-rock samples indicates a history of deposition and sedimentation, which control the diversity in bulk composition and abundance caused by the variable incorporation of iron-manganese precipitates into the deposits during variable environmental conditions. We conclude that hydrogenetic precipitation of iron-manganese oxide has taken place for more than 20 million years at a growth rate about 4-6 mm/my, in water depths below 1000m. The results indicate a fairly continuous and constant metal deposition since the middle Miocene age or older to the present. Our case study of geological sciences at a model seamount within the Japanese EEZ suggests that scientific knowledge is useful and essential in exploring mineral deposits, economic estimation, and designing systems, if supported by well-combined geological and oceanographic and biological research. The distribution map of ferromanganese deposits and geological map will be published soon in 2017 to be issued by the Geological Survey of Japan."

Jan 1, 2017