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By Caleen E. Kilby

A program of surveying and studying the surficial sediments of northern Juan de Fuca Strait was undertaken between 1988 and 199 1. Detrital sediments were mapped from the intertidal zone down to 100 m depth along the slopes of a series of shallow coastal marine terraces. The sand heavy mineral content was examined over this region and sediment geochemistry and assays were performed on selected samples both offshore and from beaches along the coast. The coastline of southwestern Vancouver Island has numerous streams, with a history of small Au placer extraction, which empty into the strait to the south. Only very minor evidence of this was seen in values from isolated locales. However, one beach presented a remarkably different mineralogy and geochemistry from the remainder of the coastline. From the beach to 800 meters offshore heavy mineral contents were greatly elevated and Ti values were as high as 1.4% of the sand fraction. Minerals were relatively fresh and angular, with mineral percents distinctly different than those found elsewhere along this coastline. No stream of substantial size crosses this largely sandy-gravel beach. A series of studies identified the source of this small marine placer as having its origins n the tailings from a submarine pipe broken short in the next bay. A Cu-Au mine 1.5 km upstream, closed by the mid 1970's, had processed its ore underground and piped the crushed tailings to the submarine discharge pipe. The crushed material has been transported and concentrated with the longshore current and been sorted by strong coastal swells. Ilmenite/titanomagnetite from the homblendized basalt of the mine is the source of the Ti enrichment.

Jan 1, 1994

By Robert G. Ditchburn

The NW caldera hydrothermal vent field at Brothers volcano, of the Kermadec-Tonga arc, has associated massive sulfide mineralization. This includes an abundance of black smoker chimneys that contain significant concentrations of copper, lead, zinc and gold (de Ronde et al., 2005; de Ronde et al, 2010, under review). [ ] The oldest volcanic massive sulphide (VMS) samples recovered so far from Brothers have been dated using radiometric methods at GNS Science and found to be c. 1000 years old. By contrast, a volcanic cone that has formed in the southern part of the caldera has no associated VMS. Only elemental sulphur and Fe-oxide crusts are present here, samples of which have been analysed for their trace elements. From d34S values of sulfates and native sulfur, and the volume of gas (dominated by CO2 and H2S) discharging at the cone site, elements being deposited here are considered more directly magmatic in origin (de Ronde et al., 2005; 2010 under review). It has been discovered that deep-seated changes in volcanic activity at Brothers affect the NW caldera and cone site simultaneously, though the mineralogy at each site is so very different. Thus, the cone site is being studied to determine if elements being deposited there can be used as predictors of potential future VMS mineralisation as similar sites have been found at other volcanoes along the Kermadec arc and elsewhere. The frequency of these deep-seated magmatic events is considered important in the formation of Cu-Au-rich mineralization along arcs. The analysis of Fe within resulting hydrothermal plumes (surveyed by surface vessels), and trace elements in rock and mineral samples, are used to help determine the influence of magmatic contributions to the hydrothermal system. To verify that plumes are a reliable proxy for hydrothermal events depositing iron on the seafloor, Fe-oxide crusts from Brothers volcano cone have been dated to see if their emplacement coincides with highly Fe-enriched plumes in the water column. The radiometric dating techniques developed for barite-rich VMS, i.e. using 228Ra and 226Ra, were unsuitable for the Fe-oxide crusts because 210Pb was the only isotope detected by gamma spectrometry. Therefore, new techniques using 210Pb, 10Be and arsenic have been established.

Jan 1, 2010

By Andreas Kaede

INTRODUCTION Due both to the political history of UNCLOS and the sensitivity of the ocean floor and environment to man made impacts, both the Convention (including also the 1994 Amendment) and subsequent codification (such as the ISA draft code on Exploitation of Mineral Resources in the Area) put a focus on information about, and conveyance of, technology employed by interested deepsea mining companies, to inter alia the Authority and developing countries. In contrast, companies usually are (or by their nature should be) interested in safeguarding their technology and business secrets in order to secure unique selling propositions in a competitive environment. On the background of the meanwhile maturing regulatory régimes on deep sea mining, the presentation will look into some of the key regulatory provisions mirroring these apparently antagonistic interests, how the players involved could deal with them, and how they might in some cases be reconciled. Progress of Presentation The presentation will start by briefly examining some classical methods of protection of technology, such as patents, copyrights, and (not the least) secrecy. It will be found that some of the statutory means of protection due to their territorial character may face problems in being implemented in areas outside national jurisdiction, such as the Area, but that, thinking globally, they nevertheless retain much of their value for the purpose of protection. Depending on available presentation time, a model case may be used to illustrate the above – and also some of the following – findings.

Jan 1, 2018

By Richard Mills

Autonomous Underwater Vehicles (AUVs) are proven technologies used across market segments for survey, exploration and environmental monitoring tasks. When coupled with other autonomous platforms or sensor packages AUVs become part of an holistic system approach to exploration and environmental assessment and monitoring. Recent developments have seen AUVs deployed remotely with instantaneous access to data via the cloud. Our goal is to deliver the capabilities of each of these elements and present a cohesive data set with automated processing tools over a cloud based interface. nmanned Technology AUVs The HUGIN AUV System is the most commercially successful AUV ever built. Operated as a single vehicle, or as part of a swarm, HUGIN’s area coverage rate is unrivalled. Equipped with a comprehensive sensor package including Kongsberg’s synthetic aperture sonar, it collects a data set. Some of these data are processed in-mission to enable operators to readily access it when the vehicle is recovered. HUGIN is well suited to mining survey and exploration. Capable of reaching 6000 metre depths and conducting missions greater than 60 hours, HUGIN collects seabed sonar imagery, sub-bottom profiles, laser and camera images plus environmental data, with sensors running concurrently.

Jan 1, 2018

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 Tetsuo Yamazaki

Manganese nodules, seafloor massive sulfides, and cobalt-rich manganese crusts in deep-sea areas have been considered as future metal sources (Mero, 1965; Halbach, 1982; Lenoble, 2000). Manganese nodules were the first recognized deep-sea mineral resource and many efforts concentrated on the R&D of mining systems (Welling, 1981; Herrouin et al., 1989; Yamada and Yamazaki, 1998) and assessment of environmental impacts (Burns et al., 1980; Foell et al., 1990; Yamazaki and Kajitani, 1999). No mining venture, however, has been active for this potential resource. The reason is that the rate of world economic growth has been slower than anticipated in 1960s. During the 10 year period of 1994-2003 (Fig. 1), on the other hand, there was about a 33% increase in the world copper demand. Of that increase, about 60% was consumed by China. Most of China?s increased copper demand took place over the final 4-5 years of that period. The growth is expected to continue for several years, and in 10 years or sooner the same situation is expected for India. Copper is the third metal in global demand, but its small abundance in the Earth?s crust is not well recognized (Table 1). From the production rate and the abundance, a copper shortage, or crisis, has a high probability than the other metals. Japan has no domestic copper resources and needs a counter measure for this potential coming copper shortage. Fortunately, Japan has a manganese nodule mining claim in the Clarion-Clipperton nodule field, Kuroko-type massive seafloor sulfide deposits in the Okinawa Trough and Izu-Ogasawara areas, and cobalt-rich manganese crusts around Okinotori-Shima and Marcus Islands. We need to re-evaluate their potential as copper resources and to realize their development.

Jan 1, 2005

By J. Bruce Gemmell

ODP Leg 158 drilled seventeen holes into the active TAG hydrothermal mound and underlying stockwork, 26°N, Mid-Atlantic Ridge. Drilling in five different areas, including a high-temperature black smoker complex and a lower-temperature white smoker vent field, revealed the multi-stage depositional history and character of sub-seafloor mineralization and alteration. The upper portion of the mound consist of massive pyrite and pyrite breccias which are underlain by pyrite-anhydrite breccias and then by quartz-pyrite breccias. Quartz-pyrite breccias grade down into silicified wallrock breccias. Chloritised basalt breccias occur at depths greater than 100 m. Several stages of quartz-pyrite±chalcopyrite veins occur in the stockwork zone and lower portions of the mound, whereas anhydrite±pyrite±chalcopyrite veins occur within the upper parts of the mound. Recovery of unaltered basalt near the edges of the mound has constrained the extent of the stockwork zone to a pipe-like feature 80 meters in diameter. A detailed sulfur isotope investigation of sulfides and sulfates within mound and the underlying stockwork zone has revealed the overall range of sulfide d34S analyses to be 0.35% to 10.27%. Anhydrite has a tight range of d34S values 20.55% to 21.56%. There are distinct differences in d34S values between the different textural types of pyrite (massive sulfide, breccia clasts, disseminations associated with alteration, and veins). The massive sulfide and breccia clasts have a similar distribution of d34S values (6%-8%), however the d34S values of the disseminated pyrite associated with the alteration are distinctly heavier (8%-10%). Vein sulfides have the lightest d34S values (5%-7%). Sulphur-isotope values at TAG are, in general, the heaviest reported for unsedimented mid-ocean ridge deposits.

Jan 1, 1998

By V. K. Banakar

The occurrence of hydrogenous ferromanganese encrustations (Fe-Mn crusts) on the Cretaceous age Afanasiy-Nikitin Seamounts (ANS) in the eastern Equatorial Indian Ocean (EEIO) was first reported by Banakar et al. (1997, Marine Geology). The major element composition of the samples from the upper flank of the ANS (~1650 m water depth) indicated enrichment of Co up to 0.9 % (Parthiban and Banakar, 1999, Indian Mineralogist). Subsequently a project supported by the Department of Ocean Development to explore the ANS for Co-enriched Fe-Mn crusts was launched in 2002 by the National Institute of Oceanography. Sampling at regular depth intervals along two transects on the slopes of the northern elevated region of the ANS was carried out. The Fe-Mn oxide deposition is evident on almost all types of substrates viz., basalts, conglomerate limestone, fossil corals etc., and the thickness of the oxide layer varies from a patina to 7 cm. The Fe-Mn crust growth is evident only above a water depth of 3200 m, below which semi-lithified carbonate ooze is dominant. The ANS Fe-Mn crusts from all the water depths exhibit Mn/Fe < 1.5 suggesting pure hydrogenetic accumulation of metal-hydroxides. Bulk sample Ce-contents for a few selected depth-representative samples are remarkably high, up to 3700 ppm with an average of ~2500 ppm. The positive Ce-anomaly decreases from ~8 at 1600 m depth to ~1.6 at 3200 m depth, which is in contrast to the modern dissolved oxygen depth-profile in the region. This observation suggests that major time-period of the Fe-Mn crust accretion history is dominated by ambient waters with lower-oxygen at deeper depths than at the intermediate depths. This in turn probably suggests a major reorganization in the deep-intermediate hydrography of the region in the past.

Jan 1, 2005

By Carl H. Hobbs

The needs of the on-going basic maintenance operations and proposed enhancement and hurricane protection projects in the City of Virginia Beach exceed the capability land-slide sources of sand. Through the past several years our studies have concentrated on locating and defining suitable quantities of sand appropriate for use on the area&apos;s beaches and assessing some of the consequences of dredging in shallow offshore areas. By providing information concerning the geological setting of sand resources, the local wave climate, and benthic infauna, the overall research project has strengthened the knowledge and understanding of several facets of Virginia&apos;s inner continental shelf. We have identified three distinct settings for deposits of beach-quality sand, two of which (filled channels and surficial shoals) are distinguishable in relatively unprocessed sub-bottom profiles and cores. The third, a sand facies within a larger stratum, is discernable only with a suite of cores. Sandbridge Shoal, about 5 km offshore of the resort and residential community of Sandbridge appears to contain a substantial quantity of sand that could be exploited with comparatively few problems. It already is designated as the source of material for use in a shoreline protection protect for a federal facility. Fluvial(?) fill of a late Pleistocene channel lust offshore of the main, commercial, resort area may offer a proximal alternative to existing and proposed resources. Ongoing work to describe the local wave climate and the possible impacts of anthropogenic alterations of the bottom topography on wave transformation and studies of the biological community as it might be affected by dredging will help fill-out our series of studies. Prior to utilization of the resource additional work is needed to provide better definition of the limits and magnitude of the sand bodies. Finally decisions concerning the use of specific resources will have to include physical, biological, economic, technical, and social considerations.

Jan 1, 1996

By David M. Holmes-Smith

Many attempts have been made to design and build an AUV that is small, meets the sensing objectives and is cost effective. Many inventors have already designed smaller vehicles but the problem observed is an increased vehicle instability resulting in instrument instability where data gathered is not trustworthy. Additional problems include instrument weight to vehicle weight ratios and the lack of space for power storage and electrical components. The UFOceanic seeks to remedy these concerns by employing a completely different design and propulsion system. Still in the design stage ? now with a mock-up unit for testing, the results are encouraging. We have chosen a very low voltage embedded systems design using multiple PIC processors and fuzzy logic programming. We are designing the craft to rotate for stability and to provide friction reduction to minimize the need for instrument stability compensation and propulsion power. Additionally, we are looking and experimenting with a number of power plant drive systems including flywheels, GNP (plasma), fuel cells and more conventional systems. We of course plan for the UFOceanic to run for months at a time supported by a self-charging system.

Jan 1, 2001

By Nicholas Dyriw, Georgy Cherkashov, Tamara Stepanova, John Parianos, Anna Firstova

"Seafloor massive sulfide (SMS) deposits are a new frontier in global metal resources. Hydrothermal chimney’s (black smokers) precipitate Cu, Zn, Ag and Au rich from hot fluids (>250°C) during interaction with cold seawater ~2-4°C. Here we compare the sulfide mineralogy and geochemistry of Cu-sulfide chimney samples from two different tectonic locations: Solwara 1, a Cu-rich, transitional arc-back arc (Arc-BA) type SMS ore deposit and; Ashadze-1, a Cu-rich, ocean ridge type SMS deposit (Hannington et al., 2011).This work represents the first stage of a project aimed at investigating and understanding the significance of high Cu concentrations in SMS systems. Comparing these particular systems is significant because they share critical similarities despite being located at different seafloor depths, hosted in different rocks and are located in two different endmember tectonic environments. Critical similarities include: 1) age of mineralization, ~6000 years to current (Firstova et al., 2016; Johns et al., 2014); and 2) high copper contents, with chalcopyrite dominating sulfide mineralization (Firstova et al., 2016; Lipton, 2012). The reason for high Cu concentrations in both of these locations is still not entirely understood. The youthfulness (<6000y to current) of both locations is important because it reduces the possibility of increased zone refining, allowing us to understand the source characteristics better. This research will advance our understanding of the copper systematics of SMS systems by investigating and comparing the mineralogical and geochemical signatures from two, Cu-rich, end-member type SMS sites."

Jan 1, 2017

By Henk van Muijen

From an interesting and intriguing scientific research topic, deep sea mining has altered into an interesting mining prospect over the last years. Ten years ago most of the focus was on geological investigations, searching for typical deep sea deposits and getting answers on where we can find them and how these deposits were formed. At this moment we know much more about the interesting deposit possibilities and with our quest for minerals, metals and other materials to feed global economic growth, answers as to the technical and economic feasibility to mine these deposits are sought. This is not a new phenomenon as we already witnessed such question late 1970?s and early 1980?s. Most of the focus was on mining manganese nodules and brines in the Red Sea driven by the report of the Club of Rome that predicted shortages in near future at that time. Development went different, but later in the 1990?s a rival of interest could be noticed for mining deep sea deposits.

Jan 1, 2010

By G. A. Tret’yakov, V. A. Simonov, I. Yu. Melekestseva, V. V. Zaykov, N. N. Ankusheva

The Kyzyl-Tashtyg massive sulfide polymetallic deposit is situated 120 km north-east of Kyzyl (the capital of Tuva Republic, Russia). It is located in the Ulug-O volcanic zone which is interpreted as the northern segment of the Kaa-Khem rift in Sayano-Tuva marginal sea, one of the Paleoasian Ocean margin (Fig. 1) [Zaykov, 2006]. Since its discovery in 1946 the deposit has been studied by many researchers. Significant information was published by Kuzebny et al. [2001] and Zaykov [2006] who proposed volcanogenic-sedimentary genesis. A single reference in English about Kyzyl-Tashtyg is available [Herrington et al., 1999].

By Chuanshun Li, Haitao Zhang, Xuefa Shi, Quanshu Yan, Zhiwei Zhu

In Expeditions 22 and 26 of China Ocean Survey (COS), Chinese and Russian scientists have Carried out a lot of work to search for hydrothermal sulfide in Southern Mid-Atlantic ridge (SMAR) 19°S, but come back empty-handed at last. The sulfide formation is closely related with the water-rock reactions which are controlled by the heat source. Melt inclusions are considered to have a unique compositions in melt to reflect the deep magma processes. Fortunately, we have found a large number of plagioclase hosted melt inclusions in SMAR19°S MORB. We have done experiments by re-homogenization and re-crystallization of these melt inclusions. During the re-homogenization experiments, the forming and melting processes of the olivine crystal inside the melt inclusions indicate that the homogeneous temperature of melt inclusions is 1190-1200??. During the recrystallization experiments, the different mineral phase assemblages show H2O inside the melt inclusions has hardly ever been loss, in addition Cr element and H2O molecule in SMAR19°S magma are heterogeneity at the time of melt inclusions trapping, and then the re-crystallization experiments provide a method to prove the microheterogeneity of basaltic magma system. Combining with the bulk rock data, this study shows that the melt inclusions are formed at a low-temperature and high-pressure condition. Eventually, this paper speculates that a low temperature heat source generated by a lower mantle potential temperature or/and a thick lithosphere indicated by the melt inclusions that not experienced the H2O loss process are beneath the SMAR19°S. The low temperature heat source transmits its heat to lithosphere through the cooling thermal boundary layer (CTBL), and the thick lithosphere can sufficiently absorb and consume the heat. Under the interaction between the heat source and lithosphere, the residue heat at the infiltration depth of sea water might have been no ability to satisfy the water-rock reactions temperature, therefore, the water-rock reaction should hardly ever appear, so the theoretical reaction zone would not exist beneath the SMAR19°S. Eventually, the interaction between thick lithosphere and the low-temperature heat source should be the dominant factor that makes SMAR19°S area have no condition to form the seafloor sulfide. However, this paper is based on melt inclusions only, in fact, melt inclusions are potential to have melt compositions produced by mineral dissolution, reaction and assimilation, and the volumes of melt inclusions are exceedingly small compared to the overall size of the magmatic systems, therefore, the extrapolation across many orders of magnitude is implicit when applying petrologic information obtained from inclusions to entire magmatic systems. Therefore, there should have other more research to verify the reliability of this conclusion.

Jan 1, 2017

By T. Yamazaki, T. Goto, R. Arai, N. Nakatani

The importance of cobalt-rich manganese crusts on the Pacific seamounts for possible future rare metal sources has been recognized these 30 years. The thin layer-type coverage and the micro-topographic undulation of basement affect not only the excavation efficiency but also the economy of mining venture. Because of these distribution characteristics, no economic feasibility has been recognized through the past economic analyses. On the basis of a recent geological study about seamount rocks, a possibility of by-product substrate recovery for phosphorous supply with cobalt-rich manganese crust mining has been highlighted. In the mining model, the substrate rocks are utilized as phosphates for agricultural and chemical usages. Under some preliminary technical and economic assumptions, the possibility of cobalt-rich manganese crust mining venture is examined. The results show a better economy of the venture including the substrate rock usage for phosphorous supply. Introduction Cobalt-rich Manganese Crusts and the Economic Feasibility Cobalt-rich manganese crusts on the Pacific seamounts received attention as potential sources for strategic metals such as Co, Ni, Cu, and Mn, due to their vast distribution and higher cobalt concentration than manganese nodules (Cronan, 1980; Halbach, 1982; Manheim, 1986). In the earlier stage, the geological distribution characteristics were reported (Cronan, 1984; Clark et al., 1984; Misawa et al., 1987; Pichocki and Hoffert, 1987) and a systematic feasibility of the mining was studied (Hawaii DPED, 1987).

Jan 1, 2018

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 A. Rona

The Mid-Atlantic Ridge in the central North Atlantic and the Gorda Ridge within the U.S. Exclusive Economic Zone off northern California and southern Oregon are yielding new discoveries of seafloor hydrothermal mineralization. The TAG hydrothermal field in the rift valley of the Mid-Atlantic Ridge near 26 degree N, 45 degree W has been a site of international collaborative research since the discovery there of extensive manganese deposits associated with low temperature hydrothermal activity in 1973 as part of the TAG (Trans-Atlantic Geotraverse Project). The first high-temperature hydrothermal activity, massive sulfide deposits and vent biota discovered in the Atlantic were found at the TAG hydrothermal field in 1985. Collaborative dive series with DSV ALVIN in 1990 and in 1991 with the two Russian MIR submersibles in the TAG field have found and sampled large inactive sulfide mounds in addition to the previously known active sulfide mound. The active sulfide mound on the floor of the rift valley is about 250 m in diameter and 40 m high with a concentric zonation of mineral types and flow regimes decreasing in temperature from 365 degree C black smokers at the center to white smokers and diffuse flow toward the margins. The recent dive series in coordination deep-towed instrument surveys have delineated a zone extending about 5 km along the lower east wall of the rift valley of inactive sulfide mounds up to a kilometer in diameter. MIR Mound in this zone consists of a central sulfide zone about 400 m in diameter and 50 m high surrounded by a halo of low-temperature deposits to 200 m wide. Inactive sulfide chimneys contain the first primary, free gold grains found at a hydrothermal site on a mid-ocean ridge (P.A. Rona, Y.A. Bogdanov, E.G. Gurvich, N.A. Rimski-Korsakov, A.M. Sagalevitch and M. D. Hannington, 199 1 EOS, Transactions, American Geophysical Union, 72:470-471 and Journal of Geophysical Research, submitted).

Jan 1, 1992

By Georgy Cherkashov, Tamara Stepanova, Anna Firstova

INTRODUCTION High tellurium contents in the ancient volcanogenic massive sulfides (VMS) and modern seafloor massive sulfides (SMS) have been reported by V.Maslennikov (Maslennikov et al., 2013). However findings of tellurium minerals in SMS are rather rare. The only reported coloradoite and bi-melonite, have been found in massive sulfides from Rainbow hydrothermal field (Fouquet, 2010). Here we present data about Te - minerals in sulfide chimneys of different ages (up to 84.7 kyr - Cherkashov et al., 2010 ) from Semyenov-2 hydrothermal field. The obtained results The Semyenov hydrothermal cluster was discovered and studied in the course of cruises 30 and 32 of R/V Professor Logachev (2007 and 2009) at 13º31´ N, MAR. This area is associated with an oceanic core complex and associated with serpentinized gabbro- peridotites and basalts. Plagiogranites and tonalites have been dredged on seafloor in the Semyenov cluster area (Cherkashov et al., 2013; Pertsev et al., 2012). In total, 25 sulfides samples have been studied. The major and minor mineralogical phases were identified using reflected light microscope. Major element compositions of ore- forming minerals were analyzed on a Hitachi S3400N scanning electron microscope at the Geomodel Center, St. Petersburg State University (St. Petersburg, Russia) with an AzTec Energy 350 (EDX) detector and an INCA 500 (WDX) detector.

Jan 1, 2018

By Jung-Keuk Kang

Recently, the Korean government prepared a strategy for deep seabed mining, which consists of three stages for 20 years until 2010. The first step of the program is focused to conduct deep seabed exploration until 1993. The apparent "hurry-and-spend to catch-up" policy that the Korean government has shown in deep seabed mineral exploration was motivated by an effort to qualify a prerequisite requirement to be a pioneer investor as a developing country under the terms of Resolution II and the New York Understanding. Since 1983, KORDI (Korea Ocean Research and Development Institute) under the auspices of the Korean government has carried out deep seabed mineral exploration. The KORDI had a joint exploration program with USGS from 1989 to 1991 aiming to evaluate the potentiality of manganese nodule in the western part of Clarion-Clipperton Zone as well as that of manganese crusts in the western Pacific. In 1992, Korean government accelerates its program by the confirmation of national policy and the equipment of new built research vessel, Onnuri-Ho. The RIV Onnuri-Ho is about 1400 G/T, which is equipped with various advanced instruments including GPS, multi-beam echosounder (Seabeam 2000), multi-channel seismic system, and MDM system.

Jan 1, 1992

By Matthew Kowalczyk, Steve Bloomer, Peter Kowalczyk

"Mineral deposits found near seafloor hydrothermal venting are of great economic interest. Valuable metals such as gold, copper, zinc, and other polymetallic sulfides are found in appreciable grades in seafloor massive sulfide (SMS) deposits associated with these vents. For mapping these deposits, electromagnetic prospecting is one geophysical method that is very useful because copper/gold rich deposits are highly conductive.Ocean Floor Geophysics (OFG) in 2008 developed the first EM system to successfully map the limits of conductive mineralization in a survey at the Solwara 1 deposit (Kowalczyk, 2008). Since then, towed coincident loop time domain systems have been developed by Waseda University (Nakayama and Saito, 2016) and have successfully detected known mineralization buried at 30m depth. Using a deep tow controlled source electromagnetic (CSEM) array, very clear anomalies have been measured (Murton, 2017) over known mineralization at the TAG field on the mid-Atlantic ridge.In 2014 and 2015, OFG partnered with Fukada Salvage and Marine Co. Ltd. and the Scripps Institution of Oceanography to map methane hydrate deposits off the coast of Japan using a towed controlled source electromagnetic (CSEM) system developed by Scripps. These hydrate deposits are resistive targets, and the Scripps system successfully mapped subsurface electrical resistivity distributions to depths of several 100 metres below the seafloor. OFG is attempting to extend the Scripps CSEM technology to map subsurface conductive SMS deposits to a similar range of depths below the seafloor."

Jan 1, 2017