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By Shinichi Takagawa

The deep sea hydrothermal deposits are one of the most prospecting resources, and various works to develop these mines are now underway. There are also various methods for the pre-site survey of the mines: acoustic survey, electro-magnetic survey, and others. However, as a precise method at the final survey, drilling/coring is indispensable to confirm the three-dimensional distribution and to grasp the dignity of the ores for the final decision of industrialization. This drilling/coring at the final survey is done at many points with distance of 15~25m between each point for on-land deposits. This means that 1km by 1km square area requires (1,000m/25m)2 ~ (1,000m/15m)2 = 1,600 ~ 4,500 holes. The drilling/coring depths will be around 30m or more for the hydrothermal deposits. This depth seems very shallow, but because the stratum is very brittle and is very difficult to core, the average core recovery ratio is around 50%, and 0% core recovery happens very often. Thus, the indispensable work of coring for grasping the dignity of ores is a very difficult work although the coring depth is shallow, and also the required number of holes is enormous. Conventional drilling/coring method on the ocean is to use drillship. However, the cost is very huge. Recently a new technique has come out which is to use remotely controlled drilling machine on seafloor. This machine seems to have a very good performance. However, it is reported that the available inclination of the seafloor where the machine sits on must be less than 15 degrees. The sea floor inclinations of active hydrothermal vents area are usually very steep and slopes of 45 degrees or more are prevailing and it seems very hard to carry out drilling/coring for the machine at these steep slopes, although it is impossible to mine the ore at these areas because the temperature is too high to work there. The inclination of the sea floor at the dead or paused hydrothermal vents area where ore recovery is possible may be not so steep, and the machine may work well. However, the required number of holes is still a very heavy burden. In order to solve these problems, the author proposes a new concept of drilling/coring system operated from a conventional research ship. This concept is still a desk plan, but the author wants to realize this system at any means.

Jan 1, 2011

By Georgy Cherkashov, Livia Ermakova

Active development of the exploration and further exploitation of deep-sea minerals requires special emphasis on the protection of the marine environment. The complexity of this subject lies in the fact that potential impact and effects of future mining activity are not completely known. One of the main sources of potential impact near the seafloor, as it expected, would be a generation of sediment plumes, their dispersion and redeposition of sediment. Meanwhile, their dimensions, rates of dispersion and redeposition are a big issue. Other plumes are expected in the surface layer as a result of discharges of processing waters and particles after sorting on board of mining vessel, and their features are also not clear. At the same time, understanding of these aspects would be crucial for definition of environment impact area, delineation and designation of different types of protected areas (Areas of Particular Environmental Interest, Impact and Preservation Reference Zones) and future assessment of environmental impacts. Attempts to address these issues demonstrated wide variations between the data of field experiments on the one hand and the results of analytical and numerical models on the other. According to in situ measurements, plumes were detected at a distance vary from one to less than 20 km [e.g., Burns et al., 1980; Sharma et al., 2001; Nautilus Minerals, 2008 etc.], whilst some models show results up to 100 km [Rolinski S. et al., 2001] and more. It seemed that results of in-situ experiments are preferable, but they were not many indeed. However, these data were used in different investigations rather widely, but their focus, as far as we know, was not on the matters related directly with plumes.

Jan 1, 2018

By P. A. Rona

The first hydrothermal mineral deposits found at a seafloor spreading center were discovered in the Red Sea by multi-national research vessels between 1963 and 1965. At that time, the deposits were considered a special case related to continental rifting and an early stage of opening of an ocean basin. Since that time, examples of almost all major varieties of volcanic- and sediment-hosted hydrothermal deposits associated with basaltic rocks in the geologic record have been found at present spreading centers. Review of over 100 hydrothermal mineral occurrences presently known at oceanic ridges and rifts indicates that a range of deposit sizes from small to large (> 1 x 106 tonnes) occurs at all seafloor spreading rates. However, larger deposits but fewer per unit length of spreading axis appear to form at slow- than at intermediate- to fast-spreading centers based on available data. Larger deposits are more common in sediment-hosted than in volcanic-hosted settings regardless of spreading rate. A spectrum of hydrothermal deposit varieties (stratiform, stockwork and disseminated sulfides; various forms of sulfate, carbonate, silicate, oxide and hydroxide deposits) occurs in almost all of the tectonic settings. High-intensity, ore-forming, subseafloor, hydrothermal convection systems that conserve heat and mass and concentrate hydrothermal precipitates are extremely localized by anomalous physical and chemical conditions relative to nearly ubiquitous low-intensity hydrothermal activity at and flanking seafloor spreading axes at all spreading rates. Two distinct shapes of volcanic-hosted

Jan 1, 1989

By M. E. Williamson

In September 2005 Williamson & Associates, Inc. delivered the BMS2 remotely operated seafloor coring system to the Japan Oil, Gas & Minerals National Corporation (JOGMEC). During acceptance trials aboard the JOGMEC research vessel R/V Hakurei Maru No. 2 the BMS2 successfully recovered 7.44 m of rock core in 3377 m water at a site near the crest of a seamount about 500 nm SE of Japan. Hydrogenous ferromanganese oxide crust, basaltic lava, sandstone and volcanic sediments were sampled with near 100% core recovery. The BMS uses rotary rod coring tools to collect samples to a maximum depth of 30 m in water depths up to 6000 m. Depending on bottom type to be sampled, the BMS tool magazine can be loaded with various drilling tools including core barrels with different bit types, drill rod and bore hole casing. The drill has 9 video cameras, a suite of sensors and 60 hydraulic functions powering thrusters, telescoping legs, seawater pumps and all of the standard drilling controls. The BMS provides deep water investigations with the functionality of conventional diamond bit rod drilling currently the mainstay of exploration programs in land mining.

Jan 1, 2005

By Malcolm Clark, Robin K. H. Falconer

There are a number of likely impacts from mining operations, but a key issue is uncertainty about the environmental effects of sediment plumes created by disturbance to the seafloor and discharge of processed waters. The New Zealand National Institute of Water and Atmospheric Research (NIWA) is undertaking a research project to improve understanding of such impacts (relevant to both mining and trawl fisheries), by examining the extent and persistence of sediment plumes, the immediate impact and subsequent recovery of seafloor exposed to these plumes, and the effect on functioning of ecologically significant species. The project will use a combination of field survey experimentation with in situ observations and controlled laboratory-based experiments. The field work begins in May 2018 when an area of up to 1km2 at depths of 400-500 m on the Chatham Rise, 450 km east the New Zealand South Island will be subjected to disturbance by an upgraded former NOAA Benthic Disturber. The suspended sediment load created by the disturbance will be tracked and monitored, with the effects on seafloor animals examined by pre-and post-disturbance sampling. A wide range of seafloor sampling, benthic landers, towed cameras, oceanographic moorings and water column monitoring will be carried out over a three week period. Monitoring surveys will be repeated in 2019 and 2020 to determine the longer-term resilience and recovery of disturbed communities. The laboratory-based side of the programme, also starting in 2018, involves holding live deep-sea corals and sponges in tanks at NIWA, and exposing them to various levels and duration of particle loads in the water in order to reveal lethal thresholds as well as sub- lethal effects of settled and suspended sediment.

Jan 1, 2018

By Jan M. Peter

Many of the Pb-Zn massive sulfide deposits of the Bathurst area in northern New Brunswick, Canada, are intimately associated with laterally continuous iron formation (IF) (Figure 1). This IF is a fossil laminated, exhalative, chemical sediment. Together, the IF and the Brunswick #12, Brunswick #6, and Austin Brook deposits (rightmost discontinuous horizon on Figure 1) are collectively referred to as the "Brunswick Belt". To date we have only studied the Brunswick Belt and have not examined the horizon along which the QSR, CNE and Flat Landing Brook deposits lie. The Bathurst area is underlain by the Tetagouche Group (Figure 2), a Cambro(?)-Ordovician sequence of metasedimentary and bimodal metavolcanic rocks that was intruded by mafic to felsic plutons and subsequently deformed during the Taconic Orogeny. The stratigraphic sequence consists of shales and greywackes that are overlain by carbonaceous shales and felsic volcanic and volcaniclastic rocks; these are in turn overlain by mafic volcanic and sedimentary rocks. The massive sulfide deposits and IF occur within the upper portions of the felsic volcanic rocks in close association with carbnaceous metasedimentary footwall rocks (Figure 2).

Jan 1, 1993

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 Gordon B. J. Fader

A regional assessment of the aggregate potential of the Scotian Shelf is presently being funded through a Canada-Nova Scotia Cooperation Agreement on Mineral Development. This assessment includes testing of seabed materials for their suitability in a variety of concrete, asphalt and other specialized applications. The glacial and postglacial Holocene history of the Scotian Shelf has been favourable for the formation of large deposits of sand and gravel that have potential for use as marine aggregate resources. Large banks and inner shelf areas of the seabed consist of basal transgressive sand and gravel of the Sable Island Sand and Gravel Formation. These sediments accumulated during the late Wisconsinan postglacial transgression, through sorting of glacial materials that were originally deposited beneath marine terminating glaciers. Some sandy deposits occur as low-stand deltas on the inner shelf at 70 m water depth and were formed during the maxi- mum low sea level stand, in early postglacial time, at approximately 12 000 yBP. Modern sediment transport processes have contributed to the formation of areas of large sand bedforms, such as the Cape Split sand wave field and other isolated sand waves of the inner Bay of Fundy, and Eastern Shoal on Banquereau. Sandy sediments, found in many transverse channels in the nearshore, offer a potential for placer gold where proximal to adjacent onshore epithermal gold deposits. Lithothamnion covered gravel occurs as a thin lag overlying glacial sediments in much of the nearshore. Relict gravel beach ridges have been eroded and redistributed through sub-littoral processes after passage of the transgressing beach front. Multibeam bathymetry, sidescan sonograms and high-resolution seismic reflection profiles are the main survey tools. Ground truth consists of large volume seabed samples, vibrocores and photographs. A preliminary assessment of the aggregate potential indicates that very large volumes of suitable aggregate lie in the offshore of southeast Canada.

Jan 1, 1995

By James R. Hein

A new data set of cobalt-rich ferromanganese (Fe-Mn) crust chemistry has been completed for the first detailed sampling of a latitudinal crossing of the Pacific equatorial zone of high biological productivity. Samples were collected in January-March, 1999, during the AVON 2 cruise aboard the R.V. Melville, Scripps Institute of Oceanography. Samples were collected from 4.6° N to 9.2° S latitudes along two ridges, the Marshall Islands-Gilbert Islands ridge (4.6° N to 3.5° S) and the Howland Island-Tokelau Islands ridge (1° N to 9.2° S). The two ridges are offset east-west in the region of overlapping latitudinal sampling by about 466 km. We determined the concentrations of 48 elements for 147 samples from 39 dredge hauls taken on 33 seamounts and island flanks that occur between the Marshall Islands to the northwest and Samoa to the southeast. Element concentrations can be examined as varying spatially and with water depth in the ocean and we examine those relationships based on statistical analysis of the chemical and spatial data. The mean Fe/Mn ratio of 1 and mean Co content of 4645 ppm are typical of West Pacific hydrogenetic crusts; but the mean Co content is low compared to those of some equatorial North Pacific sites, such as the Marshall Islands and Johnston Island EEZs. In contrast, the mean Cu concentration (1540 ppm) is 35% higher than the mean concentration for Pacific Ocean Fe-Mn crusts (998 ppm). Another striking difference is the 40% higher Ba concentrations (mean 3107 ppm) compared to typical Central and West Pacific crusts (mean 1876 ppm); but Ba concentrations are lower than those in California continental-margin Fe-Mn crusts (mean 4085 ppm). A final significant difference in Fe-Mn crust chemistry is Zr concentrations, mean 921 ppm (maximum 1523 ppm), which is about 30% higher in this data set compared to the previously determined mean value of 613 ppm for Central and West Pacific crusts. Zirconium has a strong positive correlation with Ba and a weak positive correlation with Mn.

Jan 1, 2003

By Yanis Miezitis, Gerald Mueller, Timothy F. McConachy, Ronald G. Sait, Keith R. Porritt, William J. McKay

In November 2004, Australia lodged with the United Nations Commission on the Limits of the Continental Shelf possible new maritime boundaries in relation to Australia’s continental shelf extending beyond 200 nautical miles from the Territorial Sea Baseline (Colwell and Symonds, 2005). If agreed by the commission, just over half of Australia’s land mass will lie below the sea, and Australia will have one of the largest marine jurisdictions in the world (14.41 million km2). With this jurisdiction comes a responsibility to manage and sustain the marine environment (McConachy, 2006). Knowledge of minerals and their resource potential is part of this responsibility but is generally poorly known (McConachy, 2005).

Aug 24, 2006

By Mayumy Amparo Cabrera-Ramírez

Polymetallic nodules are a widespread resource in the Pacific Ocean, particularly in the areas of Clarion-Clipperton (Cronan, 2000). The most abundant mineral phases are formed by iron and manganese oxides, with minor elements such as nickel, copper, cobalt, molybdenum and rare earths elements (Cronan, 1977; Cronan and Moorby, 1981; Iyer and Sharma, 1990; Mangini et al. 1990; Banerjee et al. 1991). In the Clarion-Clipperton Zone (CCZ), several authors mention that there are three main mineral species of manganese oxides, which have been recognized and which are associated with different processes of formation: todorokita (Mn2+, Ca, Mg) Mn34+ O7. H2), vernadite dMnO and birnessite enriched in Fe and (Na, Ca) 0.5 (Mn4+, Mn3+) 2O4. 1.5 H2O. In nodules of hydrothermal origin have been found todorokite, birnessite, vernadite, goethite and pyrolusite. Although there are many oxides and hydroxides of manganese and iron in amorphous and microcrystalline phases that make up the bulk of the nodule (Frondel et al. 1960; Cronan 1977; Dymond 1981; Calvert and Piper, 1984; Aplin and Cronan, 1985; Martin and Lallier, 1993; Achurra et al. 2009), identifying specific mineral phases is difficult due to the intergrowth of different phases and associated detrital material.

Jan 1, 2011

By Cornel E. J. de Ronde

Brothers volcano (34°51.7?S, 179°03.6?E) is a large caldera volcano that forms part of the active Kermadec arc south of 32° S, NE of New Zealand. It is an elongate edifice striking NW-SE that is ~11-13 km long by 7-8 km across. The caldera has a basal diameter of 3-3.5 km and is surrounded by 350-450 m high walls with the floor 1,850 m deep. A volcanic cone of dacite composition rises 350 m from the caldera floor and partially coalesces with the southern caldera wall. Much of the caldera construction and the location of the hydrothermal vent sites are controlled by intersecting basement structures. Three hydrothermal sites have been recognized at Brothers; NW caldera, SE caldera and cone. Multiple hydrothermal plumes were mapped from the bottom of the caldera upwards to a depth of 900 m and originate from two of the sites; one on the NW caldera wall the other atop the cone. Analyses of these plumes show that the two vent sites are chemically distinct. The cone site itself hosts three distinct vent fields (summit, upper flank, NE flank) that in 1999 had plumes (mainly from the summit) containing relatively high concentrations of gas with a shift of -0.27 pH units (proxy for CO2) and H2S concentrations up to 4,250 nM, particulate Cu (PCu) of 3.4 nM, total dissolvable Fe (TDFe) of 4,720 nM, TDMn up to 260 nM and Fe/Mn values between 4.4 and 18.2. However, in 2002 plumes from the summit vent field had noticeably lower concentrations of PCu (0.3 nM), TDFe (175 nM), and Fe/Mn values of 0.8, although similar TDMn (220 nM) and shift in pH (-0.22) suggesting a state of flux for this site. By contrast, plumes originating from the NW caldera site have much less gas with a pH shift of -0.09 units and no detectable H2S, TDFe up to 955 nM, TDMn up to 150 nM, and Fe/Mn values of 6.4, and have not changed their composition over the same three year interval indicating a more chronic hydrothermal system. Plume d3He results show helium is decoupled from more near-surface vent fluid sources although a shift in R/Ra values from 6.1 ± 0.5 in 1999 for the combined vent sites to 7.2 ± 0.1 in 2002 indicates a less radiogenic input of helium over three years, suggestive of a greater magmatic input to the system.

Jan 1, 2004

By Nobuyuki Okamoto

The 21-year long-term Japan-SOPAC Cooperative Deep-sea Mineral Resources Study Programme was completed in March 2006. The Programme, which commenced in 1985, has seen numerous marine research surveys being conducted within the Exclusive Economic Zones (EEZs) of 12 SOPAC member countries (Figure 1). The various research and government institutions that have been closely involved in this longstanding Programme include: the Japan International Cooperation Agency (JICA); Japan Oil, Gas and Metals National Corporation (JOGMEC) (formerly, the Metal Mining Agency of Japan, MMAJ) and relevant ministries of the participating Pacific Island governments.

Sep 24, 2006

By M. C. I. Modenesi, J. E. Smith, M. Salvá-Ramírez, G. M. Castro, J. C. Santamarina

Annual metal consumption per capita has increased several orders of magnitude worldwide since the turn of the 19th century, yet grades of terrestrial ores are decreasing as reserves dwindle. Consequently, deep sea metal deposits are gradually transitioning from identified resources to economically viable reserves. Deposits in the Red Sea deeps along the axial trough result from tectonic and local hydrothermal processes. Continental rifting and ocean floor spreading produce fresh oceanic crust; concurrently, seafloor evaporites flow into the spreading zone and form isolated deeps. The deeps are often filled with hot stratified brines maintained by locally discharged fluids during hydrothermal circulation. Metalliferous sediments precipitate from the brines within the deeps. The ongoing multipronged study at KAUST involves: (1) acoustic characterization of the metalliferous accumulations using advanced signal processing techniques that capture the physics of granular materials; (2) comprehensive mineralogical and textural characterization of sampled sediments using SEM, EDS, XRD, XRF, and ICP-OES; (3) multiphysics instruments deployed to measure undisturbed sediment properties in-situ; (4) development of a distributed seafloor observatory for monitoring field operations; (5) innovative concentration and separation technologies; and (6) new strategies for proper tailings disposal purposely conceived for the unique field conditions in the Red Sea deeps.

Jan 1, 2018

Clark volcano is a large volcanic center on the active arc front of the intraoceanic Kermadec arc. It is one of the two southern-most Kermadec arc volcanoes (the other being Whakatane volcano) that sits on oceanic crust before the transition to continental New Zealand, and is underlain by the 17-km-thick Hikurangi Plateau, which is presently subducting beneath the southern section of the Kermadec arc. Unusual K-rich basaltic lavas have been recovered from Clark (1.5 to 2.25 wt.% K2O), together with more typical basaltic-andesite, andesite and dacite rocks. The total volume of the Clark volcanic center is ~90 km3, calculated from the summit of the volcano down to the 2,500 m contour (which marks the inflection point of the volcano flanks with the surrounding seafloor) and comprises two separate edifices similar in size; the northern one having a volume of ~4.57 km3 and the southern one 4.43 km3. The volcano has a maximum relief of ~1,645 m from the 2,500 m contour to the summit of the shallower northern edifice shoaling to 855 m below sea level. The northern edifice is comprised of twin peaks each consisting of a constructional cone, with evidence of sector collapse having occurred between the cones. A more recent, smaller cone again has grown on the eastern flank between these summit cones. Massive, blocky lavas and coarse talus dominate the summits of the cones, with finer-grained volcaniclastic material and sediments a feature of the volcano flanks. The southern edifice is noticeably more dissected than the northern one, having a pronounced horst in the centre of the volcano bounded by 5-6 km-long faults. There is no obvious constructional cone atop the southern volcanic edifice.

Jan 1, 2011

By Alexander Malahoff

The new ship-submersible system with R/V Ka'imikai-o-Kanaloa as a mothership and the PISCES V as the submersible completed its first season of dives. The dives involved deployment of the PISCES V in the Hawaiian Islands between the months of July and October 1996. Submersible deployments up to depths of 2,000 meters in sea states up to a high three were made. The new hook and clasp deployment and retrieval connection for PISCES V to the telearm was shown to be an effective system for handling the PISCES V with the A-frame. The shipboard multibeam survey and seawater sampling capability proved to be especially effective in re-mapping the summit of the submarine volcano Loihi following a major volcano-tectonic event and for following the source and configuration of the new hydrothermal plume. Following the earthquake swarm of July 17 to August 18,1996, major changes in the geological setting of Loihi submarine volcano took place. Prior to the seismic event, the geology and structure of the summit of Loihi was represented by a platform-like area 8,100 meters long and 5,400 meters wide enclosed by the 1,200-meter depth contour. The summit was characterized by the presence of two prominent pit craters and eastern and western crater located at water depths of 1,100 and 1,370 meters, respectively. A hydrothermally active volcanic cone, named Pele's Vents, was located at a depth of 960 at the southern edge of the summit. The floor of the summit of Loihi was largely covered by prismatic talus, with interstitial hydrothermal clays. Pillow and tube lavas with volcanic cones 5 to 50 meters high were exposed along the axes of the southern and northern rift zones. The inner margin of the summit displayed fissures and normal faults with the downthrown component towards the center of the summit. The pre-earthquake structural data suggest a pre-caldera structural stage for Loihi. Maximum sustained hydrothermal activity observed on Loihi over the past 10 years existed at Pele's Vents with other sporadic venting occurs along the summit platform and along the south rift. Following the earthquake swarm, the hydrothermally saturated Pele's Vents cone gave way and slid into the inner pit crater. Subsequently, the observed above- bottom hydrothermal plume source deepened from 960 to 1,160 meters, possibly emanating from the same intrusive heat source as Pele's Vents. The observed inward collapse of the summit structures and subsequent opening of fissures gave rise to diffuse venting from the newly formed caldera-like depression with the bottom-hugging hydrothermal pool located at depth between 1,250 and 1,220 meters at the sites of the pit craters.

Jan 1, 1996

By Tobias Hens, Andrew Frierdich, Barbara Etschmann, Joël Brugger, Barrie Bolton

"Ferromanganese (Fe-Mn) nodules and crusts are prime targets for future deep-sea mining ventures due to their unusual enrichment of critical metals, such as Ni, Co, Cu, Ti, Te, Zr, Hf, Nb, Y, and REE. These metals are used in an ever increasing variety of high- and green-tech applications such as alloys, batteries for hybrid cars, fiber-optic cables, or liquid-crystal displays.1 Recovery and processing of these deposits will most likely be cost-intensive and require new solutions.2 Thus, innovative approaches towards the development of sustainable metallurgical processes represent one component that can positively affect the marine mining value chain. Dynamic mineral recrystallization of Fe- Mn oxide phases is a geochemical process that may have notable potential for future hydrometallurgical applications.Our research focuses on Mn oxides – potent trace metal scavengers with high sorptive capacity3 – and biogeochemical mechanisms that control Fe-Mn nodule and crust formation, alteration, and trace element enrichment. Biogeochemical redox cycling of Mn is characterized by microbial oxidation of aqueous Mn(II) to Mn(III,IV) oxides and (a)biotic reduction of these oxides to Mn(II)aq. During this cycling dissolved Mn(II) is in direct contact with solid-phase Mn(III,IV) oxides and can back-react via abiotic pathways (e.g., 4 and references therein). This results in continuous dynamic recrystallization of the Mn mineral substrate through coupled dissolution (trace metal release) – reprecipitation (trace metal incorporation) processes.4 We recently demonstrated in new experiments, that Ni is cycled during manganite recrystallization. It has been shown that, although Ni readily undergoes mineral-fluid repartitioning in the absence of Mn(II)aq, dissolved Mn(II) significantly catalyzes Ni exchange between solid phase and solution. Over a period of 50 days about 30 percent of the Ni atoms in Ni-substituted manganite (natural abundance composition) were exchanged with a 62Ni(II)aq isotope tracer at pH 7.5. Based on these outcomes we employed similar techniques to investigate the impact of dynamic recrystallization on Mn oxide phases in deep-sea ferromanganese nodules and crusts from three circum-Australian locations (South Tasman Rise, Lord Howe Rise, Coral Sea) and the Central Pacific Basin."

Jan 1, 2017

By S. C. W. de Jong, E. de Hoog, J. M. van Wijk, S. J. Dasselaar

Introduction Technology development for sustainable, safe, reliable and efficient mining of polymetallic nodules in the deep seas requires careful design, thorough understanding and integrated testing of all equipment, physical processes and (sub) systems involved (Dasselaar et al [1]). Proceeding from Vertical Transport System (VTS) experiments at IHC laboratory scale by Van Wijk [2], with typical system dimensions of several meters, to prototype or pilot scale testing with typical dimensions of several kilometers, is a giant leap. Naturally, intermediate steps are required in order to mitigate the possible risks in the full-scale system’s (physical) processes. Within the EU program Blue Mining (2014-2018), possibilities emerged for performing experiments at intermediate scale: the so-called medium-scale vertical slurry experiments. Near Freiberg, Germany, the village Halsbrücke possesses a 140 meter deep empty vertical mine shaft, perfectly suited for housing the test setup. For this purpose, a 318 meter long 145 mm pipeline circuit was constructed, including both a 130 meter high vertical riser and fall pipe section. A purpose-built sediment injection and separation system was deployed, including a 55 kW centrifugal pump. The riser section has been equipped with sensors capturing pressure, temperature, flow velocity, volumetric concentration and flow visualization. The planning, modification and construction of the test facility site itself is described by Müller et al [3]. The present paper describes the objectives, experimental program, equipment, and the preliminary results. Publications on in-depth results are foreseen in the (near) future.

Jan 1, 2018

By Audrey Boissier, Marie-Anne Camon, Cecile Cathalot, Yves Fouquet, Laurent Bignon, Arnaud Agranier, Ewan Pelleter, Sylvain Bermell, Florian Besson

INTRODUCTION In October 2014, on behalf of the French government, Ifremer, along with the International Seabed Authority (ISA), signed a contract to start a detailed exploration program for seafloor massive sulfide (SMS) deposits in the work plan located on the slow spreading Mid-Atlantic ridge (MAR). The contract has a fifteen-year lifetime and the related exploration program must include the outline of SMS deposits and a resource assessment, as well as detailed environmental base line studies in the contract area. The exploration for SMS deposits generally includes detection of hydrothermal plume anomalies, acquisition of surface and near-bottom geophysical data, sampling operations from the research vessel (e.g. dredges, cores), and dive operations. The environmental studies include, among others, short and long-term oceanographic measurements, water column studies, biodiversity evaluation close and far from SMS deposits, characterization of natural hydrothermal plumes and related sedimentation. The HERMINE research cruise held from March 13th to April 28th 2018 (R/V Pourquoi Pas?) was the first cruise dedicated to exploration of active and inactive SMS and to the quantification of natural chemical input to the water column. The HERMINE cruise strategy was built up around three main objectives: (i) regional exploration including the detection of plume anomalies and the research of SMS deposits, (ii) local exploration of a SMS district and (iii) integrated study of a natural hydrothermal plume. This 3-in-1 cruise required us to optimize the switch between dives and surface operations. Day-time was devoted to dive operations whereas night-time was mostly dedicated to CTD/Rosette operations. The Nautile HOV (Human Occupied Vehicle) was well suited to the working time schedule of the cruise because it was time efficient in shorter (i.e. < 10h) dives due to fast descent and ascent speed, fast submerged forward speed, high maneuverability and the ability to carry heavy science payload as well as large volume of samples. Regional Exploration The first seventeen days of the HERMINE cruise were devoted to regional exploration, i.e. the detection of new plume anomalies and the research of new sulfide mineralization in the French work plan (10 000 km2; 6 clusters).

Jan 1, 2018

By Alexander Malahoff

Field observations and sampling of land-based and submarine hydrothermal and geothermal sites show a definite link between the geological setting, fluid geochemistry and specialized assemblages of microorganisms found at these settings. Three initial sites have been chosen as a basis for these studies. The first site is located on hydrothermal vents in pit craters on the submarine volcano Lo?ihi (Hawai?i) at a water depth of 1,300 meters. The second site is within the geothermally active vents, ponds and lakes of the Taupo Volcanic Zone of New Zealand. The third site extends along the chain of volcanically and hydrothermally active volcanoes of the Kermadec-Tonga arc and back-arc system. To focus our work in New Zealand, a geomicrobiology field and experimental center has been established in Wairakei, New Zealand, with the relevant genomics, proteomic and bioinformatics work being conducted at the University of Hawaii. As part of a partnership between the University of Hawai?i, the Institute of Geological & Nuclear Sciences (GNS) and Victoria University of Wellington, a new interdisciplinary graduate course in geomicrobiology will be taught at Victoria University beginning next year. Since mineral-microbial interactions have been occurring for the past few billion years and these interactions have led to where one generates the other, a metal-bacteria research program has been initiated at GNS using arsenic-gold and other metal-bacterial interaction processes as a research objective. In this research program, we have completed the full genome of a new species of marine bacterium Idiomarina loihiensis from the Lo?ihi hydrothermal vents and identified specialized microorganisms living in pH 0.3 geothermal vent waters of White Island, New Zealand. The multidisciplinary approach to study the process of accumulation of metals in the hydrothermal systems clearly shows the path of how bacterial-mineral interaction can precipitate metal deposits. These studies will lead to new avenues for biomining, bioremediation and the understanding of the origins of life.

Jan 1, 2004