Search Documents

By Mark D. Hannington

Seafloor polymetallic sulfides have been found in diverse volcanic and tectonic settings on the ocean floor at water depths ranging from 3700 meters to <1500 meters. More than 100 occurrences of hydrothermal mineralization have been documented (including Fe-oxide deposits, Mn-crusts, metalliferous sediments, and massive sulfides), but high-temperature hydrothermal activity and large accumulations of polymetallic sulfides are known at fewer than 20 different sites. Chemical analyses of samples from these deposits indicate that they contain important concentrations of Cu, Zn, Ag, and Au, comparable to those of massive sulfide deposits on land. However, the lack of sufficient data concerning the distribution, size, and bulk composition of seafloor deposits precludes a meaningful assessment of their resource potential.

Jan 1, 1994

By James R. Hein

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

Sep 14, 2011

By 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 John C. Wiltshire

Hawai&apos;i is surrounded by a series of potentially valuable marine mineral deposits. These include manganese nodules between Hawai&apos;i and Mexico, cobalt-rich manganese crusts and phosphorites in the Exclusive Economic Zone around the Hawaiian Island Archipelago, Johnston Island and the neigh- boring island states and sand and gravel deposits off the main Hawaiian Islands largely in State waters. Hawai&apos;i has an economy that is very narrowly based on the tourist industry. In an effort to avoid the difficulties coming from such a vulnerable economy, significant efforts have been made toward economic diversification. The State has set up a range of programs looking to find new industries. New ocean industries figure prominently among these efforts as Hawai&apos;i is surrounded by ocean. Naturally, among new ocean industries the potential for new marine mineral industries is significant given that Honolulu is the only full service port in the Central Pacific and Hawai&apos;i is in the middle of the mineral belt. The port of Honolulu is now being actively used by mineral exploration vessels of several countries and with the current number of ship visits varying from 10-15 per year, this puts several million dollars a year into the State economy. It helps to fulfill the State&apos;s goal of dynamic growth in the ocean sector of the economy. Nonetheless, a major marine minerals industry, particularly one which would involve processing of minerals in Hawai&apos;i, is controversial in a State whose main source of revenue is tourist expenditures based on the image of a pristine environment. In addition to the perceived threat to the hotel and fishing industry, is the whole highly emotional debate concerning preservation and development. To complicate the issue further, the major interest in developing a marine minerals is currently largely from Korea and China rather than from domestic U.S. industry. On the other side of the debate is the fact that the State&apos;s economy is hampered by many low paying jobs and a lack of technical jobs. This is further exacerbated by the fact that lower paying jobs are held disproportionately by people of Hawaiian and Pacific Island ancestry. Naturally, this leads over time to a certain amount of resentment. The higher paying technical lobs associated with a minerals processing industry could help to alleviate this problem.

Jan 1, 1996

By Peter M. Herzig

In September-October 2002, shallow seafloor drilling using the 5 m-Rockdrill of the British Geological Survey and the German R/V Sonne has revealed critical information on the sub-surface nature of two distinct hydrothermal systems in the New Ireland fore-arc and the Manus Basin of Papua New Guinea. Drilling at the summit plateau of Conical Seamount (39 holes, 31 % recovery) south of Lihir Island in the central New Ireland fore-arc has confirmed the sub-seafloor extend of previously discovered surface gold mineralization (up to 230 g/t Au) and associated alteration to a depth of at least 4.5 m below the seafloor and further proven analogies to the giant Ladolam epithermal gold deposit on Lihir Island. Drill core samples of clay-silica alteration contain average gold grades up to 14.2 g/t Au over a length of about 30 cm (fire assay Lihir Gold Ltd. laboratory) and appear to be part of a more extensive gold zone located below a carapace of relatively fresh ancaramitic and trachybasalt. These samples contain a complex mineralogy including realgar, orpiment, galena, sphalerite, some chalcopyrite and pyrite, together with amorphous silica, and possibly cinnabar. In addition to high concentrations of gold, shipboard analyses indicate that the gold-rich samples contain high values of Pb, As, and Sb, which is a characteristic feature of a magmatic-hydrothermal style of mineralization and alteration.

Jan 1, 2002

By Kristian Drivenes, Steinar L. Ellefmo, Kurt Aasly, Ben Snook, Przemyslaw B. Kowalczuk, Rolf Arne Kleiv

"Since Ellefmo et al. (2014) published resource estimates of undiscovered seafloor massive sulfides (SMS) on the Arctic Mid-Ocean Ridge (AMOR), there has been an increased focus on establishing new knowledge about exploitation technologies for such deposits. This also includes understanding the process mineralogical properties of typical SMS deposits.The part of the AMOR that lies between Jan Mayen and the Svalbard Islands and is located within Norwegian jurisdiction and, as such, investigating the potential for mineral production from hydrothermal vent fields has been seen as strategic. The AMOR has been explored for active hydrothermal vent fields since early 2000s (Pedersen et al., 2010b). One of the active vent fields discovered, Loki´s Castle, is located in the northern part of Mohn´s Ridge. This vent field was first described by Pedersen et al., (2010a) and consists of two mounds, each approximately 100-150 m diameter and 20-30 meters high, hosting several active chimneys, up to 11 m high.Loki´s Castle has been selected as a case site in order to study the properties of typical SMS occurrences with respect to possible future deep-sea mining activities. As part of the MarMine cruise in 2016, the Loki Castle was visited and sampled for e.g. mineral characterization and mineral processing analyses. In total, more than 500 kg rock samples were collected using ROVs, and intended for further research (Ludvigsen et al., 2016). In addition to sampling mineralized rock fragments, survey data like bathymetry, magnetics and Underwater Hyperspectral Imaging (UHI) was collected using Automated Underwater Vehicle (AUV)."

Jan 1, 2017

By Irina Melekestseva

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

Sep 14, 2011

By T. E. Sedysheva

The study of Co-rich manganese crusts has reached the level which allows to start prospecting works in the observable future, and furthermore, probably, exploitation of ore deposits. In this connection, among other goals, the necessity to analyze a distribution of ore bed parameters in details is quite urgent. Foremost, these are crust thicknesses in connection with landforms and elements of submarine mountains relief. This report is based on representative sampling made in course of research cruises run by SSC Yuzhmorgeologiya over guyots of the Magellan Seamounts. Crustal covers could overlie seafloor surfaces which are confined to a various landforms and elements of relief under the condition, that they are free of sediments. These are planed parts of a summit surfaces, edges, spurs, rectilinear parts of slopes, intermountain saddles and volcanic edifices. It is known, that crustal thicknesses are different at a various forms of relief [1]. We processed statistically the data around crustal thicknesses, which were sampled by dredging and submersible drilling (Tables 1, 2).

Jan 1, 2010

By Det Juridiske Fakultet, Maria Madalena das Neves

The ocean is increasingly seen as the answer for a myriad of challenges facing humankind. In effect, in addition to being vital for transportation and communication, the oceans contain living and non-living resources that are essential to meet the demand for food, and to the development of pharmaceutical products, energy resources, and high-technology products. This entails that the oceans are under pressure by different activities: navigation, fishing, oil and gas exploration and production, renewable energy development, laying of cables and pipelines, marine scientific research, bioprospecting, and deep-sea mining for minerals and metals. The growing demand for essential minerals and metals such as cobalt, nickel, zinc, copper, and manganese, seen in tandem with technological advances in deep-sea mining, makes the latter an increasingly attractive activity, both in areas within and beyond national jurisdiction. At the same time, the further development of deep-sea mining adds to the problem of the competing uses of maritime space and accentuates the need to balance and articulate the interests of the different users of the seas (States, sponsored deep-sea mining investors, oil and gas investors, fishermen, shippers, etc.). Furthermore, as deep-sea mining activities increase and move on to an exploitation phase so does the possibility of new disputes (for instance during deep-sea mining exploitation a communication’s cable is severed, a vessel conducting deep-sea bottom fisheries damages deep-sea mining equipment, etc.).

Jan 1, 2018

By K. Vanstaen, K. M. Cooper, S. Ware, S. L. Boyd

Remediation and restoration of offshore marine habitats is a relatively new concept with attempts in European regions largely being instigated by requirements of various strategic directives including Article 2 of the Habitats Directive (1992), the EC Water Framework Directive (2000, Article 2 of the OSPAR Convention (1992) and the developing European Marine Strategy Directive. A field experiment to establish the practicality of various options for rehabilitating the seabed on the cessation of dredging has been successfully set-up. The purpose of this experiment is to investigate the practicality and effectiveness of gravel seeding as a potential restorative method which could be applied at marine aggregate extraction sites following cessation of dredging. Zone 2, within Area 408 (offshore Humber) was chosen as the experimental site as there is some evidence for persistence of sand which may have resulted from screening operations at this site.

Aug 24, 2006

By K. Vanstaen, K. M. Cooper, S. Ware, S. L. Boyd

Remediation and restoration of offshore marine habitats is a relatively new concept with attempts in European regions largely being instigated by requirements of various strategic directives including Article 2 of the Habitats Directive (1992), the EC Water Framework Directive (2000, Article 2 of the OSPAR Convention (1992) and the developing European Marine Strategy Directive. A field experiment to establish the practicality of various options for rehabilitating the seabed on the cessation of dredging has been successfully set up. The purpose of this experiment is to investigate the practicality and effectiveness of gravel seeding as a potential restorative method that can be applied at marine aggregate extraction sites following cessation of dredging. Zone 2, within Area 408 (offshore Humber) was chosen as the experimental site as there is some evidence for persistence of sand which may have resulted from screening operations at this site.

The seafloor occurrences of KODOS ferromanganese nodules can be classified into four facies based on the morphological types of nodules recovered and seafloor photographs. Facies A, B, and C are relatively unimodal whereas Facies D is bimodal in the size distribution of nodules. Both Facies A and B are highly covered by sediments, but Facies B is higher than facies A in nodule density. Facies C has a high density of small nodules and many traces of bioactivity. Facies D is irregular in nodule density, but occurs close to basement near scarps (Fig. 1). The transparent layer (TL) on subbottom profile records (von Stackelberg et al., 1987) is composed of three sedimentary units, which in cores are distinguished by color. The uppermost Unit I is postulated to be deposited during the past 0.21 Ma and the middle Unit II between 0.42 Ma and 0.21 Ma (MOMAF, 1997). There exists a hiatus between Unit II and Unit III. Unit III was deposited from 3.5 Ma to 1.5 Ma as determined by 10Be/9Be and/or 87Sr/86Sr dating (MOMAF, 2004). Internal textures observed on cut sections of nodules suggest four stages of nodule formation (Choi et al., 2000). The nuclei are either unbroken old nodules probably of hydrogenetic growth (1h and 2h) in Facies A and C, or nodule fragments probably of early diagenetic growth (2d) in Facies D, whereas there are both types in Facies B. The layers surrounding the hydrogenetic nodule nuclei are of hydrogenetic growth (3h and/or 4h) in Facies C, and are of early diagenetic growth (3d and/or 4d) in Facies A, B, and D. The layers surrounding the early diagenetic nodule fragments are mostly of early diagenetic growth (3d and 4d) in Facies A, B, and D. But hydrogenetic encrustations are also found as surface layers on the top in Facies B (Fig. 2).

Jan 1, 2005

By Alexander Malahoff

The most exciting frontier in Ocean Technology is represented by a new class of Marine Bioproducts, the source of which lies in marine microorganisms. The microorganisms include microalgae, bacteria and archaea. These organisms represent very diverse, adaptive life forms and in their metabolic processes use carotenoids, polyunsaturated fatty acids, ultraviolet blockers, as well as a wide range of enzymes that are pivotal in the production of new pharmaceuticals and nutraceutical products. These organisms cover a wide spectrum of ocean environments, from the shallow to the deep, from the normal to the extreme. The technological challenge is in the identification of candidate organisms, in the screening for valuable enzymes, and in the industrial production. A whole new range of collecting strategies involving submersibles, ROVs and in situ ocean floor instrumentation is emerging. New non-polluting industrial chemical processes involving the use of photobioreactors and extremophile bioreactors for breeding and monitoring these organisms in neo-farming technology is emerging. The commercial value of these candidate products is immense, as is the range of potential organisms. The dimension of this new industry is global. The Marine Bioproducts Engineering Center (MarBEC), funded by the National Science Foundation (NSF), has been established at the University of Hawaii. The vision of MarBEC is to develop a seamless research system stretching from undergraduate education to industry for the purposes of producing valuable marine bioproducts outside of the normal chemical factory production. MarBEC is uniquely and strategically placed in the Pacific to explore, find, and adapt highly bioactive marine micro-organisms found in the tropical ocean. We have watched the increasing need by the ever-

Jan 1, 2000

By Julian Malnic

The emerging marine minerals exploration and mining industry is currently focused mainly on the technical elements for its success such as developing exploration and mining technologies. However, in one sense, the technical challenges are quite soluble whereas those arising in the fields of the environment and public opinion could present this new generation of miners with problems that are far more difficult to overcome. One need only look at the issues currently faced by mining projects on land to see how powerful the new forces of so-called ?civil society? are in stopping mineral developments in many countries. From the geographic viewpoint, there are many countries but there is just one ocean, so the impacts experienced by any one operation are likely to have pervasive repercussions throughout the industry. A well-oiled NGO development protest lobby will see leverage in resisting this new industry and will seize on the single-ocean angle. The Australian Minerals Industry has established a voluntary Code for Environmental Management that provides an active and valuable model for satisfying the ?court of public opinion? and in delivering economic results to industry that are in current jargon, sustainable. An explanation of the Code for Environmental Management, and the reasons behind 44 companies representing more than 300 operations and 85% of Australia?s sizeable mineral production being signatory to it will be given. Participants see it as a means to future shareholder wealth.

Jan 1, 2000

By Mayumi Ito

Seafloor hydrothermal deposits are found worldwide at 700 to 3,600 meters below sea level [1] and contain base and precious metals like Cu, Pb, Zn, Au, and Ag. Some deposits were found in the Japanese exclusive economic zone and the commercial potential will depend on developments in mining and treatment costs of onshore mines. The ores require mineral processing to become concentrate for the various metal smelters and the authors are investigating mineral processing treatments of collected samples. The collected samples were classified into three components (chimney, mounds, and substrate rocks) and they were separated using a RETAC jig. The mound component contains zinc, lead, and copper minerals and further separation using flotation was investigated. This paper introduces results of the mineral processing tests using gravity separation and flotation.

Jan 1, 2011

By Sven Petersen

The southern Mid-Atlantic Ridge (SMAR) is one of the least-explored spreading centers in the world with respect to hydrothermal activity. In the past 8 years research focused mainly on the ridge segments close to Ascension Island, discovering hydrothermal fields as far south as 14°20?S (Haase et al., 2007; German et al., 2008; Tao et al., 2011). However, the vast majority of the SMAR ridge axis has never been thoroughly investigated for hydrothermal activity. In the spring of 2013 we used segment-scale AUV deployments as well as conventional CTD surveys to identify areas of hydrothermal activity along 16 mid-ocean ridge segments between 13° and 33°S, thereby covering close to 5 % of the global ridge axis in a single cruise. During cruise MSM25 of the German research vessel Maria S. Merian, we tested longrange (>100 km lines per dive) AUV deployments of GEOMAR?s AUV ABYSS (a Remus 6000 vehicle) along the spreading axis for their capability to locate active venting in a fast and efficient way on regional surveys. Since the missions covered long distances,

Sep 14, 2011

By Yoshitaka Hosoi

The survey of the cobalt-rich crust of the Republic of the Marshall Islands was carried out in 1996 and 1998, as the cooperative study project between Japan and SOPAC member countries, and at the thirteen seamounts, seafloor topographic maps and acoustic reflection intensity distribution images by MBES were obtained, and the collection of samples by dredging was conducted. On the basis of the previous results, three seamounts, MS01, MS11 and MS12 were selected for the 2002 year survey, and drilling by BMS (deep sea boring system) was conducted there, to understand the occurrence of cobalt-rich crust. At the same time, environmental survey was carried out to make clear the environmental characteristics of the area. The summary of the survey will be reported.

Jan 1, 2003

By Sang-Mook Lee

The Manus back-arc basin behind the New Britain Trench is one of the major sites of active seafloor hydrothermal vent-fields which are considered to be modern-day analogue of felsic volcanic-hosted polymetallic massive sulfide deposits abundant in ancient geological record. Many of these deposits represent multi-million dollar resources, and yet very little are known about the fundamental processes leading to their formation. In November 2000 January 2001, the PACMANUS hydrothermal system in this region will be targeted by the Ocean Drilling Program Leg 193 to investigate the internal anatomy. A number of observations that suggest that the tectonic, magmatic and hydrothermal processes in the eastern Manus basin spreading center are unusual in that they can not be explained by a simple back-arc opening due to subduction of the New Britain Trench. Geochemistry of submarine volcanoes in the eastern Manus basin, for instance, shows affinity to arc rather than back-arc type volcanoes. Yet these submarine volcanoes lie too faraway from the Benioff-Wadati zone. One hypothesis is that the magmatic and subsequent hydrothermal activity of this region is a direct result of the irregularities in the deep crust and upper mantle structure and that the tectonic process is controlled by the sharp inflection of the New Britain Trench. According to this hypothesis, the two major southeast-trending strike-slip faults in the eastern Manus Basin, Djaul and Weitin Faults, should extend farther down and join to the New Britain Trench. They would form a transform arm of the triple junction with the New Britain Trench southeast of New Britain Island and southwest of Bougainville Island forming the other two arms. A trench-trench-transform triple junction can not be stable over time, and therefore a slight change in the plate velocity may lead to a dramatic change in the configuration of the plate boundaries. If so, the instability of the triple junction may cause large tectonic deformations, such as mantle uplift under the Manus basin due to mantle rupturing by transform faults, and therefore may explain the arc-style volcanism and unusual compositions of hydrothermal deposits in the eastern Manus basin.

Jan 1, 2000

By Irina A. Pulyaeva

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

Jan 1, 2011

By Thomas Kuhn

The detailed investigation of both active and inactive submarine hydrothermal systems has gained tremendous progress during the last decades because of the increasing usage of remotely operated vehicles (ROV) as well as manned submersibles. Special aspects like the targeted sampling of chimney structures and vent fluids as well as the analysis of zonations of near-surface structures like sulfides mounds was only possible with the usage of such vehicles. However, the availability of such vehicles has been very limited because of the few number of deep-water ROVs and manned submersibles which need both a trained crew and a special research vessel. This was especially true for the German science community which did not have such devices at its disposal until recently. With the ROV QUEST 5 which is based at the University of Bremen (c/o. Prof. Dr. G. Wefer, Dr. V. Ratmeyer) this major drawback has now been eliminated.

Jan 1, 2003