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By Glen Smith

Nautilus Minerals is the world leader in exploration and development of deep ocean seafloor massive sulphide (SMS) resources. The company is currently focused on generating its resource pipeline in the Western Pacific and its first development project for recovery of high-grade copper, gold and silver mineralisation from its Solwara 1 site in the Bismarck Sea, Papua New Guinea. The Solwara 1 site is located at a water depth of 1,600 ? 1,800 meters. Over 150 SMS seafloor surface samples have been collected from chimney structures during dives made by remote operated vehicles (ROVs). In order to obtain an understanding of the sub-surface mineralisation, Nautilus carried out 4 drilling programs between 2006 and 2010 which allowed the calculation of a Canadian NI43-101 compliant resource estimate. The initial 2006 campaign was based on conventional offshore surface driven drill equipment. In conjunction with the subsea remote technology industry, Nautilus subsequently developed an ROV operated seafloor drill system with improved drill core recovery and efficiency. This technology was developed further with a 2010 - 2011 drill program to increase the available geological knowledge at Solwara 1 and adjacent prospects. his paper will provide an overview of Nautilus? SMS drilling requirements and recap the evolution of drilling technology and operations undertaken at Solwara 1 from 2006 to 2011. The paper will also discuss the potential of further developments in drilling techniques and equipment to increase or improve drilling depth, efficiency and data quality.

Jan 1, 2011

By Thomas Pichler

In the past marine mining technology has focused on bulk mining of base metals from polymetallic massive sulfides. This has not been very successful because of the relatively low unit value of these metals and other reasons such as water depth, etc.. The process of gold enrichment in hydrothermal deposits is controlled through five different factors: (1) nature and source of the solution, (2) source of the gold, (3) a mechanism for mobilizing and transporting, (4) a mechanism for deposition, and (5) a mechanism to preserve the deposit. Gold has been identified in marine polymetallic massive sulfides from various locations on the ocean floor (e.g., spreading centers, seamounts) with contents ranging up to 5 ppm Au. This is within the current range of 1.0 to 7.0 ppm gold content which classifies gold ores. The gold appears to have been derived during hydrothermal alteration of the oceanic crust. Until the present there has been little attention to the possibility of mining gold or other precious metals in the marine environment. However, the magnitude of hydrothermal alteration (seawater can penetrates to a depth of 5 km into the oceanic crust) and primary gold contents of the rocks in the pathway of the fluid indicates that major gold deposits must have formed on or in the ocean floor, but they have not been found. To find a big deposit might only take an exploration model exclusively designed for gold exploration on the ocean floor.

Jan 1, 1993

By Charles L. Morgan

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

Jan 1, 1991

By 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 Charles L. Morgan

The Minerals Management Service of the U.S. Department of the Interior and the State of Hawaii Department of Planning and Economic Development are investigating the cobalt-rich ferromanganese oxide crust deposits found within the Exclusive Economic Zones (EEZ) of the Hawaiian Islands and Johnston Atoll. The objective of this investigation is to complete a preliminary resource assessment and an Environmental Impact Statement for potential leasing of mineral rights to these crusts. The results of this effort will be summarized and published in a Draft Environmental Impact Statement in March 1986. Three oceanographic cruises to deposit sites in the Hawaiian Islands EEZ were conducted by the University of Hawaii in 1984. As a result, data and sample analysis yielded the following resource estimates (in thousand tonnes): (1) total crusts - 378,500; (2) cobalt - 2,500; (3) manganese - 76,200; (4) iron - 59,700; and (5) nickel - 1,400. These estimates do not include key factors such as deposit continuity, recoverability, and environmental sensitivity. A preliminary attempt to quantify some of these factors for one particular deposit is in progress and will consist of detailed field studies followed by laboratory analysis. Similar evaluations of the Johnston Island EEZ have also begun and are based upon field work conducted by West German researchers and the U.S. Geological Survey. The Johnston Island EEZ appears to have crust resources about as large as those contained in the entire Hawaiian EEZ.

Jan 1, 1985

By Stanley R. Riggs

Phosphate deposits on the southeastern U.S. coastal plain have long been the major force in world phosphate markets. World markets continue to grow, but the role of U.S. resources is rapidly declining. This situation results from a complex interaction of economic, political, and environmental factors. Causes for this ongoing erosion of the U. S. market include 1) escalating costs, 2) changes in land-use patterns, 3) environmental pressures oh conventional mining techniques; 4) exhaustion of shallow, high-grade resources in Florida, and 5) increased, low-cost production in other countries throughout the world. In fact, some agencies and commodity personnel predict that the U.S. will become a net phosphate importer early in the next century. If this projection is correct, the U.S. industry must look towards major changes in the near future in order to continue to compete in the world market. One possible change includes development and application of unconventional mining techniques to cheaply recover vast 'new' potential resources in areas with lower land-use pressures. These 'new' resources include 1) deep phosphorites within major sediment basins of the southeastern coastal plain and 2) subsurface phosphorites on the continental shelf and within the U.S. EEZ. These latter resources include extensive deposits in Onslow Bay, N.C.; broad regions offshore of Savannah, Ga. and Cape Canaveral, Fla.; and the central portion of the west Florida shelf. Little research and exploration has been

Jan 1, 1988

By Alexander Malahoff

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

Jan 1, 2011

By 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 Andrea Koschinsky, Luise Heinrich

(for an oral presentation) Activities for preparing future deep-sea mining offer the unique opportunity to study environmental conditions and anticipate adverse environmental impacts prior to the commercialization of the activity. Until know, environmental research has first and foremost focused on understanding direct impacts occurring at the seafloor or in the water column such as the removal of substrate, the suspension of sediment or the creation of particle plumes. Impacts occurring above the sea surface have thus far rarely been considered. The operation of deep-sea mining equipment, as well as of mining and transport vessels will be associated with a considerable energy demand. In the open ocean, this energy will be provided by heavy fuel oil (HFO), which is the cheapest and most common marine fuel. The combustion of HFO will be associated with the release of greenhouse gases and other pollutants. Deep-sea mining will thus directly add to already critical air pollution levels caused by international shipping. To contribute to a holistic assessment of deep-sea mining impacts and to address the previously outlined knowledge gap, we present the methodology to quantify the fuel consumption and associated emissions of a potential typical commercial manganese nodule mining operation in the Clarion-Clipperton Zone (Fig.1). Using the mine set up and energy demand estimates from a study commissioned by the German Federal Ministry of Economic Affairs and Energy supplemented by information from literature, we anticipate emissions of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrous oxide (NO2), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter and non-methane volatile organic compounds.

Jan 1, 2018

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 Michael R. Gipp

Marine Mining Inc. is currently exploring for marine alluvial gold and diamonds on a prospecting licence over a concession that covers 10,000 km2 of the continental shelf of Ghana. The boundaries of the concession extend from 0 30'W to 2 40'W, and between the shoreline and approximately the continental shelf edge north of 4 30'N. This concession extends from Kikam Beach in the west, to Senya Beraku in the east, a distance of approximately 240 km, and seaward an average of about 40 km. The concession is entirely underwater, with the exception of the estuaries of the Ankobra and Pra Rivers. Ghana has been a large source of alluvial gold, with historical production exceeding 25 million ounces. Southwestern Ghana is characterized by Precambrian rocks, which have been folded into a number of NE-SW trending synclines and anticlines. The most significant feature of the Birimian rocks is the presence of evenly spaced gold-bearing greenstone belts. They are 10-15 km wide, separated by about 90 km, separate basins filled by folded metasediments and granitoids. The rivers that enter the concession drain most of the exposed gold-bearing belts of Ghana. Given that approximately 2 km of erosion has taken place since the Mesozoic, and that gold mines on these belts boast proven reserves of over 55 million ounces, it is likely that large amounts of gold have been eroded out and carried to the sea. Coastal fractures, related to Precambrian structures reactivated during Mesozoic rifting, are responsible for the physiography of the coastal area, which consists of high-relief horsts separated by grabens that have been occupied and infilled by rivers or by finer sediments during times of elevated sea level. These fractures were loci of gold mineralization during the Precambrian, and are the source of alluvial gold in rivers confined by them.

Jan 1, 1998

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 Janine Lahr, Peter E. Halbach

The Manus Spreading Ridge is located within the EEZ of Papua New Guinea and lies in the Manus Basin ENE of the PNG Island and N of the Island New Britain. The divergent backarc spreading system is caused by the subduction of the Solomon plate in the South under the Bismarck plate in the North along the lineament of the New Britain trench. The rate of divergence is relatively high compared to other back arc spreading systems and amounts up to 12 cm/year [3]. Since submarine volcanism and associated hydrothermal circulation as important parts of the oceanic heat transfer system are also dependent on the rate of spreading, hydrothermal fluid venting and respective deposition of polymetallic sulfides can be expected there. In late 1985 first indications for hydrothermal activity were observed on a swell within the central rift valley of the Manus Spreading Centre during a photographic survey of the seafloor by an expedition of the Hawaii Institute of Geophysics with the American RV Moana Wave [1]. Detailed geological investigations including successful sampling were first carried out in June 1990 within the scope of the OLGA II research project (conducted by Prof. Tufar, Marburg) using the German RV Sonne equipped with a deep-sea television sledge and Tvcontrolled grab systems. Simultaneously a research cruise with the Russian RV Akademic Mstivlav Keldysh took place using the manned submersible Mir; the findings of the OLGA II cruise were immediately used for planning and organization of the Mir dives [3]. The massive sulphide samples which we used for our geochemical and mineralogical studies originate from the hydrothermal fields 1 and 2 and are from grab stations of the OLGA II expedition [4].

Sep 24, 2006

By G. Cherkashov

A new hydrothermal field with massive sulfide deposits was discovered in 2004 at 16º 38.4?N, 46º 28.5?W on the Mid-Atlantic Ridge. Hydrothermal signals had already been recorded from bottom waters and sediments in this area during cruise 19 of R/V Professor Logatchev in 2000. This site was revisited during the 24th cruise of R/V Professor Logatchev in February 2004 when samples of massive sulfides were recovered and video records of the deposits made. The basalt hosted hydrothermal field is situated at a depth of 3700-3750 m, 600 m above the inner floor on the eastern slope of the rift valley. Structurally, the new field is located at the intersection of a deep along-axis marginal fault and a transverse sub-latitudinal dislocation. Six sulfide mounds as well as associated metalliferous sediments were mapped (sampled and/or recorded by video profiling) within the hydrothermal site. The largest ore body, 500 x 225 m, in the southern part of the field consists of small blocky talus and relics of sulfide chimneys partly covered by iron oxyhydroxides. The chimneys are 1-5 m high. The southern and western boundaries of the massive sulfide deposit have not yet been delineated. More than 1,100 kg of massive sulfides and stockwork mineralization were sampled at 7 sites by dredge and TV-grab. Everywhere, iron sulfides were the principal minerals present. Pyrite in association with lesser amounts of chalcopyrite occurs in both massive sulfides and stockwork mineralization. Of particular interest is the chalcopyrite-siliceous stockwork where silicified and chalcopyritized basalts are intruded by a network of chalcopyrite veinlets. These zones could be fairly thick and enriched in base metals. Sphalerite was very rare.

Jan 1, 2004

By Akira Usui

Occurrence of hydrogenetic ferromanganese crusts has been well documented over inactive seamounts in the central and southern Pacific Ocean. It has been thus believed that the hydrogenetic crusts develop preferentially at water depths between about 800 to 2500 meters. In fact, according to the Manganese Crust Database (F. Manheim, 1988), only two occurrences are known at water depths below 5000 m out of 819 occurrences cited in the database. Unexpectedly, we found typical hydrogenetic ferromanganese crusts from deep-sea floors; 1) outcropping old volcanic basement over the Philippine Sea Plate (abandoned spreading centers and subducting old oceanic crusts) and 2) one from the slope of an abyssal hill in the Central Pacific Basin (Cretaceous deep-sea basin) at water depths ranging between 5200 to 6100 meters. We report their occurrences with submersible observations from Shinkai 6K, physical parameters (such as thickness of crusts about 2-4 cm in maximum), chemical composition, petrology of substrate, and results of Be-10 dating for some samples in comparison with typical Co-rich manganese crusts from the Central Pacific seamounts. The preliminary chemical and mineralogical analyses reveal that they are of typical hydrogenetic origin, and typical of iron-manganese oxide mineral, vernadite, slow and probably continuous growth, and lower content of Co than the Central Pacific seamount crusts. The occurrences and nature of the crusts indicate that deep-sea floors are also optimal for the growth of hydrogenetic crust even at 5000 m water depth or deeper, only if oxygenated deep waters are supplied and the sea-floor morphology keeps stable enough for significant geological time period. Additional details of chemical analyses will be prepared by November and to be shown in the conference.

Jan 1, 2001

By Mikhail P. Torokhov

Typical coastal placers leave no doubt that placer accumulation can result in significant concentration of heavy minerals in marine shallow water environment. However, the same situation is quite predictable for guyot?s slopes at stages of submarine volcano formation and later submersion of guyots to a depth of up to 3-4 km. Where these placers could be found is also clear ? in coastal facies (as typical coastal placers), and in morphological traps down guyot slopes in zones of active submarine currents. The latter could be cracks in rocks, shallow depressions, spurs, and structures, such as coral reefs, stromatholiths, and even ferromanganese crusts. The last of these have been studied carefully by the author in the Magellan Seamounts and on the Mid-Pacific Rise: tens of minerals, including mineral forms of PGE, REE, Mo, W, Te, Cr, Co, Ni, Cu, &Zn were identified as a xenogenic (trash) minerals. The detailed study of polished epoxydized sections, showed that interstitial spaces of Fe-Mn botryoids are enriched in heavy minerals (predominantly titanomagnetite). Taking into account the irregular character of crust surfaces and their position in active water environment, we can definitely state that they are the ideal traps for placer minerals. Study of guyot basaltic matter showed the presence of similar REE, PGE minerals that are in the crusts, and the same (mostly) micron sizes of minerals. High content of PGE in some basaltic varieties (up to 1 ppm) suggests that this is a reasonable source of these elements in the crusts, rather than the water column (which is normally considered to be the case by most marine scientists). Predominance of Pt in hydrogenous (?) crusts is interpreted as due to the better stability of Pt mineral forms during weathering and transportation (these are isoferroplatinum, and silicides). Comparison of 143Nd/144Nd values in bulk crusts, heavy fraction of crusts, basalts, and water column supports the author?s idea, that a significant part of REE also comes from basaltic matter (in form of monazite, CeO2 etc.).

Jan 1, 2004

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

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

Jan 1, 2017

By Alexander Malahoff

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

Jan 1, 2005

The chemical composition of the nodules varies with the type of manganese minerals and the size and characteristics of their nucleus, but those who have an economic interest have the following composition: Mn 29%, Fe 6% Si 5%, Al 3%, Ni 1.4%, Cu 1.3%, Co 0.25%, Na 1.5%, Ca 1.5%, Mg 0.5%, K 0.5%, Ti 0.2 0.2% and Ba 0.2% (Morgan, 2000; ISA, 2002). The Pacific Rim is an area of abundant occurrence of polymetallic nodules (Glasby et al., 1980; Morgan, 2000). According to these authors, the Pacific sea floor of the Clarion-Clipperton Zone (CCZ) is one of the most interesting areas in regard to the genesis of polymetallic nodules. Their abundance in the ocean floor is very variable, as there are places where they cover more than 70% of the ocean floor. The nodules can be found at any depth, but the highest concentrations are between 4000 and 6000m (Morgan et al., 1993). In studies conducted in the EEZ of the Mexican Pacific are those made within the project "Research on the origin, process and distribution of minerals in the Pacific ocean floor in the Exclusive Economic Zone of Mexico". Within this project Rosales (1989) conducted studies on the origin, process and distribution of polymetallic nodules, finding that a number of processes give origin to nodules, being diagenesis one of the main mechanisms of elements that contribute to the nodules. Besides hydrothermal processes that are carried near the East Pacific Rise at 21° N, inputs are contributing to the nodules metallic elements and sediments, especially in regions close to the dorsal, as a greater influence hydrogenetic processes occurs westward (Rosales and Carranza, 1990). In 1993, after cruise MIMAR II, Carranza and Rosales refer that metals such as Cu, Co, Ni, Sn, Fe, Mg, Pb, Zn and Ba may have a relationship with the East Pacific hydrothermal activity and sea currents carry these metals in solution to the Clarion-Clipperton fracture area, where there are hydrogenic metals sources (Al, Fe and Mn).

Jan 1, 2011

By Dennis Sánchez Mora, John Jamieson

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

Jan 1, 2018