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By L. B. Khershberg

Marginal seas of the Russian Far East constitute the northwestern segment of the Pacific underwater belt distinguished by distinct metallogenic specialization of shelf-extended ore-bearing magmatic complexes and associated polycyclic mineralization. The coastal part of this vast region is known to contain both multiple placer manifestations and deposits, and non-metalliferous minerals. The latter are sedimentary deposits, the products of weathering, which contain re-deposited placer minerals in industrial concentrations developed on the shelf by certain geological processes. The shelf part of the Far Eastern seas is a seawater-filled continental margin. Complex geophysical mapping and drilling from ships of shelf sedimentary thickness and foundation has revealed the units of contemporary and ancient relief accompanied by formation of industrial concentrations of placer gold, cassiterite, titanium-magnetite, zircon, monzonite, and other components at different stages of placer formation. According to the information collected by prospecting by ?Dalmorgeologia? Co. Ltd. and other companies, placer-host structures within trans-placer-concentrating structures (land-shelf) are: shelf-extended river plains, contemporary and ancient shorelines, beaches, drained areas, spits, bars, detritus deficit zones, and terraces and bodies accumulated underwater in the areas where along-shoreline flows unload their detritus. They all could be used as criteria/signs for mapping and targets for placer prospecting.

Jan 1, 2004

By David S. Cronan

The traditional method of deep sea manganese nodule exploration is to conduct grid survey and sampling on successively finer scales until a suitable deposit has been delineated. Clearly this is both time consuming and ultimately self-defeating if large areas of the ocean floor are to be explored on a human timescale. A conceptual deductive approach would be preferable if one could be found, as it would aim to outline areas of potentially economic nodules on the basis of easily measurable oceanographic parameters. An attempt to achieve this aim in the Central Pacific is outlined below. Nodule Distribution in the Central Pacific Ocean Maps of ore grade nodules in the Central Pacific show that they are confined to two zones trending roughly east-west which are well separated in the eastern Pacific but which tend to converge towards 170-180ºW. They follow the isolines of intermediate biological productivity in the surface waters, strongly suggestive of a biological control on their distribution. Within these zones the nodules preferentially occupy basin areas. Thus they are found in the Penrhyn Basin, Tokelau Basin, Central Pacific Basin, Clarion Clipperton Zone and Tiki Basin. Nodules in all these areas have features in common and are thought to have obtained their distinctive composition by similar processes.

Jan 1, 2003

By S. W. Chang, James R. Hein, S-R. Lee, A. Zondervan, H. Choi

"Nine Fe-Mn nodules from the extensive nodule field in the east of Campbell Plateau of southwest Pacific Ocean beneath the Deep Western Boundary Current (DWBC) and Antarctic Circumpolar Current (ACC) were analyzed for the 10Be/9Be dating by AMS (Accelerator Mass Spectroscopy) at IGNS, New Zealand.Several types of nodule morphology were identified including distinctive discoidal forms with overgrowths resulting possibly from overcrowding and partial sediment burial. Five principal nodule facies were also recognized by location and occurrence (Fig. 1) (Wright et al., 2005). Fe-Mn nodules show various concentric internal growth textures, such as, cuspates, large parabolic cuspates, pseudo-columnar, columnar, globular, and laminated, which vary even in a nodule with hydrogenetic, early diagenetic, or mixed origin. Each texture shows micro-textural varieties and different mineralogy and/or chemistry. The genesis of each internal texture was indicated by the REE patterns, the mineralogy of Mnoxides, and the Mn/Fe ratios."

Jan 1, 2017

By Tatiana ?. Sedysheva, Vladimir V. Ivanov, Michail E. Melnikov, Irina A. Pulyaeva

"INTRODUCTIONHydrogenetic 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 [3, 4 - 8]. Now, commercial interests gain more and more attention. Mining systems are being developed which involve fragmentation of the crusts and their separation from the substrate. The effectiveness of such activities greatly depends on physico-mechanical characteristics of the crusts and rocks on which they form. This determines the importance of the engineering geological study of the objects.This article comprises the results of the engineering geological studies of the crusts samples (72 samples) and their underlying rock substrates (75 samples), which were carried out during the research cruises 6-06, 6-07, 6-08, 6-13 (2006-2013) on the Magellan Seamounts guyots in the Western part of the Pacific Ocean by the specialists of the State Scientific Centre Yuzhmorgeologia [10 - 13, 19, 20]. The authors of the article directly participated in the studies mentioned above.MethodsEngineering geological studies were carried out on board of the research vessel Gelendzhik and in the laboratories of NPA «Sevmorgeologiya». The studies involved the determination of the following parameters:"

Jan 1, 2017

By Usui Akira

Mode of occurrence and compositional variations of iron-manganese deposits from seamounts around the NW Pacific submarine island-arc area are described on the basis of on-site description during the Moana Wave Cruise MW9507 and other Japanese cruises, as well as geochemical and mineralogical analyses and dating on collected samples. Hydrogenetic and hydrothermal iron-manganese crusts occur at more than 80 sites out of 150 dredge hauls within a small area of 200x 200 km in the back arc region. The hydrogenetic crusts may have grown continuously at slow rates, but 2-3 times faster than those from the Central Pacific, associated with depletion of Co, Cu, and Ni contents. The site-maximum thickness of the hydrogenetic deposits trends to increase with the increase of distance from the active volcanic chain or the age of substrate volcanic rocks. Also the observed great local variations in thickness within single sites and on small scales may be resulted from post-depositional geological activity at the seamounts such as calcareous sedimentation, collapse of volcanic body and mass wasting,. On the other hand, the rapid hydrothermal manganese mineralization has occurred in place and time during arc volcanism and rifting and is still in progress at modern active areas. The ninety ICP/ES chemical plus XRD analysis show that these deposits are of distinct composition by origin or topographic provinces, but small-scale variation of the deposits of each origin and micro-scale depth variation are not clear.

Jan 1, 2000

By Thomas Kuhn

Germany?s industry heavily depends on the continuous import of mineral commodities such as manganese, copper, nickel, and molybdenum. Due to the strong increase in metal prices since 2002 Germany?s federal geological survey, the Bundesanstalt für Geowissenschaften und Rohstoffe (Federal Institute for Geosciences and Natural Resources, hereafter called BGR) applied for a license area for the exploration of deep-sea manganese nodules in the Pacific manganese nodule belt between the Clarion and Clipperton fracture zones. A 75,000 km2 covering license area was eventually granted to the BGR by the International Seabed Authority (ISA) in 2006. It is separated into two parts: ?W1? (17,000 km2) and ?E1? (58,000 km2; Fig. 1). The BGR obtained initial information on the abundance and grade of nodules in the license area from samples collected during three cruises with R/V Valdivia and one cruise with R/V Sonne between 1976 and 1978 (Rühlemann et al., 2009). Since the accuracy of navigational data obtained during these cruises is outdated and sample coverage is unevenly distributed and sparse in many parts of the license area, BGR has started a new exploration program to investigate the German license area according to the rules, regulations and procedures issued by the ISA for the exploration of Mn nodules in the Area.

Jan 1, 2010

By Andrew E. Grosz

The Atlantic Continental Shelf (ACS) of the United States includes about 391,000 km2 extending from the shoreline to the 200-m isobath. It varies in width from a fraction of a kilometer (offshore of southern Florida) to about 150 km (offshore of Cape Cod, MA). The contained volume, of sand and gravel is estimated to be on the order of 3-7 x 1.011 m3. Concentrations of potentially commercially important heavy minerals (HM) exist locally, particularly in high-energy depositional environments (for example in channels, tidal deltas, ridge and swale areas, and submerged former shoreline complexes). Recently completed and ongoing studies of HM assemblages in vibracore samples from the south shore of Long Island Sound, NY, offshore of Ocean City, NJ, offshore of Cape May, NJ, offshore of the mouth of Chesapeake Bay, VA, offshore of Myrtle Beach, SC (grab samples), and the ACS offshore of Florida provide the information base for this presentation (Table 1). The surficial sediments of the ACS contain local concentrations of HM that compare favorably to those in currently mined onshore deposits as shown

Jan 1, 1988

By Raymond A. Binns

Drilling into an active hydrothermal system linked to convergent-margin felsic magmatism is a listed priority of the Ocean Drilling Program that addresses several fundamental geoscience issues. Solid and fluid products of felsic rock-water interaction, and the consequences for global chemical fluxes and for ore deposition, should differ from those in basaltic mid-ocean ridge environments already successfully tested by Legs 106, 139, 158 and 169. So, too, will fracturing controls on fluid pathways, and sources for metals and ligands. Researching the subsurface volcanic, structural/hydrologic, and mineralisation/alteration architecture of a drilled felsic-hosted system also has economic implications, especially for land¬based mineral exploration. A first-order hypothesis to be tested states that fluids derived from volatile-rich magmas are more important than recirculated seawater in convergent-margin hydrothermal systems - economic geologists increasingly appeal to this for creating "world-class" massive sulfide orebodies. Another hypothesis proposes "subhalative" massive sulfide deposition within hydraulically expanded volcanic products as a factor in generating large orebodies. Many second-order hypotheses such as leaching fractionated volcanics to cause gold enrichment in back¬arc systems also need testing. The thoroughly surveyed, active, PACMANUS hydrothermal field in the Eastern Manus back-arc basin of Papua New Guinea will be the site for ODP Leg 193 commencing in November 2000. It lies near the crest (1655-1750 m) of high-standing Pual Ridge, a 40 km-long edifice of dacite/rhyodacite with basal andesite all having geochemical and isotopic affinities with modern arc volcanoes of nearby New Britain. PACMANUS includes at least three focussed, high-temperature "smoker" sites with Cu+Au-rich massive sulfide deposits, and a field of diffuse, lower temperature venting through intensely altered dacite where modelling indicates significant subsurface mineralisation. Isotopic characteristics of deposits and vent fluids suggest magmatic contributions to the mineralising fluids.

Jan 1, 2000

By Ulrich Schwarz-Schampera

Submarine hydrothermal vents and associated mineralization on the Tonga arc have been identified in the summit calderas of two shallow-water volcanoes. The highest temperature vents (up to 270°C) occur at water depths between 430 and 540 meters below sea level (mbsl) near the summit of one volcano at 24°S (volcano 19). Clusters of large barite, anhydrite, and sulfide chimneys on the summit cone are vigorously discharging clear hydrothermal fluids with temperatures on the seawater boiling curve. There is abundant evidence of phase separation and associated gold and base metal precipitates. Pyrite, marcasite, wurtzite-sphalerite, tennantite, and chalcopyrite line the interiors of the highest temperature vents. Acid-sulfate alteration of basalts and basaltic andesites is evidenced by intense silicification and the presence of abundant alunite. One volcano at 21°S (volcano 1) has a chain of explosion craters on the flank of a neovolcanic scoria cone and associated massive pyrite, barite and native sulfur deposits at a water depth of 210 mbsl. Intergrowths of pyrite and enargite are associated with intensely argillic altered basaltic andesites. The reported alteration and Au-enriched mineralization styles of these vent fields are similar to other shallow water hydrothermal systems at island arc volcanoes and contribute to the diversity of seafloor hydrothermal activity in the western Pacific region.

Jan 1, 2010

By Fernando J. A. S. Barriga

"Recent concerns over the availability of many mineral raw materials, and newly available technological developments, produced renewed interest in deep-sea mining. However, environmental concerns, with variable degrees of justification, are raising opposition to the concept. The forecast for the behavior of consumption versus availability of many raw materials, nearly all critical metals, arguably show that consumption will grow much faster than resource discovery onshore. Finding new sources of raw materials seems inescapable. The deep seafloor stands out as the only likely candidate.Sea Floor Mining and the EcosystemMarine mining has already started, decades ago, for diamonds, currently up to depths near 400m. Although the industry recognizes there is a footprint, it considers the footprint quite minor, because the area mined is small: in Namibia, where offshore diamond mining is now 70% of the country’s total, only 3% of the concession of 3,700 sq miles (9600km2) have been mined. As plans to mine deep-sea massive sulphide deposits and polymetallic nodules progress, the environmental concerns grow. Some of these concerns are as follows:?The deep-sea ecosystems are composed of long-lived species, with low rates of reproduction. The environment may not recover from mining on a human time scale;"

Jan 1, 2017

By G. B. Carpenter

The United Nations Law of the Sea (LOS) Convention includes provisions (Article 76) for establishing the outer limits of a coastal State's continental shelf and for denoting the seaward extent of sovereign rights over natural resources. Determination of a coastal State's continental margin, according to Article 76, must consider eight factors: 1. The territorial sea baseline 2. The 2,500-meter isobath 3. The foot of the continental slope 4. A line 200 nautical miles seaward of the territorial sea baseline 5. A line seaward of the foot of the continental slope connecting the points where sediment thickness divided by distance to the foot of the slope equals .01 6. A line 60 nautical miles seaward of the foot of the continental slope 7. A line 100 nautical miles seaward of the 2,500-meter isobath 8. A line 350 nautical miles seaward of the territorial sea baseline Figure 1 shows the preliminary limits for each of the Article 76-based definitions for a portion of the U.S. Atlantic continental shelf. The additional areas gained beyond the 200- nautical mile Exclusive Economic Zone (EEZ) are highlighted. The first three factors are baselines from which the distance provisions of Article 76 are measured. Factors 4-8 are distance- from-baseline provisions for establishing the continental shelf limits. Factor 5, also known as the Depth of Sediment Limit or "Irish Formula", was calculated using sediment thickness data from seismic linesand isopach maps. All other factors were determined from digital hydrographic data. The Depth of Sediment Limit is the most advantageous method for the area shown in Figure 1. It is especially useful for introverted coastlines such as the Georgia Embayment and New York Bight areas. The 200-mile line is advantageous for protruding coasts such as those off major capes, e.g., Cape Hatteras. The 2,500-meter isobath plus 100-mile line gains

Jan 1, 1995

By Grigori Abramov

As we enter into the 21st Century, miners are looking more attentively at new mining technologies allowing decrease environment damage along with operational cost. This technic would allow developing of poor and difficult mineral deposits, including the World Ocean offshore zone. Borehole Mining is an underground/underwater remote method of mining carried out from floating platforms or vessels. Definition of Borehole Mining (BHM), working schematic, main technical data and its advantages are given. The method is currently in use in mining of different type of raw materials, such as: uranium, iron ore, quartz sand, coal, polymetallic ores, phosphate, gold, diamonds, rare earths, amber and more. It is also in use in oil and gas stimulation, salt domes storages building and environmental problems solution. Recently recorded data of Borehole Mining productivity (80-100 t/hour/hole) and a depth of mining (over 1 km) has been achieved in a last couple years. Remoteness of method not only secures complete safety of operations but also allows wide sector of underwater applications. The World leaders in Borehole Mining are Russia and the United States. Based on previous experience the Universal Tool for Seabed Borehole Mining has been developed for wide sector of usage: from exploration and mining - through oil & gas stimulation to souterrain storages construction and lake's bottom cleaning.

Jan 1, 2000

By Charles L. Morgan

In June 1996, the United Nations International Seabed Authority opened shop in Kingston, Jamaica as an autonomous international organization charged with the administration of seabed mineral developments in all areas beyond national jurisdictions. The Authority is a consequence of the 16 November, 1994 entry into force of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and the 1994 Agreement relating to the Implementation of Part XI of UNCLOS. The total seabed area included within the Authority?s purview has yet to be assessed accurately, but clearly constitutes the largest single jurisdiction on the planet. The Authority is governed by legislative bodies called the Assembly and the Council and an administration called the Secretariat. The Assembly includes representatives of the 132 member states which are currently parties both to UNCLOS and to the 1994 Agreement. These member states directly fund the operations of the Secretariat. They include most of the world?s developed nations, island nations, and others among the 188 independent countries which are members of the United Nations. Notably absent are the United States and Canada, which are the only developed coastal states not represented. The Council is a 36-member subset of the Assembly representatives selected through a somewhat involved process designed to achieve a balanced representation of the specific interests of the members. Ultimate responsibility for the Authority?s actions resides in the Assembly, but most initiatives originate in the Council. Also included in the Authority are two subsidiary advisory bodies, the Finance Committee, which reviews the Secretariat?s budget, and the Legal and Technical Commission, which evaluates claims and drafts technical regulations. The Secretariat itself includes a staff of about 30, including 15 highly qualified and competent attorneys, accountants, engineers, and scientists. Details describing the composition and activities of these bodies can be found at the Authority?s website (http://www.isa.org.jm).

Jan 1, 2000

By James R. Hein

Ferromanganese oxyhydroxide crusts (Fe-Mn crusts) precipitate out of cold ambient seawater onto hard-rock surfaces at water depths of about 600-4000 m throughout the ocean basins. Fe-Mn crusts concentrate most elements in the Periodic Table above their mean concentration in the earth's crust (continental plus oceanic crust), except for the major rock-forming oxides and also notably gold and palladium. Tellurium is concentrated greater than any other element relative to its earth's crust mean (about 1 ppb). For example, mean contents of the elements heretofore known to be most enriched in crusts, Mo, Tl, Sb, Co, Mn, Bi, As, Se, and Pb are enriched 100 to 1000 times over their earth's crust mean, whereas the mean Te content in Fe-Mn crusts is enriched about 50,000 times. However, the distribution of Te in the earth is poorly known. Estimates of the mean Te content of the earth's crust range from 0.36 to 10 ppb, with 1 ppb being the most commonly cited mean content (compilations in Levinson, 1974 and Govett, 1983). If we took the highest estimate of 10 ppb, then Te would be enriched in Fe-Mn crusts five times more than the next most enriched element, or 5000 times the estimated maximum mean earth's crust.

Jan 1, 2000

By Tetsuo Yamazaki

Manganese nodules on deep ocean floors have continuously received attention as potential sources for strategic metals such as Co, Ni, Cu, and Mn, due to their vast distribution and relatively higher metal concentrations (Mero, 1965; Cronan, 1980). Several registered Pioneer Investors have already identified promising sites in deep-sea regions for manganese nodule mining (ISA, 1998), and appropriate mining technologies have been developed during the last thirty years by the international consortium and several nations (Welling, 1981; Kaufman et al., 1985; Bath, 1989; Charles et al., 1990; Yang and Wang, 1997; Yamada and Yamazaki, 1998; Hong and Kim, 1999; Muthunayagam and Das, 1999). The mining feasibility for manganese nodules, including an economic evaluation, has been examined in detail by some researchers (Andrews et al., 1983; Hillman and Gosling, 1985; Charles et al., 1990; Soreide et al., 2001).

Jan 1, 2011

By S. Rajendran

Gas Hydrates (Methane Hydrates) are solid, ice ? like substances composed of water and natural gas. They occur naturally in areas of the world where methane and water can combine at appropriate conditions of temperature and pressure and are found in the ocean bottom sediments and in some permafrost areas. Besides temperature and pressure, factors like bathymetry, sediment thickness, sedimentation rates, and total organic carbon content (TOC) also control gas hydrate formation in the sea. The stability of gas hydrates depends on the critical high pressure ? low temperature combination (0-17 bars, 0-25ºC), which in turn dependent on the mix of gases from which the mineral is formed. As the critical parameters can be altered by deposition, erosion or slumping of sediments, formation or melting of ice cover, rise and fall of sea level and sudden temperature changes induced by tectonic activities, current flows or volcanisms, the gas hydrates tend to be very unstable. It is becoming increasingly evident that naturally occurring gas hydrates are significant component of the shallow geosphere and are of societal concern in at least three major ways: as an energy resource, a geologic hazard and a major contributor for climatic changes.

Jan 1, 2010

By T. Schoening

The exploration of the seafloor regarding the abundances of poly-metallic nodules has received growing attention recently. Image-based exploration using cameraequipped deep-sea observation systems has been introduced successfully to increase spatial resolution in the exploration process but the evaluation and interpretation of the huge amount of image data creates a serious bottleneck. In this paper we present a new software solution to the problem of automatic detection and segmentation of poly-metallic nodules in underwater images, which is not only accurate but so fast that real time image analysis is definitely in reach. Thus, an application on an AUV (Autonomous Underwater Vehicle) seems possible in the near future.

Sep 14, 2011

By Natalia Konstantinova, Kira Mizell, James R. Hein, Georgy Cherkashov

"Ferromanganese crusts and nodules from the Amerasian basin of the Arctic Ocean are characterized by a unique composition compared to crusts formed elsewhere in the global ocean (Konstantinova et al., 2017; Hein et al., 2017). One of the most significant differences from global ocean crusts is the high detrital mineral content; mass balance calculations show that it may be as high as 35% in some samples (Hein et al., 2017).These Arctic Ocean Fe-Mn crusts also typically have three distinct megascopic layers, except for thin crusts; less commonly, four layers are noted for thick crusts. The age of initiation of Fe-Mn crust growth in the Amerasia Basin varies from 14.8 Myr to 0.7 Myr ago based on the Manheim and Lane-Bostwick (1988) Co chronometer, Be isotopes, and Th excess methods (Dausmann et al., 2015; Konstantinova et al., 2017; Hein et al., 2017).Samples and MethodsFourteen Fe-Mn crust samples recovered on Russian and U.S. research cruises were chosen for analyses based on their morphology, composition, water depth, genetic type, and location in Amerasia Basin. Seven samples from four distant dredge sites along Mendeleev Ridge and seven samples from four locations on the Chukchi Borderland are included (Fig. 1). Dredge site water depths vary from 3850 to 2100 m with the deepest samples from the Chukchi Borderland. Many of the selected samples were described in previous publications (Konstantinova et al., 2017; Hein et al., 2017)."

Jan 1, 2017

By Jai-Woon Moon

Lemkein seamount located in the west of the Kuwajleen Atoll of RMI is a relatively samll, simple-shaped, peaked type seamount with its base at 4,500 m and summit at 1,452 m water depths. Ferromanganese crusts were identified in the water depth range between 2,000 m and 2,500 m, and they were mostly observed on the northern slopes of the seamount. Among various substrate rocks, breccia occurred most commonly with crusts and formed the thickest crust layers. Average thickness of the Lemkein crusts was about 5 cm. Their chemical compositions were similar to other crusts found in the RMI area; Mn=25.82%, Fe=15.29%, Co=0.74%, Ni=0.56%. Lemkein crusts were characterized by their four distinctive internal layers; 1) Massive Layer 1; 2)Porous, Fe-stained or sediment infilled Layer 2; 3) Massive to slightly porous Layer 3; and, 4)Massive, Dense, Phosphotized, CFA veined Layer 4. Layers 1 and 2 were generally similar in composition, but highest Co concentrations were measured in Layer 1 while relatively higher concentrations of Al, Rb, Fe, and Ti were observed in Layer 2. Layer 3 showed higher concentrations of Ca and P than Layers 1 and 2. Based on the Co-chronography, the age of Layer 1 is 0¡?6 Ma (growth rate = 1.50 mm/Ma), Layer 2 is 6¡?15 Ma (1.75 mm/Ma), Layer 3 is 15¡?27Ma (1.76 mm/Ma), and Layer 4 is 27¡?45 Ma (2.06 mm/Ma). These preliminary results indicated that high Co contents in Layer 1 resulted from slow growth rates; Layer 2 was formed under relatively strong influence of high terrestrial input; and, Layer 3 was probably affected by a minor phosphatization event occurring in 15 Ma.

Jan 1, 2000

By Cornel E. J. de Ronde

Volcanic arcs, including both island arc and intra-oceanic arc systems, combined extend for ~22,000 km around the Earth, with the majority (~20,000 km) occurring in the Pacific basin. These arcs are host to over 700 volcanoes of which ~200 are submarine and as such represent great potential for hosting massive sulfide deposits formed at seafloor hydrothermal vent sites. The Kermadec arc extends for ~1,200 km northeastwards from the North Island of New Zealand and forms the southern part of the ~2,500-km-long Tonga-Kermadec intra-oceanic arc system. At least 94 volcanoes are known to exist along this system with 74, or about 80%, being submarine. At least 33 volcanoes occur along the Kermadec part of the arc with all but one (Raoul Island) being submarine. The first sulphides recovered from the entire Tonga-Kermadec arc were in 1996 from the Brothers and Rumble II West volcanoes of the southern Kermadec arc. The 1998 R/V Sonne research cruise recovered a more comprehensive suite of mineralised samples from Brothers, and also found evidence for hydrothermal venting at Monowai, Vulkanolog, Rumble III and Clark volcanoes. The March 1999 NZAPLUME cruise systematically surveyed 260 km of the southern Kermadec arc and found that 7 of 13 volcanoes were hydrothermally active, with the vent fields either located within calderas (e.g., Brothers, Healy, Rumble II West) or atop volcanic cones (e.g., Clark, Tangaroa, Rumble V, Rumble III). The May 2002 NZAPLUME II cruise surveyed a further ~580 km of the mid-segment of the Kermadec arc, from Brothers to volcano 'L', a submarine volcanic edifice 35 km NW of Macauley Island. This cruise surveyed 13 major volcanoes and 8 smaller volcanic edifices and confirmed hydrothermal venting at the Vulkanolog site, and discovered new vent fields atop a volcanic cone within Macauley caldera, immediately offshore Macauley Island, and another at the summit of volcano 'L'. A further new site was found atop a volcanic knoll immediately S of Healy caldera during time-series sampling of the vent sites found during the 1999 cruise. All the vent sites discovered along the Kermadec arc occur in water depths between 1650 and 150 m.

Jan 1, 2002