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By Marlene Olivares Cruz

The particles that make up the deep-sea sediments have two main sources: 1) those that are created in situ from dissolved components and 2) those that are washed into the ocean in solid phases from the continents, atmosphere, space and interior of the Earth. Many particles as they sink through the water column reaches the seabed and are known as pelagic sediments with terrigenous, biogenic, authigenic, and cosmogenic components. Among the minerals found in the terrigenous fraction of pelagic sediments are quartz, clay minerals, feldspar, micas, ferromagnesians, and the biogenic fraction with remains of siliceous organisms, such as, radiolarian and diatoms. The chemical nature of marine sediments is controlled by the contribution of particulate matter derived from various sources with varying compositions for the fixing of elements during deposition and the compositional changes carried out within the sediments during diagenesis. In the last decade there have been several studies on the mineralogical composition of seabed sediments, suspended particulate materials and cores, together with paleontological and geochemical data are used for paleoclimatic and paleoenvironmental reconstructions, analyze changes in sea level, stratigraphic correlations and identify past and

Sep 14, 2011

By Laura Moore

The southern shoreline of Monterey Bay, extending from Moss Landing to the Monterey Peninsula, consists of sandy beaches backed by an extensive Flandrian and pre-Flandrian dune complex. This length of shoreline, proximal to areas of urban expansion, is currently being considered for development. For this reason, it is extremely important to understand the variability of beach and dune position along this stretch of coast through time. Previous studies of southern Monterey Bay have documented relatively high erosion rates of 2-8 ft/yr due to a net deficit in the sand budget. Although the sediment transport system in this region is not well understood, estimates for the sediment deficit in southern Monterey Bay range from 200,000 to 1,500,000 yd3/yr. A possible cause of the erosional regime in the southern bay is the removal of sediment by coastal sand mining operations. Based on agency reports and mining permit applications, approximate volumes of sand removed by mining range from 300,000 to 450,000 yd3/yr. These volumes are significant when compared with estimated values for the sediment budget deficit. The sand of southern Monterey Bay, a valuable commercial resource because of its hardness, roundness, amber color and range of usable grain sizes, has been removed from the surf zone, beaches and dunes of Marina and Sand City by four companies since 1906. Information regarding the cross-shore location of sand removal and the exact amounts of sand removal through time is proprietary and poorly documented. However, records documenting the time at which each company commenced and terminated mining do exist. This information suggests that the greatest amount of sand was removed between 1950 and 1968 when three mining companies were operating concurrently.

Jan 1, 1994

By Porter Hoagland

It is well known that significant quantities of mineral deposits exist in the oceans. Most of these resources cannot yet be classified as economic "reserves" in the strict sense of the term, but they serve as backstops to deposits of identical minerals produced onshore. The prospects for the commercialization of ocean mineral resources will depend upon factors affecting both supply and demand, including, among other things, changes in consumption patterns, technological developments, new discoveries, developments in markets for complements and substitutes, and environmental regulation. In this presentation, we examine broad trends in mineral prices, as one of the most summary measures of the prospects for the commercialization of ocean minerals. Further, we report on any recent developments in the relevant product markets that may affect the potential for commercialization.

Jan 1, 1996

By R. D. Hamer

"The Atlantis II Deposit comprises metalliferous sediments (Zn+Cu+Ag+Au) accumulating in a composite, axial basin, 2,000m beneath the surface of the Red Sea. The basin contains warm, highly saline water. It is located approximately half way between Jeddah and Port Sudan within the Exclusive Economic zones of Saudi Arabia and Sudan. The Deposit was discovered in 1963 and evaluated by drilling in the 1970s and 1980s. This phase defined an initial resource of approximately 90Mt. More recent estimations have refined this figure to an Inferred Resource of approximately 80Mt (CIM compliant).The Mining Licence to develop and extract the Atlantis II Deep Deposit was granted to Manafai International Trade in 2010 by the joint Saudi-Sudanese Red Sea Commission. Manafai is poised to embark on a renewed phase of exploration and evaluation, including the completion of a Definitive Feasibility Study (DFS) and leading to the successful exploitation of the Deposit in a safe, environmentally sound, economically viable and socially responsible manner.The Deposit is forming in a complex basin adjacent the median rift, where sea floor spreading has operated during the last 5Ma. It is a Hydrothermal-sedimentary Deposit. The mineralised sedimentary rocks rest directly on sea floor basaltic rocks. They are produced by the exhalation of metal-rich, hydrothermal brines from fissures associated with the central rift and cross-cutting fracture zones. Up to 25m of metal-rich sediments have accumulated over an area exceeding 57km²."

Jan 1, 2017

By P. U. W. Appel

Despite the very large offshore Exclusive Economic Zone (EEZ) area of Greenland (in excess of 2 mill. km2) virtually no work has been carried out on marine minerals on the ocean floor. Apart from a single reconnaissance survey by a mining company, major activities have been those of oil companies exploring the West Greenland shelf in the early seventies. The West Greenland shelf and its extensions is the most obvious area for year-around accessability when looking for marine mineral deposits. So far, only one onshore placer deposit has been found - ilmenite deposit near Thule, NW Greenland, whereas a gold placer in South Greenland presently is being evaluated.

Jan 1, 1988

By Alexey Musatov, Georgy Cherkashov

Based on geochronological data it was confirmed that hydrothermal discharge has an episodic character: active and inactive periods of the seafloor massive sulfides (SMS) formation alternate (Cherkashov et al., 2017). There is an assumption of correlation of the periods of magmatic and hydrothermal activity with the stages of glaciation (Lund et al., 2016). During the cold periods, the level of the ocean was reduced from 70 to 150 m depending on the glaciation scale (Spratt, Lisiecki, 2016). As a result, the hydrospheric pressure on the upper mantle decreased and could provide increased magmatic and hydrothermal activity (Lund, Asimow, 2011). This assumption is confirmed by the correlation of warming and cooling stages with increasing of hydrothermal input to the bottom sediment near hydrothermal fields. According to data (Lund et al., 2014, 2016; Middleton et al., 2015) the peaks of hydrothermal activity, expressed in the layers of metalliferous sediments at the East Pacific Rise and the Mid-Atlantic Ridge, roughly correspond to the last two periods of cooling (20 and 60 ka). To test this hypothesis, we tried to compare the sequence of warm and cold periods in the Pleistocene with the dating of SMS reflecting the periods of hydrothermal activity. Results SMS samples were obtained from 12 sites within the Russian Exploration Area at the MAR segment 12-20°N. The results of dating 198 samples by the 230Th/U method demonstrated the absence of correlation between hydrothermal activity periods in different hydrothermal fields (Cherkashov et al., 2017). It was proposed that each field has its own evolutions scenario. Considering this point, only the oldest SMS dating for each field which fixed the beginning of hydrothermal activity was selected for comparison with the cold/warming periods.

Jan 1, 2018

By H. L. Gibson, U. Schwarz-Schampera, Mark Hannington

Ancient ore deposits provide important clues for the understanding of the origin and distribution of modern submarine hydrothermal systems. An analysis of the formation conditions, tectonic settings, and preservation of ancient seafloor mineral deposits from the recent geological past to the late Archean sheds light on the time-space relationships and diversity of mineral deposit types likely to be found in the modern oceans. Microplate tectonics that characterized ancient ore-hosting greenstone belts were strikingly similar to those active in volcanic arc environments of the western Pacific today. In such complex settings, oblique collisions, opposing subduction zones, and rapid changes in stress regimes (e.g., from compressional to tensional and back to compressional) were common, causing juxtaposition of diverse styles of mineralization. The world-class base metal deposits of the late Archean Abitibi greenstone belt of Canada, for example, were formed within a relatively short time span of ~20 m.y., in response to successive arc rifting, back-arc basin development, and exhumation of accretionary complexes along major arc-parallel crustal-scale faults. Similar processes and environments are important settings for metallogenesis in modern submarine volcanic arcs. Active marginal basins of similar size and representing similar stages of evolution are well represented in the western Pacific today and contain a similar suite of mineral deposit types. Examples from the eastern Manus Basin and adjoining New Ireland Basin (PNG) and in the Lau-Tonga-Kermadec arc-backarc system illustrate these similarities. Certain gold-rich volcanogenic massive sulfide deposits at the southern margin of the Abitibi greenstone belt (e.g., Bousquet and LaRonde deposits in the eastern Blake River Gp.) may be important ancient analogs of newly discovered gold-rich black smoker deposits found along the active fronts of today's submarine volcanic arcs.

Sep 24, 2006

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 nucleus, generally : Mn> Fe> 6> Si> Al> Ba> Ni> Cu > Co. The Pacific Rim is an area of abundant occurrence of polymetallic nodules and 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 6000. Hydrothermal processes that occurs near the East Pacific Rise at 21° N, may inputs metallic elements to nodules and to pelagic sediments, especially in regions close to the dorsal, as a greater influence hydrogenetic processes are present westward Metals such as Cu, Co, Ni, Sn, Fe, Mg, Pb, Zn and Ba show 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).

Sep 14, 2011

By Tao Chunhui

The seabed deposits type and distribution are very complex at the hydrothermal field. In this paper, we provided an approach to study the seabed deposits classification at the Precious Stone Mountain hydrothermal field (PSMHF) using MultiBeam sonar data . The PSMHF was found in the Galapogas microplate at the Leg 3 of the Chinese COMRA 21st Cruise. Using this approach, the seabed deposits at the PSMHF are mainly classified into three types, which are rock, breccia and sediment, respectively. We can find the distribution of the three types of seabed deposits according to the sonar backscatter data. The rocks are mostly distributed around the hydrothermal vent. The breccia are located at the foot of the vent. Most sediments are distributed at the southwest to the vent due to bottom current. Combining with seabed video, TV-Grab sample and the backscatter data, we draw the map of the seabed deposits distribution at the PSMHF.

Sep 14, 2011

By Tetsuo Yamazaki

Natural methane hydrate has been scientifically studied as a carbon reservoir globally. However, in Japan, the potential for energy resource has been industrially highlighted. There is less domestic oil and natural gas resources in Japan, but many potential deposition areas for methane hydrate in ocean around Japan are the reasons. Less CO2 discharge from methane compared with coal, oil and conventional natural gas when the same calorie value we get is considered as the advantage for energy resource. However, because methane hydrate distributes in shallower sediment layer in ocean floor, accidental leakage of methane may occur while we utilize methane hydrate. Methane itself has 21-times impact on the greenhouse effect, if it reaches the atmosphere. Therefore, it is necessary to estimate the behavior in the environment after the leakage, if we want to use methane hydrate as energy resource. The mass balance after leakage of methane on seafloor and in water column is numerically studied through the analyses of methane emissions from natural cold seepages and hydrothermal activities in this research. The outline structure of mass balance ecosystem model shown in Fig. 1 is introduced. A numerical early diagenetic model CANDI (Carbon And Nutrient Diagenesis) developed by Boudreau (1996) for simulating the biogeochemical processes such as organic matter, oxidant, nutrient, bi-product, and pH diagenesis in aquatic surface sediments and C. CANDI improved by Luff and Wallmann (2003) for describing the formation process of calcium carbonates in CANDI are used as bases of the ecosystem modeling in surface sediment layer around seafloor methane emission. Two functions such as methane bubble dissolution and bacterial methane oxidation in water column are added to an existing physical plume dispersion model by Doi et al. (1999).

Jan 1, 2005

By Yuta Yamamoto

Seafloor massive sulfides (SMS) which contain Au, Ag, Cu, Zn, and Pb have been interested in as a target of commercial mining these 15 years. Japan has large potential of SMS and a national R&D project for the mining has been active these 5 years. However, the economy of SMS mining is very bad, because the waste tailing disposal cost is very expensive in Japan. A slurry flushing method is experimentally examined in this study for the improvement of the economy. During the flushing, because of density difference between the metal-rich ore and the waste rock, a kind of gravity separation is possible. The results suggest a possibility of the actual application.

Sep 14, 2011

By Sup Hong

Herein, concept designs of two different types of mining robots are concerned, which are aimed for developments of deep seabed mineral resources: polymetallic nodules (PMN) and seabed massive sulfides (SMS), respectively. Continuous mining concepts are presented based on technical and environmental feasibility, where the environmental and functional differences for commercial productions are investigated. Needs and roles of versatile mining robots are explained as a key of continuous mining system. The functional requirements and design characteristics of mining robots to satisfy the top requirements from customers are described comparatively. Schemes of axiomatic design and quality function deployment (QFD) are utilized: functional requirements (FR) are defined, technical requirements (TR) are figured out, design parameters (DP) are derived, and degrees of importance of design parameters are evaluated. Analogy and discrepancy in remote operation methods are put side by side. A pilot scale mining robot for PMN and a commercial scale one for SMS are suggested in form of concept designs. PMN mining robot is shaped as a multiple configuration of unit robot modules in side dimension, in which the unit robot module consists of two tracks and two pick-up modules. SMS mining robot is based on a four-tracked vehicle. Main platform is mounted on the vehicle through turn-table. Excavation device consists of two-articulated boom and cutter tool. Crushing-and-pumping units are placed same in both robot platforms.

Jan 1, 2011

By Takafumi Kasaya, Katz Suzuki, Yoshifumi Kawada

"INTRODUCTIONThe area beneath the seafloor preserves valuable resources that are inevitable to sustain our industrial society. Hydrocarbon resources such as petroleum and natural gases are one of the representative examples, which have been mined over a century (Brandt et al. 1998). In addition, submarine resources such as methane hydrates, ferromanganese crusts, and metal deposits of hydrothermal origin have long been known (Rona 2003; Kvenvolden and Rogers 2005), although methods of their mining have not yet been developed. All of these resources are distributed heterogeneously, and various exploration techniques have been developed and examined. The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) is conducting a project on the development of exploration methods of these unexploited resources (Urabe et al. 2015; also see http://www.jamstec.go.jp/sip/images/pamphlet_e.pdf). The present study particularly focuses on our attempt on the developing an exploration method of hydrothermal ore deposits.Seafloor hydrothermal ore deposits are associated with submarine volcanoes of mid-ocean ridges, hot spots, and island arcs, and back arcs (Hannington et al. 2010). Active hydrothermal systems discharging high-temperature fluids can be detected above the seafloor as anomalies of temperature, turbidity, and acoustic impedance (e.g. Kasaya et al. 2015). However, because of the temperature limitation of mining (Boschen et al. 2013), the target of mining may be extinct and probably buried. To explore buried hydrothermal ore deposits from the vast seafloor area, geophysical surveys that can obtain information below the seafloor must be required. Several techniques including magnetic, electrical, and gravitational methods have been developed (e.g. Jones 1999; Kowalczyk 2008). Although physical properties taken by these methods are sensitive to the presence of hydrothermal deposits, difficulties are sometimes encountered. For example, anomalies of magnetic susceptibility and electrical conductivity, which characterize the presence of ore deposits, may be found above non-hydrothermal bodies such as volcanic bodies and reservoirs of hydrothermal fluids (e.g. Honsho et al. 2016). Thus, combinations of multiple methods must be used to specify the existence of buried hydrothermal ore deposits"

Jan 1, 2017

By H. Oda, L. E. Fong, K. K. McBride, B. P. Weiss, F. J. Baudenbacher, A. Usui

Fine-scale dating is a key parameter in characterizing the growth history of hydrogenetic ferromanganese crusts. We once compared several dating methods, micropaleontological (calcareous nanofossil), radiometric (10/9Be), and paleomagnetic (step-wise measured inclination) methods on single samples, but these independent methods were not consistent with each other (Joshima & Usui, 1999). For example, a 4-cm thick crust was dated as 3Ma by the fossil-paleomagnetic combined method, while it dated older than 5.5 Ma by Be-10 dating. This discrepancy suggests a question if the Be-10 radiometric method can give us false ages or growth rates (Usui et al., 2002) because of post-depositional change, diffusion or other reasons. In order to answer the question, we conducted ultra-fine magnetostratigraphy with a SQUID microscope on the same hydrogenetic Mn crust sample. Rock magnetic measurements revealed that the main magnetic mineral is well dispersed single domain grains, which is typical to magnetite but not yet specified (Oda, 2005).

Aug 24, 2006

By Ning Yang, Yuxiang Chen, Ming Chen

An ultraviolet laser Raman spectrometer was developed to detect and analyze material components of seawater, seafloor sediment and rock at a depth of 7000m maximally. Wave length of the excitation resource of the spectrometer is set to 355nm, which can enhance eigen scattered intensity and detecting sensitivity, and avoid fluorescence interference. Miniaturization design was adopted for deep-sea application. Design of the optical system and pressure cartridge, material selection and seal design of the observation window, and design of the Lithium batteries are the key technologies in the procedure of research and development. The spectrometer was carried by a Lander sank to sea bottom of the Pacific's Mariana Trench for verification. During the sea trials, data acquisition for Raman spectra was conducted for analyzing seawater in the detection area, and the spectrometer was verified synthetically. According to the data, the spectrometer is stable and practicable with high resolution and precision, and it is appropriate to detect and analyze composition of substance under the tremendous ocean.

Jan 1, 2017

By M. E. Williamson

A seafloor based robotic drilling system is being developed for the National Institute of Ocean Technology in Chennai, India to support a National initiative for marine methane hydrate research. The system will be capable of core sampling to 150m below the seafloor in 3000m of water under telemetric control of an operator onboard a research vessel at the surface. Unlike previous robotic drilling systems, this unit (designated the ACS) will use wireline methodology to reduce the number of tool handling operations required to complete the borehole (conventional rod drilling requires 2025 tool handling operations to complete a 100m hole, while wireline requires only 48 operations to reach the same depth).

By Wenbin Ma, Cees van Rhee, Dingena Schott

Since the concept of deep sea mining (DSM) was proposed by J. L. Mero with his book, The Mineral Resources of the Sea, in the 1960s, many research and significant developments have been implemented. However, its commercial mining process still has not yet commenced. One of the most important issues is that a sustainable DSM transport plan is difficult to determine, taking into consideration the DSM technological, economic, and environmental aspects simultaneously. The objective of this paper is to propose a method to determine the sustainable DSM transport plan utilizing a fuzzy analytic network process method, which is a typical multi-criteria decision making method (MCDM). The DSM transport plans evaluating major criteria consist of technological, economic, environmental, and social aspects with both qualitative and quantitative attributes. Different major criteria include several sub-criteria, respectively:  Technological aspect: energy consumption, proven technology, technology reliability, production rate, technology availability;  Economic aspect: gross income, capital cost, operation and maintenance cost, investment recovery period;  Environmental aspect: species disturbance variance, severity of ill effect, turbidity of ocean water, total organic carbon content, sedimentation thickness;  Social aspect: social acceptability, policy support; The weights for all evaluating criteria and sub-criteria are determined through a questionnaire survey interviewing experts at different research fields. All the transport plan candidates are ranked based on a comprehensive index. The conducted research in this paper is meaningful to promote the DSM commercialization process.

Jan 1, 2018

By Hans Smit

The face of mining as we know is changing as mining companies all over the globe realize the reality of accessing the vast mineral wealth contained on, and under, our ocean floors. With some land based mineral deposits being fully exploited across the world, deep sea mining is set to revolutionize global approaches to the search for precious metals and other sought after minerals. Previously, the financial and technological implications of deep sea mining outweighed the benefits of access to the mineral rich deposits identified all around the world. The process of marine diamond mining off the west coast of southern Africa started in the late 1950s, and subsequently continued by De Beers to the present day, has proven to be an excellent proving ground for the development of technology and mining systems that ensure a sustainable and financially viable business.

Jan 1, 2011

By Sung-Hyun Park

Core sediment samples collected from the KODOS area of the Clarion-Clipperton Fracture Zone in the NE Equatorial Pacific were analyzed for chemical and mineralogical compositions to investigate the depth- and time-related variation of paleoenvironmental and paleoceanographic conditions during their deposition. These core sediments are divided into three layers from top to bottom by its color; 1) brown layer (Unit I), 2) pale brown layer (Unit II), and 3) black brown layer (Unit III). Geochronology of 10Be indicated the depositional age of Quaternary for Units I and II and of late Pliocene for Unit III with a potential short hiatus between them. Analyses of interelemental correlation identified three major groups of elemental groups that show moderate-to-strong correlations: 1) Al, Ti, K, and Fe representing for terrestrial alumino-silicate fraction of sediments, 2) Ca, P, REEs, Cu, and Zn for biogenic apatite, and 3) Mn, Ni, and Co for hydrogenous Mn-oxide. With an exception, Fe content was very high and showed fair correlations with Mn, Ni, and Co in Unit III. Unit III shows high smectite but low quartz and illite contents compared to the overlying two units, indicative of reduced supply of terrestrial materials. In a meanwhile, major elements (Fe2O3, CaO, P2O5), minor elements (Cu, Zn) and REEs are highly enriched in Unit III compared to the upper two units. All these elements other than Fe reflect the fraction of biogenic apatite, which indicates higher fraction of biogenic components in Unit III. This is also supported by higher amount of smectite formed by the consumption of siliceous biogenic components. The reduced supply of terrestrial material and/or increased productivity of surface water at the time of Unit III deposition are attributed to Pliocene warming preceding Northern-pole glaciation during Quaternary. Unit III also includes clinoptilolite and unidentified 8Å mineral, likely amphibole, that are absent in Units I and II, suggestive of the possibility of different source region and/or materials during Pliocene. Higher contents of Mn and Fe in Unit III are likely due to the high fraction of Mn-oxide that was formed by diagenetic process after deposition.

Jan 1, 2003

By Valcana Stoyanova

Data and information for this study were collected in June-July 2009 onboard the RV Yuzhmorgeologiya in the area covers about 7000 km2 in the eastern part of the CCFZ between 10º05? - 10º55?N and 119º25? ? 121º08?W. In accordance with the IOM research program the cruise was intend to acquire both geological and environmental data and information necessary for delineation of nodule deposits and also data for identification of the baseline of benthic ecosystem. Having implementation of its 15-year plan of work for exploration under the contract with ISA, current activities of IOM were focused on nodule fields within prime areas that could be mined in the future. Bottom photographs obtained by towed deep-sea vehicle NEPTUN along 6 profiles with common length about 300 km (Fig. 1). In total, about 11,500 digital photographs (what cover approximately 40,000 m2 of the ocean floor) were analyzed for assessment of nodule coverage and investigation of megafauna (animals, visible in photographs, the dimension more than 2 cm). The giant single-cell organisms Xenophyophorida were the most multiple animals in seabed photographs. Their number on the site area averaged 1187 ind/ha. However, the vertical camera position does not allow counting all xenophyophorids, therefore their valid number is represented 10 times more. According to all available information these protozoans play the relevant role in assemblage of deep-water environment, giving for other animal groups an [ ] additional source of nutrition and a substratum for settlement and attachment. The ophiuroids are found in assemblage with xenophyophorids in many cases, standing on a sediment at their base.

Jan 1, 2010