scholarly journals Insights into Extinct Seafloor Massive Sulfide Mounds at the TAG, Mid-Atlantic Ridge

Minerals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 302 ◽  
Author(s):  
Berit Lehrmann ◽  
Iain Stobbs ◽  
Paul Lusty ◽  
Bramley Murton
Keyword(s):  
Mineral Resources ◽  
Massive Sulfide ◽  
Economic Potential ◽  
Black Smoker ◽  
Iron Mineral ◽  
Weathering Processes ◽  
Mid Atlantic Ridge ◽  
Third Dimension ◽  
Seafloor Massive Sulfide ◽  
Good Agreement

Over the last decade there has been an increasing interest in deep-sea mineral resources that may contribute to future raw metal supply. However, before seafloor massive sulfides (SMS) can be considered as a resource, alteration and weathering processes that may affect their metal tenor have to be fully understood. This knowledge cannot be obtained by assessing the surface exposures alone. Seafloor drilling is required to gain information about the third dimension. In 2016, three extinct seafloor massive sulfide mounds, located in the Trans-Atlantic Geotraverse (TAG) hydrothermal area of the Mid-Atlantic Ridge were drilled. A mineralogical and textural comparison of drill core and surface-grab samples revealed that in recent ceased mounds high-temperature copper assemblages typical for black smoker chimneys are still present whereas in longer extinct mounds the mineralogy is pre-dominated by an iron mineral assemblage. Zinc becomes remobilized early in the mound evolution and forms either a layer in the upper part of the mound or has been totally leached from its interior. Precipitation temperatures of sphalerite calculated using the Fe/Zn ratio can help to identify these remobilization processes. While the Fe/Zn ratios of primary sphalerites yield temperatures that are in very good agreement with fluid temperatures measured in white smokers, calculated temperatures for sphalerites affected by remobilization are too high for SMS. Overall drilling of SMS provides valuable information on the internal structure and mineralogy of the shallow sub-surface, however, additional drilling of SMS, at a greater depth, is required to fully understand the processes affecting SMS and their economic potential.

scholarly journals Pyrite Varieties at Pobeda Hydrothermal Fields, Mid-Atlantic Ridge 17°07′–17°08′ N: LA-ICP-MS Data Deciphering

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 622
Author(s):  
Valeriy Maslennikov ◽  
Georgy Cherkashov ◽  
Dmitry Artemyev ◽  
Anna Firstova ◽  
Ross Large ◽  
...  
Keyword(s):  
Low Temperature ◽  
Massive Sulfide ◽  
Black Smoker ◽  
Fine Grained ◽  
Framboidal Pyrite ◽  
Icp Ms ◽  
Mid Atlantic Ridge ◽  
Seafloor Massive Sulfide ◽  
Hydrothermal Fields ◽  
Feeder Zone

The massive sulfide ores of the Pobeda hydrothermal fields are grouped into five main mineral microfacies: (1) isocubanite-pyrite, (2) pyrite-wurtzite-isocubanite, (3) pyrite with minor isocubanite and wurtzite-sphalerite microinclusions, (4) pyrite-rich with framboidal pyrite, and (5) marcasite-pyrite. This sequence reflects the transition from feeder zone facies to seafloor diffuser facies. Spongy, framboidal, and fine-grained pyrite varieties replaced pyrrhotite, greigite, and mackinawite “precursors”. The later coarse and fine banding oscillatory-zoned pyrite and marcasite crystals are overgrown or replaced by unzoned subhedral and euhedral pyrite. In the microfacies range, the amount of isocubanite, wurtzite, unzoned euhedral pyrite decreases versus an increasing portion of framboidal, fine-grained, and spongy pyrite and also marcasite and its colloform and radial varieties. The trace element characteristics of massive sulfides of Pobeda seafloor massive sulfide (SMS) deposit are subdivided into four associations: (1) high temperature—Cu, Se, Te, Bi, Co, and Ni; (2) mid temperature—Zn, As, Sb, and Sn; (3) low temperature—Pb, Sb, Ag, Bi, Au, Tl, and Mn; and (4) seawater—U, V, Mo, and Ni. The high contents of Cu, Co, Se, Bi, Te, and values of Co/Ni ratios decrease in the range from unzoned euhedral pyrite to oscillatory-zoned and framboidal pyrite, as well as to colloform and crystalline marcasite. The trend of Co/Ni values indicates a change from hydrothermal to hydrothermal-diagenetic crystallization of the pyrite. The concentrations of Zn, As, Sb, Pb, Ag, and Tl, as commonly observed in pyrite formed from mid- and low-temperature fluids, decline with increasing crystal size of pyrite and marcasite. Coarse oscillatory-zoned pyrite crystals contain elevated Mn compared to unzoned euhedral varieties. Framboidal pyrite hosts maximum concentrations of Mo, U, and V probably derived from ocean water mixed with hydrothermal fluids. In the Pobeda SMS deposit, the position of microfacies changes from the black smoker feeder zone at the base of the ore body, to seafloor marcasite-pyrite from diffuser fragments in sulfide breccias. We suggest that the temperatures of mineralization decreased in the same direction and determined the zonal character of deposit.

The oldest seafloor massive sulfide deposits at the Mid-Atlantic Ridge: 230Th/U chronology and composition

2015 ◽  
Vol 42 (1) ◽  
Author(s):  
Vladislav Kuznetsov ◽  
Eriks Tabuns ◽  
Kathrine Kuksa ◽  
Georgy Cherkashov ◽  
Fedor Maksimov ◽  
...  
Keyword(s):  
Massive Sulfide ◽  
Hydrothermal Activity ◽  
Ocean Floor ◽  
Hydrothermal Field ◽  
Sulfide Deposits ◽  
Massive Sulfides ◽  
Geochemical Properties ◽  
Geochemical Study ◽  
Mid Atlantic Ridge ◽  
Seafloor Massive Sulfide

Abstract A geochronological and geochemical study on 10 samples of seafloor massive sulfides (SMS) from the inactive Peterburgskoye hydrothermal field at the Mid-Atlantic Ridge (MAR) was carried out. The 230Th/U ages of the SMS are the oldest for the Quaternary hydrothermal ores ever found at the ocean floor. According to them the hydrothermal activity at Peterburgskoye field started at least 170 ka and continued down to 63 ka. The oldest hydrothermal ores from this field consist mainly of pyrite and chalcopyrite and have geochemical properties typical for SMS associated with basalts.

Seafloor Massive Sulfide Deposits of the Northern Equatorial Mid-Atlantic Ridge

2013 ◽  
Vol 53 (5) ◽  
pp. 680-693 ◽  
Author(s):  
G. A. Cherkashov ◽  
V. N. Ivanov ◽  
V. I. Bel’tenev ◽  
L. I. Lazareva ◽  
I. I. Rozhdestvenskaya ◽  
...  
Keyword(s):  
Massive Sulfide ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Mid Atlantic Ridge ◽  
Seafloor Massive Sulfide

scholarly journals Prospectivity Mapping for Magmatic-Related Seafloor Massive Sulfide on the Mid-Atlantic Ridge Applying Weights-of-Evidence Method Based on GIS

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 83
Author(s):  
Lushi Liu ◽  
Jilong Lu ◽  
Chunhui Tao ◽  
Shili Liao
Keyword(s):  
Massive Sulfide ◽  
Spreading Rate ◽  
Mineral Prospectivity Mapping ◽  
Spreading Ridges ◽  
Mid Atlantic Ridge ◽  
Slow Spreading ◽  
Mineral Prospectivity ◽  
Seafloor Massive Sulfide ◽  
Crust Thickness ◽  
Prospectivity Mapping

The Mid-Atlantic Ridge belongs to slow-spreading ridges. Hannington predicted that there were a large number of mineral resources on slow-spreading ridges; however, seafloor massive sulfide deposits usually develop thousands of meters below the seafloor, which make them extremely difficult to explore. Therefore, it is necessary to use mineral prospectivity mapping to narrow the exploration scope and improve exploration efficiency. Recently, Fang and Shao conducted mineral prospectivity mapping of seafloor massive sulfide on the northern Mid-Atlantic Ridge, but the mineral prospectivity mapping of magmatic-related seafloor massive sulfide on the whole Mid-Atlantic Ridge scale has not yet been carried out. In this study, 11 types of data on magmatic-related seafloor massive sulfide mineralization were collected on the Mid-Atlantic Ridge, namely water depth, slope, oceanic crust thickness, large faults, small faults, ridge, bedrock age, spreading rate, Bouguer gravity, and magnetic and seismic point density. Then, the favorable information was extracted from these data to establish 11 predictive maps and to create a mineral potential model. Finally, the weights-of-evidence method was applied to conduct mineral prospectivity mapping. Weight values indicate that oceanic crust thickness, large faults, and spreading rate are the most important prospecting criteria in the study area, which correspond with important ore-controlling factors of magmatic-related seafloor massive sulfide on slow-spreading ridges. This illustrates that the Mid-Atlantic Ridge is a typical slow-spreading ridge, and the mineral potential model presented in this study can also be used on other typical slow-spreading ridges. Seven zones with high posterior probabilities but without known hydrothermal fields were delineated as prospecting targets. The results are helpful for narrowing the exploration scope on the Mid-Atlantic Ridge and can guide the investigation of seafloor massive sulfide resources efficiently.

scholarly journals Composition and Formation of Gabbro-Peridotite Hosted Seafloor Massive Sulfide Deposits from the Ashadze-1 Hydrothermal Field, Mid-Atlantic Ridge

Minerals ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 19 ◽  
Author(s):  
Anna Firstova ◽  
Tamara Stepanova ◽  
Georgy Cherkashov ◽  
Alexey Goncharov ◽  
Svetlana Babaeva
Keyword(s):  
Massive Sulfide ◽  
Hydrothermal Field ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Mid Atlantic Ridge ◽  
Seafloor Massive Sulfide

Economic Seafloor Massive Sulfide Mining by Japan’s Model

2016 ◽  
Author(s):  
Tetsuo Yamazaki ◽  
Yosuke Takeda ◽  
Rei Arai ◽  
Naoki Nakatani
Keyword(s):  
Papua New Guinea ◽  
Waste Disposal ◽  
Mining Operation ◽  
Massive Sulfide ◽  
Sea Surface ◽  
Flexible Link ◽  
Private Companies ◽  
Mining Site ◽  
Seafloor Massive Sulfide ◽  
Disposal Cost

Because of the higher Au, Ag, and Cu contents, seafloor massive sulfides (SMS) have received much attention as future commercial mining targets by private companies and nations. One of them, Solwara 1 Project in Papua New Guinea (PNG), is scheduled to start the commercial mining operation from 2018. Because the mining site is inter-island area and almost no cost is necessary for the waste disposal in PNG, the economy of the mining is expected very well. In contrast with this, because all the SMS distribution sites in Japan locate outer ocean areas and the waste disposal cost on land in Japan is very expensive, the economy of SMS mining in Japan is quite negative. In order to overcome the problems, a self-standing riser with flexible link to the sea surface platform and a primary ore separation on the seafloor prior to the ore lift-up are proposed. The improved SMS mining concept named Japan’s model is examined.

scholarly journals Quantitative Expression of the Burial Phenomenon of Deep Seafloor Manganese Nodules

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 227
Author(s):  
Akira Tsune
Keyword(s):  
Recent Progress ◽  
Mathematical Expression ◽  
Mineral Resources ◽  
Economic Potential ◽  
Visual Data ◽  
Manganese Nodules ◽  
Quantitative Expression ◽  
Size Number ◽  
Polymetallic Nodules ◽  
Geological Origin

Manganese (polymetallic) nodules on the deep seafloor in the open ocean have attracted great interest because of their economic potential. Visual data on nodules found on the deep seafloor such as photographs and videos have increased exponentially with the recent progress of related technologies. These data are expected to reflect useful information for estimating these mineral resources, as well as understanding their geological origin. Although the size, number, and coverage of manganese nodules have been measured in seafloor images, the burial of such nodules has not been sufficiently examined. This paper focuses on mathematical expression of the burial of the manganese nodules and attempts to quantitatively elucidate relations among burial degree and nodule geological parameters. The results, that is, a dataset obtained by calculations of relations among parameters, are also utilized for considerations of quantitative expression of burial. These considerations are expected to contribute to a better understanding of the geological origin of manganese nodules.

scholarly journals Chemical Mass Balance, Depositional Efficiency, and Rates of Formation of Seafloor Massive Sulfide Deposits

2020 ◽  
Author(s):  
John Jamieson ◽  
Dennis Sanchez Mora ◽  
Ben Peterkin ◽  
Thibaut Barreyre ◽  
Javier Escartin ◽  
...  
Keyword(s):  
Mass Balance ◽  
Massive Sulfide ◽  
Chemical Mass Balance ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Seafloor Massive Sulfide
Sign in / Sign up

Export Citation Format

Share Document