Modern Sea-Floor Massive Sulfides and Base Metal ResourcesToward an Estimate of Global Sea-Floor Massive Sulfide Potential

2010 ◽  
Author(s):  
Mark Hannington ◽  
John Jamieson ◽  
Thomas Monecke ◽  
Sven Petersen
Keyword(s):  
Base Metal ◽  
Massive Sulfide ◽  
Massive Sulfides ◽  
Sea Floor

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.

Auriferous chert, banded iron formation, and related volcanogenic hydrothermal alteration, Atik Lake, Manitoba

1989 ◽  
Vol 26 (12) ◽  
pp. 2676-2690 ◽  
Author(s):  
Louis R. Bernier ◽  
Wallace H. MacLean
Keyword(s):  
Hydrothermal Alteration ◽  
Earth Element ◽  
Massive Sulfide ◽  
Iron Formation ◽  
Small Scale ◽  
Banded Iron Formation ◽  
Sulfide Deposits ◽  
Sea Floor ◽  
Facies Metamorphism ◽  
Altered Basalt

Small-scale alteration pipes and stratiform alteration in Archean glomeroporphyritic tholeiitic basalts at Atik Lake, Manitoba, stratigraphically underlie silicate-oxide banded iron formation (BIF) and auriferous sulfide-bearing chert. The auriferous chert is locally interbedded with graphitic argillite, indicating euxinic conditions during deposition. Cordierite–gedrite rocks formed by recrystallization of alteration assemblages during the lower amphibolite-facies metamorphism (T = 550 °C, P = 2.5 kbar). Al2O3, TiO2, Zr, and Nb, which were relatively immobile during alteration, have been used to monitor igneous differentiation and alteration. Volcanogenic hydrothermal alteration resulted in depletion of Ca, Si, Mg, Na, and Sr in the altered basalt and the addition of K, Fe, Rb, and Ba. This was accompanied by mass and volume losses of up to 25%. The mineralizing fluid was reducing and somewhat acidic. Rare-earth-element (REE) profiles of BIF and graphitic argillite, normalized to Archean shale, are less steep ((La/Lu)N = 0.51 and 0.49 respectively), than those of both mineralized chert ((La/Lu)N = 0.04) and recent sea-floor, siliceous, gold-enriched massive sulfides ((La/Lu)N = 0.11). REE profiles and Boström's plot suggest that the auriferous, sulfide-bearing chert formed by mixing of hydrothermal and detrital components. The overall chemical changes in the Atik Lake alteration system are comparable to those in Noranda-type massive-sulfide deposits. The trace-metal association in the auriferous chert is similar to that at some modern sea-floor hydrothermal sites.

Contribution of magnetic modeling to the discovery of a hidden massive sulfide body at Hajar, Morocco

Geophysics ◽  
1991 ◽  
Vol 56 (7) ◽  
pp. 983-991 ◽  
Author(s):  
A. Bellott ◽  
J. Corpel ◽  
R. Millon
Keyword(s):  
Gravity Data ◽  
Massive Sulfide ◽  
Magnetic Survey ◽  
Massive Sulfides ◽  
Magnetic Modeling ◽  
Gravity And Magnetic ◽  
Gravity Response ◽  
Modeling Techniques ◽  
Magnetic Model ◽  
D Model

The Hajar prospect is located in the Guemassa Paleozoic massif, about 30 km southwest of Marrakesh, Morocco. Visean volcano‐sedimentary formations are present in this massif and in the Jebilets massif north of Marrakesh. In these formations, syngenetic massive sulfides occur, and one of these bodies, Kettara in the Jebilets, has been partially mined. Using the Kettara magnetic anomaly to establish the magnetization parameters, we performed a preliminary interpretation of the Hajar anomaly. Our 2.5-D model determined the depth of the structure to be about 150 to 200 m below the surface. This relatively shallow depth was a decisive factor in siting a reconnaissance drillhole, which encountered massive sulfides between 158 and 276 m. After completing a systematic gravity and magnetic survey, 3-D magnetic modeling was attempted, constrained by the results of four drillholes. Now that more than 20 holes have been drilled, this magnetic model still conforms to the newly revealed geology. Unfortunately, it was not possible to extract useful information concerning the orebody from modeling and interpreting the gravity data. The gravity response is masked by disturbances such as faults and variations in depth and nature of the Visean basement. The discovery of the Hajar deposit shows that magnetic investigations, improved by pertinent modeling techniques, can be used at various stages of exploration to help recognize and define massive sulfide bodies.

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