scholarly journals The internal structure of an active sea-floor massive sulphide deposit

Nature ◽  
1995 ◽  
Vol 377 (6551) ◽  
pp. 713-716 ◽  
Author(s):  
Susan E. Humphris ◽  
P. M. Herzig ◽  
D. J. Miller ◽  
J. C. Alt ◽  
K. Becker ◽  
...  
Keyword(s):  
Internal Structure ◽  
Massive Sulphide ◽  
Massive Sulphide Deposit ◽  
Sulphide Deposit ◽  
Sea Floor

Evolution of an active sea-floor massive sulphide deposit

Nature ◽  
10.1038/29279 ◽  
1998 ◽  
Vol 394 (6694) ◽  
pp. 668-671 ◽  
Author(s):  
C.-F. You ◽  
M. J. Bickle
Keyword(s):  
Massive Sulphide ◽  
Massive Sulphide Deposit ◽  
Sulphide Deposit ◽  
Sea Floor

An Ordovician rift environment for the Memphremagog polymetallic massive sulphide deposit, Appalachian Ophiolite Belt, Quebec

1991 ◽  
Vol 28 (12) ◽  
pp. 1887-1904 ◽  
Author(s):  
Jacques Trottier ◽  
Alex C. Brown ◽  
Michel Gauthier
Keyword(s):  
Massive Sulphide ◽  
Massive Sulphide Deposit ◽  
Sulphide Deposit ◽  
Oblique Collision ◽  
Sea Floor ◽  
North American Continent ◽  
Ophiolite Belt ◽  
Sedimentary Sequences ◽  
The North ◽  
Taconic Orogeny

The Memphremagog polymetallic massive sulphide deposit occurs at the contact between a pillowed volcanic sequence and a detrital sedimentary sequence consisting principally of shale and greywacke. The deposit, situated about 100 km east of Montréal in the Appalachians of southeastern Quebec, is composed of massive sulphide breccia. Major minerals include pyrrhotite, pyrite, sphalerite, galena, chalcopyrite, and calcite, with minor amounts of arsenopyrite, freibergite ((Cu,Ag,Fe)12Sb4S13), meneghinite (CuPb13Sb7S24), gudmundite (FeSbS), and kersteritic stannite (Cu2(Fe,Zn)SnS4). The mineral assemblage, metal content, and primary textures are comparable to modern sea-floor sulphide mounds enclosed by thick sedimentary sequences deposited in basins such as the Guaymas Basin in the Gulf of California.Although the footwall basalt unit is interstratified with the St-Daniel Formation of the Ophiolite Belt, it possesses a transitional geochemical signature of alkaline affinity that is uncharacteristic of ophiolitic basalts. We propose that this volcanic unit was emplaced within a transtensional basin of a rifted fore-arc system that formed during the Taconic orogeny as a result of diachronous oblique collision of an island- arc system (Ascot–Weedon?) with the North American continent. During magmatic activity, a hydrothermal system was imprinted on the volcanics and underlying sediments. Subsequent hydrothermal fluid emanations led to the formation of the Memphremagog sulphide deposit, which is quite distinct from sulphide deposits generally found within ophiolite belts.

U–Pb zircon geochronology from the Alexander terrane, southeast Alaska: implications for the Greens Creek massive sulphide deposit

2016 ◽  
Vol 53 (12) ◽  
pp. 1458-1475
Author(s):  
Patrick J. Sack ◽  
Ron F. Berry ◽  
J. Bruce Gemmell ◽  
Sebastien Meffre ◽  
Andrew West
Keyword(s):  
Inductively Coupled Plasma ◽  
Volcanic Rocks ◽  
White Mica ◽  
Massive Sulphide ◽  
Late Triassic ◽  
Massive Sulphide Deposit ◽  
Sulphide Deposit ◽  
Southeast Alaska ◽  
Northern Portion ◽  
Greens Creek Mine

This paper presents results of a laser ablation – inductively coupled plasma – quadrapole mass spectrometer (LA–ICP–QMS) U–Pb dating study of small in situ zircon grains from samples collected in the vicinity of the Greens Creek massive sulphide deposit, on northern Admiralty Island, southeast Alaska. The Greens Creek mine is a volcanogenic massive sulphide deposit in the central portion of the Alexander Triassic metallogenic belt (ATMB) and is one of the top global silver producers despite having a dominantly mafic metavolcanic stratigraphic footwall. The stratigraphic footwall is a Mississippian mafic metavolcanic sequence with a protolith age of approximately 340–330 Ma. The first U–Pb zircon constrained chronostratigraphy for the area places the deposit near, or at, the base of the host Late Triassic stratigraphy just above an approximately 100 million year old unconformity and probably 10–15 million years older than mineralization at the Palmer and Windy Craggy deposits in the northern portion of the ATMB. The stratigraphic location of the Greens Creek deposit is atypical for a syngenetic massive sulphide deposit, and this may, at least partly, explain its unusual metal endowment. Pre-mineralization Permian U–Pb zircon metamorphic ages are consistent with published 273–260 Ma white mica ages related to the collision of the Admiralty and Craig subterranes, the basement to the ATMB. The much older age of the footwall rocks and their Permian pre-mineralization metamorphism demonstrates that though the mafic volcanic rocks are not genetically linked to the deposit, they likely influenced the style of alteration and mineralization.

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