Volcanic-associated massive sulphide base metals

Franklin, J M

doi:10.4095/207974

Cited by 34 publications

(33 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…drothermal systems ksociated with VHMS deposits (e.g., Sangster, 1972;Lydon, 1984). Chlorite-rich alteration is more common close to copper-rich ores, especially those containing magnetite or pyrrhotite, such as the Archean Noranda-type Cu-Zn deposits (e.g., Franklin, 1995); and quartz-rich alteration may be present close to gold-rich ores (e.g., Henty). Carbonate alteration may occur in both the chlorite and sericite zones but is more commonly associated with the zinc-(e.g., Rosebery, Thalanga) and gold-rich deposits (e.g., Henty) than the copper-rich deposits.…”

Section: Conditions Offormotion Ofht~drothemal Alteration In Vhms Stjmentioning

confidence: 99%

The Spectrum of Ore Deposit Types, Volcanic Environments, Alteration Halos, and Related Exploration Vectors in Submarine Volcanic Successions: Some Examples from Australia

Large¹

2001

Economic Geology

View full text Add to dashboard Cite

Variations in shape, metal content, alteration mineralogy, and volcanic host rocks of the ore deposits in the two major volcanic-hosted luassive sulfide (VHMS) districts of eastern Anstralia, the Cambrian Mount Read Volcanics and the Camhro-Ordovician Mount Windsor snbprovince, strongly reflect their volcanic environment, conditions of ore forination. and hvdrothermal alteration orocesses.prol,~l,ly iorn.rJ r t t l~~r ,I. the sed flojr r ,:, Hrllvrr Qltc lli\.er or hy rcpl~crmrnt of pun,~ts volcnnicl~snc IIU,,+, Jirrzdv Irlo\r. thr s,u f.wr T e., H,n.l,cn . The, iounrull ulrrrdi<)n ~cs,ci~rrd unh rhccr nolvmrtrlllc . . \'HhlS Jc~>u\lts u,n\ controllrd I. ! hoit-rock pc;lllc.~l,rl~ty .r~d iroro\tty which arc it1 turn rr!,t+d n) n)lcxn>c Cicirs r\pv deucr oiir~zu.nl.c. 111d ~\ ? . v o I~. t~~i z~~u~r~t r n l nrchitccturc Fucustneof llvurotllrrrnul fluids ihlno synvold&c sGctures has resurted in well-zoned chlorite-sericite footwall aheracon p;pes within footwall l a"; at Hellyer. On the other hand, diffnse fluid flow through veIy thick pninice breccia at RosebeIy and Hercules has resulted in strata-hound, sericite-dominated footwall alteration zones parallel to the paleosea floor and the ore lenses.Massive and disseininated, pyitic Cu-Au deposits, such as those in the Mount Lyell field and at HighwayReward. formed by subsea-floor replacement and are associated with only minor nnc-lead massive sulfide ore. These deposits formed from higher temperature fluids (>30OeC), in which copper transport is enhanced, and are commonly located in felsic volcanic centers do~nh~ated by shallow porphyitic intrusions (e.g., HighwayReward). The Cn-An ore lenses may be strata-bound (e.g., Mount Lyell) or crosscutting pipes (e.g., HighwayReward) depending on the structure and permeability characteristics of the felsic volcanic host rocks. The presence of high-sulfidation alteration minerals (e.g., pyrophyllite, zunyite) in some of the Cu-An deposits (e.g., Mount Lyell field) indicates that fluids were relatively acidic and snggests the possibility of magmatic fluid input into the hydrothemal system. Alteration zonation associated with the Cu-An VHMS deposits is more symmetrical than that of the Zn-rich deposits, with sericite-rich alteration extending into the hanging wall, in keeping with the subsnrface replacement origin of these de osits J . ' Synvolcanic gold-rich deposits, with high gold/base met ratlos are less common than the Cu-Au and Znrich VHMS ore types. The gold-rich ores (e.g., Henty, South Hercules) are strata bonnd in nature, have low sulfide contents, and are associated with central zones of intense silicification, surrounded hy envelopes of sericite-pyite and carbonate alteration. Volcanological and geochemical studies at Hen? indicate the gold-rich ore formed by the replacement of particular volcanic units deposited in a relatively shallow water environment dominated by volcaniclastic facies, lavas, and limestones.This spectrum of Cu-Au, Zn-rich, and Au-only deposits in the Mount Read Volcanics and the Mount ...

show abstract

Section: Conditions Offormotion Ofht~drothemal Alteration In Vhms Stjmentioning

confidence: 99%

The Spectrum of Ore Deposit Types, Volcanic Environments, Alteration Halos, and Related Exploration Vectors in Submarine Volcanic Successions: Some Examples from Australia

Large¹

2001

Economic Geology

View full text Add to dashboard Cite

show abstract

“…The several volcanogenic massivesulfide deposits (VMS) of the Clinton River district, Quebec, and at Ledge Ridge, Maine, occur within the syncline (map D). When the effects of Acadian compression are removed, the faulted anticline has the appearance of a spreading ridge with an axial half-graben that contains VMS deposits distributed along the graben-valley floor, much as shown by Franklin (1986, fig. 8) for modern spreading ridges.…”

Section: Connecticut Valley Trough (Cvt)mentioning

confidence: 99%

“…Such accumulations, called Kuroko-type VMS deposits if they are hosted by volcanics, or Besshi-type if they are largely hosted by sediments, are known to have accumulated on the sea floor, or not far below, in areas of active subaqueous volcanism and high heat flow (see Franklin, 1986;Lydon, 1988). Sea-floor mineralization is an appropriate term for the process.…”

Section: Geologic Favorability For Individual Nonpegmatitic Deposit Tmentioning

confidence: 99%

“…They may be grouped into five broad recognition criteria, assembled from many sources by the author, augmented by information from J.F. Slack (in McCammon, 1986, p. 1-12, and more recent discussions), and supplemented by review papers that incorporate research on modern sea-floor VMS deposits (Franklin, 1986;Lydon, 1988). The following five criteria, modified from Moench (1990, p. J17-J18), are designed specifically for the variably metamorphosed volcano-sedimentary rocks of the project area.…”

Section: Geologic Favorability For Individual Nonpegmatitic Deposit Tmentioning

confidence: 99%

“…Metabasalt of the lower member locally contains gedrite, and is chemically depleted in calcium and sodium and enriched in magnesium. Felsic metavolcanic rocks of the upper member are widely pyritic and are variably converted to quartz-muscovite schist and metachert; this type of alteration possibly exemplifies the "lower strataform alteration" of Franklin (1986). The most impressive zone of pyritic quartz-muscovite schist occurs immediately below the upper contact of the Ammonoosuc Volcanics northeast of the Hampshire Hills prospect, where the Ammonoosuc is unconformably overlain by a local thin layer of calc-silicate rock and quartzite at the base of the Quimby Formation.…”

Section: Areas Olv2 (Grids 4f To 6f)mentioning

confidence: 99%

See 2 more Smart Citations

Tectonic lithofacies, geophysical, and mineral-resource appraisal maps of the Sherbrooke-Lewiston area, Maine, New Hampshire, and Vermont, United States, and Quebec, Canada

Moench¹,

Boudette²,

Phillips³

1999

View full text Add to dashboard Cite

Mineralogy and chemical aspects of some ophiolitic metaultramafics, central Eastern Desert, Egypt: Evidences from chromites, sulphides and gangues

Abdel‐Karim

El-Shafei

2017

Geological Journal

View full text Add to dashboard Cite

Handling editor: P. HorváthChromites and sulphides are the most common ore minerals in the ophiolitic metasomatized ultramafics (~790 Ma) of Um Halham, Fawakhir and Barramiya, central Eastern Desert, Egypt.These ultramafics exhibit variable degrees of alteration and metasomatism and include massive serpentinites (serpentinized peridotite and serpentinite), tremolite-talc rocks, talc-carbonate rocks, listwaenite-like rocks and typical listwaenite.The alteration of chromite to Cr-magnetite was accompanied by the formation of chloritic aureoles due to the release of Al and Mg from chromite. Textural and compositional features of the chromites suggest a greenschist up to lower amphibolite facies metamorphism (at 500-600°C), which is facial with the host ultramafics. The chromites exhibit a boninitic affinity and a forearc suprasubduction setting of the present ophiolite assemblages. The variability of chromite chemistry indicates a melt-rock reaction, together with the water-bearing melt which is necessary for crystallizing chromite. Pentlandite, pyrrhotite, arsenopyrite, gersdorffite and pyrite are the most common sulphide minerals. Gold occurs either as an invisible phase associated with gersdorffite, arsenopyrite, and As-rich pyrite or as native nuggets in listwaenites of Barramiya area. Gangue metasomatized phases associated with these ore minerals are identified as sericite, carbonate and chlorite. The investigated sericite ranges in composition from mariposite (>0.5% Cr) to fuchsite (>1% Cr), which indicates typical listwaenites. Five varieties of carbonate minerals are identified; magnesite, breunnerite, dolomite, calcite and ankerite.The CO 2 -rich fluids are released during progressive decarbonation reactions in carbonate-bearing metasediments, whereas Ni and As-rich fluids are attributed to nearby granitic intrusions affected on serpentinites and leached Ni and precious metals like gold forming As-Ni-rich fluids. These metasomatic fluids are thought to reflect a range of melts derived from a compositionally evolving source during subduction initiation in a forearc environment.

show abstract

Volcanic-associated massive sulphide base metals

Cited by 34 publications

References 0 publications

The Spectrum of Ore Deposit Types, Volcanic Environments, Alteration Halos, and Related Exploration Vectors in Submarine Volcanic Successions: Some Examples from Australia

The Spectrum of Ore Deposit Types, Volcanic Environments, Alteration Halos, and Related Exploration Vectors in Submarine Volcanic Successions: Some Examples from Australia

Tectonic lithofacies, geophysical, and mineral-resource appraisal maps of the Sherbrooke-Lewiston area, Maine, New Hampshire, and Vermont, United States, and Quebec, Canada

Mineralogy and chemical aspects of some ophiolitic metaultramafics, central Eastern Desert, Egypt: Evidences from chromites, sulphides and gangues

Contact Info

Product

Resources

About