A Mineralogical, Geochemical and Thermal Profile Through the Agrokipia “B” Hydrothermal Sulfide Deposit, Troodos Ophiolite Complex, Cyprus

Herzig, Peter

doi:10.1007/978-3-662-02538-3_12

Cited by 14 publications

(14 citation statements)

References 28 publications

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“…Chlorite contains up to 1.5 wt% MnO [Herzig, 1988;Gillis and Robinson, 199la], with individual samples varying by up to 1 wt%. The compositions of void-filling and groundmass replacing phases are indistinguishable.…”

Section: Composijion and Occwence Of Secondary Mwralsmentioning

confidence: 99%

Patterns and processes of alteration in the lavas and dykes of the Troodos Ophiolite, Cyprus

Gillis¹,

Robinson²

1990

J. Geophys. Res.

112

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Alteration panenu in the lavas and dykes of the Troodos Ophiolite, Cypnu, record a compte~ ~st~ of axial hydrochennal alteration, crustal aging, and.subsequent uplift ~d c;rnptac~ent of ~e ophiolite. ~1eld mappina shows that distribution of five alteration zooes, each ~ith duunct rruneralog•cal, gcochermcal, and hydroloaic characteristics, is influenced by igneous stratigraphy, st~cture~ a~d the nature a.nd thickness of the overlying aedimenu. Paragenetic aequences of ICCOlldary ~erals indicate .that alteration conditions changed proareasively as the crust cooled and moved o(f~Uls. Along spreading axes, low temperatures ~SO"C) were mainuined by the rapid flow of seawater m and out of the lavas, and .only minimal alteration took place. In contrast, lower water/rock ratios and hlgh~r te.mperarures (>200°C) m the dykes promoted extensive seawater·rock interaction. Althou~~ the sharp rue .m ~perarure between the two reJ.imes generally coincides with the lava-dyke transJUoo, late· stage mtrus1ons or hydrothermal upwellina zooes locally cause high·temperarure alteration to extend upward .into the lavas. As a segment of crust moved off·axis, temperatures remained tow in the lavas and proaress1vety decreased, ~rom. >250" 10 <80"C in the dykes. High permeability in the uppermost lavas led to the downward rruarauon of an oxidati~e alteration front whose thickness and spatial distribution was dependent upon the. rate and nature of sedimentation and, thus, the original seafloor morphology. Although field relations sho.w that alteration has a consistent vertical pattern in Troodos, the alteration zooes are not laterally oonunuous, and the stratigraphic depth of their boundaries varies considerably. IN1ROOUC110NEarly studies of the massive sulfide deposits [Constantinou and Govett, 1973) and alteration patterns within the Troodos ophiolite [Gass and Smewing, 1973) contributed greatly to the development of models for oceanic hydrothermal systems [SpooMr et al., 1977; C haprno.n and SpooMr, 1977] and subseafloor metamorphism [Coleman, 1977]. Subsequent discovery of high-temperature vents at mid-ocean ridges [e.g., Edmond et al., 1979), seamounts [MalaJwff et al., 1982], and back arc basins [Horbie et al., 1986] showed that hydrothermal circulation is a fundamental process in many oceanic environments.Mineralogical and chemical zonations within the Troodos massive sulfide ore deposits indicate that they formed from hydrothermal flu1ds whose compositions were remarkably similar to those venting on the seafloor today [Adamides, 1987;Herzig and Friedrich , 1987;Richards et al., 1989). Fluid compositions in Troodos were buffered by epidosites at conditions similar to those inferred for the root-zones of active systems at mid-ocean ridges [Bowers and Taylor, 1985;Richardson et al., 1987;Schiffman et al., 1987;Schiffman and Smith, 1988;Seyfried et al., 1988;Von Damm, 1988] . Because of these and other similarities, the upflow zones of the Troodos hydrothermal systems are thought to be ancient analogues of modem active systems [Oud...

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Section: Composijion and Occwence Of Secondary Mwralsmentioning

confidence: 99%

Patterns and processes of alteration in the lavas and dykes of the Troodos Ophiolite, Cyprus

Gillis¹,

Robinson²

1990

J. Geophys. Res.

112

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“…Euhedral tabular barian-muscovite and Mn-rich chlorite are surrounded and partially replaced by sulfides (mainly poikiloblastic pyrite). Enrichment in Ba of sericite/illite in VMS-hosting rocks is characteristic (Herzig, 1988). Chlorite laths along muscovite exfoliation planes are present, suggesting that chloritization followed sericitization as as is typical in footwall pipes close to the VMS mineralization (e.g.…”

Section: Strataboundmentioning

confidence: 92%

“…9A) indicates a substitution of Fe for Zn (e.g. Herzig, 1988). The Cu content of sphalerite is as much as 1.16 wt.…”

Section: Ore Mineral Geochemistrymentioning

confidence: 99%

“…The incorporation of Fe into sphalerite structure in exchange of Zn has long been recognized as a function of the pressure, temperature and sulfidation state of the hydrothermal fluid sphalerite precipitated from (e.g. Scott and Barnes, 1971;Scott, 1973Scott, , 1976Scott, , 1983Herzig, 1988;Keith et al, 2014). Hannington and Scott (1989) even viewed in the composition of the sphalerite a powerful prospecting tool for Au in VMS deposits as those conditions influencing gold grades (roughly, T<300ºC and high S 2 activities) translate into low Fe contents (<10 mole % FeS) in coeval sphalerite.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

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Mineralogy, geochemistry and sulfur isotope characterization of Cerro de Maimón (Dominican Republic), San Fernando and Antonio (Cuba) lower Cretaceous VMS deposits: Formation during subduction initiation of the proto-Caribbean lithosphere within a fore-arc

Torró

Proenza

Melgarejo

et al. 2016

Ore Geology Reviews

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“…These are predominantly stockworkmineralized zones similar to those associated with many of the massive sulphide deposits of Cyprus (e.g., Herzig 1988;Richards et al 1989). Stockwork mineralization also occurs at several locations north of the town of Springdale, in the Stirling, Sullivan Pond, and Lady Pond prospects.…”

Section: Mafic Volcanic Hosted Vms Depositsmentioning

confidence: 96%

Characteristics of gold mineralization in volcanogenic massive sulphide deposits of the Notre Dame Bay area, central Newfoundland

Santagulda¹,

Hannington²

1996

Can. J. Earth Sci.

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A reconnaissance study of 19 volcanogenic massive sulphide deposits in the Notre Dame Bay area indicates Au concentrations of up to 30 pprn (Betts Cove), and elevated gold contents (> 1 pprn Au) have been found in samples from 10 additional past producers and developed prospects. Systematic trends in the occurrence of gold are observed in two principal sulphide assemblages: polymetallic, pyrite -sphalerite -chalcopyrite -galena f arsenopy rite assemblages (type I) and pyrite-chalcopyrite + sphalerite f pyrrhotite assemblages (type 11). Type I assemblages occur in deposits with dominantly felsic host rocks, whereas type I1 assemblages are restricted to deposits in mafic-dominated ophiolite sequences. Free gold grains were observed in samples from eight different deposits in both type I and type I1 assemblages. X-ray emission spectra and electron microprobe analyses of the gold indicate that most grains are electrum, although a Au-bearing telluride occurs at Point Leamington. Ion microprobe analyses indicate that as much as 50% of bulk gold may be present as "invisible gold" locked in pyrite or arsenopyrite (up to 140 pprn Au at Point Leamington). Well-preserved primary depositional features in gold-bearing sulphides from several deposits suggest that the gold in type I assemblages is syngenetic. A strong correlation between gold and a polymetallic suite of Zn, Ag, Pb, As, and Sb, similar to that observed in Kuroko-type massive sulphides and in modem seafloor sulphides, supports a primary origin for gold in type I assemblages. In type I1 assemblages primary depositional features have been largely destroyed by deformation and annealing of sulphide grains. Gold is locally enriched in Zn-rich sulphides, and sulphides containing abundant pyrrhotite have the lowest gold contents. However, consistent geochemical associations with other elements are not observed, and this may reflect the strong remobilization of gold during structural deformation. The abundant free gold in some type I1 assemblages is a product of recrystallization during deformation and was derived locally from primary gold originally present in the host sulphides.

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A Mineralogical, Geochemical and Thermal Profile Through the Agrokipia “B” Hydrothermal Sulfide Deposit, Troodos Ophiolite Complex, Cyprus

Cited by 14 publications

References 28 publications

Patterns and processes of alteration in the lavas and dykes of the Troodos Ophiolite, Cyprus

Patterns and processes of alteration in the lavas and dykes of the Troodos Ophiolite, Cyprus

Mineralogy, geochemistry and sulfur isotope characterization of Cerro de Maimón (Dominican Republic), San Fernando and Antonio (Cuba) lower Cretaceous VMS deposits: Formation during subduction initiation of the proto-Caribbean lithosphere within a fore-arc

Characteristics of gold mineralization in volcanogenic massive sulphide deposits of the Notre Dame Bay area, central Newfoundland

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