Volcanogenic Massive Sulphide Ore Volcanogenic Massive Sulphide Ore DepositsDeposits

Presented byPresented by::Mostafa Abdel-Azim Mohamed MasoudMostafa Abdel-Azim Mohamed Masoud

Supervision bySupervision by::Dr. Ahmed Mohamed ZayedDr. Ahmed Mohamed Zayed

11 ) )IntroductionIntroduction

Volcanogenic massive sulphide deposits)VMS)Volcanogenic massive sulphide deposits)VMS)are type of metalsulphides ore deposits mainly are type of metalsulphides ore deposits mainly Cu-Zn-Pb which are associated with volcanic Cu-Zn-Pb which are associated with volcanic activity and hydrothermal solutions in activity and hydrothermal solutions in

submarine environmentsubmarine environment. .

--This type of deposits was firstly discovered in This type of deposits was firstly discovered in the Red Sea in the mid of 1960sthe Red Sea in the mid of 1960s

22 ) )Smokers and its typesSmokers and its types

Generally, the smokers are plumes of hot Generally, the smokers are plumes of hot black or white hydrothermal fluids getting black or white hydrothermal fluids getting out from chimney-like ventsout from chimney-like vents..

There are two types of smokers, There are two types of smokers, blackblack and and white smokerswhite smokers..

Types of smokersTypes of smokers

11 ) )Black smokers due toBlack smokers due to high content of sulphideshigh content of sulphides

--In modern oceans, these In modern oceans, these deposits )VMS) are deposits )VMS) are associated with sulfurous associated with sulfurous plumes called Black plumes called Black smokerssmokers

22))White smokers due to White smokers due to high content of calcium high content of calcium sulphate )anhydride) and sulphate )anhydride) and barium sulphate )barite)barium sulphate )barite)

33 ) )Size)reserve) and mineralogySize)reserve) and mineralogya) Size (reserve)a) Size (reserve)

The majority of the world deposits are small and about The majority of the world deposits are small and about 80%of all known deposits fall in size range 0.1-10 Mt80%of all known deposits fall in size range 0.1-10 Mt..

b) Mineralogyb) MineralogyThe mineralogy It is simple and often consist of over The mineralogy It is simple and often consist of over 90% iron sulphide usually as pyrite90% iron sulphide usually as pyrite..

--Chalcopyrite, Sphalerite, and Galena may be major Chalcopyrite, Sphalerite, and Galena may be major constituent depending on deposit classconstituent depending on deposit class..

--Magnetite and Tetrahedrite may be found in minor Magnetite and Tetrahedrite may be found in minor amountsamounts..

--The gangue is Quartz, but occationally Carbonate The gangue is Quartz, but occationally Carbonate is .developed and chlorite and sericiteis .developed and chlorite and sericite..Talc is found due to of metasomatismTalc is found due to of metasomatism..

44 ) )TextureTexture The original genetic texture The original genetic texture is colloform banding and is colloform banding and often gradded bedding often gradded bedding has also been reported, has also been reported, but due to the high degree but due to the high degree of metamorphism, of metamorphism, recrystallization of the recrystallization of the grains occurs, and the grains occurs, and the colloform banding is colloform banding is destroyed and a new destroyed and a new texture is produced which texture is produced which is called granular textureis called granular texture.. Pyrite with granular texture

Shape of Chimneys of the Black smokersShape of Chimneys of the Black smokers

55 ) )Stages of formationStages of formation

66 ) )Host rockHost rockThe most important host rocks are the felsic The most important host rocks are the felsic rocks specially is rhyolite )felsic) and is rocks specially is rhyolite )felsic) and is

often maficoften mafic . .

77 ) )EnvironmentEnvironment

Is submarine environment which is associated with Is submarine environment which is associated with volcanic activity and hydrothermal processesvolcanic activity and hydrothermal processes..

88 ) )OriginOrigin There is today a wide agreement that these deposits are There is today a wide agreement that these deposits are submarine-hydrothermal in origin, but there is a submarine-hydrothermal in origin, but there is a divergence of opinion to as to whether the solutions divergence of opinion to as to whether the solutions responsible for their formation are magmatic in origin responsible for their formation are magmatic in origin or they represent circulating sea wateror they represent circulating sea water..

But, most workers favoring the hypothesis that ,these But, most workers favoring the hypothesis that ,these deposits are composed of sea water which has circulated deposits are composed of sea water which has circulated deep in the crust according to isotope analysis for the deep in the crust according to isotope analysis for the solutionssolutions..

99 ) )Tectonic settingTectonic setting--Tectonically, these Tectonically, these

deposirs are formeddeposirs are formed::

11 ) )On the sea-floor On the sea-floor spreading centersspreading centers..

22 ) )Island arc as Besshi-Island arc as Besshi-type depositstype deposits..

33 ) )At oceanic or back arc At oceanic or back arc spreading ridges as spreading ridges as

Cyprus- type depositsCyprus- type deposits . .

1010 ( (ClassificationClassificationThere are many types of classificationThere are many types of classification::

11 ) )Iron, iron-copper, iron-copper zinc, and iron-copper-zinc-Iron, iron-copper, iron-copper zinc, and iron-copper-zinc-lead, but generally the copper is not found on its ownlead, but generally the copper is not found on its own..

22 ( (Classification of LydonClassification of LydonFour regions are plotted on Four regions are plotted on Cu-Pb-Zn ternary diagram Cu-Pb-Zn ternary diagram which are weighted in which are weighted in tones of ore metal tones of ore metal contained in the depositcontained in the deposit

33 ) )Classification of HutchinsonClassification of Hutchinson

1212 ) )Shape of the depositionShape of the deposition

If the density )salinity) of the If the density )salinity) of the hydrothermal solutions is hydrothermal solutions is greater than the density of greater than the density of seawater, aseawater, a bowl-shaped bowl-shaped deposits are formeddeposits are formed

If the density )salinity) of the If the density )salinity) of the hydrothermal solutions is hydrothermal solutions is lesser than the density of lesser than the density of seawater, a seawater, a mound-mound-shapedshaped deposits are deposits are formedformed

1313 ) )Occurrence in EgyptOccurrence in Egypt 11 ) )Umm Samuiki which is Zn-Cu-Pb depositsUmm Samuiki which is Zn-Cu-Pb deposits

22 ) )Helget )Cu 2.9%, Zn 13.6%Pb11.4% -Reserve 15,000 t)Helget )Cu 2.9%, Zn 13.6%Pb11.4% -Reserve 15,000 t)

33))El-Maakal)CU 3.5%-Zn 17%-Pb 2%-but the reserve is very El-Maakal)CU 3.5%-Zn 17%-Pb 2%-but the reserve is very small)small)

44 ) )DerhibDerhib

55 ) )El AtshanEl Atshan

Umm Samuiki

ReferencesReferences

11 ) )WikipediaWikipedia

22 ) )Rushdi Said, Geology of Egypt,1993Rushdi Said, Geology of Egypt,1993

33 ) )Anthony .M. Evans, Ore Geology and Anthony .M. Evans, Ore Geology and Industrial Minerals,1992, Blackwell Industrial Minerals,1992, Blackwell PublisherPublisher . .