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http://www.zinc.org/basics/zinc_uses

http://www.gravitaexim.com/usesoflead.html

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0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

Z i n c

( t o n n e s )

List of countries by zinc production

From Wikipedia

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0

100

200

300

400

500

600

700

800

900

China Australia USA Peru Mexico Canada Poland Sweden IrishRepublic

India SouthAfrica

Morocco Kazakhstan

L e a

d ( m i l

l i o n t o n n e s )

Major lead production countries in 2003

From EconomyWatch

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Modern Passive Margins

94,000 km aggregate length

oldest one is ~175 m.y.r. Bradley, 2008

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Sediment-hosted Zn-Pb deposits

Contrasting tectonic settings: Attributes, survival, etc

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0

5

10

15

20

25

30

35

40

194519501955196019651970197519801985199019952000

Discovery Year

P b + Z n (

M t )

Discovery Year vs Pb+Zn (Mt)

Hilton-George FisherRed Dog &Kholodninskoye (23.5

Mt)

HYC

Century

Howards Pass

Rampura- Agucha

Changba-Lijagou

Anarraaq

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Recent Summaries of Carbonate-Hosted Pb-Zn Deposits

MISSISSIPPI VALLEY-TYPE LEAD-ZINC DEPOSITS

SUZANNE PARADIS, PETERHANNIGAN, AND KEITH DEWING

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MVT and CD Pb-Zn OresTransport and Deposition

Extraction and transport : At temperatures < 250 C, Mobilein presence of Oxidized su l fur and immobile in presence ofReduc ed su l fur (the sulfur god!). Requires minimumsalinity of ~ 10 wt%

Deposition : Mainly increase in r educed s u l fur (i.e., lo c alsul fa te reduct io n or f lu id m ixing w i th reduc ed sul fur) .

Sullivan: Hot and reduced: Carbonate poorsequence, complex metal, > Metal concentrations inore fluid possible. Uncommon. BHT like?

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Tectonic Settings of CD and MVT DepositsMost Important Distinguishing Feature: sediment sequence,

textures, deposit morphology, preservation

Special Continental Rift -Sag basins: AFew CD

Bradley, 2008

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Sediment-Hosted Pb-Zn Ag ( low Cu)

Mississippi Valley-type (MVT) and Clastic Dominated(traditional SEDEX) Zn-Pb

Ore assemblage: mainly sphalerite, galena and iron sulfides

Alteration & gangue: mainly calcite/dolomite/sideriteusually low silica

Defining moment in the genesis of these deposits is the

tec tonic se t t ing where the ores are deposited in eithercarbon ate or c las t ic sedim entary sequ ences .

Redox controlled extraction-transport - deposition

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Skarn-Distal Skarn-Polymetallic Vein- CRD- MVT

Confusion between MVT Zn-Pb and carbonate-hosteddeposits: skarn minerals, geologic setting, minor andtrace elements.

Carbonate-Hosted - not necessarily MVT!

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Sediment-hosted ores are difficult to date.Classification: Dependence on Ore Textures.

Reocin SpainTunisia

N. Arkansas, USAJinding, Yunan China

Classifications

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SEDEX Definition Carne and Cathro (1982): Laminated, exhalative sulfides in fine-grained clastic,

carbonate, and metasedimentary rocks.

Exhalative

component inherent in the term SEDEX

Direct evidence of an exhalite not required includes sub-seafloor systems .

. Assumed Age of mineralization same

or close to

age of host rocks

Consider Sedex a sub-type of clastic dominated Pb-Zn: clear evidence for exhalite!

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Sediment-Hosted Lead-Zinc Ores

Clastic Dominate (CD) Pb-Zn (Sediment Exhalative -SEDEX): Usuallyhosted by siliciclastic lithologies in clastic-dominated sedimentary

sequences in passive continental margins and a few continental rift-sag basins and continental back arcs: seafloor replacement orexhalative, diagenetic replacement.

Mississippi Valley-Type (MVT) Pb-Zn: Hosted in platformcarbonates in passive margins within orogenic forelands.

Located in extensional domains associated withcontractional events: Diagenetic to burial replacement-toorogenic basin inversion and deformation.

Sphalerite replaced carbonate unit in

clastic dominated sedimentarysequence No exhalite!

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Modern Passive Margins

94,000 km aggregate length

oldest one is ~175 m.y.r. Bradley, 2008

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Passive Margins and CD Pb-Zn Deposits

Bradley, 2008Passive margins fromBradley, 2008; Depositsfrom Leach et al., 2005

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Worlds Greatest

Factory forEvaporites andEvaporative fluids

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Red Sea Evaporite Factory

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Genesis , At t r i t ion and

Preservat ion

Life Cycle of Passive Margins

Evaporative Factories:Passive margins andocean closure basins

(foreland basins)

Wilson Cycle of Ocean Basins

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Age of Mineralization CD - assumed to be same or close to age of host

rock (syn-sedimentary, early to late burialdiagenesis.

MVT ores are epigenetic -- form near age of hostrock (Irish, Canning basin) to tens to hundreds ofmillion years younger

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N U M B

E R O F

P A S S I V E

M A R G I N S

AGE (Ma)

100

24222018161412108642

90

80

70

60

50

40

30

20

10

00 500 1,000 1,500 2,000 2,500 3,000

P b + Z n

( M t )

PHANEROZOIC PROTEROZOIC ARCHEAN

Neo- Meso- Paleo-

2nd O 2 GOE

*

* *

GOE Great Oxidization Event

2nd O 2 Second Great Oxidization Event

UN

PM

BA

CSRF Passive Margins through time

Indicates poorly constrained ageBHT

PM: Passive marginBA: Back arcCS: Continental sagRF: Continental rift

BHT: Broken Hill-type

MIS

MIS Mass Independent Sulfur Isotopes

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From Hazen et al., 2008 Canada's Mackenzie Mountains

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MVT and Evaporites

Oxygenation of the Hydrosphere

Stored Evaporative Fluids

CD Pb-Zn and

evaporites: Red Dogpresentation

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0

5

1 0

1 5

2 0

2 5

Top 30 MVT Deposits

Taylor et al., 2010; Leach et al., 2005

MVT deposits generally cluster in districts with manydeposits

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SoutheastMissouri

Land District

Modified from Ohle, 1996

l

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A. Vent-proximal (e.g. Sullivan, Lydon 1996; Goodfellow et al. 1993)

B. Vent-distal (e.g. HYC, Large et al. 2001)

C. Replacement of oil trap(e.g. Century, Broadbent et al. 1998)

D. Carbonate replacement(e.g. Anarraaq, Kelley et al., 2004a)

Tend to be tabular

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Reocin Mine, Spain: Massive sulfidereplacement of internal sediments

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Velasco et al. 2003

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Fluid Inclusion Temperaturesand Salinities

MVT Temperature: ~50C to 250C but typically between90C and 150C: Salinities ~ 15 to >35%

CD Temperatures poorly defined: Measured between~120C to ~250C but a few to possibly to ~300 C

(Low silicification: ~ < 200C)

CD salinities are poorly defined: Red Dog and Centurybetween 10 and 30 wt % and MVT mostly between 15 to

35 wt %

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Topographic Fluid Drive: ManyMVT

Reflux or densitydriven: Many CD

Many fluid flowmechanisms canwork no uniquemodel

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Sources of Sulfur

Origin al Seawater su lfate in basin watercolumn or as pore fluids, sedimentary sulfate,infiltrating seawater, connate seawater --reduced by a variety of processes andpathways. May be distal and temporalseparated from ore.

Bacterial mediation (< 100 C

Thermochemical SO 4 reduction in presence oforganic matter(>~150 C)

Thermal cracking of Sulfur-bearing organicmatter

C i T i C l fl id

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Concentration vs. Temperature in Crustal fluids

From Yardley 2005

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Fluid mixing: seawater, basin waters and pore fluids, TSRfrom seawater sulfate in rich organic muds and anoxic, pHand temperature changes

Precipitation ofCD ores by avariety of fluid-fluid and fluid-sediment- rockreactions

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Metals carried by low reduced sulfur fluid that mixes with reduced sulfur-rich fluidPotential for significant acid production/carbonate dissolution

Mixing of metal-rich fluid with reduced sulfur-rich fluid

Mixing of metal-rich fluid with local H 2S gas reservoir

CD (seawater & pore water mixing)

Sulfide precipitationMechanisms

Two fluid mixingmodels: metal-

bearing fluid mixes

with reduced sulfurfluid

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Most common alteration- CD and MVT

Dolomi te - Commonly low Fe near ore and high Fe distal in H 2Sreservoir, CL luminescence: Mn as activator, Fe quench

Sideri te common - especially in Australian CD examples.

Ore-stage si l ic a typically minor - often equivocal in CD

Volcanic associated CD (e.g., Sullivan)-tourmaline, garnet etc).