comparing metallogenic and phosphogenic events in the ... fratura/falha mina/depÓsito pb-zn...

$: Comparing metallogenic and phosphogenic events in the ... FRATURA/FALHA MINA/DEPÓSITO Pb-Zn ANOMALIA BOUGU\ER:MÍNIMOS LOCAIS (< -65 mGal) N.REDENÇÃO CABOCLO ... Sto.Antonio do$
Aroldo MisiAroldo Misi

ComparingComparing metallogenicmetallogenic andand phosphogenicphosphogeniceventsevents in in thethe intracratonicintracratonic andand passivepassive--

marginmargin ProterozoicProterozoic basinsbasins ofof thethe SF SF CratonCraton: : TheThe BambuBambuíí/Una /Una andand Vazante Vazante GroupsGroups

Aroldo MisiAroldo MisiGrupo de Grupo de MetalogêneseMetalogênese e Explorae Exploraçção Mineralão Mineral

Universidade Federal da BahiaUniversidade Federal da Bahia

(([email protected]@gmail.com))


Irecê Sub-Basin (Una Gr.)

S. Francisco BasinBambuí Group

Brasilia Fold BeltVazante Group

Proterozoic Basins

Una-Utinga Sub-BasinUna Group

22


Distribution of rifting and collisional ages

Rodinia Gondwana (Condie, 2002)

33


ProterozoicProterozoic SedimentSediment--HostedHostedPbPb--ZnZn depositsdeposits ofof thethe São Francisco São Francisco CratonCraton

150Km

1 - Vazante2 - M. Agudo3 - Januária-Itacarambí4 - Montalvânia5 - S. Ramalho6 - N. Redenção7 - Irecê

384246

10

14

18

4

78

2

3

9

5

1

6

8 - M. Gomes9 - Melancias

1

Vaz. Group

10 - Galena (Caboclo) –

10

44

Chapada Diamantina Group


Chapada DiamantinaChapada Diamantina

Pb-ZnUna-Utingasub-basin

Irecêsub-basin

Pb-Zn

Sete Lagoas 1

Sete Lagoas 2

Sete Lagoas 3

L. Jacaré/S.Sta.Helena

Phanerozoic Neoprotero

zoic

Fault

Conceição Filho et al., 2003

CôcosCôcos--MontalvaniaMontalvania (São (São Francisco Francisco BasinBasin))

55


PHANEROZOICPROTEEROZOICARCHEANFAULT

BRASI LI

A FOL D

BEL T

VAZANTE

M. AGUDO

Zn-Pb deposit

South São Francico Craton

10 0 10 20 30m

Nível (-83)

Nível (-116)

Nível (-150)

Nível (-50)

Falha Principal

BLOCO ABLOCO B

BLOCO C

SAD

NJK

JK

JK

JK

GHIGHIGHIGHI

LLLL

L

KJ

GHI

DAR

DAR

DAR

DAR

DAR

SAD

SAD

Br. dol.

Br. dol.M

M

M

M

IC-4

IC-33

IC-23IC-9

IC-14

N-1

IC-25

IC-2

IC-7IC-8

IC-16

IC-15

JK-1

IC-13

GHI-11

GHI-12

IC-10IC-34

IC-38

IC-12 IC-19IC-41

IC-21

IC-3IC-11

IC-1Br. dol.

Morro Agudo Mine

66


STRATIGRAPHIC CONTROLS STRATIGRAPHIC CONTROLS AND CORRELATIONSAND CORRELATIONS

Oolitic limestone

Pelite and marl

Zn-Pb depositsDolostone

Laminated limestone

Diamictite

CYCLE 2

CYCLE 1

SETE LAGOASVAZANTE JANUÁRIASERRA DORAMALHO

IRECÊ & UNA-UTINGA

0.70755

0.70757

0.70766

0.70767

0.707550.70780

0.70756

0.70773

0.70690 ?

0.70684 ?

730 to 600 Ma.

77


50 100

100

150 200

200

250 300

300

400

500

600

T (oC)Número de medidas

M. AGUDOM. AGUDO

100

200

300

400

500

600

700

800

0 5 10 15 20 25 30 35 40 45 50wt% NaCl

Número de medidas

N.REDENN.REDENÇÇÃOÃO

MVTMVT MVTMVT

M. AGUDOM. AGUDO

N.REDENN.REDENÇÇÃOÃO

Mississipi Mississipi ValleyValley--typetype (MVT) (MVT) depositsdeposits ??

88


0

10

20

30

0 50 100 150 200 250 300 350

Temperatura de homogeneização (Th)

Salin

idad

e (%

NaC

l equiv.)

1

2

3

N.Redenção

M. Agudo

S. Ramalho/Montalvânia

Vazante

Irecê

1

3

2

MVT

IRISH

SEDEX

HOMOGENIZATION TEMPERATURES AND SALINITIES FROM PRIMARY FLUID INCLUSIONS

H

99


ModelModel ofof fluidfluid circulationcirculation appliedapplied to to thethe ZnZn--PbPbmineralizingmineralizing fluidsfluids in in thethe ProterozoicProterozoic basinsbasins ofof thethe SFCSFC

NEOPROTEROZOIC

A

1

2

3

4

5

U, Th

Sources: Spirakis & Heyl, 1998; Sangster et al., 1998; Fehn, 1985; O’ Connor, 1986

High Heat Production (HHP) granites:- Elevated heat flow (>60mW m-2)- U-Th rich (U>6ppm and/or Th>25ppm)- Strong negative Bouguer anomalies

MESOPROTEROZOIC

High radiogenic heat liberated bylate episode of fracturing

HHP K-rich granites (below) arepossible sources for Zn and Pb

-Paleoproterozoic and Archeanbasement w/ high heat flow-Paleoproterozoic U-Th-K richgranites-Negative Bouguer anomalies

Sources: Iyer & Hamza, 1992; Iyer et al., 1996; Misi, 1999; Misi et al., 2005

Conceptual modelS. Francisco Craton

1010


15

16

17

18

10 15 20 25 30 35

206Pb/204Pb

207 P

b/20

4 Pb Irecê

Lagoa Real(1.7-1.8 Ga)

M. do Gomes

RatioRatio plotsplots for for IrecêIrecê/M.do Gomes (/M.do Gomes (IrecêIrecê subsub--basinbasin) ) andand S.do Ramalho (S.Francisco S.do Ramalho (S.Francisco BasinBasin) )

sulfidessulfides andand for Lagoa Real for Lagoa Real granitesgranites

Lagoa Real Granites:U = 4 – 20 ppm

Th = 17 – 76 ppm(Maruéjol et al., 1987)

HHP granites?

Misi et al., 2004

1111


IRECÊ

M.AGUDO/VAZANTE

CSFFRATURA/FALHA

MINA/DEPÓSITO Pb-Zn

ANOMALIA BOUGU\ER:MÍNIMOS LOCAIS (< -65 mGal)

N.REDENÇÃO

CABOCLO

NEGATIVE BOUGUER ANOMALIES AND

Pb-Zn MINERALIZATION

1212


1,7 Ga1,7 Ga U, ThU, Th

Pelites (Neoproterozoic)

Zn-Pb (Neoproterozoic)

Carbonates (Neoproterozoic)

Siliciclasts, carbonates(Mesoproterozoic)

Granites

W E

Caboclo (Mesoproterozoic)

M. AgudoVazante

IrecêN.Redenção

Vale S.Francisco

Basement

A POSSIBLE METALLOGENIC EVOLUTION A POSSIBLE METALLOGENIC EVOLUTION MODEL FOR THE MODEL FOR THE ZnZn--PbPb DEPOSITS OF THE DEPOSITS OF THE

SÃO FRANCISCO CRATONSÃO FRANCISCO CRATON

U, Th

?

1313

?


Cedro do Abaeté

1

3

4

5

6

7

8

1

9

5

3

67 8

PhosphatePhosphate depositsdeposits ofofthethe S. Francisco S. Francisco

CratonCratonN

E

S

W

Campos Belo

Nova Roma

Formosa

Cabeceiras

Vazante

Lagamar

Rocinha

PHANEROZOIC

NEOPROTEROZOIC(São Francisco Supergroup)

MESOPROTEROZOIC(Espinhaço Supergroup)

PALEOPROTEROZOIC-ARCHEAN(Basement)

4

Irecê9

2

2

1414


20% of the phosphate production of the world comes from 20% of the phosphate production of the world comes from Precambrian and Cambrian Precambrian and Cambrian phosphoritesphosphorites..

The formation of The formation of phosphoritesphosphorites is episodic and related to is episodic and related to events of global extent. events of global extent.

During the During the ProterozoicProterozoic the most important the most important phosphogenicphosphogenicevents occurred in the events occurred in the NeoproterozoicNeoproterozoic Era: (i) 700Era: (i) 700--800 800 Ma and (ii) 620 Ma (Cook & Ma and (ii) 620 Ma (Cook & ShergoldShergold, 1980)., 1980).

Some factual information about Some factual information about phosphoritesphosphorites and and phosphogenesisphosphogenesis

1515


Snowball EarthSnowball Earth

Paul Hoffman: www.snowballearth.org

Marinoan tillite

1616


Glacial events and phosphate depositsNeoproterozoic Era

321

Phosphoorites

Glacigenic diamictites12

3

SturtianMarinoan/VarangerianGaskiers

0.7050

0.7060

0.7070

0.7080

0.7090

1717


P CYCLE AND PP CYCLE AND P22OO55

CONCENTRATION CONCENTRATION

Fe, Mn

Fe, MnSW

P Fe-Mn

P Mat.Org.

P A.Mar P A.Mar

Organic accumulation

P P

Wind (5%)

Rivers (95%)

Cook & Shergold, 19861818


5

2

6

3

8

8 IRECÊ

7

VAZANTEBAMBUÍ

UNA

Stratigraphic controls of the phosphate Stratigraphic controls of the phosphate deposits: related to glacial events ?deposits: related to glacial events ?

1 COROMANDEL

3 LAGAMAR

5 NOVA ROMA, C. BELOS,M. ALEGRE, FORMOSA

6 CEDRO DO ABAETÉ

7 CABECEIRAS

? ?

1

2 ROCINHA

Cycle 1

Cycle 2

1919

?


Aragonite ppt.)

Irecê Basin

Dolomite

Fe oxide

IrecêIrecê

?

Cycle 2

Cycle 1

Diamictite Phosphorite

Bebedouro Fm.

2020

δ13C= -4‰ PDB

δ13C= -6‰ PDB


Irecê (Una Group)

Stromatolitic phosphoriteInitial reserves: 240 Mt 14% P2O5

Lagamar (Vazante Group)

Banded phosphorite Initial reserves: 5 Mt 35% P2O5

Rocinha (Vazante Group)

Banded phosphorite Initial reserves: 200 Mt 12% P2O5

Fosforito

Calcilutito


LeastLeast 8787Sr/Sr/8686Sr Sr ratiosratios fromfromRocinha, Lagamar Rocinha, Lagamar andand IrecêIrecê

8787Sr/Sr/8686SrSr

PhosphoritePhosphorite MicriteMicrite

ROCINHAROCINHA

LAGAMARLAGAMAR

5680

Sr (ppm)

2095

PhoosphoritePhoosphorite

0.70766

0.70767

0.70760

-

IRECÊIRECÊ 623 0.71263 0.70762


P

P

P

Misi et al., 2007 (modified)

2323

δ13C= -4‰ PDB

δ13C= -6‰ PDB

δ13C= -5‰ PDB


520520

15.49

15.59

15.69

15.79

17.55 17.65 17.75 17.85 17.95

206Pb/204Pb

207Pb/2

04Pb

680

I

II

III

�

�

�

�

Morro Agudo

Vazante

Fagundes

Ambrosia

(b)

15,7

15,9

16,1

16,3

16,5

16,7

16,9

17,1

20 24 28 32 36 40 44

206Pb/204Pb

207Pb/204 P

b

Age = 690 ± 74 Ma

MSWD = 13

Fosforitos de Lagamar

LGAM -11

690 ± 74 Ma.

680 to 640 Ma.

Pb-Pb isotope age: Zn-Pb deposits, Vazante

Pb-Pb age (leachates): P deposits, Vazante

Ages of Zn-Pb and Phosphate deposits, Vazante Group

PhosphoritesLagamar, Vazante

M.Agudo, Vazante,Fagundes, Ambrósia

15,0

15,60

15,70

15,80

17,2 18,2 19,2 20,2

206Pb/204Pb

207Pb/2

04 P

b

UC

Rosh Pinah and

Skorpion, Namibia

Vazante, M.Agudo, Fagundes and Ambrósia., Brazil

Kabwe, Zambia15.8

15.7

15.6

15.5

17.2 18.2 19.2 20.2

Comparing w/ Neoproterozoic equiv. in Africa

2424


EstimatedEstimated ages ages fromfrom δδ3434S S ofof sulfatessulfates

T

K

J

T

P

P

M

D

S

O

0+15 +20 +25 +30 +35 +40

100

200

300

400

500

600

700

800

900

1000

+15 +20 +25 +30 +35 +40

Pε

ε

δδδδ34S

Cenozoic

Mesozoic

Paleozoic

Geo

logical Periods

Age (m

illions of ye

ars)

δδδδ34S

SULFATES(CDT)

Irecê +29 (n = 13)

Nova Redenção +37,5 (n = 4)

Morro Agudo/

Vazante +24,6 (n = 19)

Misi et al., 2005

2525


S. da Lapa

M. do Calcário

S. do Poço Verde

S. do Garrote

Lagamar

Rocinha

Sto.Antonio do Bonito

PP

P

Zn

Zn

Re-Os: 1.1 Ga(1), (2)

Re-Os: 1.1 Ga(2)

U-Pb (Zr detritico) max.:

0.93 Ga(1) and 0.95 Ga(3)


1.35 Ga(3)


1.95 Ga (SHRIMP)(3)

(1) Azmy et al., 2008(2) Kaufman et al.,2007 (unp.)(3) Rodrigues et al., 2008(4) Misi et al., 2007

87Sr/86Sr (carb. fluorap):

0.70767(4)

The Vazante Group: Ages

Conventional units (Formations)(Dardenne et al., 2001)


0.94 Ga(3)


1.25 Ga(3)

Re-Os: 1.3 Ga(2)

2626


(1) Azmy et al., 2008(2) Kaufman et al.,2007 (unp.)(3) Rodrigues et al., 2008(4) Misi et al., 2007

The Vazante Group now: A possible interpretation

S. da Lapa

M. do Calcário

S. do Poço Verde

S. do Garrote

Lagamar

Rocinha

Sto.Antonio do Bonito

PP

P

Zn

Zn

Re-Os: 1.1 Ga(1), (2)

Re-Os: 1.1 Ga(2)


0.93 Ga(1) and 0.95 Ga(3)


1.35 Ga(3)


1.95 Ga (SHRIMP)(3)

87Sr/86Sr (carb. fluorap):

0.70767(4)

Conventional units (Formations)(Dardenne et al., 2001)

Work hypothesis

Older units

Vazante/BambuíU-Pb (Zr detritico) max.:

0.94 Ga(3)


1.25 Ga(3)

Re-Os: 1.3 Ga(2)

2727

Aroldo MisiAroldo Misi 2828

SeismicSeismic sectionsection acrossacross thethe SW SW borderborder ofofthethe SF SF CratonCraton ((byby Petrobras)Petrobras)

Aroldo Misi

CONCLUSÕESCONCLUSÕES

�� Os Os eventoseventos metalogenmetalogenééticosticos (Zn(Zn--PbPb) e ) e fosfogenfosfogenééticosticos dasdas baciasbaciasProterozProterozóóicasicas intracratônicasintracratônicas e de e de margensmargens passivaspassivas do Crdo Crááton ton do do SãoSão Francisco Francisco estãoestão relacionadosrelacionados a a eventoseventos globaisglobais ocorridosocorridosdurantedurante a Era a Era NeoproterozNeoproterozóóicaica. .

�� EssesEsses eventoseventos estãoestão bembem representadosrepresentados no no GrupoGrupo VazanteVazante, , ememduasduas seseççõesões com com idadesidades distintasdistintas, , separadasseparadas porpor umauma falhafalha de de empurrãoempurrão, , queque colocacoloca sequênciassequências maismais antigasantigas((mesoproterozmesoproterozóóicasicas), ), mineralizadasmineralizadas emem ZnZn--PbPb, , sobresobre outrasoutras maismaisnovas (novas (neoproterozneoproterozóóicasicas), ), mineralizadasmineralizadas emem fosfatofosfato. .

�� Os Os modelosmodelos de de exploraexploraççãoão mineral mineral devemdevem considerarconsiderar a a possibilidadepossibilidade de de existiremexistirem outrosoutros depdepóósitossitos econômicoseconômicos de de metaismetais--base base principalmenteprincipalmente nasnas baciasbacias de de margemmargem passivapassiva, , porporcausacausa dada maiormaior espessuraespessura do do pacotepacote sedimentarsedimentar. Os . Os fosforitosfosforitospodempodem corrercorrer tantotanto nasnas baciasbacias intracratônicasintracratônicas comocomo nasnas de de margemmargem passivapassiva, , emem ambientesambientes sedimentaressedimentares ppóóss--glaciaisglaciais.... 29

comparing metallogenic and phosphogenic events in the ... fratura/falha mina/depÓsito pb-zn...

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