Depósitos de Skarn de Cobre

8/17/2019 Depósitos de Skarn de Cobre

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Depósitos de

Skarn de Cobre Yacimientos de Minerales II

Alumno: ESPIRITU PUJAY,

Junior A.



ANTAMINASKARN Cu!n



Ubicación



"I#. $. Premine %&'sio(ra%&' o) t&e Antamina area, *it& %lace names re)erred to in t&e te+t, illustratin( t&e clusterin( o) A(earin( P!n -ein de%osits

around a(o Antamina documented ' /odenlos and Eric0sen 123445. Also indicated are t&e Conton(a P!nCuA( mine 4 0m to t&e nort&nort&*est o)

a(o Antamina and -eins aout 466 m nort&east o) Conton(a. / 7 /arr8n, C 7 Casualidad, Cc 7 Condorcocc&a, " 7 "ortuna, JE 7 Julia Eloisa, P 7

Poderosa, P% 7 Puta%u9uio, R 7 Recom%ensa, Rd 7 Rosita de ro, S" 7 San "rancisco, SR 7 Santa Rosa, UP 7 Usu Pallares. T&e -ie*%oints )or

%&oto(ra%&s in "i(ures ;, <, 2$, and 24 are s&o*n as =e'es.> 1Contour inter-al is $66 m.5



"I#. $. Premine %&'sio(ra%&' o) t&e Antamina area,

*it& %lace names re)erred to in t&e te+t, illustratin(

t&e clusterin( o) A(earin( P!n -ein de%osits

around a(o Antamina documented ' /odenlos

and Eric0sen 123445. Also indicated are t&eConton(a P!nCuA( mine 4 0m to t&e nort&

nort&*est o) a(o Antamina and -eins aout 466 m

nort&east o) Conton(a. / 7 /arr8n, C 7 Casualidad,

Cc 7 Condorcocc&a, " 7 "ortuna, JE 7 Julia Eloisa, P

7 Poderosa, P% 7 Puta%u9uio, R 7 Recom%ensa,

Rd 7 Rosita de ro, S" 7 San "rancisco, SR 7

Santa Rosa, UP 7 Usu Pallares. T&e -ie*%oints )or

%&oto(ra%&s in "i(ures ;, <, 2$, and 24 are s&o*n

as =e'es.> 1Contour inter-al is $66 m.5

EscenarioGeológicoRegionalRelaciones Estrati(r?@cas



"I#. . In)erred strati(ra%&ic column in t&e mine area com%ared *it& t&at )or t&e Jumas&a and CelendBn "ormations, com%iled )rom oser-ations 1/ena-ides,

2345 on t&e measured sections in t&e RBo Puc&ca -alle', a%%ro+imatel' $6 0m nort& o) Antamina. T&e contact et*een t&e Jumas&a and CelendBn

"ormations coincides *it& t&e oundar' et*een t&e Turonian and Coniacian sta(es and is indicated *it& a solid lineD un0no*n sta(e oundar' locations

&a-e een a%%ro+imated and indicated *it& das&ed lines and 9uestion mar0s. T&e strati(ra%&ic inter-al inter%reted to &ost t&e s0arn is s&o*n. Inset s&o*san outline o) t&e re(ional strati(ra%&ic section.

Columna Estrati(ra@ca



"I#. 4. Structural (eolo(' o) t&e Mara8n t&rust and )old elt in t&e

-icinit' o) Antamina, illustratin( t&e mar0ed c&an(e in t&e orientations o)

t&rust )aults and )old a+es across a nort&easttrendin( Fone t&rou(&

Antamina 1a)ter E(eler and de /oo', 234D Gilson et al., 23;, 2334D

Coin( et al., 233D Jaca', 233D and Strusie-icF et al., $6665. T&e

nort&eastsout&*estH trendin( loci o) t&ese c&an(es in structural attitude

is indicated ' t&e &ea-' das&ed line, *&ic& is oset in a le)tste%%in(

sense in t&e -icinit' o) Antamina. T&is area is t&e location o) t&e

%ro%osed crossstri0e structural discontinuit' discussed in t&e te+t. Inset

s&o*s t&e location o) t&e ma% area relati-e to t&e uari 123i5, Sin(a 123

5, Re9ua' 1$6i5 and a Uni8n 1$65 9uadran(les. No attem%t &as een

made to estalis& continuit' et*een t&e ma% units o) Gilson et al.

123;, 23345 nort& o) 3L 6 S and t&ose o) Coin( et al. 12335 to t&esout&. T&e undated -olcanic roc0s o) Pam%a JunBn &a-e een assi(ned to

t&e Cali%u' Su%er(rou% 1see te+t )or discussion5.

#eolo(Ba Estructural delCom%leo Maraon



"I#. . Sim%li@ed (eolo(' o) a%%ro+imatel' <,666 0m$ o) t&e Mara8n

t&rust and )old elt in t&e re(ion around AntaminaD t&e dominantl' u%%er

Miocene Cordillera /lanca at&olit& is remo-ed 1c). "i(s. 2 and 45,reOectin( t&e (eolo(' at t&e time o) intrusion and mineraliFation in t&e

late Miocene. T&e nort&eastsout&*est trendin( crossstri0e structural

discontinuit' t&at %asses t&rou(& Antamina is delimited ' &ea-' das&ed

lines. Mississi%%ian to o*er Jurassic sedimentar' roc0s are asent

eneat& t&e Cretaceous #o'llaris9uis(a #rou% nort&east o) Antamina

alon( t&e crossstri0e structural discontinuit' ut are %resent nort& and

sout&east o) t&e crossstri0e structural discontinuit', e+ce%t *&ere cut

out ' )aultin(. An unusual aundance o) i(neous odies intrudes t&e

Mara8n /elt alon( t&e crossstri0e structural discontinuit', com%ared to

transects to t&e nort& and sout&. A)ter E(eler and de /oo' 12345, Gilson

et al. 123;, 23345, Coin( et al. 12335, Jaca' 12335, and Strusie-icF

et al. 1$6665.



EscenarioGeológico LocalRocas Sedimentarias

"I#. ;. T&e t*o distinct &ost roc0 t'%es o) t&e Antamina

s0arn s'stem: an u%%er se9uence o) t&inedded, silt'

limestones, &ere lar(el' con-erted to calc&orn)elses,

assi(ned to t&e CelendBn "ormation 1Ce5, and a lo*er

se9uence o) t&ic0edded, relati-el' %ure limestones t&at

)orm marles, inter%reted as t&e Jumas&a "ormation 1J5.

ocations )rom *&ic& t&e %&oto(ra%&s *ere ta0en areindicated in "i(. $. P&oto(ra%&s ta0en in 233; t&rou(&

2333D t&is rid(e &as no* een lar(el' remo-ed ' mine

de-elo%ment. 1a5 T&e sout&east side o) uerada

Antamina, loo0in( sout&east. T&e contact 1lon( lac0

das&es5 et*een t&e Jumas&a and CelendBn "ormations is

%laced at t&e to% o) t&e u%%ermost massi-e t&ic0edded

limestone 1%ale (ra' and5 de)ormed ' t&e Antamina

anticline. Note t&e irre(ular u%%er, sout&eastern contact o)

t&e s0arn 1lon( *&ite das&es5, &ere lar(el' con@ned to t&e

Jumas&a "ormation. 15 oo0in( nort&east at t&e &ead o)

uerada Antamina s&o*in( t&e distinct control o) eddin(

in t&e CelendBn "ormation on s0arn de-elo%ment.



"I#. <. T&e Jumas&a and CelendBn "ormations. 1a5 Cli)ormin( t&ic0 eds o) massi-e limestone on t&e sout&east Oan0 o) uerada Calla%o 1see "i(. $ )or

location5. 15 Massi-e limestone o) t&e Jumas&a "ormation, s&o*in( Outed *eat&erin( 1sout& o) Yanacanc&a area, "i(. $5. 1c5 U%%er: massi-e 1i.e.,

unlaminated and *it& no %re)erred orientation o) )ossils5 %elec'%od caronate *ac0estone o) t&e Jumas&a "ormation 1QQ CMA63, 244 m5. o*er: s&eared

)ossili)erous caronate *ac0estone, e9ui-alent to u%%er %iece, not marmoriFed, ut *it& a stron( %re)erred orientation 1QQ CMA63, 26 m5. 1d5 More

recessi-e *eat&erin(, -e(etated, t&inedded limestones and marls o) t&e CelendBn "ormation cro%%in( out on t&e sout&east slo%es o) uerada A'as& near

its intersection *it& uerada Tucus& 1see "i(. $ )or location5. P&oto(ra%& ta0en in 233;D t&e lo*er &al) o) t&is area is no* oscured ' construction o) t&e

tailin(s dam. 1e5 Nodular limestone o) t&e CelendBn "ormation, consistin( o) li(&t (ra', coalescin(, caronateric& nodules se%arated ' *is%s o) dar0 (ra'calcareous siltstone 1"ortuna Mine area, see "i(. $D &ammer )or scale5. 1)5 U%%er: CelendBn "ormation nodular limestone 1QQ CMAC, $$2 m5. o*er:

lenticular eddin( inter%reted as s&eared nodular limestone o) t&e CelendBn "ormation 1QQ CMAC4, <;.4 m5.



"I#. 3. MarmoriFed Jumas&a "ormation. 1a5 Sutle eddin(, de@ned ' %or%&'rolast aundance 1outlined5 in calcitic marle, di%s moderatel' sout&*est and

is o-er%rinted ' a nort&eastdi%%in( %lanar )aric 1loo0in( nort&*est, %ortal o) ul0 sam%le adit, 46 m sout&*est o) *est s&ore o) a(o AntaminaD &ammer

)or scale5. 15 Sutle eddin(, de@ned ' sli(&t color dierence and dierential erosion 1outlined5, reOectin( cr'%tic dierence in %or%&'rolast aundance in

calcitic marle 1loo0in( nort&*est, 46 m sout&*est o) *est s&ore o) a(o AntaminaD $6 cm noteoo0 in )ore(round )or scale5. 1c5 Medium edded la'er o)

li(&t (reen, @ne(rained, dio%sidic calc&orn)els de@nes eddin( *it&in coarse(rained calcitic marle near t&e to% o) t&e )ormation 1loo0in( nort&east, 66

m sout&*est o) t&e *estern s&ore o) a(o AntaminaD 24 cm ruler )or scale5. 1d5 U%%er: mottled (ra' calcitic Jumas&a "ormation marle *it& ti(&tl' )olded,

oudina(ed, dar0(ra' silt' laminae. o*er: mottled *&ite and (ra' marle *it& ti(&tl' )olded u (arnetric& la'er, similar in s&a%e to t&e silt' la'er in t&e

u%%er core 1QQ CMA6<, $2< m5. 1e5 /anded (ra' Jumas&a "ormation marle s&o*in( de-elo%ment o) a%%ro+imatel' 26 %ercent lac0 sca%olite cr'stals

*it&in dar0er la'ers 1QQ CMA2, $$ m5. 1)5 U%%er: *&ite marle in (ra' Jumas&a "ormation marle ot& as %atc&es t&rou(&out and locall' around-einlets and st'lolites 1QQ CMA2, $$< m5. o*er: -einletcontrolled *&ite marle in (ra' Jumas&a "ormation marle cut ' irre(ular -einlets *it&

c&al0'*&ite *ollastonitic sel-a(es 1QQ CMA$, 2 m5. Scale ars in centimeters.



"I#. 26. orn)els, s0arnoid, and *ri((lite de-elo%ed in t&e CelendBn "ormation. 1a5 Irre(ular stoc0*or0 o) sealed )ractures controllin( de-elo%ment o) li(&t

(ra' tremolitic calc&orn)els in li(&tro*n %&lo(o%itic calc&orn)els 1on t&e sout&east rid(e crest, center o) "i(. 2$cD 24 cm %encil )or scale5. 15 Calc&orn)els

)acies *it& distal, li(&tro*n, -er' @ne (rained %&lo(o%itic calc&orn)els at u%%er le)t, li(&t(ra' tremolitic in t&e center, and %ro+imal, li(&t(reen medium

(rained dio%sidic calc&orn)els at lo*er ri(&t. T&ese )acies are unusuall' closel' s%aced ecause t&e' are on t&e mar(in o) a narro* di0e, a%%ro+imatel' 46

m sout&east o) t&e main intrusion 1same location as aD 44 mm lens ca% )or scale on t&e )ar le)t5. 1c5 S%arse, lar(e, medium(reen dio%sidic nodules in %ale

(ra' calc&orn)els 1ase o) clis, nort&east o) a(o AntaminaD 26 cm 0ni)e )or scale5. 1d5 er' aundant coalescin( dio%sidic nodules *it& calciteearin(

calc&orn)els matri+ 1ase o) clis, east o) a(o AntaminaD 24 cm %encil )or scale5. 1e5 Irre(ular concentric andin(, inter%reted ' /odenlos and Eric0sen

123445 to e o) al(al ori(in, ut reinter%reted as *ri((lite te+ture o) metasomatic re%lacement ori(in 1ase o) clis, east o) a(o AntaminaD 24 cm %encil )orscale5. 1)5 /andin( de-elo%ed in calc&orn)els and a%%arentl' controlled ' nort&east stri0in( )ractures 1on t&e rid(e crest sout&east o) Antamina -alle', ust

east o) t&e east end o) "i(. 2$cD 44 mm lens ca% )or scale5.



"I#. 22. ocal (eolo(' o) t&e Antamina area 1modi@ed a)ter Coin( et

al.,233D #lo-er, 233;, un%ulis&ed re%ort to Com%anBa Minera

Antamina S.A., imaD Palomino, 233;, un%ulis&ed re%ort to Com%anBa

Minera Antamina S.A., imaD and o-e and Clar0, 233<, un%ulis&ed

re%ort to Com%anBa Minera Antamina S.A., ima5. T&e %&'sio(ra%&' o)

t&is area is s&o*n in "i(. $. T&e areas de%icted in "i(. 2 are indicated

' t&e t&ree dia(onal rectan(les. AT 7 Antamina t&rust, "T 7 "ortunat&rust, " 7 le)tste%%in( alle' )ault, Y/PT 7 Ya9uirs&/u9ue Punta

t&rust.



"I#. 2$. P&otomosaics illustratin( t&e structure and strati(ra%&'

o) t&e Antamina mine area. ocations )rom *&ic& t&e%&oto(ra%&s *ere ta0en are indicated in "i(. $. T&e -ie*s in 1a5

and 15 loo0 nort&*est, *&ereas t&ose in 1c5 and 1d5 loo0 sout&.

P&oto(ra%&s ta0en in 233; t&rou(& 2333D muc& o) 1a5, 15, and

1c5 &as no* een remo-ed ' mine de-elo%ment, and t&e

s0'line o) 1d5 &as een modi@ed. 1a5 T&e nort&*est side o) t&e

Antamina -alle'D t&e irre(ular u%%er or nort&*estern contact o)

t&e s0arn 1lon( *&ite das&es5 cuts o t&e strati(ra%&ic contact

1lon( lac0 das&es5 o) t&e Jumas&a 1J5 and CelendBn 1Ce5

"ormations. 15 T&e sout&east Oan0 o) t&e rid(e e+tendin(

nort&east o) Cerro /u9ue Punta 1i.e., t&e o%%osite side o) t&e

rid(e illustrated in c5, -ie*ed )rom t&e Yanacanc&a area. 1c5 T&e sout&east side o) t&e Antamina -alle'D t&e irre(ular u%%er,

sout&eastern contact o) t&e s0arn 1lon( *&ite das&es5 cuts o

t&e strati(ra%&ic contact 1lon( lac0 das&es5 o) t&e Jumas&a 1J5

and CelendBn 1Ce5 "ormations. 1d5 T&e nort&*est Oan0 o) t&e

rid(e e+tendin( nort&east o) Cerro Ya9uirs& 1i.e., t&e o%%osite

side o) t&e rid(e illustrated in a5. "aults and )old a+es are

s&o*n ' solid lac0 l ines, t&e strati(ra%&ic contact et*een t&e

Jumas&a 1J5 and CelendBn 1Ce5 "ormations ' lon( lac0 das&es,

t&e contact o) t&e s0arn ' lon( *&ite das&es, intrusi-e contacts

' solid *&ite lines, intrusions ' crosses. AT 7 Antamina t&rust,

Ce 7 CelendBn "ormation, "T 7 "ortuna t&rust, J 7 Jumas&a

"ormation, T 7 scarina t&rust, " 7 sur)ace e+%ression o) t&e

nort&eastern se(ment o) t&e alle' )ault, Y/PT 7 Ya9uirs&/u9ue



"I#. 2. Sc&ematic dia(ram illustratin( t&e lateral ram% model )or t&e structural settin( o) t&e Antamina de%osit. oo0in( sout& so t&at t&e )ace o) t&e

lateral ram% is e+%osed, s&o*in( oset anticlines %roduced in t&e &an(in( *all o) a t&rust )ault ' t*o )rontal ram%s se%arated ' a lateral ram%. 1a5

#eometr' o) t&e )ault %rior to mo-ement. 15 #eometr' o) t&e )oot*all 1&an(in(*all loc0 remo-ed5, s&o*in( t&e sout&*estdi%%in( )rontal ram%s lin0ed

' a nort&eaststri0in( lateral ram% or trans)er )ault. 1c5 A)ter minor t&rust mo-ement, oset ram%cuto anticlines %roduced in t&e &an(in( *all o) t&e

t&rust )ault, *it& more intense nort&eaststri0in( )racturin( ao-e t&e lateral ram%, re%resented ' das&ed lines. 1d5 an(in( *all cuto anticlines

se%arated )rom )aultend anticlines ' additional t&rust mo-ement. E+tensi-e )racturin( de-elo%ed in t&e t&rust s&eet *&ere it Oe+ed o-er t&e lateral

ram%.



Qia(ramaes9uem?tico aescala Re(ional

"I#. 2. Re(ionalscale sc&ematic dia(rams,

loo0in( east, illustratin( t&e %ro%osed structurale-olution o) t&e Antamina area. 1a5 In t&e Middle

or earl' ate Jurassic, t&e Gest Peru-ian trou(&

started to de-elo% t&rou(& )ormation o) an en

ec&elon %attern o) le)tlateral (ro*t& )aults on t&e

*estern ed(e o) t&e Mara8n metamor%&ic

com%le+. T&e Mississi%%ian to o*er Jurassic

sedimentar' roc0s t&at o-erla' t&e metamor%&ic

com%le+ are remo-ed )rom t&e dia(ram )or clarit'

1a)ter M(ard, 23<;5. 15 Also in t&e Middle or

ate Jurassic, minor e+tension at an an(le to t&e

trans)orm )aults se(mented t&e continentalasement, %roducin( on t&e %romontories

structural &i(&s %arallel to t&e ori(inal osets,

suc& as t&e uerococ&a arc&, alon( *&ic& t&e

Mississi%%ian to o*er Jurassic sedimentar' roc0s

*ere eroded. In t&e ate Jurassic t&e C&icama

#rou% *as de%osited in t&e *estern, dee%er

*ater %art o) t&e asin, not illustrated. 1c5

Cretaceous clastic and caronate 1#o'llaris9uis(a

and Mac&a' #rou%s5 sedimentation on t&e Yauli

s&el) *as not stron(l' controlled ' t&e

se(mentation alt&ou(& caronate )acies ma'

&a-e e+tended )art&er sea*ard adacent to

%romontories. 1d5 atest Cretaceous to Paleocene

de%osition o) red eds 1c&ec0eroard %atterned5

*as controlled ' t&e se(mentation, *it&

de%ocenters in t&e reentrants. 1e5 In t&e Eocene

Incaic oro(en', maor stri0e deOections and en

ec&elon )old %atterns t&at con)orm to t&e

se(mentation o) t&e asement de-elo%ed in t&e

Mara8n t&rust and )old elt. Reentrants ecame

structural salients, and %romontories ecamestructural recesses. 1)5 In t&e Miocene, additional

u%li)t o) t&e uerococ&a arc& reacti-ated



"I#. 24. Sc&ematic dia(rams, loo0in( east,

illustratin( t&e %ro%osed localscalestructural e-olution o) t&e Antamina area. 1a5

Structural elements in t&e Antamina area

%rior to intrusion and mineraliFation: )rontal

t&rust ram%s oset ' t&e alle' lateral

ram%, *&ic& *as localiFed ' a o( in t&e

transcurrent alle' )aultD )aultend)old

anticlines o-erl'in( t&e to%s o) t&e oset

)rontal ram%sD stron(l' de-elo%ed nort&east

stri0in( )racturin( %arallel to and o-erl'in(

t&e lateral ram%D and u%*ard)annin( a+ial

clea-a(e in t&e o-erl'in( anticlines. 15 East*est com%ression oli9ue to t&e alle' )ault

induced nort&sout& e+tension and allo*ed

intrusion o) di0es in *in( crac0s localiFed at

t&e end o) one se(ment o) t&e alle' )ault.

1c5 Rela+ation o) east*est com%ression

allo*ed east*est e+tension mani)ested as

nort&sout&Hstri0in( normal )aultin( in t&e

o( et*een t&e t*o se(ments o) t&e alle'

)ault. 1d5 MonFo(ranitic ma(ma intruded t&e

%arallelo(rams&a%ed e+tensional re(ime

et*een t&e t*o se(ments o) t&e alle'

)ault, and ultimatel' (enerated s0arn ore. 1e5

Rene*ed east*est com ression )ormed



"I#. 2. Sc&ematic, e+%loded isometric loc0 dia(ram o) t&e Antamina de%osit. oo0in( nort&, s&o*in( t&e maor )olds and t&rust )aults, t&e alle' )ault 1"5,

t&e e+tent o) s0arn de-elo%ment *it&in and adacent to t&e intrusion, t&e e+tensi-e calc&orn)els and s0arnoid de-elo%ment in t&e CelendBn "ormation, and

t&e restricted marmoriFation o) t&e Jumas&a "ormation. T&e oset Antamina anticline 1AA5 is indicated, ut t&e in)erred alle' lateral ram% is &idden )rom

-ie* in t&is %ers%ecti-e.



Coroccoha!coSKARN Cu!n



Ubicación

"I#. 2. Ma% o) Peru s&o*in( t&e location

o) Corocco&ua'co in t&e Anda&ua'las

Yauri elt 1)rom Ma&er and arson, $66;5. =e'es.> 1Contour inter-al is $66 m.5



"I#. $. Strati(ra%&ic column o) t&e Tinta'a district, Peru. S0arn )orms in t&e

"erroama "ormation. Ada%ted )rom Qe a CruF 123345 and !*en( et al. 1233;5. .>

1Contour inter-al is $66 m.5

Escenario delDeposito



"I#. . #eneraliFed (eolo(ic ma% o) t&e Tinta'a district, Peru. Ada%ted )rom Qe a CruF 123345 and Es%irilla R. 1$665.

S&o*n is t&e outline o) t&e de%osit at Corocco&ua'co and t&e location o) "i(ure 1mine section 2665 and "i(ure 4. inter-al

is $66 m.5



"I#. . #eolo(ic cross section alon( mine section 266 at Corocco&ua'co, s&o*in( t&e location o) drill &ole traces 1numered ao-e t&e (round sur)ace5. Note

t&e (eneral la'ered nature o) t&e s0arn alteration in t&e "erroama "ormation *&ic& lies et*een t&e o-erl'in( massi-e diorite sill and t&e underl'in( iotite

&orn)els o) t&e Mara "ormation.$66 m.5



"I#. 4. #eolo(ic section s&o*in( (eneraliFed (eolo(' and s0arn alteration t&rou(& Corocco&ua'co %arallel to t&e maor )old a+es in t&e

district 1N$LG5 at eastin( 2., )rom nort&in( 266 to 466 1a%%ro+ 2 0m5. Not s&o*n is a%%ro+imatel' 266 m o) t&e o-erl'in( diorite

sill co-erin( t&is %art o) t&e de%osit u% to t&e sur)ace. Qrill traces mar0ed *it& W are %roected onto t&e section )rom ;6 mD all ot&ers are

*it&in 46 m o) t&e sectionm.5



"I#. . Sc&ematic dia(ram o) s0arn %ara(enesis and later alteration at Corocco&ua'co. Qata tem%eratures are

(eneral ran(es and &a-e een in)erred )or nonsilicate minerals )rom Ouid inclusion anal'sis o) calcsilicate

minerals and 9uartF.



"I#. ;. Maor element data (ra%&s o) Corocco&ua'co intrusi-e

roc0s relati-e to t&e laeled a-era(e -alues o) i(neous roc0s )rom

dierent s0arn t'%es )rom Meinert et al. 1$6645. T&e *&ite and

lac0 =+> s'mols on eac& (ra%& re%resent t&e a-era(e -alue )or

Corocco&ua'co and Tinta'a %or%&'ries, res%ecti-el'.Can'on

1/in(&am C'nD anier et al., 23;<5.

"I#. <. Ternar' dia(rams o) (arnet and %'ro+ene end memers

)or s0arn minerals )rom Corocco&ua'co. ate %'ro+enes are

distinctl' enric&ed in &edener(ite com%onent relati-e to earl'

%'ro+ene. S0arn (arnet is &i(&l' andraditic and t'%ical o) ot&er

o+idiFed co%%er s0arns..



Minerali"ación

Ma(netita

Co%%er mineraliFation commenced as tem%eratures decreased to t&esaturation o) c&alco%'rite X ornite in t&e Ouid and e-entuall' to t&estailit' o) Curic& %&ases, *it& %reci%itation %roal' commencin( around

66LC. T&is is in)erred )rom t&e Ouid inclusion data deri-ed )rom -ein anddisseminated 9uartF *&ic& eit&er occurs *it&, or occu%ies, a %ara(enetic%osition similar to sul@des. T&e aundance o) remnant interstitial calcite indistal (arnet could )acilitate metal %reci%itation )rom c&loride com%le+es 'consumin( acid in a decaronation reaction li0e,

. o*e-er, t&e maorit' o) ma(netite re%laces calcsilicate minerals.Retro(rade ma(netite alteration o) s0arn li0el' occurred )or se-eralreasons alt&ou(& t&e %rocesses ma' not &a-e een mutuall' e+clusi-e. Inman' dierent Fones in t&e de%osit ma(netite occurs in (reen (arnet and

%'ro+ene s0arn distal to Ouid sources. T&is su((ests a c&an(e leadin( toma(netite de%osition t&at consistentl' occurred in certain Fones *it&similar (eoc&emical conditions t&rou(&out t&e de%osit at ot& &i(& andlo* ele-ations. "or ma(netite t&at re%laces more distal s0arn minerals,t&is c&an(e is li0el' related to c&an(es in tem%erature and o+idation stateo) t&e Ouid durin( %ro(rade alteration 1Jo&nson and Norton, 23<45



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Depósitos de Skarn de Cobre

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