depositos epitermals_ejemplos
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Epithermal Systems
Low and high sulphidation deposits
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Submarine Epithermal Systems
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The significance of Epithermal
Deposits as a Gold Resource
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Distribution of Epithermal Deposits
High Sulphidation
Low Sulphidation
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Surface expression of a
low sulphidation
epithermal deposit
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Low Sulphidation Deposits
Ore Styles and Alteration Assemblages
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Low Sulphidation Deposits
luid !nclusion Temperatures and Salinities
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Low Sulphidation Deposits
Oxygen and "ydrogen !sotopic Data
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Low Sulphidation Deposits
Temperature#p" $onditions
%&&
'&&
(&&
)&&* ) ( ' % +
o$
Log m,-
.m"-
/usco0ite ,#feldspar
,aolinite
Andalusite
( ,AlSi(O1 - ) "- 2 ,Al(Si(O*&3O"4) - + SiO) - ) ,
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The Low Sulphidation Epithermal 5The Low Sulphidation Epithermal 5
Geothermal Lin6Geothermal Lin6
$hampagne 7ool8 9ew :ealand
;p to aira6ei Geothermal
7ower 7lant8 9ew :ealand
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The Low Sulphidation Epithermal 5The Low Sulphidation Epithermal 5
Geothermal Lin6Geothermal Lin6
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Geothermal >ell ScalingsGeothermal >ell Scalings
from $erro 7rieto8 /exicofrom $erro 7rieto8 /exico
Electrum
$halcopyriteSphalerite
$lar68 ?@R@ >illiams#?ones8 A@E@8 3*
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$ontrols on the Solubility of Gold
Au3"S4)# -"- - &@% ")O
2 Au - )")S -&@)%O)
Au$l)# - &@%")O
2 Au - )$l# - "- -&@)%O)
>illiams#?ones et al@ )&&<
Au3"S4o - &@% ")O
2 Au - ")S -&@)%O)
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A model for the formation of low
sulphidation epithermal deposits
*4 /agmatic 0apour condenses in meteoric water
)4 Gold transported as Au 3"S4)#
(4 >ater rises and boils8 releasing ")S and destabiliCing Au3"S4)#
'4 Gold deposits as the nati0e metal
Au3"S4)# - "- - &@% ")O
2
Au - &@)%O) - )")S
Removed by boiling
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Epithermal Systems"igh sulphidation deposits
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"igh Sulphidation Deposits
Ore Style and Alteration Assemblages
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Acid#Sulphate Alteration
uggy silica Ad0anced argillic alteration
All components of the roc6
leached lea0ing behind 0uggy
silica 3p" *4
Alunite 3,Al(3SO'4)3O"4+,aolinite 3Al)Si)O%3O"4'FuartC and 7yrite
7yrite
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$onditions of Acid#Sulphate Alteration
,ing et al@8 )&*'
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The high sulphidation 7ascua epithermal
deposit8 $hile
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/ineraliCation at 7ascua
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"igh Sulphidation Deposits
Oxygen and "ydrogen !sotopic Data
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"igh Sulphidation Deposits
luid !nclusion Temperatures and Salinities
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A /odel for the ormation of "igh A /odel for the ormation of "igh
Sulphidation DepositsSulphidation Deposits
$oo6e and Simmons8 )&&&
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$ontrols on the Solubility of Gold
Au3"S4)# -"- - &@% ")O
2 Au - )")S -&@)%O)
Au$l)# - &@%")O
2 Au - )$l# - "- -&@)%O)
>illiams#?ones et al@ )&&<
Au3"S4o - &@% ")O
2 Au - ")S -&@)%O)
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Sangihe
Lessons from !ndonesia
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The Sangihe Au#Ag Deposits
Py I Au 1.1 ppm Ag 33 pp
Py II Au 1 ppm Ag 81 pp
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Copper mapfor Py II atSangihe
Gold map for
pyrite atPasua
Cu !green" As
!#lue" maps for pyrite atPasua
/etal Coning in pyrite
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The Lycurgus $up 5 dichroic glass and nanogold
A possible explanation for in0isible goldH in pyrite 5 electrostatic attraction
of negati0ely charged nanogold particles to the surfaces of positi0ely charged
pyrite >illiams#?ones et al@ )&&<
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The Sangihe /odel
King et al.(2014)
$awah I%en High Sulphidation 'pithermal
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$awah I%en & High Sulphidation 'pithermal(eposit in the )a*ing+
(aite (ome
Alunite,pyrite
Aid la*e pH -.
)ining sulphur
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/H0 !gas" 2 /S0!gas" 0S !solid" 2 0H0S/ !gas"
H0S/!a4" 0H2 2 S/0&
Sulphur condensation
and acidity creation
+&& o$
p" #O@+
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Sampling the gases
Giggenbach bottle
Gas condenser
9ew dome
Alunite.pyrtite AuI
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Acid Sulphate Alteration at ,awah !Jen
$ristobalite#alunite spineResidual silica in andesite
pillow
Alunite#pyrite alteration Alunite#pyrite 0ein
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Distribution of Alteration at ,awah !Jen
Scher et al@ 3)&*(4
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Gold Sil0er mineralisation at ,awah !Jen
Sangihe
Sangihe
,awah !Jen
,awah !Jen
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Solubility of Sil0er in "$l#")O apour
Sil0er solubility increases with hydration
Migdisov and Williams-Jones (2013)
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Epithermal Au Ore Formation
apour#dominated hydrothermal plume rises from magma transporting
Au and depositing it as temperature drops below '&&°$
Hurtig and Williams-Jones (2014)
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References
>illiams#?ones8 A@E@ and "einrich8 $@"@8 )&&%8 apor transport of metals and
the formation of magmatic#hydrothermal ore depositsB Econ@ Geol@8*&&8 p@*)1K#*(*)@
,ing8 ?@8 >illiams#?ones8 A@E@8 0an "insberg8 @8 and >illiams#?ones8 G@
"igh sulfidation epithermal pyriote#hosted Au 3Ag#$u4 ore
formation by condensed magmatic 0apors on Sangihe !sland8
! d i E i G l *&< *K&% *K((
$oo6e8 D@R8 Simmons8 S@@8 )&&&@ $haracteristics and genesis of
epithermal gold deposits@ !nB "agemann8 S@G@8 rown8 7@E@ 3Eds@48
Gold in )&&&8 Re0iews in Econ@ Geol@ 0ol@ *(@ Society of Economic
Geology8 oulder8 $O8 pp@ ))*5)''@
$lar68 ?@R@ and >illiams#?ones8 A@E@8 3*illiams#?ones8 A@E@8 Leonardson8 R@>@8 "odgson8 $@?@8
Sil0a87@8 TMlleC8 $8 ega8 ?@8 and RoJas8 @8 )&&%a8 Geology and
genesis of the multistage high#sulfidation epithermal 7ascua Au#Ag#
$u deposit8 $hile and ArgentinaB Econ@ Geol@8 0@ *&&8 p@ '+(5'
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