Transcript
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
A LECTURE ON
EPITHERMAL
Gold Quartz Vein, Acu pan
GOLD DEPOSITS
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
An tamok Mine, 2005
1/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
OUTLINE •
INTRODUCTION – Why Is Epithermal Deposit Important? – Historical Perspective – What is an Epithermal Deposit? – Classes of Epithermal Deposits
•
CHARACTERISTICS OF EPITHERMAL DEPOSITS
•
KEY PROCESSES IN THE FORMATION OF EPITHERMAL DEPOSITS
•
HIGH SULFIDATION DEPOSITS
•
INTERMEDIATE AND LOW SULFIDATION DEPOSITS
•
GEOTHERMAL WATERS, STEAM HEATED ZONES, WATER TABLE MOVEMENT
•
EPITHERMAL VEIN TEXTURES
•
EXPLORATION IMPLICATIONS
Quartz - trus cottite Vein, Lebong Dono k, 2007
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
2/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
WHY IS EPITHERMAL DEPOSIT IMPORTANT?
Bonanza Gold From Sleeper Deposit, Nevada http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Saunders 2010 3/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
BECAUSE OF GOLD!
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
4/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Average grade of primary gold discoveries and gold produced over time. Mine production data for 1950 to 2000 from Mudd (2000) and 2000 to 2010 production data from Fellows (2010).
Gold Price Today Sept 17, 2010: US$1,273.30 per troy ounce!
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
5/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
•Peak Au discoveries – 1988 •Steady decrease from 19902010 •Discoveries in late1980s
>200M oz Au/yr
•Discoveries in 2010 estimated <80M oz Au •Cost of exploration is increasing from: Newly discovered gold resources (including by-product gold) compared to world gold production (with and without South Africa). Scenarios presented cover a range of possible resource conversion factors (40 to 100 percent). Source: McKeith, Schodde & Baltis, SEG Newsletter April 2010
$3/oz – 1950 -1960 $20/oz – 1980s $40/oz -2000s
What does this means? The world needs more exploration geologists now and in the next decade!
THE FUTURE OF GEOLOGY & MINING STUDENTS IS BRIGHT!
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
6/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Epithermal Gold Deposits A v er y i m p o r t an t s t y l e o f g o l d d ep o s i t
Can be very big:
•
•Lihir, PNG 170 Mt @ 3.5 g/t Au (595 t or 19.13 Moz Au) •Porgera, PNG 85 Mt @ 5.8 g/t Au, 33 g/t Ag (493 t or 15.85 Moz Au & 2,805 t Ag)
Can be very rich:
•
•Cripple Creek, USA 630 t Au in veins grading 15 to 30 g/t •Hishikari, Japan 264 t Au, Honko veins 70 g/t Au, 49 g/t Ag Gold from Leb ong Tandai Drillcor e, 2007
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
White, 2009 7/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
LIHIR, PNG Steam rises from the active hydrothermal system at Ladolam gold mine on Lihir Island, Papua New Guinea. Ladolam contains ~600 tonnes of gold and could have formed in 55,000 years. Photo by K. Brown and S. Simmons.
PORGERA, PNG Porgera is a very big gold and copper deposit in the highlands of PNG. It is both an open pit and underground operation by Barrick Gold Corporation, the largest gold mining company in the world.
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
8/193
5/25/2018
HISHIKARI MINE, JAPAN
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
The Hishikari mine (above) is located in northern Kagoshima Prefecture. The hot water seeping into mineshafts is supplied to the nearby hot spring spa. Photo credits: National Institute of Advanced Industrial Metal Science andCo., Technology (AIST) and Sumitomo Mining Ltd .
Hishikari gold mine’s Keisen No. 3 vein (left). The gold grade at Hishikari is 10X the average of worldwide deposits and contains 264 tonnes Au (8.5 Moz Au). http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
9/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Relative Amounts of Gold 50% Witwatersrand 12% Epithermal 10% Porphyry (+ intrusion hosted) 12% Sediment hosted (incl. 4% “Carlin”) 9%
Greenstone lode (mesothermal or “orogenic”)
7%
Other (Fe Fm, VHMS, etc.) Arribas, 2000
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
10/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
11/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
HISTORICAL PERSPECTIVE
• Mining of gold dates back to prehistoric time (placer). • Gold ore mined before 2500 BC. • Gold discovered in California, 1848. • The word e p i t h e r m a l was defined by W. Lindgren in 1922 & 1933. Early underground mining http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
De Re Metallica , Agricola 1556
12/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
What is an Epithermal Deposit? “Epithermal” was derived from two Greek words ep i – above and t h e r m e - hot springs. It refers to deposits formed at low temperature and shallow depths .
The term Epithermal was first defined by Lindgren (1922, 1933) based on observations of -mineralogy of ores and alteration -textures of ores and alteration and inferences about -temperature of deposition -depth of formation Quartz-amythest vein, Lebong Tandai
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
13/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
What is an Epithermal Deposit? Epithermal deposits are recognizable by their •Characteristic m in e r als and te x tu r e s •Characteristic h y d r o th e r m a l a lter a tio n m in e r alo g y and zoning
These characteristics aided by fluid inclusion data indicate that epithermal deposits •Formed at low temperatures (100 to 320 C , typ ically ) 160 to 270 Celsiu s °
°
°
°
•Developed at shallow crustal levels (<1 km , typically 50 to 7 00 m d e p th b e lo w th e w a te r tab le )
Classification of epithermal deposits depends on m u l t i p l e features. Hedinquist et al., 2002; N. White, 2009 Quartz-amythest vein cut by white quartz vein, Lebong Tandai
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
14/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Schematic section showing the depositional and crustal depth(2004) of the Modified from environment Poulsen et al. (2000) and Robert main gold systems. http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
15/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
What is an Epithermal Deposit? • Epithermal deposits include a wide range of deposit styles – th e y a r e n o t a ll th e sa me ! • The different deposit classes are not fully characterized nor fully understood. • Not all epithermal deposits contain gold – some are dominated by other metals, notably Ag, Zn, Pb, Cu, Sn.
• Some closely nrelated intrusions, are not. The relatedare intrusions e ed n otot be porphyrysome copper-related intrusions. • Many different terms have been used to classify epithermal deposits – terminology is very confused! http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
16/193
History of Nomenclature for Epithermal Deposits (Sillitoe and Hedinquist, 2003)
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Goldfield type
Ransome (1907)
Alunitic kaolinic gold veins
Sericitic zinc-silver veins
Gold-silver-adularia veins
Gold-alunite deposits
Argentite-gold quartz veins
Gold quartz veins in rhyolite
Argentite veins
Gold telluride veins
Base metal veins
Gold selenide veins
Fluoritic tellurium-adularia gold veins
Secondary quartzite
Emmons (1918)
Lindgren (1933) Fedorov (1903); Nakovnik (1933)
Acid
Alkaline Epithermal
Sillitoe (1977) Buchanan (1981)
Enargite-gold
Ashley (1982) Hot-spring type
High Sulfur
Low sulfur
Acid sulfate
Adularia-sericite
Giles and Nelson (1982) Bonham (1986, 1988) Hayba et al. (1985) Heald et al. (1987)
High sulfidation
Low sulfidation
Hedinquist (1987)
Alunite-kaolinite
Adularia-sericite
Berger and Henley (1989)
Type 1 adularia-sericite
Type 2 adularia-sericite
Albino and Margolis (1991)
High sulfidation
High sulfide + base metals, low sulfidation
Low sulfide + base metals, low sulfidation
Sillitoe (1993)
High sulfidation
Western andesite assemblage, low sulfidation
Bimodal basalt-andesite assemblage, low sulfidation
John et al. (1999), John (2001)
High sulfidation (HS)
Intermediate sulfidation (IS)
Low sulfidation (LS)
Hedinquist et al. (2000)
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
17/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Three Classes of Epithermal Deposits
Three classes based on the fluids that formed the epithermal deposits: 1. High
Sulfid ation (HS) -
Magmatic
2. Int erm ediate Sulfid ation 3. L o w
(IS) - Magmatic-Meteoric
S u lfid a tio n (L S ) - Meteoric
N. White, 2009 http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
18/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Au-Ag-Cu http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Au-Ag-Zn-Pb
Au-Ag N. White 2009
19/193
5/25/2018
Characteristics
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Fluids:
Magmatic dominant in core mixed with meteoric on margins M et a l A s s o c i a t io n s :
1
I-type: a) Cu-Au-Ag b) Zn-Pb-Ag
2
S-type: Sn-Ag (Zn-Pb)
3
A-type: Au-Ag
Alteration:
1a, b and 2: proximal very acid 3 proximal not seen; distal neutral Examples:
1a) Lepanto, Philippines 1b) Cerro de Pasco, Pero
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
2
Cerro Rico de Potosi, Bolivia
3
Porgera, PNG
N. White, 2009 20/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Characteristics Fluids:
Dominantly meteoric, with high salinity magmatic fluids at depth M et a l A s s o c i a t io n s :
Ag-Zn-Pb-(Au) Ag-Zn-Pb-(Cu-Sn) Alteration:
Mostly neutral pH Examples:
Fresnillo, Mexico
Comstock, USA Acupan and Antamok, Philippines Cikotok, Indonesia Aisasjur, Indonesia http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Modified from N. White, 2009
21/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Characteristics
Fluids:
Meteoric (± magmatic) M et a l A s s o c i a t io n s :
Au-Ag (very minor Zn, Pb) Alteration:
Hypogene - neutral pH; Gas condensates - acid Examples:
McLaughlin, USA Hishikari, Japan Lebong Donok, Indonesia Gunung Pongkor, Indonesia Waihi, New Zealand Diwalwal?, Philippines N. White, 2009 http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
22/193
5/25/2018
Epithermal Deposits Characteristics EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Quartz-adularia-clay veinlets, Acupan
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
23/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
24/193
5/25/2018
Tectonic Setting of Gold-rich Epigenetic Mineral Deposits EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Groves et al., 1998 http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
25/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
26/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Styles and Geometries of Epithermal Deposits Diagram shows the influence of structural, hydrothermal and lithologic controls on permeability or fluid conduits.
Sillitoe, 1993 http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
27/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
28/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
29/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
30/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
31/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
32/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
33/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
34/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
35/193
5/25/2018
Hydrothermal Alteration – LS & HS Epithermal Systems
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
36/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
37/193
Tarutung, North Sumatra, Indonesia
5/25/2018
Very young opaline vein deposited from hot spring coming out of a vertical fracture EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Ages of Epithermal Deposits • Epithermal deposits are most
common in young environments (due to preservation, not process) • They can be found whenever
favourable geology is preserved • Youngest deposits are forming
NOW; oldest known are Early Archean
North Pole Mining District, Pilbara, Western Australia
3.5 billion year-old epithermal vein texture
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
38/193
5/25/2018
Epithermal Deposits Key Processes
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
39/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
40/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
41/193
Boiling is the critical process to deposit high amount of gold in LS epithermal deposits.
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
•Au concentration in deep water prior to boiling & gas loss: 10 µg/kg •Au concentration in hot spring waters: <0.1 µg/kg •Au precipitates during ascent & boiling Colloform-crustiform banded quartzadularia choking a geothermal pipe.
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
42/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Porgera Zone 7, PNG Bonanza epithermal quartz
Sleeper Deposit, Nevada High grade bonanza colloform
gold-silver mineralization with wire gold, quartz and roscoelite.
banded gold and chalcedony
Corbett, 2002 http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Saunders, 2010 43/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
44/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
45/193
5/25/2018
Silica deposition by cooling EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Ta r u t u n g o p a l ve i n , No r t h Su m a t r a
Hedinquist et al., 1998
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
46/193
5/25/2018
Silica deposition is affected by pH
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
•
Neutral pH - Quartz, chalcedony and amorphous silica deposit - Spectacular textures!
•
Acid pH - Silica deposition suppressed - No siliceous veins
Low sulfidation vein texture, Mc Laughlin, California, USA (Phot o by Y. Matsu hisa) http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
47/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
48/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
49/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
50/193
Significance of Alunite 5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Its formation requires 1. Acid conditions 2. High sulfate 3. Available alkalis
These conditions can occur from 1. Magmatic gases (HS) 2. Near-surface condensation of boiled off gases (HS, IS, LS) 3. From supergene oxidation (any sulfide rich rock)
Lithocap from the Baguio District http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
51/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
52/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Pearly radial cluster of pyrophyllite, Hillsboro District, North Carolina, USA
Radiating fans of goldenbrown pyrophyllite needles, Champion Mine, California, USA
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
53/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
54/193
5/25/2018
High Sulfidation Deposits EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Lepanto Quartz-Alunite Zone
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
55/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
56/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
57/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
58/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
59/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
60/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Satsuma volcanic –hydrothermal system. 870°C fumaroles vent from summit of rhyolitic dome; acidic hotspring (pH 1.5) rich in Fe and Al leached from host rock discharge from volcano flanks to the sea.
Kawah Ijen: World’s Largest H2SO4 Crater Lake
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
61/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Ijen Crater, East Java, Indonesia – 1 km wide & 200 m deep lake filled with a solution of H2SO4 & HCl with a pH of 0.5 & temperature of about 33°C. Photo: Ulet Ifansasti/Getty Images, 2009
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
62/193
KAWAH IJEN, JAVA
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Somebody having fun rafting in the highly acidic water of Ijen Crater. Aluminum can dissolving in the acid water of Ijen Crater.
Kawah Ijen, East Java, Indonesia
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
63/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Condensation of magmatic vapor + HCl + SO2 generates acidic waters (pH ~1 or less): Causes leaching of rocks (vuggy quartz), and hypogene advanced argillic alteration (alunite, kaolinite)
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
64/193
Kawah Ijen, East Java 5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Sulfur miners
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
65/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
66/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
67/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
68/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
69/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
70/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
71/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
72/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
73/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
74/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
75/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
76/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
77/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Lepanto lithocap outcrop to south
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
78/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Surface projections: Lepanto Far Southeast Victoria
Mohong Hill
Lithocap
From Palidan slide http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
79/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
80/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Lepanto Spanish Adits Outcrop of Lepanto enargite-luzonite ore http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
81/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
82/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
83/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
84/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
85/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
86/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
87/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
88/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
89/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
90/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Epithermal Vein Deposits
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
91/193
5/25/2018
Low- and IntermediateSulfidation EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Aisasjur, Indonesia
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
92/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
93/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
94/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
95/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
96/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
97/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
98/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
99/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
100/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
101/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
102/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
103/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
104/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
105/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
106/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
107/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
108/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
109/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
110/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
111/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
112/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
113/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
114/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
115/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
116/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
117/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
118/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
119/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
120/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
121/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
HISHIKARI MINE, JAPAN http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
122/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
The Hishikari mine (above) is located in northern Kagoshima Prefecture. The hot water seeping into mineshafts is supplied to the nearby hot spring spa. Photo credits: National Institute of Advanced Industrial Science and Technology (AIST) and Sumitomo Metal Mining Co., Ltd .
Hishikari gold mine’s Keisen No. 3 vein (left). The gold grade at Hishikari is 10X the average of worldwide deposits and contains 264 tonnes Au (8.5 Moz Au).
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
123/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
124/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Lebong Donok Gold Mine, Bengkulu, Indonesia http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
125/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Sumatra Copper and Gold, Ltd.
Lebong Donok Stope Grades http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
126/193
More than 1.3 Moz Au and >70.5 Moz Ag produced to 1938 5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
3.24 Mt @ 12.8 g/t Au & 70.5 g/t Ag
Sumatra Copper and Gold, Ltd.
Donok LS Epithermal Veins http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
127/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Donok Vein 3 - colloform banded & vughsquartz-adularia
Footwall of Main Donok Vein (qtz-caltruscottite) inside Lubang Kacamata (“Eyeglasses” Dutch Tunnel)
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
128/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
129/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
130/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
131/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Aisasjur, West Papua, Indonesia http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
132/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Au - BLEG
Ag - BLEG
Aisasjur IS Veins West Papua, Indonesia
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
133/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
ASD-28: 6m @ 2.54 g/t Au from 139.3m – 145.3m depth
ASD-5 at 266.5m depth: 5.36 g/t Au & 1570
ppm As
Hydro-brecciated stibnite cement siltstone with
ASD-5 at 270.35m depth: 15.6 g/t Au & 4790
ppm As
Aisasjur, West Papua, http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
134/193
Indonesia 5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Laser ablation of pyrite from Aisasjur drillhole ASD27. Micron size Au and As occur at the rims
of the pyrite.
Macalalad, 2009
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
135/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
136/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
137/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
138/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
139/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
140/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
141/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Geothermal Waters Steam-heated Zones
142/193
5/25/2018
Water Table Movement
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
143/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Neutral pH
144/193
5/25/2018
chloride water
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
•The deep geothermal fluid –
neutral, low salinity •Alters rock to illite, illite-
smectite or smectite (depending on T) •At surface produces boiling pools with clear water and silica sinters •This is th e p o te n tia l o r e flu id f o r l o w s u l f i d at i o n d e p o s i t s
Ta r u t u n g h o t s p r i n g
North Sum atra, Indon esia
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
145/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Geothermal Plant, Tiwi, Albay, P hoto : NP C http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
146/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Geothermal Plant, Wairakei, New Zealand
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
147/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
148/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
149/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Pho to: N. Macalalad, March 2010
Champagne Pool Waiotapo New Zealand Tarutung Hot Spring & Silica Sinter – North Sumatra
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
150/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
R. Gonzales, 2006
Tarutung Silica Sinter – North Sumatra http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
151/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
R. Gonzales, 2006
Tarutung Silica Sinter – North Sumatra http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
152/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Micro terraces
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
Spiky tubes and flake
Stalactites R. Gonzales, 2006
Acid bicarbonate water
153/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
• Boiling deep fluids expel steam, CO 2
and H2S
•Gases condense into groundwater to
produce weakly acid water (H2CO3 and H2S) •Alters rock to produce illite-smectite, calcite and pyrite – can be v e r y w id e - spread
•Water is clear, spring deposits
travertine •NOT related to ore
T r av e r t i n e d e p o s i t s , M am m o t h H o t Spring s, Yellow sto ne National Park, USA
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
154/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
155/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
156/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Acid sulfate water http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
•Boiled off CO and H S
157/193
2 5/25/2018
2
condense above water table
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
•Atmospheric O2 oxidizes H2S to H2SO4 – strongly acidic •Rock alters to kaolinite and alunite, partly dissolves •Form steaming ground, collapsing ground and mud pools at surface •Colored water •Responsible for “silica cap” •NOT related to ore Yellow-green colored lake, NZ (top) and the colored lakes of Kelimutu, Indonesia (bottom)
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
158/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
159/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
160/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
161/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
162/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
163/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
164/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Collapsing ground, Rotorua, NZ
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
165/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Mud Pool, Rotorua, New Zealand http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
166/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
167/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
168/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
169/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
170/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
171/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
172/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
173/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
174/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
175/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
176/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Epithermal Quartz Vein Textures
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
177/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
L e b o n g D o n o k L S V ei n Tex t u re s
EPITHERMAL QUARTZ VEIN TEXTURES http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
178/193
Primary Growth Textures 5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Dong, Morrison & Jaireth, 1995
PRIMARY GROWTH TEXTURES
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
179/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Crustiform
Cockade
Moss
Comb
Zonal
Moss, plane polarized light Photos: Dong Morrison & Jaireth 1995
EPITHERMAL QUARTZ VEIN TEXTURES http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
180/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Dong, Morrison & Jaireth, 1995
RECRYSTALLIZATION TEXTURES http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
a.
b.
Mosaic aggregates of microcrystalline quartz crystals with highly irregular and interpenetrating grain boundaries. Feathery 1:a feathery appearance in
181/193
the rims of the crystals with euhedral cores seen only as slight optical
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
c.
d.
e.
f. All samples from Pajingo, Afarti and Crakow (Queensland, Australia), crossed polars. Scale bars = 0.2 mm
differences in maximum extinction positions. In another position (e .g. bottom center) the quartz crystal displays a very similar interference color between the euhedral core and rims Feathery 2: a feathery appearance seen as patches throughout quartz crystals Flamboyant 1: radial or flamboyant extinction of individual quartz crystals with more or less rounded crystal outline.In this sample, the flamboyant texture is well developed in the rims of crystalline quartz crystal with more or less euhedral cores. Flamboyant 2: flamboyant extinctions seen through the crystals with rounded surface in bands. Ghost spheres: solid and/or fluid inclusion defined spheres with thin microcrystalline quartz crystals.
EPITHERMAL QUARTZ VEIN TEXTURES http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
182/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Dong, Morrison & Jaireth, 1995
REPLACEMENT TEXTURES http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
a.
b.
Lattice bladed: a network of intersecting silica blades with polyhedral cavities. Lattice bladed: in thin section, each blade consists of a series of parallel
183/193
blade consists of a series of parallel seams separated by quartz crystals
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
c.
d.
e.
f.
All samples from Bimurra and Woolgar (Queensland, Australia).
or crystallites which have grown symmetrically about the seams and perpendicular to them.,B imurraQ, ueensland Ghost bladed: blades are identified on the polished surface of the hand specimens by the concentration of impurities. This texture commonly occurs in crustiform bands and lacks the cavities between blades. Ghost bladed: aggregates of quartz crystals with superimposhed bladed texture identified by outlines of impurities and finer grain size. Parallell bladed: silica blades are parallel within each group but adjacent groups have different orientation. Parallel bladed: each group is composed of a set of parallel-oriented quartz crystals which have more or less rectangular shape.
Scale bars = 0 2 mm
REPLACEMENT TEXTURES – BLADED QUARTZ, HISHIKARI
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
184/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Lattice-type Bladed Quartz
Parallel-type Bladed Quartz
Photos: Etoh Izawa & Watanabe 2002
REPLACEMENT TEXTURES http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
185/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
a. Pseudoacicular aggregates of silica minerals commonly associated with adularia or its weathered products (kaolinite or illite) display radial acicular appearance caused by differences in color and/or relief in hand specimens. b. Pseudoacicular : acicular appearance is indicated under the microscope by linear arrangement of fine-grained quartz crystals and linear distribution of clay minerals. Crossed polars. c . Saccharoidal: loosely packed fine-grained quartz aggregate, having sugary appearance in hand specimens. d . Saccharoidal: under the microscope slender subhedral crystals are randomly distributed in a matrix of smaller anhedral grains. Crossed polars. All samples from Queensland, Australia. Scale bars = 0.2 mm, metric bars = I cm.
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
186/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
187/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
A. Lattice-type
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
B. Parallel-type
Schematic models of the formation process of lattice-type (A) and parallel-type (B) bladed quartz.
188/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
A1, B1 - calcite Precipitation of bladed A2, B2 - Precipitation of adularia and quartz A3, B3 - Dissolution of calcite A4
- Subsequent quartz overgrowth sometimes occurs
Bladed quartz, Tambang Sawah, Bengkulu, Indonesia
Etoh et al 2002
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
189/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
190/193
5/25/2018
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
191/193
5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
REFERENCES Dong, G., Morrison,G and Jareth, S., 1995. Quartz textures in epithermal veins, Queensland – classification, origin, and implications; Economic Geology, Vol.
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
192/193
90, 1995, pp.1841 1856. 5/25/2018
EPITHERMAL GOLD DEPOSITS-AdU.ppt - slide pdf.c om
Etoh, J.,mineralization Isawa, E. and in Watanabe, K., 2002. Bladed quartz and its relationship gold the Hishikari low sulfidation epithermal gold deposit, to Japan; Economic Geology, Vol. 97, 2002, pp. 1841 –1851. Hedinquist, J., Arribas, A., Einaudi, M. and Sillitoe, R., 2002. Abstract: Exploration for and assessment of epithermal precious-metal deposits: critical characteristics, and their variations, Denver Region Exploration Geologists’ Society. andNevada: gold textures in bonanza oresand of the Sleeper for Saunders, 1994. Silica Deposit,J.,Humbolt County, evidence for colloids implications epithermal ore forming processes; Scientific Communications, Economic Geology, Vol. 89, 1994, pp. 628-638. White, N., 2009. Epithermal gold deposits: presentation at Gold Deposit Workshop 2009, 11-12 October, 2009, Semarang, Indonesia. White, N. and Hedenquist, J., 1995. Epithermal gold deposits: styles,
http://slide pdf.c om/re a de r/full/e pithe r ma l-gold-de posits-a duppt
193/193
