1. UBAHAN HIDROTERMAL

2. Hydrothermal circulation in a continental setting –
Minerals form in hydrothermal veins,
disseminated deposits and grade into pegmatites.

3. Hydrothermal circulation on the ocean floor.
Seawater circulates through the ridge basalt. Most minerals form when the hot water exits into the cold deep ocean water. Sulfide minerals form “black smokers”, sulfates form “white smokers”. Minerals are typically volcanogenic massive sulfides.

5. Origin of Hydrothermal Fluids
The hydrothermal solutions could be derived from several sources including:
Juvenile water
Connate water
Meteric water
Water released during progressive metamorphism

6. Juvenile Water
Juvenile means waters released by melting which have never been at the surface before
Often from granitic intrusions

7. Connate Water
Connate water is water trapped in the interstices of sediments at the time of deposition, and which has been out of contact with the surface for a substantial time, often a large part of a geologic period or longer

8. Economic Minerals from Hydrothermal Alteration
Rocks formed in this manner are hosts for gold, copper, and copper-zinc
In sheared or metamorphosed mafic rocks, nickel-copper and asbestos deposits are found
Lead-zinc-silver veins are found in slates, quartzites, and phyllites, and sometimes as replacement minerals in limestones

9. The silicates in igneous rocks (feldspar, hornblende and micas) are altered by reaction with hydrothermal solutions to form characteristic alteration minerals:
Propylite (chlorite and epidote form)
Argillite (clay minerals form)
Sericite (mica forms from clays)

13. ALTERASI TIPE 1

32. Indonesia Geothermal Reserve No Location Resources Reserves Total
Speculative
Hypothetic
Probable
Possible
Proven 1
Sumatera
4,975
2,121
5,845 15
380
13,336 2
Jawa
1,960
1,771
3,265
885
1,815
9,696 3
Bali-Nusa Tenggara
410
359
973 -
1,757 4
Sulawesi
1,000 92
982
150 78
2,302 5
Maluku
595 37
327
959 6
Kalimantan 45 7
Papua 75

33. Power Plant (MW) (PLTP=Geothermal Power Plant)No
Working Area
Location
Turbine Capacity
Operator
Total Cap. 1
PLTP Kamojang (Pertamina)
West Java
1 x 30 MWe 2 x 55 MWe 1 x 60 MWe
PLN PLN PLN
200 2
PLTP Lahendong (Pertamina)
North Sulawesi
2 x 20 MWe 1 x 20 MWe
PLN 60 3
PLTP Sibayak (Pertamina)
North Sumatera
1 x12 MWe
Pertamina 12 4
PLTP Salak (Chevron GSI)
3 x 60 MWe 3 x 65 MWe
PLN CGS
375 5
PLTP Derajat (Chevron GSI)
1 x 55 MWe
255
1 x 90 MWe
CGI
1 x 110 MWe 6
PLTP Wayang Windu SE
227
1 x 117 MWe 7
PLTP Dieng (Geo Dipa Energi)
Central Java
1 x 60 MWe
GDE
Total
1,189