Introduction to! Economic Geology!

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1 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Introduction to Economic Geology

2 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Introduction The field of Economic Geology is a specialized aspect of geology, concerning the identification and provenance of natural mineral deposits which are of economic interest to society. Where to find it? Look around you

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Economic Geology is essentially a branch of applied geology.

3 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Economic Geology is essentially a branch of applied geology. The end products of manufacturing are the result of the acquisition of mineral resources from their point of deposition. There a number of depositional settings which cover almost every environmental setting across the entire Earth. Determining the likelihood, quantity of resources available and mineralisation processes are the key aspects of economic geology. The economic value of these resources is strongly influenced/governed by demand from society. Survey Methods: Geological mapping Structural features Gravity/resistivity survey Alteration mineralogy Mineralisation Geochemical analysis Drilling

4 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Geological Mapping and Structures Geological maps are the basis for all local and regional analysis. Deciphering the history and emplacement of successive rock units allows us to establish the likelihood of finding exploitable resources. Finding these resources and knowing how they formed can lead us to further if not bigger resources connected to them.

5 KYUSHU UNIVERSITY Geological Surveying (Field mapping of structures) Economic B4, M1, M2 Geology Students, Laboratory Dept. Earth Resources Engineering, Kyushu University Department of Earth Resources Engineering Geological Mapping and Structures Geological maps are the basis for all local and regional analysis. Deciphering the history and emplacement of successive rock units allows us to establish the likelihood of finding exploitable resources. Finding these resources and knowing how they formed can lead us to further if not bigger resources connected to them.

6 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Structural Geology Plays an important role in many aspects of economic geology: Zone of high fluid input Deep seated faults provide conduits for heat transfer Localize mineralisation to a traceable source The present is the key to the past - James Hutton

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals): Most important metals are termed precious as their crustal

7 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals): Most important metals are termed precious as their crustal abundances are several orders of magnitude lower than that of the common rock forming elements. These are geochemically referred to as either the Chalcophile elements (Sulfide affinities) or Platinum Group elements (common in native form).

8 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals): Most important metals are termed precious as their crustal abundances are several orders of magnitude lower than that of the common rock forming elements. These are geochemically referred to as either the Chalcophile elements (Sulfide affinities) or Platinum Group elements (common in native form).

9 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering The Mobile Crust Always on the move

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals): Although precious and semi-precious metals are not abundant

10 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals): Although precious and semi-precious metals are not abundant in the crust, they are mobilised by fluids associated with magmatism and subsequent volcanism in the shallow crust. These volcano-magmatic activities form conduits and zones of high heat flow, generating thermal convecting and advecting aqueous fluids which transport metals in dominantly bi-sulphide, bichloride or carbonate complexes. Ash HF HCl SO 2 CO 2 H 2 SO 4 H 2 O

11 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals) Corbett & Leach (1997)

12 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals)

13 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation

14 Kyushu Island and major epithermal deposits Geological & Structural Setting Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Tsurumi Taio Deposit Kuju Unzen Aso Hishikari Deposit Kirishima Sakurajima 25 km 50 km Nansatsu Area Kaimon Geological Survey of Japan (1995)

15 Kyushu Island and major epithermal Au-Ag-Cu deposits Epithermal Au and Ag deposits Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Kyushu Epithermal overview Majority low-sulfidation epithermal Taio Deposit Kuju Tsurumi Ranging from 5 to 0.8 Ma Unzen Aso Related to calc-alkaline volcanism Magnetite series magmatism 132 E Most economic deposits hosted in the southern province. Hishikari Deposit Kirishima 32 N Au Total Reserves Nansatsu District t Kushikino Deposit Kago Dep. Sakurajima t 26-8 t Hosts classic high-sulfidation epithermal deposits. 50 km Nansatsu Deposits Fig. 2-6 area Kaimon Satsuma Iwojima Low Sulfidation Deposit High Sulfidation Deposit Active Volcano Single low-sulfidation deposit in the southwest, whilst the southeast has many low-sulfidation deposits in the Quaternary volcanic rocks.

16 Economic Geology Laboratory Characteristics of depositional area Southwest Nansatsu District KYUSHU UNIVERSITY Department of Earth Resources Engineering

17 Characteristics of depositional area Nansatsu Economic Geology high-sulfidation Laboratory type KYUSHU UNIVERSITY Department of Earth Resources Engineering Nansatsu-type Characterstics Composed of residual silica bodies Vuggy silica texture from leached host Shrouded in advanced argillic alteration Disseminated ore High-sulfidation state mineralogy Enargite/luzonite, native Au, pyrite Typical temperature range C Supergene remobilisation, enriching Au ore Goethite, scordorite and jarosite products

Characteristics of depositional area Nansatsu Economic Geology high-sulfidation Laboratory type KYUSHU UNIVERSITY Department of Earth Resources Engineering Nansatsu-type Characterstics Native Au

18 Characteristics of depositional area Nansatsu Economic Geology high-sulfidation Laboratory type KYUSHU UNIVERSITY Department of Earth Resources Engineering Nansatsu-type Characterstics Native Au Composed of residual silica bodies Vuggy silica texture from leached host Shrouded in advanced argillic alteration Disseminated ore High-sulfidation state mineralogy Enargite/luzonite, native Au, pyrite Typical temperature range C Supergene remobilisation, enriching Au ore Goethite, scordorite and jarosite products Kasuga high-sulfidation deposit high-grade ore

19 Kago mining area Geology Economic Geology and structure Laboratory Geological KYUSHU Overview UNIVERSITY Department of Earth Resources Engineering Kago Mine

20 Kago mining area Geology Economic Geology and structure Laboratory KYUSHU UNIVERSITY Vein Structural Framework Department of Earth Resources Engineering Kago Mine

21 Kago mining area Mining Economic activity Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Tunneling systems Kago Mine

22 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Ore and gangue petrography

23 Analytical techinques Ore and gangue petrography pol Common ore minerals: Pyrite, polybasite (pol), chalcopyrite (cpy), covellite (cv), electrum (el). Covellite is secondary product, from the breakdown of chalcopyrite. Electrum Characteristics High-grade ores: Anhedral course-grained ( 200µm), hosted in quartz breccias and outside colloform bands. Low-grade ores: Fine-graine ( 50µm), hosted between microcrystalline and crustiform banded quartz.

24 Analytical techinques Ore and gangue petrography Quartz Textures Colloform, moss, flamboyant, microcrystalline, chalcedonic Adularia Textures Colloform and crustiform are common in banded ore veins. Cockade growth is present on brecciated ore veins.

Analytical techinques Fluid inclusion microthermometry

temperature and salinity of the fluids that carried the

This can give us insights into the thermal regime with

25 Analytical techinques Fluid inclusion microthermometry Introduction A technique used to determine the temperature and salinity of the fluids that carried the metals to their point of deposition. This can give us insights into the thermal regime with which precipitation took place. This can assist us in terms of stable isotope mass spectrometry.

Analytical techniques Stable isotopic measurement Quartz δ 18 O Fractionation interpretation for fluids Ore bearing quartz: Precipitation temp. 220-240 C Suggesting δ 18 O range of -6.5 to -0.

26 Analytical techniques Stable isotopic measurement Quartz δ 18 O Fractionation interpretation for fluids Ore bearing quartz: Precipitation temp C Suggesting δ 18 O range of -6.5 to -0.3 based on Clayton et al. (1972). Kushikino quartz (Matsuhisa et al. 1986) Kago quartz (This study) Chalcedonic quartz: Precipitated at low temp C, based on Kita et al. (1985) fractionation equations for a composition analogous to ore bearing quartz veins.

27 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering A N35 E B N49 E C 4.5 ± 0.9 Ma Kasuga Deposit 5.5 ± 0.4 Ma Mt. Sonomi 4.0 to 4.23 ± 0.1 Ma Kago Deposit sea-level? Shimanto Supergroup Silicified zone 300 m Nansatsu Group (upper) Ata Pyroclastics Ito Pyroclastics Weakly silicified zone Ore vein Inferred extention Inferred Fault Exploration Boring core High-sulfidation Nansatsu-type Au-Cu type Temperature Range: C Host: Nansatsu Group Alteration type: Adv. Argilllic Mineralogy: Enargite/luzonite, Au Fluid Characteristics: Mixed Hypogene to late-stage supergene Low-sulfidation (adularia-quartz) Au-Ag type Temperature Range (mode): Host: Shimanto Supergroup Alteration type: Illite, Smectite Mineralogy: Pol, ccp, cv, py, el Fluid characteristics: Meteoric dominant Water-rock interaction, recirculated

28 Economic Geology Laboratory Regional associations Au composition KYUSHU UNIVERSITY Department of Earth Resources Engineering Kago deposit shows a similar Au composition to surrounding regional low-sulfidation deposits.

29 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Fluids and the root of ore precipitation (metals)

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Copper is a semi-precious metal, essential for telecommunications and microprocessors.

30 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Copper is a semi-precious metal, essential for telecommunications and microprocessors. The development of infrastructure in a growing economy relies heavily on resources from very large deposits (the porphyry Cu-Au, Cu-Mo deposits) of the Circum-Pacific region. Southern parts of Peru and Chile are the biggest producers of copper ore concentrates on the planet. Owing to their abundance of porphry mineralisations along the volcanic front of the East Pacific. Batu Hijau Porphyry Cu-Au (Indonesia)

Economic Gold Geology (Au) Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Bornite (Cu 5 FeS 4 ) Copper is a semi-precious metal, essential for telecommunications and

31 Economic Gold Geology (Au) Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Bornite (Cu 5 FeS 4 ) Copper is a semi-precious metal, essential for telecommunications and microprocessors. The development of infrastructure in a growing economy relies heavily on resources Chalcopyrite from very large deposits (the porphyry Cu-Au, Cu-Mo deposits) of the Circum-Pacific region. (CuFeS 2 ) Southern parts of Peru and Chile are the biggest producers of copper ore concentrates on the planet. Owing to their abundance of porphry mineralisations along the volcanic front of the East Pacific. Quartz (SiO 2 ) 2.5cm Batu Hijau Porphyry Cu-Au (Indonesia) Batu Hijau Porphyry Cu-Au Ore

32 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Copper is a semi-precious metal, essential for telecommunications and microprocessors. The development of infrastructure in a growing economy relies heavily on resources from very large deposits (the porphyry Cu-Au, Cu-Mo deposits) of the Circum-Pacific region. Southern parts of Peru and Chile are the biggest producers of copper ore concentrates on the planet. Owing to their abundance of porphry mineralisations along the volcanic front of the East Pacific.

33 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) REE Elements Nd Neodymium Dy Dysprosium Y Yttrium (semi)

34 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) REE Elements Nd Neodymium Dy Dysprosium Y Yttrium (semi)

35 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) REE Elements Nd Neodymium Dy Dysprosium Y Yttrium (semi)

36 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) REE Elements Nd Neodymium Dy Dysprosium Y Yttrium (semi)

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) Rare

37 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) Rare Earth Elements are by their very nature difficult to obtain. Although more abundant than the precious metals the greatest difficulty relates to their difficulty in excavation. The current principle repository for most REE metals is the Bayan Obo deposit (China). Other mines coming on stream are located in the USA and Mongolia.

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Rare Earth Elements are by their very nature difficult to obtain.

38 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Rare Earth Elements are by their very nature difficult to obtain. Although more abundant than the precious metals the greatest difficulty relates to their difficulty in excavation. The current principle repository for most REE metals is the Bayan Obo deposit (China). Other mines coming on stream are located in the USA and Mongolia.

39 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Metals for life Sustainable energy solutions require greater consumption of rare earth elements (REE) Rare Earth Elements are by their very nature difficult to obtain. Although more abundant than the precious metals the greatest difficulty relates to their difficulty in excavation. The current principle repository for most REE metals is the Bayan Obo deposit (China). Other mines coming on stream are located in the USA and Mongolia.

Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Frontiers in geology Black Smokers Scarcity of resources means we have to look to more exotic locations for

40 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Frontiers in geology Black Smokers Scarcity of resources means we have to look to more exotic locations for resources Black smokers are vents situated several km below the surface Typically situated over spreading ridges or subduction trenches, these contain abundant heavy metals in the chimney structures.

41 Economic Geology Laboratory KYUSHU UNIVERSITY Department of Earth Resources Engineering Frontiers in geology Black Smokers

The Occurrences of Base Metal Mineralization in Cikadu-Cisungsang Area, Banten Province, Indonesia*)

The Occurrences of Base Metal Mineralization in Cikadu-Cisungsang Area, Banten Province, Indonesia*) Rosana, M.F., Haryanto, A.D., Yuniardi, Y., Yuningsih, E.T. Department of Geology, Padjadjaran University