Tectonic and Structural Controls to Porphyry and Epithermal Mineralization in Cenozoic Magmatic Arcs of SE Asia and the W Pacific STEVE GARWIN Independent Consultant sgar@iinet.net.au Grasberg, 24 Mt Cu / 2560 t Au CET Seminar Series 13 th September, 2013 UWA Perth
Cenozoic Magmatic Arcs and Au-(Cu) Deposits of SE Asia and W Pacific >10 M Oz Au Resource > 5 M Oz Au Resource (Garwin et al., 2005)
Gold and Copper Contents (%, metric tonnes) of Deposit Styles in SE Asia & W Pacific 3 2 6 Au 15 2 Cu 28 Deposits > 5 M Oz Au (Garwin et al., 2005)
GOLD AND COPPER - GOLD DEPOSITS SOUTHEAST ASIA Average Gold Grade (g/t Au) Deposit Size (million tonnes) Low- and intermediate-sulfidation classifications for data in this plot were made by Garwin in 2002; the classifications were revised by Garwin et al. (2005).
Porphyry and Epithermal Deposits Controls to Mineralization: SE Asia W Pacific Neogene to Pleistocene magmatic activity Subduction slab discontinuity (e.g., kinks / tears) Fault inversion along collisional margin & crustal delamination (New Guinea) Arc-transverse fault zone(s) that control magmatism & sedimentation structural link to the mantle Region of contraction / uplift / exhumation Structural settings favorable to focus heatand fluid-flow (e.g., stress-transition regime)
SE Asia Tectonic Elements, Cenozoic Magmatic Arcs and Large Porphyry and Epithermal Deposits Shown on Sea-floor Bathymetry and DEM
Digital Elevation Model and Bathymetry of Indonesia 105 00 E 115 00 E 125 00 E 135 00 E 0 00 0 00 10 00 S Investigator Ridge Roo Rise 10 00 S 105 00 E 115 00 E 125 00 E 135 00 E DEM Bathymetry USGS EROS Data Centre 250 meter resolution NOAA-AVHRR Sandwell database 1000 meter resolution Elevation 2000m 1000m 200m 50m 0m Bathymetry 0m 200m 3000m 0 400 800 KM
Indonesian Region Tectonic Elements >10 M Oz Au Resource > 5 M Oz Au Resource
Indonesian Region Tectonic Elements >10 M Oz Au Resource > 5 M Oz Au Resource Interpretation of tectonic elements for the Indonesian region, after Garwin et al. (2005). Tectonic elements and lineaments are interpreted from digital topography models, satellite gravity and bathymetry, and Radarsat (ERS) data described by Garwin (2000), and reflect compilation and modification of the results of Hamilton (1979), McCaffrey (1988 and 1996), Hutchison (1989), Garwin (1996), Hall (1996), Simandjuntuk and Barber (1996), and Snyder et al. (1996). The magmatic arcs and orogenic belts are modified from Hamilton (1979), Hutchison (1989), Carlile and Mitchell (1994), and Garwin (1996, 2000).
Indonesian Region Earthquake Hypocenters (1973-2010) >10 M Oz Au Resource > 5 M Oz Au Resource Mw > 4.0 (hypocenters above depth of 25 km are not shown)
Indonesian Region Gold and Copper Deposits Martabe >10 M Oz Au Resource > 5 M Oz Au Resource
Indonesian Region Gold and Copper Deposits Martabe >10 M Oz Au Resource > 5 M Oz Au Resource Major gold and copper districts, deposits and prospects of the Indonesian region (after Garwin, 2000). The magmatic arcs and orogenic belts are modified from Hamilton (1979), Hutchison (1989), Carlile and Mitchell (1994) and Garwin (1996). The tectonic features and lineaments are interpreted from the digital elevation model, AVHRR, satellite gravity, bathymetry and Radarsat (ERS) databases and reflect the results of previous authors, such as Hamilton (1979), McCaffrey (1988, 1996), Hutchison (1989), Pulunggono (1993), Garwin (1996), Hall (1996), Simandjuntuk and Barber (1996) and Snyder et al. (1996).
INDONESIAN REGION TECTONIC ELEMENTS & PORPHYRY DEPOSITS 30 o 40 o Toba Martabe EQ <300km EQ >600km Krakatoa T. Bukit 60 o >70 o
EAST SUNDA & BANDA ARCS, INDONESIA EARTHQUAKE FAULT PLANE SOLUTIONS Hypocenter depths < 30 km Batu Hijau T Bukit Elang Roo Rise 55 o 65 o 500 km N15 o E subduction at 7 cm/yr. Strike-slip Reverse Normal 2-3 mm/yr E-W extension on strike-slip faults. (Modified from McCaffrey, 1988)
East Sunda Arc Metal Deposits, Geology, DEM / Bathymetry Roo Rise (Maryono and Setijadji, 2012)
Simplified Geology of Sumbawa Differential Exhumation Least uplifted Eastern block Western block Soripesa Hu u Central block Elang Most uplifted
INTRUSION-RELATED MINERALIZATION & TECTONICS Uplift Amphibole Crustal-scale arc-transverse fault system occurs in the arc above a kink, or tear, in the subducting slab Rapid rise of asthenospheric melts and efficient release of mineralizing fluids at high crustal-levels
Tectonic Framework of Luzon, Philippines 100 km 60 o (Garwin et al., 2005) 30 o 70 o Uplift from ~ 4 Ma Scarborough Seamounts >10 M Oz Au Resource
Sea-floor Bathymetry of Luzon, Philippines Stuart Bank Vigan High Lepanto - FSE Baguio Sto. Thomas Scarborough Seamounts
Papua New Guinea and Papua, Indonesia Au (Cu) Deposits and Settings (Garwin et al., 2005) Golpu >10 M Oz Au Resource > 5 M Oz Au Resource
Papua New Guinea Basement Faults and Cross-Sructures >10 M Oz Au Resource (Gow and Walshe, 2005)
Neogene Thrust Inversion of Mesozoic Extensional Faults in Cratonic Basement Porgera Example (~ 6 Ma) (Hill et al., 2002)
Geodynamic Model for Structural Setting to Pliocene Cu-Au Deposits in Papuan Fold Belt of New Guinea (Hill et al., 2002)
Lithospheric-scale Cross Section for Central Range, Papuan Fold Belt - New Guinea at 6 Ma. Comments Delamination commences at ~ 8 Ma and ceases at ~ 4 Ma Thick-skinned Imbrication of cont. basement Craton GB PG Fold and Thrust Belt Thin-skinned Mapenduma anticline forms above reactivated normal faults Lithospheric mantle Asthenospheric mantle Transitional crust Mafic / alkaline magma pools near base of craton Early Jurassic oceanic crust Removal of lith. mantle leads to isostatic uplift (Cloos et al., 2005) Ideal setting for focused heatflow and intrusion-related mineralization
EXHUMATION RATES - OROGENIC REGIONS Exhumation Rate (mm/ yr) Alps, Italy Batu Hijau Alpine Fault, NZ Grasberg Atauro Island West Solomon Is: 8 mm/yr (50 K yrs) Alpine Fault, NZ: 7-8 mm/yr (14 K yrs) Longitudinal Valley Fault, E. Taiwan: 23 mm/yr (8 yrs - now) Boso, Japan Alpine Fault, NZ Roti Island Kupang Semau Island Duration (mybp to present)
Porphyry and Epithermal Deposits Controls to Mineralization: SE Asia W Pacific Neogene to Pleistocene magmatic activity Subduction slab discontinuity (e.g., kinks / tears) Fault inversion along collisional margin & crustal delamination (New Guinea) Arc-transverse fault zone(s) that control magmatism & sedimentation structural link to the mantle Region of contraction / uplift / exhumation Structural settings favorable to focus heatand fluid-flow (e.g., stress-transition regime)
Porphyry and Epithermal Deposits Favorable Geological Settings: Asia / Pacific Dilational zones in long-lived fault systems Basement high / dome / anticline / horst-block Batholith / horst margins in zones of low mean-stress Dike swarms as paleo-stress indicators -orientation, composition and age Thin, young cover sequences in arc-transverse belts - volc-sed basins, alt magmatic centers, po intrusions Mineralized rock fragments in cover sequences
BATU HIJAU MINE 2011 Looking southwest
REFERENCES sgar@iinet.net.au Carlile, J. C., and Mitchell, A. H. G., 1994, Magmatic arcs and associated gold and copper mineralization in Indonesia, in van Leeuwen T. M., Hedenquist, J. W., James, L. P., and Dow, J. A. S., eds., Mineral deposits of Indonesia; discoveries of the past 25 years., Journal of Geochemical Exploration v. 50; 1-3, p. 91-142. Cloos, M., Saphie, B., van Ufford, A.Q., Weiland, R.J., Warren, P.Q., and McMahon, T.P., 2005, Collisional delamination in New Guinea: The geotectonics of subducting slab breakoff, Geological Society of America, Special Paper 40, 50 p. Cooke, D.R, Heithersay, P.S., Wolfe, R., and Calderon, A.L., 1998, Australian and western Pacific porphyry Cu-Au deposits, AGSO Journal of Australian Geology & Geophysics, 17(4), pp. 97-104. Corbett, G.J., and Leach, T.M., 1998, Southwest Pacific Rim gold-copper systems: Structure, alteration and mineralization, Society of Economic Geologists Special Publication 6, 240 p. Garwin, S.L., 2000, The setting, geometry and timing of intrusion-related hydrothermal systems in the vicinity of the Batu Hijau porphyry copper-gold deposit, Sumbawa, Indonesia: Unpublished Ph.D. thesis, University of Western Australia, Nedlands, Western Australia, Australia, 320 p. (plus figures and appendices). Garwin, S., 2002, The geologic setting of intrusion-related hydrothermal systems near the Batu Hijau porphyry copper-gold deposit, Sumbawa, Indonesia, in Goldfarb, R.J. and Nielsen, R.L. eds., Integrated Methods for Discovery: Global Exploration in the 21 st Century, Society of Economic Geologists, Special Publication 9, p. 333-366. Garwin, S., Hall, R., and Watanabe, Y., 2005. Tectonic setting, geology and gold and copper mineralization in Cenozoic magmatic arcs of Southeast Asia and the west Pacific, in Hedenquist, J., Goldfarb, R. and Thompson, J. (eds.), Economic Geology 100 th Anniversary Volume, Society of Economic Geologists, p. 891-930. Gow, P.A., and Walshe, J.L., 2005. The role of pre-existing geologic architecture in the formation of giant porphyryrelated Cu + Au deposits: examples from New Guinea and Chile, Economic Geology, Society of Economic Geologists v. 100, pp. 819-833.
REFERENCES sgar@iinet.net.au Hall, R., 2002, Cenozoic geological and plate tectonic evolution of SE Asia and the SW Pacific: computer-based reconstructions, model and animations: Journal of Asian Earth Sciences, v. 20, p. 353-434. Hamilton, W., 1979, Tectonics of the Indonesian region: U.S. Geological Survey Professional Paper, v. 1078, p. 345 p. Hill, K. C., Kendrick, R. D., Crowhurst, P. V., and Gow, P. A., 2002, Copper-gold mineralisation in New Guinea; tectonics, lineaments, thermochronology and structure, in Korsch, R. J., ed., Geodynamics of Australia and its mineral systems; technologies, syntheses and regional studies, Blackwell Scientific Publications for the Geological Society of Australia. Melbourne, Australia, p. 737-752. Hutchison, C.S., 1989, Geological Evolution of Southeast Asia, Oxford Monographs on Geology and Geophysics, 13, Carendon Press, Oxford, United Kingdom, 368 p. Kerrich, R., Goldfarb, R. J., Groves, D. I., and Garwin, S., 2000, The geodynamics of world-class gold deposits; characteristics, space-time distribution, and origins, in Hagemann S.G., and Brown, P.E., eds., Reviews in Economic Geology, v. 13, p. 501-551. Mitchell, A. H. G., and Leach, T. M., 1991, Epithermal gold in the Philippines; island arc metallogenesis, geothermal systems and geology, Academic Press, London, United Kingdom, 457 p. Seedorff, E., Dilles, J.H., Proffett, J.M., Einauidi, M.T., Zurcher, L., Stavast, W.J.A., Johnson, D.A., and Barton, M.D., Porphyry deposits: Characteristics and origin of hypogene features, in Hedenquist, J., Goldfarb, R. and Thompson, J. (eds.), Economic Geology 100 th Anniversary Volume, Society of Economic Geologists, p. 251-298. Sillitoe, R.H., and Gappe, I.M., Jr., 1984, Philippine porphyry copper deposits; geologic setting and characteristics: UNDP Technical Support for Regional Offshore Prospecting in East Asia; United Nations, Economic and Social Commission for Asia and the Pacific, 89 p.
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