Tectonics and Metallogeny of Mainland Southeast Asia
Implications for Exploration and Discovery Opportunities
Neal Reynolds CSA Global
9/03/2015 www.csaglobal.com 1 Introduction
• Mainland Southeast Asia mineral industry remains underdeveloped; limited endowment or unrealised potential? • Metallogeny and potential is generally not well understood • Reflects a range of factors from geological to historical and political • Present day operating and investment environment remains challenging in most jurisdictions • Investment in exploration can minimise exploration risk through optimised understanding of metallogeny and discovery opportunities Masan Resources Nui Phao W-F-Cu-Au-Bi project, Thai Nguyen, Vietnam Padaeng Zn Mine, Mae Sod, Thailand Geotectonic Setting
• SE Asia – Eastern Tethyan belt • Collage of continental fragments rifted from Gondwana between the Devonian and Permian and accreted to Asia between the Triassic and Cretaceous • Metallogenic history intimately related to cycles of rift, drift, convergence and collision • Improving understanding of tectonic evolution provides the framework for metallogenic targeting • Consider also correlations with China
From Metcalfe http://metcalfeian.com/web-data/Research/PalGeog/Palaeogeog.html From Reynolds & Large, 2010, SEG Special Publication 15
Tectonic Setting and Evolution
• Convergence and collision on N Gondwana margin; Neoproterozoic to Silurian 50°E50°E50°E 70°E70°E70°E 90°E90°E90°E 110°E 110°E 110°E 130°E 130°E 130°E • Rift and drift of Cathaysia from Gondwana; Silurian-Devonian • Rift and drift of Sibumasu from 20°N20°N20°N Gondwana; Carboniferous to early Permian • Convergence and arc volcanism on Indochina and Simao margin; 0°0°0° Carboniferous to Triassic • Collisional orogeny - Asian accretion in the Triassic Indosinian orogeny
20°S • Continental arc – Jurassic to 20°S20°S Palaeogene subduction on the Indian and Pacific margins • Collisional orogeny with the Nias 40°S terranes in the Upper Cretaceous, and 40°S40°S India in the Eocene-Oligocene • Transcurrent ‘extrusion’ of SE Asia in the Oligocene-Miocene Hall http://searg.rhul.ac.uk/current_research/plate_tectonics/ POLYPHASE METALLOGENY
Stampfli and Borel, http://www.unil.ch/igp/page76652.html SE Asia Metallotects
Twelve significant metallotects: West 1. Indo-Burman ophiolitic belt Burma 2. Myanmar-Tengchong volcanic arc terrane 3. Slate belt Sibumasu 4. Shan-Thai block/W Sumatra terrane 5. Doi Inthanon – Changning-
Menglian belt
6. Sukothai-Malay volcanic arc/fold
belt
7. Pak Lay-Loei-Phetchabun-N
Cambodia-E Malay volcanic Indochina arc/fold belt terrane 8. Indochina craton platform 9. Kontum Block/SE Vietnam arc 10.Truong Son fold belt 11.Dai Nui Con Voi block S China terrane 12.Cathaysia block/SE China arc
Metallogeny and Potential
• Understanding of mineral potential depends on understanding of tectonic evolution and related mineral systems • Deposit preservation related to uplift and erosion is of critical importance especially for epithermal Au and porphyry Cu systems • For metallic minerals, large to world class deposits of Cu, Cu-Au-Mo, Au-Ag, REE, Ni- Cu, Fe, Fe-Ti-V, Zn-Pb-Ag, Sn-W, and Al exist within the region or in metallogenic belts that run into the region • Additional significant districts and deposits of gemstones, jade, coal • Despite limited past exploration, mineral- system understanding in the context of regional metallotectonic belts can be used to prioritise potential and opportunities • Regional to belt-scale analysis
Selected Priority Belts
1. Early Mesoproterozoic sedimentary Cu-Ag in South China terrane 2. Early Mesoproterozoic IOCG Cu-Au-U-REE in South China terrane 3. Early Palaeozoic Cu-Zn-Ag-Au VHMS in Truong Son Belt, Indochina terrane 4. Early Ordovician Pb-Ag-Zn-Cu VHMS in Sibumasu terrane 5. Early Ordovician Pb-Zn-Ag Irish-type in Sibumasu terrane 6. Middle Devonian SHMS Zn-Pb-Ag in S China terrane 7. Carboniferous SHMS Zn-Pb-Ag in Sibumasu terrane 8. Carboniferous to Triassic VHMS Cu-Zn and Zn-Pb-Cu-Ag-Au on Indochina fringing back-arc basins 9. Early Permian porphyry/skarn Cu and carbonate-replacement Au in Truong Son back-arc 10. Permo-Triassic skarn Fe in Truong Son back-arc 11. Mid Permian intrusive-hosted Ni-Cu and Fe-Ti-V in Emeishan LIP, S China terrane 12. Permo-Triassic porphyry Cu-Au, epithermal Cu-Au and skarn Fe on Indochina margin 13. Triassic orogenic Au, Sibumasu/Indochina collision zone 14. Late Triassic greisen and skarn Sn-W, Sibumasu 15. Late Triassic anthracite, Indochina 16. Late Triassic “Carlin-like” Au, South China 17. Late Triassic MVT Zn-Pb-Ag, South China 18. Cretaceous MVT Zn-Pb-Ag, Sibumasu 19. Jurassic-Cretaceous (Yanshanian) intrusive-related Cu-Au, Sn-polymetallic, Zn-Pb-Ag, Sn-W, and Sb
20. Mid-Cretaceous potash, Indochina block (Udon c. 300 Mt at 24% K2O, sylvinite) 21. Late Cretaceous greisen and skarn Sn-W, Sibumasu 22. Eocene porphyry Cu-Au-Mo in the Jinshajiang - Ailoshan suture zone 23. Oligocene alkaline intrusive-related REE, Indochina 24. Oligo-Miocene porphyry and epithermal Cu-Au in the Myanmar arc 25. Mio-Pliocene “Carlin-like” sediment-hosted epithermal Au in the Myanmar back-arc 26. Quaternary bauxite, Indochina block 27. Quaternary to Recent ion-adsorption REE, South China
Proterozoic Cratons and Basins of the South China Terrane • Limited Precambrian geology in SE Asia – Yangtze and Cathaysia blocks of South China terrane • South China situated next to eastern Australia in Rodinian reconstructions • Late Palaeoproterozoic to early Mesoproterozoic Dongchuan-type sedimentary copper deposits in the Kangdian district of Yunnan and Sichuan • Dongchuan district c. 300 Mt at 1% Cu • Dolostone-hosted associated with discordant diapir breccia bodies • IOCG – Yunnan (Lalachang, Dahongshan) to NW Vietnam (Sin Quyen), continuation CNMC Sin Quyen Cu Mine, Lao Cai, Vietnam of the Yangtze block offset along the Red River Fault • Sin Quyen c. 52.8 Mt at 0.91% Cu, 0.44 g/t Au, 5.4% Fe and 0.70% combined Ce, La, Pr and Nd • Mesoproterozoic or Palaeoproterozoic? • Vietnam sector poorly explored
Li et al., 2007
Cambro-Ordovician Volcanism and Basins on the Sibumasu Terrane Margin • Bawdwin volcanic centre; Early Ordovician rhyodacitic complex,
overlying Cambrian flysch • Active northern Gondwana plate margin or Serindian convergence? • Structurally controlled lodes; 1938 ‘reserve’ 10.8 Mt at 22.8% Pb, 13.9% Zn, 1.05% Cu and 670 g/t Ag • Carbonate-hosted Pb-Zn-Ag-Ba deposits in Early Ordovician platform sequences over 1000 km of strike from Kanchanaburi to western Yunnan • Conformable Pb isotopes, similar to From Metcalfe http://metcalfeian.com/web-data/Research/PalGeog/Palaeogeog.html Bawdwin From Bender, 1983 • Tuff zircon U/Pb c. 464 Ma – similar Modified after Carpenter, 1964 age to Bawdwin? • Metallogenic event of regional significance
Lower Ordovician ‘Irish-type’ Zn-Pb-Ag-Ba
• Stratabound disseminated to semi- massive sulphide in shallow water clean limestone • High Ag, low-Fe sphalerite, elevated Sb, As, Hg; associated barite • “Irish-type” in back-arc setting? • Similar age to Admiral Bay in W Australia (74Mt at 3.1% Zn, 2.9% Pb, 18 g/t Ag; 12% Ba • Kanchanaburi c. 8 Mt at 7% Pb, 3% Zn and 100g/t Ag • Li district – Phu Mai Thong (>7 Mt) massive bedded barite deposit • Mae Chong – stratabound disseminated to semi-massive Zn-Pb-Ag, >10 sq km fault controlled system, intersections up to 13% Zn, 2% Pb and 40 g/t Ag • Bawsaing district – extensive small lead and barite deposits and oxidised zinc; Kanchanaburi folded stratabound sphalerite-rich mineralisation in • No systematic modern exploration in chlorite-carbonate phyllite Thailand or Myanmar • Yunnan – Menxing and Dongshan Kanchanaburi carbonate-hosted sphalerite-
Bedding-parallelrich early barite replacement ore, Phu Mai style Thong mineralisation mine
Carboniferous SHMS in Sibumasu • Carboniferous extension and incipient rifting in NE Gondwana;
• Late Carboniferous to Late Permian rift and drift of Sibumasu • Deepening sequences overlying Visean platform carbonates • Rift-sag basinal deposits; SHMS in Sibumasu and Indochina • Sopokomil SHMS, Sumatra; 24.3 Mt at 10.3% Zn, 6.0% Pb, and 8.3 g/t Ag (Measured, Indicated and Inferred) • Stratabound massive sulphide over 4 km in carbonaceous dolomitic shale/siltstone unit on NE side of Sopokomil Dome
• Trangressive deepening sequence; From Metcalfe http://metcalfeian.com/web-data/Research/PalGeog/Palaeogeog.html hangingwall calci-turbidites • Accidental discovery of a large polydeformed but classic SHMS mineral system From Stampfli and Borel, http://www.unil.ch/igp/page76652.html Carboniferous to Triassic VHMS • Active Indochina/Simao margin and peripheral rifted
arc terranes; Loei, Sukothai and Changning-Menglian belts • Gold-rich polymetallic VHMS in back-arc settings: Sukothai VHMS; e.g. Dapingzhang (Cu), Nam Rin (Ba-Au + Zn), Tasek Chini (Malaysia Ba-Cu-Zn-Au) Changning-Menglian belt – Permo-Triassic arc and back-arc volcanism Laocang (20 Mt at 4.3% Zn, 6.6% Pb, 151 g/t Ag and 0.11% Cu), Yagra (c. 1 Mt cont. Cu) Gacun 44 Mt at 5% Zn, 4% Pb, 0.4% Cu
MassiveFrom pyrite Stampfli and and barite, Borel, Namhttp://www.unil.ch/igp/page76652.html Rin Early Palaeozoic VHMS in the Truong Son Belt
• Duc Bo polymetallic deposit in central Vietnam • Cryptic suture in Truong Son belt of uncertain but probable Palaeozoic age – accretion of Indochina terranes to South China across the Song Ma suture • Back arc in central Truong Son? • Late Ordovician to Silurian closure and deformation, granite intrusion, and orogenic gold mineralisation
Gold and Copper in the Truong Son Early Permian Back-Arc
• Permo-Triassic arc volcanism on the Indochina/Simao margin – Loei and Sukothai to Changning-Menglian belts • Early Permian porphyry back-arc centres in the Truong Son belt; low- grade Cu-Mo porphyry, Cu skarn, and carbonate-replacement (“Carlin”) gold • Sepon (c. 96 Mt at 2% Cu and 3.6 Moz Au); • Phu Kham (c. 311 Mt at 0.5% Cu and 0.2 g/t Au); • Kham Thong Lai (c. 89 Mt at 0.44% Cu, 0.18 g/t Au, 1.7 g/t Ag • Phuoc Son, Xa Khia, Ban Bac etc. in southern belt • Thach Khe iron skarn 370 Mt at 59% Fe • Hoa Binh sediment-hosted gold belt; Kim Boi, Cam Thuy, etc.
From Tate, 2005 From FromStampfli Manini and etBorel, al., 2003http://www.unil.ch/igp/page76652.html Gold and Copper in Chatree low-sulphidation Permo-Triassic Arcs gold deposit, Thailand
• Permo-Triassic arc volcanism on the Indochina/Simao margin – Loei- Phetchabun-Pak Lay and Sukothai to Changning-Menglian belts • Early Triassic low-sulphidation epithermal deposits in the Loei- Phetchabun-Pak Lay belt; Chatree (c. 5 Moz Au), Ban Houayxai (c. 36 Mt at 1.2 g/t Au, 7.7 g/t Ag) • Structural and stratigraphic controls • Early Triassic porphyry and skarn C-Au deposits in the Loei-Phetchabun-Pak Lay belt; Phu Thep (c. 264 Mt at 0.43% Cu, 0.13 g/t Au), Phu Lon, Tungkhum Au skarn • Triassic epithermal deposits in Thailand Okvau gold deposit, Cambodia in the Sukothai belt; Mae Chan etc. • Late Triassic to Jurassic IRG in back-arc; Okvau 15.6 Mt at 2.4 g/t Au for 1.2 Moz Phu Thep porphyry/skarn Cu-Au and From Cummings et al., 2008 telescoped epithermal Au, Thailand From Tangwattananukul et al., 2009 Mid Permian intrusive-hosted Ni-Cu-PGE and Fe-Ti-V
• Emeishan Large Igneous Province, Yangtze craton of South China Terrane • Flood high-K basalts and intrusions • Significant Ni-Cu and Fe-Ti-V mining district in Yunnan and Sichuan • Limahe and Baimazhai, Ni-Cu, sulphide-rich, PGE-poor; Yangliuping and Qingkuangshan, sulphide poor, PGE-rich • Layered Fe-Ti-V deposits, e.g. Baima, Panzhihua etc. • Vietnam intrusive province north of the Song Ma Suture • Ban Phuc etc.
From Song et al., 2008 Indosinian Orogenic Gold
• Late Triassic to Jurassic culmination of Indosinian orogeny; collision of Sibumasu with Indochina/South China and of South China with North China and Tarim • ‘Slate belt’ deposits in Carboniferous Permian flysch; Myanmar and Thailand • Small high-grade vein deposits • Modi Taung, Bang Saphan etc • Orogenic gold deposits in the Raub- Bentong suture zone, Malaysia and Thailand; Raub, Penjom, Selinsing, Mae Moh, etc. Selinsing gold deposit, Malaysia
Modi Taung gold deposit, Myanmar From Stampfli and Borel, http://www.unil.ch/igp/page76652.html Heinda palaeo-placer tin SE Asia Tin Belt deposit, Myanmar
• 2800 km long belt from eastern Myanmar through peninsular Thailand and Malaysia to the Indonesian “Tin Islands” of Bangka and Belitung • Total estimated production c. 9.6 Mt of tin, or 54% of the world's tin production • Mainly related to two evolved granite belts: • Central or Main Range belt in western peninsular Malaysia, southern peninsular Kelapa Kampit zinc-lead-silver-tin skarn, Belitung Thailand; Late Triassic age S-type biotite island, Indonesia granites resulting from crustal thickening following Indosinian collision. • Western belt in northern peninsular Thailand, western Thailand and Myanmar; Late Cretaceous I-type/A-type granites in an extensional Andean-type continental back-arc setting following West Burma arc collision • Most production from palaeo-placers, much from offshore dredging • Almost no modern exploration focused on hard-rock potential Batu Besi tin-silver-iron skarn, Belitung island, Indonesia 9/03/2015 18 Mawchi Mine wolframite-mineralised veins, Myanmar
Yanshanian Continental Arc Belt Polymetallic Metallogeny
• Extensive and large mineral systems accompanying staged Jurassic and Cretaceous continental arc magmatism on the SE China margin; huge economic importance • Spatially and temporally zoned as arc developed from I- to A-type magmatism • Extensions in NE and SE Vietnam
9/03/2015 19 Yanshanian Continental Arc Belt Polymetallic Metallogeny
• ‘Carlin-like’ sediment-hosted Au deposits of the ‘Golden Triangle’, Dian-Qian-Gui (Triassic Youjiang basin); Jinfeng (Lannigou, c. 1.8 Moz at 3.7g/t Au), Shuiyindong (c. 3 Moz at 5 g/t Au) • Typically carbonate and siltstone host rocks, strong structural control • Youjiang transform fault-related; uncertain Yanshanian age • Song Hien basin in Vietnam – Triassic volcanics
• Structurally controlled and replacement high- grade Zn-Pn deposits in Kangdian district of Sichian-Yunnan-Guizhou; ; Huize district, Daliangzi,etc. From • Fault-hosted and -controlled massive Zheng and High-grade Wang sphalerite-galena replacement, breccia, and cavity fill (1991) ore, with open- • Deposits in Sinian and Carboniferous space fill textures limestones • High-grade deposits with large oxide resources • Ag, Cd, Ga, Ge credits • Uncertain post-Permian age
9/03/2015 20
Yanshanian Continental Arc Belt Polymetallic Metallogeny
• Mid-Jurassic porphyry Cu; Dexing district c. 1500 Mt at 0.43% Cu, 0.02% Mo, 0.16g/t Au • Late Jurassic polymetallic Zn-Pb-Au-Ag; Fankou, Shuikoushan • Late Jurassic – Early Cretaceous intrusive- hosted W-Sn-Mo-(Cu-Bi) and Zn-Pb • Nanling region – 90% of China’s tungsten, e.g. Yaogangxian etc • Early Cretaceous high-sulphidation epithermal gold; Zijinshan • Late Cretaceous large skarn and greisen Sn- polymetallic deposits; Geijiu, Dulong (33 Mt at 5.12% Zn, 0.56% Sn, and 0.17% W), Dachang (c. 144 Mt at 0.7% Sn, 2.4% Zn, 0.3% Pb, >100 g/t Ag), Da Lien (Nui Phao) • Nui Phao Project under development by Masan Resources in N Vietnam 97 Mt at 0.18% WO3, 7.73% CaF2, 0.18% Cu, 0.08% Bi, and 0.18 g/t Au • Palaeocene sediment-replacement Au and Ag; Changkeng, Fuwan
9/03/2015 21 Nui Phao W-F-Cu-Bi-Au deposit, Vietnam Cretaceous Zn-Pb MVT Jinding
Daliangzi • Padaeng (Mae Sod) supergene oxide Zn deposit (hemimorphite) c. 1.8 Mt cont. Huize Zn, no Pb, no sulphide • Mineralisation close to major NW- trending fault zone • Small Pha De Zn-Pb sulphide deposits stratabound in ferroan-dolomitised oolitic limestone
• Replacement, breccia and cavity-fill Long Keng low-Fe sphalerite, galena and pyrite • Jurassic shallow-water carbonates peripheral to clastic basin; narrow belt Padaeng extends NW into Myanmar Mawki • Mawkhi Zn-oxide (willemite) deposit hosted in Triassic dolostone in same belt • Long Keng – 0.4 Mt at 35% Zn as smithsonite hosted by Triassic dolostone in central Shan State Long Keng Zn deposit, Myanmar
Padaeng district and mine from Reynolds et al., 2003
From Li and Kyle Himalayan MVT Zn-Pb (1997)
• Jinding - largest Zn-Pb deposit in China; c. 200 Mt at 6.1% Zn, 1.3% Pb, almost 15 Mt Zn+Pb • Stratabound cavity-fill and replacement in Paleogene of Lanping-Simao basin • Cretaceous-Tertiary foreland basin with evaporites. • Paleogene fold and thrust belt with late extension High-grade banded replacive sulphide • Mineralisation postdates thrusting, pull- apart basin controlled by left-lateral High-grade NW-trending regional faults smithsonite ore • Host carbonate-cemented sandstones and fanglomerate breccias • Simple mineralogy and chemistry, abundant barite and celestite • Extensive oxide ore zones • Bitumen association • Possible analogues in eastern China – Wulagen etc.
Eocene porphyry Cu-Au-Mo along the Ailoshan and Jinshajiang Suture belt
• Yulong district in Tibet associated with Late Eocene potassic alkaline porphyry intrusions intruding the Simao block • Yulong c. 700 Mt at 0.94% Cu an 0.022% Mo for 6.5 Mt Cu copper, together with. • Post-collisional extensional strike-slip regime accompanying Indian collision • Reactivation of melting in the Neo-Tethyan subduction zone between Indochina-Simao and South China during renewed compression. • Southeast continuation in Sichuan (Xuejiping), Yunnan (Machanqing, Tongchan, Beiya) and the Palaeogene alkaline magmatic province of Northern Vietnam (Phu Sam Cap, Huoi Say) • Tongchan district Cu-Au associated with syenite intrusions, carbonate-replacement Au in host rocks (Chang’an) • Phu Sam Cap porphyry-hosted Au-Cu project • Huoi Say high-sulphidation Cu-Au vein system
9/03/2015 24
REE-U-F in NW Vietnam
• Nam Xe and Dong Pao REE-U-Nb-F-Ba deposits associate with alkaline intrusive complexes • Nam Xe REE-U-Nb – vein deposit in marble with 8-10% REO enriched in supergene • Nam Xe is LREE-rich; the Muong Hum prospect is a HREE deposit • Sichuan deposits in the same belt are associated with carbonatite and syenite and include Maoniuping (China’s second largest REE resource) and Dulucao • Maoniuping c. 2.6 km vein system with c. 1.2 Mt at 2.89% REO
9/03/2015 25 Oligocene-Miocene Myanmar Arc and Back-Arc
• Palaeogene oblique subduction with discrete sub-aerial volcanic centres along the Central Myanmar Arc • Monywa early Miocene high-sulphidation epithermal copper deposit (c. 1.88 Bt at 0.37% Cu) • Shangalon Cu-Au porphyry (Oligocene); Tonbon skarn, etc
Continuation of Gangdese arc, Tibet; Jiama Kyaukpahto stockwork veined argillic altered sandstone (1.17 Bt at 0.41% Cu, 0.04% Mo, 0.1g/t Au) Monywa mine looking toward Letpadaung • Epithermal and sediment-hosted gold associated with Neogene extension and magmatism along the Sagaing Fault zone; Kyaukpahto (>6 Mt at 3g/t), Gegalaw, etc. • Neogene transcurrent faulting and magmatism in the Mogok Belt; mesothermal gold, IRG/skarn? – Kwinthonze, Tayetkhone etc.
Kyaukpahto fluidised breccia and chalcedonic silicification Final Points
• Significant mineral systems and belts can be related to specific phases of orogenic cycles and time windows • Recognition of prospective tectonic setting and correlations can guide regional targeting, and/or prioritisation of opportunities
• Uplift and subsidence history is critical in determining potential, especially for epithermal and porphyry systems • Tertiary to Recent subsidence especially in southern Southeast Asia can lead to preservation of porphyry and epithermal systems at low elevations
• The potential of most of mainland SE Asia is highly under-explored and often unrecognised • Discovery history of deposits like Sopokomil provides a salutary lesson on finding unexpected deposit types in previously unrecognized target terrain
• Models and regional correlation provide a framework, but every district is different and must be individually understood for exploration and evaluation to be effective • Understanding sedimentary, tectonic, structural and intrusive history is important in understanding and targeting most mineral systems in many settings; use of dating control, isotopic and geochemical signatures are all important and should not be considered fringe activities