MSDP insights from new GSSA mapping Stacey McAvaney, Mario Werner, Carmen Krapf, Mark Pawley, Ben Nicolson and Claire Wade 11th August 2016, Mineral Systems Drilling Program Open Day Outline • Southern Gawler Ranges margin GSSA project • Mapping as part of the Mineral Systems Drilling Program • Map products and releases • MSDP Map Series • Southern Gawler Margin Regolith Map • Mapping highlights Department of State Development 2 Southern Gawler Ranges margin project • Characterise mineral systems associated with GRV-HS magmatism • Lithological and structural controls on mineralisation • 1590 Ma palaeosurface • Thickness of GRV Department of State Development 3 MSDP Mapping Department of State Development 4 Role of field mapping in drilling program • Constrain interpretation of geophysics • Stratigraphy • Structural geology and tectonic evolution • Regional vs deposit-scale alteration systems • Two-dimensionality of contact relationships Department of State Development 5 Field mapping 669 Field observations 169 rock samples 62 geochemistry analyses 57 thin sections 13 geochronology samples Department of State Development 6 Field mapping data delivery www.sarig.pir.sa.gov.au/Map Department of State Development 7 Geological core logging Department of State Development 8 MSDP Mapping products Department of State Development 9 Six Mile Hill Surface Geology Department of State Development 10 previous mapping new mapping Department of State Development 11 Regolith Map of the southern Gawler Ranges Margin https://sarigbasis.pir.sa.gov.au/WebtopEw/ws/samref/sarig1/image/DDD/RB201600015.pdf Department of State Development 12 Regolith material Regolith landforms Regolith transported vs. in situ Nine Mile Dam Six Mile Hill vitric tuff New outcrops of lower GRV Roopena Basalt northern extension of known outcrop O’Reily Dam felsic porphyritic volcanic Parkinson Dam quartz-phyric rhyolite lava agate 10 km Department of State Development 14 Six Mile Hill Bimodal mafic and effusive-explosive felsic volcanic Sequence in lower GRV Department of State Development 15 Six Mile Hill Lanzarote, Canary Islands Department of State Development 16 Peltabinna Volcaniclastic marker horizon in upper GRV siltstone Pondanna Dacite mud flow deposit Eucarro Rhyolite debris flow deposit Department of State Development 17 Peltabinna Volcaniclastic marker horizon in upper GRV outcrop MSDP 05 & 07 Department of State Development 18 Peltabinna Quartz-muscovite-fluorite greisen alteration in Hiltaba Suite granite enriched in Sn (114 ppm), Cu (163 ppm), Zn (197 ppm), Pb (125 ppm), Bi (37 ppm), As (5 ppm), Sb (0.4 ppm) depleted in K2O (3.2 wt%), Na2O (0.1 wt%), CaO (0.3 wt%), Sr (7 ppm) muscovite altn in granite malachite staining in granite TMI 10 km qtz-mu replacement of fdspar greisen cpy 100K geology 10 km Department of State Development 19 Plutonic to subvolcanic facies of GRV – Mount Double Hiltaba Suite along southern GRV margin andesite dyke dacite dyke rhyolite dyke Waulkinna Hill Tin Hut 10 km Department of State Development 20 Mount Double Archaean vs Palaeoproterozoic granitic basement? Sleaford Complex Pinbong Suite 2550–2440 Ma (1735–1700 Ma) Waddikee Rocks Poverty Corner Peter Pan Platforms Little Pinbong Rockhole Department of State Development 21 Mount Double Sleaford Complex Pinbong Suite Department of State Development 22 Future directions • Defining new volcanic succession at Six Mile Hill • Significance and lithospheric/tectonic controls on basaltic magmatism on eastern margin of GRV • Olarian faulting, potential controls on volcanism • Hutchison Group stratigraphy: resolving ~2550 Ma, ~1790 Ma and ~1740 Ma max. dep ages Department of State Development 23 Contact Department of State Development Level 4, 101 Grenfell St Adelaide, South Australia 5000 GPO Box 320 Adelaide, South Australia 5001 T: +61 8 8463 3162 E: [email protected] www.statedevelopment.sa.gov.au .