Uranium in the Frome Embayment: Recent results from Geoscience Australia s Onshore Energy Security Program Simon van der Wielen A. Britt, E. Bastrakov, A. Cross, S. Jaireth, M. Le Gleuher, A. Schofield, R. Skirrow
Outline Conceptual Model Mineral Systems approach Mapping REDOX Conclusions
Conceptual Sandstone U System Models Single fluid model Oxidised fluid carrying Uranium. In-situ reductant. Two fluids model Oxidised fluid carrying Uranium. Reduced (hydrocarbons or H 2 S) fluid acting as a reductant.
Mineral systems work flow The why question Why is the ore body there? 5 Questions 1. Geodynamics 2. Architecture 3. Fluid reservoirs 4. Fluid drivers & pathways 5. Deposition Inputs from: Data compilation Data collection Modelling & simulation (Andy Barnicoat) The where question Where is the next ore body? ew technique to map REDOX
Can geological logs be used to map REDOX? 40 years of Uranium exploration in the Frome Region. Some compiled digital drilling datasets PIRSA LITH and STRAT databases Scanned open file reports available via the internet
Oxidised Words Red Pink Maroon Orange Yellow Saffron Purple Ochre Mustard Mottled Reduced Words Green Blue Black Olive Khaki Dark Grey Fresh Gley Ferruginous Ferric Laterite Lateritic Limonite Hematite Goethite Martite Maghemite Specularite Pyrite Mundic Chalcopyrite Chalcocite Marcasite Galena Sphalerite Pyrrhotite Magnetite Sulphur, Sulphur Sulphides, Sulphides Manganese Mn Iron Fe FeO Fe 2 O 3 Oxide FeOx Glauconite Chlorite Biotite Garnet Olivine Peridotite Actinolite Pyroxene Amphibole Hornblende Gypsum Blown Dune Duricrust Ferricrete Lignite Coal Organic Carbonaceous Graphite Bitumen Creosote Petrol Kerosene Hydrocarbons H 2 S Odour
Deciphering Geological Code From this: Ple gy-br wkly ox vfg mx slty-chty AB wth com fg bk bi+mt spots & bi vnlts. Vmnr VQ as abv. Tr-vmnr Ma fract fil-vnlt, 1 spk in ox qz vn fragt. Com mnr gy ox-wthd py & tr cp or tarn Py? To this: Pale grey-brown, weakly oxidise, very fine grain matrix, slightly cherty albitite with common fragments of black biotite (+/- magnetite spots) and biotite veinlets. Very minor quartz vein as above. Trace-very minor marcasite fracture filled-veinlet, one speck in oxidised quartz vein fragments. Common minor grey oxidised-weathered pyrite and a trace of chalcopyrite or tarnished pyrite?
o Data 1 1 1 0 0 0-1 -1-1 -1-99999 -99999-99999 -1-1 -1-1 Example Drill Log Oxidised words are highlighted (RED) Reduced words are highlighted (BLUE) REDOX Zones : Oxidised (1) Reduced (-1) Mixed (0) o Data (-99999)
Study Area Four Mile Beverley EL 5/6 Key: Oxidised Mixed 345 km Oban Goulds Dam Honeymoon Radium Hill Mutooroo 450 km Reduced U Deposit Vertical Exaggeration = 25
REDOX drill holes Four Mile Beverley EL 5/6 Key: Oxidised Mixed 345 km Oban Goulds Dam Honeymoon Radium Hill Mutooroo 450 km Reduced U Deposit Vertical Exaggeration = 25
250 m Top of Cretaceous Bulldog Shale 56.5 km 76 km Key: Stratigraphic Markers From Drilling Vertical Exaggeration = 100
Top of Eyre Formation 250 m 56.5 km 76 km Key: Stratigraphic Markers From Drilling Vertical Exaggeration = 100
Top of amba Formation 250 m 56.5 km 76 km Key: Stratigraphic Markers From Drilling Vertical Exaggeration = 100
Topography 250 m 56.5 km 76 km Key: Stratigraphic Markers From Drilling Vertical Exaggeration = 100
Geological Voxet 250 m 56.5 km Key: Recent Sediments amba Formation Eyre Formation Cretaceous Sediments 76 km Vertical Exaggeration = 100
REDOX from drilling 250 m Key: Oxidised Mixed Reduced 56.5 km 76 km Vertical Exaggeration = 100
250 m REDOX in the Cretaceous Sediments Bulldog Shale Key: Oxidised Mixed Reduced 56.5 km 76 km Vertical Exaggeration = 100
REDOX in the Eyre Formation 250 m Key: Oxidised Mixed Reduced 56.5 km 76 km Vertical Exaggeration = 100
REDOX in the amba Formation 250 m Key: Oxidised Mixed Reduced 56.5 km 76 km Vertical Exaggeration = 100
REDOX in Recent sediments 250 m Key: Oxidised Mixed Reduced 56.5 km 76 km Vertical Exaggeration = 100
REDOX in all sediments 250 m Key: Oxidised Mixed Reduced 56.5 km 76 km Vertical Exaggeration = 100
Plan looking down onto formation surfaces Quaternary Surface amba Surface 20 km Eyre Surface Cretaceous Surface Oxidised Mixed Reduced
amba Fm. Eyre Fm. Redox Carbonaceous Material Redox Carbonaceous Material 50 km 50 km Redox Key: Redox Key: Lignite Pyrite Oxidised Lignite Pyrite Oxidised Mixed Mixed Reduced Reduced Hematite Limonite Materials Key: Hematite Limonite Materials Key: Occurrence Occurrence Sand Gravel Sand Gravel Carbonate carbonate Pebbles Carbonate carbonate Pebbles
Legend Springs Deposits (OZMI) Uranium Occurrences Redox Drill Holes eogene Paleochannels Paleogene Paleochannels Oxidised Mixed Redox State Reduced Top of amba Formation EL 5 and 6 Regional Contexts Redox Patterns Recent sediments highly oxidised amba Formation mixed redox state Eyre Formation reduced Cretaceous sediments highly reduced Possible -S reduced paleochannel in the amba Formation
Conclusions Geoscience Australia has developed an innovative technique to map and visualise REDOX state of sediments in 3D. Gross pattern of oxidised near surface and reduced at depth in Frome region. orth-south(?) oriented paleochannels in the amba Formation; re-evaluate regionally. Mineral system science provides exploration with a contextual framework for targeting.
Conclusions 1. Geodynamic and Tectonic Evolution Literature Review Timing of Uranium Systems 2. Architecture Data compilation 3D gocad Model 3. Fluid and Metal Reservoirs umerical modelling 4. Fluid Pathways and Drivers umerical modelling 3D gocad Model 5. Depositional Mechanism Petrographic study Mapping REDOX gradients Uranium ore-forming systems of the Lake Frome region, South Australia: Regional spatial controls and exploration criteria REPORT OUT LATE 2009