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Potential Field Interpretation of the Capricorn Orogen. JAMES GOODWIN. Worms, forward modelling and 3D inversion. Purpose. Investigate regional-scale crustal architecture Relationship between Pilbara/Capricorn/Yilgarn Compare with seismic line interpretation. Interpretation Techniques.
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Potential Field Interpretation of the Capricorn Orogen JAMES GOODWIN Worms, forward modelling and 3D inversion
Purpose • Investigate regional-scale crustal architecture • Relationship between Pilbara/Capricorn/Yilgarn • Compare with seismic line interpretation Interpretation Techniques • Image processing • Multiscale edge detection (worms) • Forward modelling • 3D inversion (unconstrained)
Seismic line 10GA-CP1 Surface Geology Magnetics RTP Hamersley Hamersley Ashburton Nanjilgardy Fault Hamersley
Seismic line 10GA-CP1 • Leake Springs Metamorphics = correlative of Upper Wyloo Group (Cawood and Tyler 2004; Sheppard et al., 2007) Hamersley Group Leake Springs Metamorphics Ashburton Fm Edmund Group Collier
Seismic line 10GA-CP1 Bouguer Gravity Gravity Worms Magnetics Worms Hamersley Hamersley Karra Well Fault (SW dipping) Ashburton Baring Downs Fault Hamersley
0 mGals S N GRAVITY -100 mGals Hamersley 1000 nT 3.2 / 0.10 MAGNETICS RTP -1000 nT 0 2.8 2.67 UWG 2.6 2.9 2.6 LWG 2.6 Fortescue Group 2.8 2.7 2.7 Granite-Greenstone 2.7 Baring Downs Fault Bandee 2.8 2.9 Lower Crust Depth (km) 30 2.9 2.9 Mantle Hamersley Group 3.2 Off line effects 60 MAGNETIC INVERSION GRAVITY INVERSION
Seismic line 10GA-CP2 Surface Geology Gravity Worms Magnetics Worms Magnetics RTP Bouguer Gravity Edmund Group Lyons River Fault Collier ? contact Moorarie Supersuite Durlacher Supersuite Leake Springs Metamorphics Durlacher Supersuite Cardilya Fault Moogie Metamorphics
S GRAVITY N -10 mGals Leake Springs Metamorphics -50 mGals MAGNETICS RTP 2.7 / 0.05 Edmund Group 500 nT 2.6 -500 nT Durlarcher Moorarie 2.6 2.67 2.67 2.6 2.6 2.85 UWG 2.9 2.8 Glenburgh Terrane 2.77 2.8 Lyons River Fault 2.8 / 0.02 LWG Bandee Seismic Province 2.9 2.9 2.9 Mantle 3.2 MAGNETIC INVERSION Edmund Group Lyons River Fault Glenburgh Terrane Bandee Seismic Province GRAVITY INVERSION
Seismic line 10GA-CP3 Gravity Worms Magnetics RTP Magnetics Worms Surface Geology Bouguer Gravity Dalgaringa Supersuite Errabiddy Shear Zone Narryer Terrane
Seismic line 10GA-CP3 10GA-CP3 BIF 74257
MAGNETIC INVERSION Narryer Terrane Glenburgh Terrane GRAVITY INVERSION Errabiddy Shear Zone
Key Findings • Forward models suggest the seismic line interpretation is consistent with potential field data. • Hamersley Group has the potential to extend as far south as the Edmund Basin • Magnetic anomalies attributed mainly to the Hamersley Group, Leake Springs Metamorphics and BIF 74257 • Yilgarn-Capricorn boundary is south-dipping