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Potential Field Interpretation of the Capricorn Orogen
Potential Field Interpretation of the Capricorn Orogen
JAMES GOODWIN
Worms, forward modelling and 3D inversion
Potential Field Interpretation of the Capricorn Orogen
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)
Potential Field Interpretation of the Capricorn Orogen
Seismic line 10GA-CP1
Hamersley
Hamersley
Hamersley
Ashburton
Magnetics RTP
Surface Geology
Nanjilgardy
Fault
Potential Field Interpretation of the Capricorn Orogen
• Leake Springs Metamorphics = correlative of Upper Wyloo Group (Cawood and Tyler 2004; Sheppard et al., 2007)
Seismic line 10GA-CP1
Ashburton Fm
Hamersley Group
Collier
Edmund Group
Leake Springs Metamorphics
Potential Field Interpretation of the Capricorn Orogen
Hamersley
Hamersley
Hamersley
Ashburton
Bouguer GravityGravity Worms
Magnetics Worms
Seismic line 10GA-CP1
Continuation Height
56703
40502
28930
20664
14760
10543
7531
5379
3842
2744
1960
1400
Karra Well Fault
(SW dipping)
Baring Downs Fault
Potential Field Interpretation of the Capricorn Orogen
MAGNETIC INVERSION
GRAVITY INVERSION
GRAVITY
MAGNETICS
RTP
Baring Dow
ns Fault
Hamersley GroupOff line
effects
0
30
60
Depth
(k
m)
0 mGals
-100 mGals
1000 nT
-1000 nT
2.72.6
2.7
2.6
3.2
2.92.92.9
3.2 / 0.10
2.92.82.67
2.72.8
2.8
2.6
Mantle
Lower Crust
Granite-GreenstoneBandee
UWGLWG
NS
Hamersley
Fortescue Group
Potential Field Interpretation of the Capricorn Orogen
Seismic line 10GA-CP2
CollierMoorarie
Supersuite
Durlacher Supersuite
Moogie Metamorphi
cs
Edmund Group
Leake Springs Metamorphics
Lyons River Fault ? contact
Surface GeologyMagnetic
s RTPMagnetics WormsGravity Worms
Bouguer Gravity
Durlacher
Supersuite
Cardilya Fault
Potential Field Interpretation of the Capricorn Orogen
Bandee Seismic Province
Glenburgh Terrane
MAGNETIC INVERSION
GRAVITY INVERSION
GRAVITY
MAGNETICS RTP
Bandee Seismic Province
Glenburgh Terrane
Edmund Group
Durlarcher Moorarie
-10 mGals
-50 mGals
500 nT
-500 nT
2.852.77
2.9
3.2
2.8
2.9
2.8 / 0.022.8
2.672.62.62.6
2.9
2.92.67
2.6
NS
UWG
LWG
Mantle
Leake Springs Metamorphics
2.7 / 0.05
Edmund Group
Lyons River Fault
Lyons River Fault
Potential Field Interpretation of the Capricorn Orogen
Seismic line 10GA-CP3
Errabiddy Shear
Zone
Narryer Terrane
Dalgaringa Supersuite
Surface GeologyMagnetic
s RTPMagnetics WormsGravity Worms
Bouguer Gravity
Potential Field Interpretation of the Capricorn Orogen
BIF 74257
Seismic line 10GA-CP3
10GA-CP3
Potential Field Interpretation of the Capricorn Orogen
Seismic line 10GA-CP3
Potential Field Interpretation of the Capricorn Orogen
Narryer Terrane Glenburgh Terrane
Errabiddy Shear Zone
MAGNETIC INVERSION
GRAVITY INVERSION
Potential Field Interpretation of the Capricorn Orogen
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
