i2+3: total systems analysis of the mt isa eastern succession · pmd crc i2+3: total systems...
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I2+3: Total systems analysis of I2+3: Total systems analysis of the Mt Isa Eastern Successionthe Mt Isa Eastern Succession
Project Leader: Tom BlenkinsopJames Cook University, CSIRO, GA, Melborne, Monash
Tim Baker, Evgeniy Bastrakov, George Gibson, Roland Maas, Geordie Mark, Barry Murphy, Roger Mustard, Mike Rubenach, Peter Southgate, Lucas Marshall, John McLellan, Nick Oliver, Pat Williams, Yanhua Zhang, Bruce GolebyPeter Jones, Cathy McKeagney, Mohammed Sayab, Kris Butera Cameron Huddleston-Holmes, Piter Lepong
Program: TerranesLinkages: I1, I4, A1, H1, F1, F2, F4, M3Commencement Date: 1-2-2002Project Duration: 3 years
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• Project Overview• Project Highlights• Integration• Student participation• Outlook
pmd CRCProject AimsProject Aims• Establish a tectonothermal history for the Eastern
Succession • Characterise the spectrum of fluid compositions
produced by crystallizing magmas• Develop a preliminary tectonostratigraphic model at
the supersequence level• Identify, and rank the importance of, all necessary
ingredients for the spectrum of IOCG deposits in the district
• Generate advanced targeting tools based on new data and methods
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Modular StructureModular Structure
Module 2Key Ingredients
for IOCG’s
Module 3Tectonothermal Evolution
Module 4Tectono-
stratigraphy
Module 5Numerical modelling
Module 6Targeting tools
Module 1Structural Framework
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Serial Cross Sections,Potential Field Validation
Module 1:Module 1:Structure HighlightsStructure Highlights
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Winberugranite
Squirrel Hills Granite
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Module 3:Module 3:TectonothermalTectonothermal Evolution HighlightsEvolution Highlights
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pmd CRCModule 5:Module 5:Numerical Modeling HighlightsNumerical Modeling Highlights
• Geochemical• Mechanical
pmd CRCGeochemical Geochemical ModelingModeling
Alteration simulation for regional albitisation
pmd CRCMechanical Mechanical ModelingModeling
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West
East
Arrows: fluid flow velocities White lines: contours of shear strain rate
pmd CRCConclusionsConclusions1. In the early stages of the isan orogeny, the Leichardt
River Fault Trough was much more favorable for mineralization than the Eastern Fold Belt
2. During orogeny, shear strain localised in the Eastern Fold belt, which became the focus of later mineralization.
3. Mineralization in the eastern sucession may be due to deep-sourced Fluids leaching mafic slabs and interacting with surface-sourced Fluids near thrust faults and granites.
pmd CRCModule 6: Module 6: Targeting Tools HighlightsTargeting Tools Highlights
•Clustering of Mineral Deposits
•Fault Roughness and Mineralization
•Weights of Evidence and Fuzzy Logic
•New Tools
pmd CRCClustering of mineral depositsClustering of mineral deposits
• The North West Queensland Mineral Province Report has been used to analyse the spatial distribution of mineral deposits.
• Ag-Pb-Zn, Au-Cu, Cu and Au deposits have quite distinct degrees of clustering and different fractal dimensions.
• This implies different genetic processes for each deposit type. For example, Au deposits are highly clustered, perhaps due to more concentrated fluid flow than in other types of mineralization.
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r, m
D = 0.25
D = 0.40
D = 1.47
D = 1.44
pmd CRCFault Roughness and MineralizationFault Roughness and Mineralization
Rationale:Bends and Jogs on faults are well-known to control syntectonichydrothermal mineralization; a method of quantifying fault irregularitymay reveal significant aspects of fault-related mineralization
L ~ e 1-D
L - length of fault, e -ruler dimension, D - Fractal Dimension
D increases with fault irregularity
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Pilgrim Fault, central segment
Mount Gordon fault, central segment
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Dc Regrn Error R ErrorMt Gordon 1.0091550 0.0007165 0.8911650 0.0009250Termite South 1.0067350 0.0024855 0.3873250 0.0010150Cloncurry Central-S 1.0057350 0.0007245 0.7579550 0.0013850Fountain Range 1.0053100 0.0006655 0.7746250 0.0007300Term C +N 1.0051450 0.0006290 0.7800300 0.0008050Pilgrim North 1.0045100 0.0007625 0.6771300 0.0006300Mt Remarkable 1.0037850 0.0006900 0.6515750 0.0005750Pilgrim Central 1.0020550 0.0016915 0.1897550 0.0000050Cloncurry N&S 1.0015379 0.0009302 0.2327500 0.0009621Pilgrim Central-South 1.0004000 0.0111190 0.1318550 0.0018100
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Weights of Evidence AnalysisWeights of Evidence Analysis
Knowledge vs Data driven approaches ( Bonham-Carter 1994)
There are several alternative models for the genesis of IOCG depositsThere is evidently considerable variation in IOCG deposit types
pmd CRCTargeting toolsTargeting tools
Neural network
Fuzzy logic
Weights of Evidence
Targets
Rock types
Structure
Worms
Geochemistry
Fractals
Geological history
Geophysics
pmd CRCBayesian probabilityBayesian probabilityThe Contrast C: ln( Odds of a deposit given the presence of...
Odds of a deposit given the absence of….)
C > 0 - Greater association than by chanceC = 0 - Chance associationC < 0 - Less association than by chance
The Posterior Probability PThe probability of a deposits occurring given thepresence of map patterns a, b, c, d….
pmd CRCMartin Higham – Developer and Software Support
MI-SDM (MapInfo Spatial Data Modeller) v1.50• Is an extension to MapInfo Professional which provides advancedspatial modelling with the goal of predicting the probability ofoccurrence of point objects.•Weights of Evidence, Fuzzy Logic and Neural Networks techniques can be used to model spatial patterns.
Kenex Knowledge Systems Ltd
Greg Partington – Mentoring in GIS Prospectivity
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Training RegionCloncurry – Selwyn(6 x 100K Sheets=17,285km2)
“Deposit” Training Pointsn = 29, inc. •Defined Resources•Historical Production of •> 1000 tonnes Coppercf. smaller prospects
pmd CRCRock TypeRock Type
Geol_15RockClass by RockClass
Basalt (497)Calc-silicate (1303)Cover (2381)Dolerite (1244)Gabbro (6)Gneiss (16)Granite (812)Limestone (81)Misc Vein (8)Pelitic schist (1058)Quartzite (646)Qz-hematite (39)Rhyolite (503)Sandstone (6)Siltstone/Shale (427)Slate (71)
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--80# Stream 80# Stream GeochemGeochemCopperCopper
Stream Builder v2.02Drainage Network and catchment analysis
Used the 9 Second DEMDigital Elevation Model of Australia v2.1250m Grid (Geoscience Australia).
Mean Cu (ppb) value assigned to catchment area (generally ≥ 2km2).
Anomalous threshold ≥ 53 ppb Cu.
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SSE FaultsSSE Faults
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Magnetic WormsMagnetic WormsDistance toDistance to
pmd CRCMajor magnetic Worm surfaces:Coloured by MaxW
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Magnetic WormsMagnetic WormsWmaxWmax
pmd CRCTarget MapTarget Map
WofE PosteriorProbability
0 to 0.0109 (62362)0.0109 to 0.0531 (17643)0.0531 to 0.1537 (7175)0.1537 to 0.3664 (3734)0.3664 to 0.9557 (1641)
15 Evidential Layers:
(1) Copper(2) Geology(3) Gravity (average)(4) Wmax of Magnetics(5) Medium & Major faults buffer(6) Wmax of Gravity(7) Gold(8) Felsic Intrusion buffer(9) Magnetics rtp 1vd(10) SSE faults buffer(11) Gravity distance worm(12) Magnetic distance worm(13) Magnetics rtp(14) Mafic buffers(15) SSE vs All Intersections buffers
pmd CRCTarget MapTarget Map
Looking under cover10 Evidential Layers:
(1) Gravity (average)(2) Magnetics rtp(3) Magnetics rtp 1vd(4) Medium & Major faults buffer(5) SSE faults buffer(6) SSE vs All Intersections buffer(7) Wmax of Magnetics(8) Wmax of Gravity(9) Magnetics distance worms(10) Gravity distance worms
WofE PosteriorProbability
0 to 0.00108 (33223)0.00108 to 0.00321 (17744)0.00321 to 0.00826 (8068)0.00826 to 0.02092 (3654)0.02092 to 0.1 (1300)
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Fuzzy Logic results
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New ToolsNew ToolsDeveloped through this project:•MI SDM fault intersection tool•MI SDM fault bend tool
In Development:•Advanced Fault Bend Tool•Fault Jog tool
•Use of worms for the first time in targeting
pmd CRCIntegrationIntegration•Analyses carried out for both Eastern and Western successions:
- Mechanical modeling, - Clustering of mineral deposits, - Effect of fault roughness
•Clear links developing with modeling and fluids projects
•3D model will be contiguous from East to Western Successions
•Deep Seismic section will be reprocessed and reinterpreted across the whole inlier•Close involvement with project A1
pmd CRCStudent projects in I2+3Student projects in I2+3Student Project Title Supervisor YearsLucas Marshal Breccias in the Mt isa Eastern Succession Nick Oliver 2000-2003 John Mc Lellan Numerical modelling in the Hammersly and Nick Oliver 2002-2005
Eastern Succession Mohammed Sayab Structural and metamorphic evolution of key Mike Rubenach 2002-2005
areas in the Eastern Fold Belt, Mount Isa InlierKris Butera Mafic Geochemistry of the Mt. Isa Eastern Mike Rubenach 2003-2006
SuccessionPiter Lepong Crustal Architecture of the Mt Isa Eastern
Succession as revealed by geophysical interpretation and inversion Tom Blenkinsop 2003-2006
NarakuNarakubatholithbatholith
CloncurryCloncurrywormworm
CloncurryCloncurryfaultfault
LevukaLevukashearshear
Ernest HenryErnest Henrymagnetic domainmagnetic domain
BuriedBuriedintrusion?intrusion?
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Mt Isa Seismic Section Mt Isa Seismic Section --Piter Piter leponglepong, , Bruce GolebyBruce Goleby1. Reprocessing 1. Reprocessing 2. Reinterpretation2. Reinterpretation
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MacCready et al.1998
pmd CRCI2+3 PlansI2+3 Plans33--D model of the Eastern SuccessionD model of the Eastern Succession
GocadGocad
•Interpretation and Integration of Seismic Data
•Construction of major geological surfaces
•Interpretation of Geological data, X sections
•Geophysical Inversion (Mike Barlow)
•Interpretation of Worms(input from Barry Murphy, Mike Etheridge)
pmd CRCOutlookOutlookOver one more year in the project
•Need to finalise and integrate results: especially earlyconfidential work that is now accessible (worms)
•Focus on the 3-D model and geological history for integration
•Targeting tools showing most potential direct application to industry
NB: All results are currently available on the Twiki site