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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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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