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(Spectral reflectance characteristics of typerocks from the Tennant Creek mineral) (field,) (Northern) (Territory,) (Australia) (Belinda Smith1, Jonathon Huntington2 and Andy Green31Northern Territory Geological Survey, Australia, 2HyLogging Systems Group, CSIRO NSW, Australia,3OTBC Pty Ltd, Sydney, Australia) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Aims) (of) (the) (Project) () (Digitise type example rocks from TennantCreek to produce an Atlas (reference library) Check mineralogy of type example rocks Assist geologists in becoming familiar withTennant Creek lithologiesEncourage consistency with geological loggingHighlight mineralogy changes within and between rock types with implications for increasing the understanding of regional geology) () () (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Previous) (Work) () (Company-specific Rock) (Boards) ((Emmerson) (Resources)) (Data) (Metallogenica) (Labelled rock names; mineralogy not always noted) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(TC8 Orebody) (NORTHERN TER) (Why) (Tennant) (Creek) (mineral5.5Moz Au;188,000t Cu) (field?) () (Traditional mineralisation hosted inironstone bodiesDistinct mineralogical zonation associated with Cu, Au, Bi mineralisationAlteration can be mapped using theHyLoggerCan cataloguing the spectral characteristics help answer questions on mineralogy changes associated with mineralisation?) () () () (RITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Previous) (Work) (Data Metallogenica Tennant Creek) (Seven plates of samples from Tennant CreekNone with spectral dataThirty-three plates with spectral data (graphs) fromAustraliaNo spectra (TSG or other format) suppliedNo TIR) (Samples 1 4: massive hematite, quartz>>magnetite ironstoneSamples 3, 4,9, 10: pyrite, chalcopyrite, bismuthinite stringers and disseminations Samples 11 17, 8: chlorite and quartz- chlorite alteration of schist; dolomitised brecciaSamples 18 20: metasiltstone to fine metagreywackeSamples 5 7: Jasper and hematitic shale) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Previous) (Work) (Olympic DamWith spectra on paper(not in digital format)) (VNIR and SWIRno TIR) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(WhatdidScan Emmerson rock board Samples already selected by) (we) (do?) () (core using HyLoggerTM 3-7Emmerson Resources) ( 934 spectra from 60 samplesImported into TSG; matched to TSA and also used RSM (Restricted Set of Minerals) for TIRAveraged spectra for type example rocks (n = 10) to use for comparison with similarly named rocksOnly averaged spectra that were relatively homogenousCreated Atlas of type example rocksCompare / Contrast spectra for similarly-named samples are there differences not seen visually?) () () () (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Tennant) (Creek) (Atlas) (Talc dolomite rockMag susc = 0.18 x10-3Talc with minor dolomite stringers) (VNIR / SWIRStrong talc response with diagnostic absorptions at 1392nm, with rippling features between 2077 and 2227nm) (TIRStrong talc response at 9445nm) (Dolomite RockMag Susc = 0.249x10-3Banded dolomite; originally described as dolomite quartz rock) (VNIR / SWIRDiagnostic 2320nm dolomite absorption.) (TIRDiagnostic dolomite responses;quartz absent) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Visually) (similar) (Tinto) (ironstone) (Tinto Magnetite Hematite; mag susc 1476 x10-3 SI unitsQuartz>white mica>magnetite>hematite) (Tinto Hematite rock; mag susc 300 x 10-3 SIunits) (Chlorite-hematite) (Distinctly different TIR spectral response; quartz-rich vs) (quartz-poor) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Unalteredsiltstone) (Sedimentssandstone) (siltstone) (sandstone) (VNIR-SWIR (380 2500nm)) (TIR (6000 15000nm)) (Muscovite and quartz-rich; minor chlorite.) (Sandstones have a higher quartz:) (white mica component than siltstones.Sandstone has ~2209nm AlOH feature (no variation)) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Chlorite) (alteration) (of) (Sediments) (Chlorite alteration often noted in sediments (potentialindicator of proximity to mineralisation?)Greenish tinged sediments chloritic sediments Compare with unaltered sediments; lower AlOH wavelength (~2198nm vs 2205 2209nm) Chlorite not apparent in SWIR) (AlOH absorptions(2198nm) but little/no chlorite (!)) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Domaining in the TIR using RSM(Restricted Set of Minerals)Modelling using the RSM (to minimisemixing non-uniqueness)Gives normalised average unmixing weights for minerals) () () () (Quartz-rich and quartz-poor ironstones withwhite mica common in quartz-rich; chlorite common in quartz-poor ironstoneschlorite altered sediments are chlorite-poor carbonates are quite uniform (11.2m)) () (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Findingsfrom) (HyLogging) (the) (Type) (Example) (Rocks) () (Ironstone rock types are quartz-rich or quartz-poor (notalways visually apparent)Chlorite alteration of sediments considered an important indicator of proximity to alteration associated with mineralisation.Greenish sediments are not necessarily chlorite-alteredSome changes in AlOH (white mica) composition noted in different sediments;) () () () (unaltered sediments 2205 - 2209nmchlorite-altered sediments are around 2198nm) () (Can the Library spectra be used to map changeswithin a logged rock type?) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(UsingtheLibrarySpectraGiganticProspectDD84GI1) (SWIR mainly aspectral) (hematite ironstone) (quartz hematite ironstone) (TIR mainly quartz) (VIS minor hematite, unknown) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(GiganticProspectDD84GI1) (Differentiating) (the) (ironstone) (libraryspectrum) (Quartz hematite) (Hematiteironstone) (Change in colour;Change in vis spectraMatched to similar spectra in libraryonly showed as unknown in TSAV) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(ConclusionsMislabelled mineral identification possibly need to standardise rock names when logging? (quartz dolomite; chlorite magnetite)Atlas could be used as a reference tool to standardise logging amongst TC geologists Need to add and validate more reference rocksLibrary spectra can highlight spectral differences in ironstones (rocks with few diagnostic TSA matches)) () () () (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Further) (Work) () (Add to the Library current Library hasonly TC8 mineralisation style rocks Recently identified different mineralisation style (shear-zone at Monitor / Goanna) West Warrego ironstones have ?epidoteAre there mappable changes in AlOH and chlorite composition related to mineralisation?) () (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(AcknowledgmentsRocky Osborne and Steve Russell; Emmerson Resources) (Martin Schodlok, CSIRO) (Ralph Bottrill and Richie Woolley; MRT) (Darren Bowbridge; NTGS) (NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(Northern Territory)NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs

(1) ()

(NORTHERN TERRITORY GEOLOGICAL SURVEYwww.minerals.nt.gov.au/ntgs)

(XRD) (Validation) () (Hematite Shale (RSDD004 180.18m)TSG shows hematite (Vis), minor chlorite; quartz + white mica (TIR)) (XRD indicates Quartz (50%-65%),Hematite (15%-25%), Fe-Chlorite (15%-25%), Mica (2%-5%), Siderite (chlorite>magnetite) (XRD: Fe-Chlorite (65%-80%), Magnetite(10%-15%), Pyrite (5%-10%), Chalcopyrite (2%-5%), Quartz (2%-5%), Arsenopyrite (