Igneous Intrusive Rocks of the Peake and Denison Ranges Within the Adelaide Geosyncline

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-GIÜEOIJS IìÜTFÈIJSIVE R.OCKS OF TI;IE PE.ã,KE .ã.¡ÜED DEDÜTSO¡Ü FI.ãNGES T'i'ITIT-¡Ü 1FI:[E .â'EDEI,.â'IDE GEOSYIÜCI,IìÜE

\/OLL[&fE I f = Figrures, Plates, Captions, Irfaps, Tabl.es and Appendicies.

By:

Robert Sinclair Irlorrison B.Sc. (Acadia, L98L) B.Sc. Hons. (Adelaide, 1982)

The Department of Geology and Geophysics The University of Adelaide South Australia.

This thesis is submitted as fulfilment of the requirements for the degree of Doctor of Philosophy in GeologY at The University of Adelaide South Australia.

February 298à, l-988. Resubmitted March 3L-t, 1989.

n¡ q: t c! Jr '"f.' .''ì r ll,r.-¡. lci- I\ \, \ , .' ì T.ã.BI,E OF COIÜTEIÜTS

Chapter One: Symopsis of tlre Adelaide Geoslmcline. Figure 1.1: General Geology of Èhe Adelaide Geosynclj-ne. Figure L.2= Structural Geology of the Adelaide Geosybcline. Figure l-.3: Stratigraphic Nomenclature for the Adelaide Geosyncline. Figure L.5.4: Cross-Section of Adelaidean Evaporite Deformation. Plate 1.1-: Diapiric Breccia. Plate L.2z Diapiric Breccia and Contacts. Table L.3.1: RepresentaÈive Geochemistry of Callanna Group Volcanics in the Adelaide Geosyncline. Table 1.3.2: Representative Geochemistry of Burra Group Volcanics in the Adelaide Geosyncline. Table 1.3.3: Representative Geochernistry of the Umberatana Group Volcanic Equivalents. Table l-. 3.5: Representative Geochemistry of Moralana Supergroup Volcanics in the Adelaide Geosyncline.

Chapter thtos Igmeous Intn¡sions of the Adelaide Geoslmcline: A Revies. Figure 2.Lz lgneous Rocks of the Adelaide Geosyncline and Kanmantoo Trough. Figure 2.7.1-'. Geology of a Northern Section in the willouran Ranges. Figure 2.8: Geology of the Margaret Inlier in the Peake and Denison Ranges. Table 2.Iz Geochemistry of Igneous Rocks in the Adel-aide Geosyncline. TabTe 2.3. 2z Geochemistry of the Anabama Granite. TabIe 2.52 Geochemistry of Early Adelaidean Volcanics in Diapirs. Table 2.7.2¿ Geochemistry of the Intrusive lgneous Rocks of the Arkaroola Region (aft,er Tea1e & Lottermoser, 1987). Table 2.82 GeochemisÈry of the Intrusive lgneous Rocks of the lrlillouran Ranges.

Chapter Tlrree: Field ceol.ogr1r and Petrography of tbe Intnrsives of the Pealce and Denison Ranges. Figure 3.2.L'. Classification of the Bungadillina Suite.

PIate 3 .1_: Igneous Intrusives of the Peake and Denison Ranges. PIate 3.22 Contact Relations of the Bungadillina Suite. Plate 3.3: Xenoliths within Èhe Bungadillina Suite. PIate 3.4: Dykes and Sills of the Bungadillina Suite. PIate 3.5: Cumulate and Assorted Features of the Bungadillina Suite. Location Maps for the Peake and Denison Ranges and Specific Map Areas wíthin the Peake and Denison Ranges. Map A: Northern Sector of the Northwestern Zone. Map A': Southern Sector for the Northwestern Zone. Map B: Northern Sector for the Northern Zone. Map B': Southern Sector for the Northern Zone. Map C: Central Zone. Map D: Central-East Zone. Map E: Southeastern Zone. Map F: South-CenÈra1 Zone (!{est). Map F': South-Central Zone (East). Map G: Southern Zone. Map H: Northeastern Zone. Map I: Southeastern Zone. Table 3.22 Percentage Modal Mineralogies of Representative Intrusives in the Peake and Deni son Ranges.

Chapter For¡r: lf,ineralogy of the Intnrsives of tlre Peake and Denison Ranges. PLate 4.Lz Mineralogy and Petrography - Textures. Plate 4.22 Mineralogy and PeÈrography - LiÈhologies. P]ate 4.32 Mineralogy and Petrography - Minerals. Plate 4.42 Mineralogy and Petrography - AlteraÈion. Figure 4.3: !{hole-Rock Geochernistry for the Bungadillina Suite. Figure 4.42 Mineral Chemistry for Garnets of the Bungadillina Suite. Figure 4.5.L¿ Pyroxene Classification for the Bungadillina Suite. Fígure 4.5.2r Pyroxene Zoning (core to rim) Chemical Variations. Figure 4.5.3: Sodium Contents of Pyroxenes of the Bungadillina SuiÈe. Figure 4.5.42 Detailed Classification and Chemical Zoning in Pyroxenes of the Bungadillina suite. Figure 4.5.5: Comparison of Who1e-Rock and Pyroxene Mg Numbers. Ficrure 4.5.62 Pvroxene Chemical Variations: 41, Mn and Fê¡c.oc.¡. Fifure 4.6.L2 AirphiboLe Classification for the' BungadilLina Suite. Figure 4.6.22 Àrnphibole Chemistry Variations for the Bungadillina Suite. Figure 4.6.3? Arnphibole Chemistry Variatj.ons for the Bungadillina Suite. Figure 4.6.42 Comparison of Àmphibole and Whole-Rock Mg Numbers. Figure 4.6.5: Arnphibole Chemistry Variations Between Different Plutonic Groups in the Bungadillina Suite. Figure 4.7 Biotite Chemistries and Classification. Figure 4.7 .22 Comparison of Biotite and lfho1e-Rock Mg Numbers. Figure 4.8 Plagioclase Variations in Zoned Crystals. Fígure 4.8 .22 AIkaIi Feldspar Variations in Zoned Crystals. Figure 4.8 âo Feldspar Ternary Diagrams. Figure 4.L0.1: Classification of Chlorite from the Bungadillina Suite. Table 4.8.L: Co-existing Feldspar Geothermometry.

Chapter Five: Geochenistry of the Intnrsive Rocks of Tlre Peake and Denison Rantgtes. Figure 5.2.r.. CLassification of the Bungadillina Suite. Figure 5.2.2. Classification of the Bungadillina Suite. Figure 5.3.1: hlhole-Rock Geochemistry of the Bungadillina Suite. Figure 5.3.22 hlhole-Rock Geochemistry of Èhe Bungadillina Suite. Figure 5.3. 3: hlhole-Rock Geochemistry of Èhe Bungadillina Suite. Figure 5.3 .4: !{hole-Rock Geochemistry for the Bungadillina Suite. Figure 5.3.5: Vühole-Rock Geochemistry for the Bungadillina Suite. Figure 5. 3 .6: I¡lhole-Rock Geochemistry for the Bungadillina Suite. Figure 5.4.1: Who1e-Rock Geochemistry of the Bungadillina Suite. Figure 5.4.22 Whole-Rock Geochemistry of the Bungadillina Suite. Figure 5.6.1: Rubidiun - Strontium Whole-Rock Isotopes of the BungadíIlina Suite. Figure 5.7 .1-z Comparative Trace-Element Diagrams lilithin the Bungadillina Suite. Figure 5.7 .22 Comparative Trace-Element Diagrams Vf,íthin the Bungadillina Suite, and with Average ttType" Granites from the Lachlan Fold BeIt. Table 5.1: Summary of the Geochemistry of the Intrusives of the Peake and Denison Ranges. Table 5.6.1- Rb-Sr Isotopes for Intrusives of the Peake and Denison Ranges. TabLe 5.6.22 Carbon and Oxygen fsotope Geochemistry for Carbonates of the Peake and Denison Ranges. chapter six: comparative Geochenistrlz of tlre rntn¡sives of tl¡e Pealse anO Denison Ranges with lgmeous Roclss of t.he Adelaide Geoslmcline, Lachlan FoId BeIt and Gasler Craton- Figure 6.2.L2 Comparative Whole-Rock Geoche¡nistry for Igneous Rocks of the Adelaide Geosyncline, Kanmantoo Trough and tttypett Granites. Figure 6.2.22 Comparative Whole-Rock Geochemistry for lgneous Rocks of the Adelaide Geosyncline, Kanmantoo Trough and tttypett Granites. Figure 6.2.32 Comparative l{hole-Rock Geochemistry for lgneous Rocks of the Àdelaide Geosyncline, Kanmantoo Trough and tttypett Granites. Figure 6.3.1: Comparative Whole-Rock Geochemistry for lgneous Rocks of the Adelaide Geosyncline, Kanmantoo Trough and tttypet' Granites. Figure 6.3.22 Comparative !{hole-Rock Geochemistry for lgneous Rocks of the Adelaide Geosyncline, Kanmantoo Trough and t'typett Granites. Figure 6.3.3: Comparative Whole-Rock Geochemistry for Igneous Rocks of the Adelaide Geosyncline, Kanmantoo Trough and tttypett Granites. Figure 6.5: Comparative Geochemistry: Tectonic Discrinínation Diagrams. Figure 6.6.L2 Geochemistry of the Anabama Granite. Figure 6.6.22 Geochemistry of the Anabama Granite. Figure 6.72 Comparative Trace Element Diagrans.

Chapter Seven: Petrogenesis of Intnrsives of tlre Peake and Denison Ranges. Figure 7.4.L'. Silica Saturation versus the Differentiation Index (D.r. ). Figure 7.4.22 RL - R2 Tectonic Discri¡nination Diagram. Figure 7 .62 Least-Squares Fractionation Modelling. Figure 7.72 Trace Element Fractionation Modelling. Figure 7.LO: Geochemical and Tectonic Classification of the Bungadillina Suit,e. Figure 7.tL: Schematic Cross-Section of the Mantle and Crust for The Bungadillina Suite. Figure 7.J,2: Schematic Cross-Section for Bungaditlina Suite Emplacement in Adelaidean Strata. Table 7.72 Partition Coefficients for Trace Elenent ModelIing of the Bungadillina Suite.

Chapter Eight: Inplications of Igmeous Activíty in the Peake and Denison Ranges witlrin the Adelaide Geoslmcline. Tab1e 8.4: Igneous Activity in the Adelaide Geosyncline.

Apoendicies l,Iicrofiche Appendicies: Appendies A-L (inctusive) . Appendix A: Petrographic SummarY - Intrusives of the Peake and Deníson Ranges Appendix B: Major and Trace Element Geochemistry of the Intrusives of the Peake and Denison Ranges. Appendix BL: Trace Element Analyes of 7OO0 Series Intrusives of the Peake and Denison Ranges by Comlab Pty. Ltd- Àppendicies C - L: Electron Microprobe Analyses of the Intrusives of the Peake and Denison Ranges. C: Clinopyroxenes. H: Chlorite. D: Amphiboles. f: Epidote. E: AIkaIi Feldspar. J: Garnet. F: Plagioclase Feldspar. K: Oxides. G: Biotite. L: Sphene. Other Appendici.es: Appendix M: Least-Squares Mass Balance Ca1culations. Appendix N: (Preprint) Morrison R.S. & Foden J.D. , L989: A zoned Middle Cambrian pluton in the Pëake and Denison Ranges, South Australia. In: (J. Jago: ed. ) Brian Daly Memorial Volume. GeoL. Soc. AustraTìa. Äppendix O: (Preprint) Foden J.D., Turner S. & Morrison R.S., L989: Tectonic implications of Delamerian magmatism in South Australia and htestern Victoria. In: (J. Jago: ed.) Brian DaIy Memorial Volume. GeoL. Soc. Australìa. Appendix P: (Copy) Morrison R.S., 1986: Early Pal-aeozoic plutonism in the Peake and Denison Ranges, South Austral-ia. Geo7. Soc Aust. Abst. 15.

Figure 1.1. General Geology of the Adelaide Geosyncline. Sinptified map of the Adelaide Geosyncline showing rnajor chronostratigraphið uníts, including zones of diapiric breccia, of Àdelaidean añd óarnbrian age (aft,er Forbes, 1983). The ínliers of the peake and Denison Ranges are depicted in the top left of the maP: Note elongate north-south ãones which correspond to the major Delamerian fold pattern (c.f. Fig. L.2). trr\ TEAAE ANU |DENiSON ßÁâ,GES STRUCTURAL GEOLOGY OF THE s WILLOURAN ADELAIDE GEOSYNCLINE REGION BI DENISOrl F./¡,ì,GEs II{LIER 'à k MT. BABBAGE II{LIER o À a \ M1. PA¡TITER ¡NLIER 3l

F

n LAKE ". .'slu.Airr..:...: FROßIE SHELF

INDERS

w ILLY AMA INLIE R + 2 - o + I m + 32000' + I +

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34000'

SPEI'íCEF GU¿F sCA LE 1 o o t 0 I km HOUGHTON INLIER LOCATION MAP

ADELA'DE I I N.T. I

d GULF OF a-L.D. w.A. a ST. V'NCENî u s.Á"

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KATMANToo.fFo.u GH MYPONGA INLIER ê

t vtc. Itrzood lsgo@' AFTEF RIITLAilD .t tl lqnl Þcu /ñuu rôôt Fignrre L.2. Structural Geology of the Adelaide Geosyncline. Simplified structural map of the Adetaide Geosycline and Kanmantoo Trough depicting major structural zones (after Rutland et ãI., L981). aléo aeþictea are the rnajor Archaean to Middle Proterozoic crystalline basement cratons and inliers surrounding and within the AdèIaíde Geosyncline. Note insert map of the Peake and Denison Ranges at top left oi map. The Margaret Inlier is located innediately south of thè Denison tnlier. No structural zone has been designated for the peake and Deníson RangTes. Note also that the Outer FTeurieu Arc encompasses and lies to the southeast, of the Kanmantoo Trough. Fl¡urc 1.3: Chrono¡tretlgrephlc end Mefor Lltho¡tretlgrephlc Unlt¡ ln thc Adcl¡ldc Gcoryncllno.

ìf{or Lltlo¡tretlgelllc Urltr () Lake Frome Group t{ (, o o C Middte o. N N a f lllrrealpa Llnestone Kanmantoo o o Cambr ian (I'o G o L CL Bllly Creek Fornatlon Group u¡ o c'ol - a ¡ 546 t'b a -{L(I'o Hawker Group NormanvÍ Ile a () EarIy LO. À- o. of Group Cambr Ían 2u) Uratanna Fornatlon 57O l,lt \NN l,þJor Hlatus o l,lf lpena Group Mar i noan f o 72o-75o ¡'tr l- Sturtian c Ol o t- (r, o o ) Umberatana Group U)

- (, lhJor Hlatus C o Burra Group ¡{ o a Torrens i an J É N O o o o o at L - L c Ol o a ¡- o a ¡- o Emeroo Subgroup u¡ o o L o_ Ê, L E at a À o. U) O 8O0 Ma = tJiIIouran Cal lanna Curdímurka Sub ro Group Arkaroola Subgroup

42OO Ma lûJor Unconforntty Pre-AdelaÍdean Pre-Adelaidean

After PreÍss (7987) Figure 1.3. Stratigraphic nornenclature for the Adelaide Geosyncline. Presentation of major chronostratigraphic and lithostratigraphic unit,s for the Adelaidean and Cambrian sequences in the Adelaide Geosyncline (after Preiss I 1987). ^AIso presented are approximated ages for deposition of some of the units. trÍguno L "5 "42 Sehonnat f e Roprosontat lon oll Fno-Dollannor ûan Evapon i to DÍapÍ n -llndueod Adollaldoam Dollonunatlom ûur tho Foako amd DoorÍs@n Raolgos"

unb.ratana and younger sodlnents; atI Ylth a hlgñ porc-Yatcr contcnt -----/\\.

Klnk foldlng of Burra Oroup Cap Rock. scdlncnts caused by tatcret colprcsslon fron cvaporltc

Intru

Lovêr Câllanna Oroup: Cadlarcena Volcanlcs, Yotnghusband Cong.. Coontnaree Dolo¡rlte, Figure L.5.4 . Cross-section of Àdelaidean Evaporite Deformation. Diagramatic cross-section representation of Adelaidean strata during (pre-Delamerian) evaporite diapirisn. Al-though the diagrarn is highly stylized, the rnajor features depicted are the types of aeãormatión which may accompany diapirism. The severity of deformation decreases with distance ahray from the rising diapir. The amount of exhumed pre-evaporite maÈerial incorporated into the rising diapir, relaÈive to the amount of evaporite material itself, is unknown.

Plate 1.L: DiapÍric Breccia.

Top Lett: Tntense kink folding in Burra Group sediments. Hinge orientation generally east-west. Located at Edith Spring. Hammer at bottom left of photograph is approximately 1m in length. This style of folding is considered to have been caused by evaporite diaplrism (stage 1- in formation of diapiric breccia). Bottom Left; Close up of kink folding in Burra Group sediments. Located at Edith Spring. Note brittLe deformation or buckling, causing prominent fracture cleavage along fold hinges (stagg 1 in diapiric Ëreccia forrnation). Bungadiltina suite (albitite?) intruding along fold hinge indicating intrusion postdates buckling. Hammer handle is o.42rn in length. Top Right: Juxtaposed blocks of Burra Group siltstone which have fo-rmed- in respónse to further large-scale buckling of strata during diapir emplacement (stage 2 in formation of diapiric breccia). Note very slight displaceneñt of blocks causing little deformation or fomãtion óf natrix along block contacts. Note also Bungadillina suite intruding aÌong fold hinge to the left of the photograph. SmaIIer plutons are córnmonly fouñA intruding distorted/contorted strata in lnis stage of diapiric breccia development. Hammer handle is lm in length. locátion: Northwest Map F, adjacent sample locaLity 195241. Right centre: Largely monolithologic diapiric breccia composed of gulra croup interbedáed shal-e and carbonate surrounding a 2m carbonate clast (Skilloqal-ee dolomite?) . Very angular clast-supported.breccia with ninor na{,rix suggests linited transportation (stage 3 in breccia development). Represeñts inÈermediate stage between cornplete breccia mobiliZation and separation of clasts along kink fol-d hinges. Location: Edith Spring Creek; east of sample locality l757ll (Map I). Bottom Right: To far left of photograph is remobilized diapiric breccia 1Átage 4 or 5 in development of diapiric breccia). This material.is ieadily recognized by rounded Adelaidean sediment clasts supported by a finèr grained (sandy and sílty) natrix cemented by carbonate. immediately right of this material is the light-coloured carbonate-hosted 'rshale sñeathtt or O.5m wide diapir rnargin shear zone oriented approximately top to bottom of photograph. These zones are separated Ëi a dashed-Iinã. This shear zone is commonly flow-lineated parallel to the contact with Èhe surrounding strata, and lacks the äbundant larger clasts of the aforemenÈioned diapiric breccia. Immediatety ábove 1-rn long hammer handle is 0.1-0.2m wide zone of (stage 5) êarbonate-hosted breccia intruding the sub-horizontal strata ifeft to right). These zones are separated by a solid line. Below Èammer to tñe bottorn right of the photograph are buckled (kink folding) Burra Group beás, representing stage 1 in diapiric breccia development. Location: Edith Spring Creek; easÈ of L757Ll (Map I). ;it^

r) 'i'

I I

\ Plate L.2= Diapiric Breccia and Contacts.

Top Left: Remobilized diapiric breccia (stage 5) contact wi relativety undisturbed Burra Group siltstone and quartzite. Breccia is composed largely of coarsely crystalline carbonate with clasts seen immediately above hammer. Note flow-lineation of carbonate-hosted breccia accompanied by marginal deformation of host strata indicating direction of flow (right to left). Length of hammer handle is 0.42n in Iength. Location: Edith Spríng Creek, east of 17571,1 (Map I). Last viewed in August, L984; subsequently covered by flood deposits (August, 1986). Bottom Left: Remobilized (stage 4 or 5) diapiric breccia showing variety of rounded Adelaídean sediment clasts in a finer-grained carbonate-cemented groundmass. Buckled Burra Group beds are to the immediate foreground. Note the contact lacks a shear zone. Length of hammer handle is approximately 1m. LocatÍon: Edith Spring Creeki east of l757Ll (Map I). Top Ríght: Albítite (Bungadillína suite) clast in diapiric breccj-a (stage 4). Location: East of 1751,61 (easterm Map E). Mídd7e Riqhti A monzonite pluton contact with folded Burra Group shaLe and interbedded carbonate. Note lack of contact meÈamorphism or significant alteration. AIso note passive intrusion of the monzonite body. If the intrusion had been forceful, Èhen the crest of the fold to the left of the photograph would'more tikely be oriented away from the pluton margin and not towards it. Slight buckling in strata may indicates stage l- in formation of diapiric breccia. Location: Adjacent 17567 I (MaP F'). Bottom Right.. Biotite lanprophyre dyke l-Scm wide intruding diapiric breccia (stage 3: clast-supported). Intrusive relations indicate dyke postdates brecciation, but the relationship between this style of breccia and Delamerían tectonism remains uncertain. Location: Adjacent l757Ll (MaP I). Table 1.3.l-: ve of Callanna Volcanics the Geosvnc lfooltana Volcanics (16) Noranda Volcanics (8) rrt. ? Range llean Range l,[ean Sioz 43.52 52.92 47.97 46-90 51.50 49.55 TiO= 1. 03 L.7A L.44 2 -06 2.42 2.30 AIzOg 11.43 14.93 13.81 t2.20 13.80 12 .85 FezO= 1.99 2.93 2.54 13.10 19.10 t_5.30 FeO 7.97 LT.74 LO.L7 I,lnO o. 09 o.75 o.32 o. 05 o. 09 o. 07 Drgo L.79 13.66 8.52 4.98 7.35 6.22 CaO 1.48 9.42 5.27 1.99 6.55 4.94 NazO L.87 5.95 3.20 4.42 5.95 5.11 KzO o.56 3.62 1.91 o.34 1.88 0.99 PzOs o.10 o.16 o.L2 o.13 o.22 o.L7 L.O.I. 2.O3 8. 05 4.39 L.7L 2.44 2.24 TotaI 99.L9 -t-OO.14 99.66 99.47 -l-OO.28 99.74 Trace Elements Sc 2A 47 4I v 205 - 374 313 380 Cr 193 372 257 e;- ino 109 Ni 50 100 76 Rb 24- r22 66 I 70 29 Sr 69 195 1t_5 60 360 185 Y t-6 30 3 20 40 33 Zr 56 Lo6 80 r20 t70 L49 Nb 3 6 4 6 L4 11 Ba 94 1034 343 60 120 88 Ce 19- 33 26 <20 -60 29 Nd 5-L2 9

IÍooltana Volcanics from D. Hilyard' 1986. t{oranda Volcanics from S.A.D.Itl.E. 6438 RS445-452 (Farrand & Bracket numbers (#) refer to number of analyses- Table L.3.1 continued Re sentative Geochemis of Callanna VoIc CS Geos rne Cadlareena Volcanics (8) Gairdner Dyke Swarm (2O) wt. ? Range Mean Range Mean Sioz 46.57 66.00 50.53 48.49 55. L3 52.2L TiOz o.70 L.92 L.49 L.47 2.90 1.98 AlzOs LL.93 1,4 .67 L3.38 1-2 .66 L6.66 1,4.87 FezOc 8.39 l_0.90 9.89 FeO L.40 3 .60 2.23 7.56 16.00 L2.26 MnO 0.0L o.24 o. L3 o.1,2 L.1,4 o.32 Mgo o .29 1l_.53 6 .69 2.46 8.54 5 .82 CaO o .87 1,L.99 7.39 3.94 16.5L 9. L9 NazO o.23 4.45 2.98 L.75 3.73 2.41, KzO 0.35 ]-2.29 2 .66 o.07 2.98 o.78 PzOs 0. t_l_ 0.L8 0. l_5 o.12 0.56 o.27 L.O.I. 0.60 3 .46 2.49 0.30 7.90 2.50 TotaI 96.93 -rO2.33 1_00.01_ 99.98 -1_00.02 99.99 Trace Elements (ppn)

Sc 54 55 55 L0 42 3L v L20 600 330 t_03 465 330 Cr 80 520 308 l_0 205 93 Ni l-o 320 L43 6 1,54 82 Rb 1_ l_ 280 83 2 93 22 Sr 34 260 L49 t_08 538 2r6 Y 28 30 29 I7 3L9 47 Zr 75 1,25 97 83 413 L57 Nb 7 9 I 4 27 1- 1- Ba 70 3 950 899 31_ 1-288 2L2 Ce 29 36 33 L9 LL4 40 Nd 9 I7 l_3

Cadlareena VoLcanics from Ambrose et a7| 1-98L. Gairdner Dyke Swarm and Port Pirie Volcanics from Woodget, t987. Bracket numbers (#) refer to number of analyses. Table 1.3.1 continued ve of Callanna Ine. Beda Volcanics (16) Depot Creek Volcanics (6) rârt. ? Range llean Range llean sio2 44 .20 51.40 47.55 42. 50 52.94 49.66 TiOz 1 .51 4.39 2.56 1. 59 t_.91 L -75 ÀIzOo 10 .30 14.80 13. 04 L4. 37 - 1-6.7r L5.L2 FezOg 5 .59 8.94 7.24 FeO 3 .50 a.97 5.95 10.84 18.89 13.16 llnO o .11 o.62 o.30 o. 06 o.30 o.15 l{go 3 .39 - t-o.30 7.50 7.70 13.77 LO.26 CaO 1 .74 7.06 4.6L o. 09 o .44 4.43 NazO t_ .66 6.42 3.83 o.L2 4 .07 2.to KzO

Sc 25 60 38 39- 52 44 v 220 440 387 280 432 370 Cr 30 225 119 r62 254 2L6 Ni 40 105 70 LO7 L57 L22 Rb 4 r.30 57 10 119 55 Sr 20 2to a7 24 320 L32 Y 24 42 31 17 29 24 Zr 60 320 165 79 106 92 Nb I2 24 16 4 L2 7 BA <1_O 1150 269 L34 t209 408 Ce 30 70 43 L7 34 26 Nd I L4 10

Beda Volcanics from S.A.D.IIi.E. 6334 RS94-99, 6434 RS1-lO- Depot Creek Volcanics from Woodget, 1-9f37. Bracket numbers (#) refer to number of analyses. Table I.3 .22 esentative Geochemis of Burra Volcanics n the Adel-a Geosvnc ne. Port Pirie Volcanics (e) wt. å Range Mean SiOz 42.44 s1 .58 47.80 liOz t.69 3.88 2.58 AIzOs 12.02 l_8.60 1,4 .85 FezOs FeO l_5.9L 23 L2 t_8.31_ MnO 0.02 o 51 0.19 Mgo 0.88 7 93 4.94 CaO o.22 6 97 3 .89 NazO 0.1_9 2 68 L.43 KzO o.74 l_ t_ 79 5.44 PzOs o .20 0 31_ o.24 L.O. r. L.70 8 40 3.92 Total 98 .46 -1-00 . 0l- 99 .67 Trace Elements (ppm)

Sc 36 64 49 V 349 Ll_5L 5L4 Cr 42 352 l_11_ Ni 36 148 74 Rb L9 438 2L2 Sr L2 t_3 9 68 Y Zr Nb 820 L4 Ba 90 41,5 25L CE Nd

Port Pirie Volcanics from ú{oodget | L987. Bracket numbers (#) refer Èo number of analyses. Table 1.3.3: tive Geocheni of the Umberatana va en

lfantapella Volcanics rrt. ? RS-l1 RS-12 RS-13 RS-286 sio2 43.10 43.20 45.80 42.40 TiO= 3.r2 2.52 2.96 3.22 Al=Oo 14.80 L1.80 14.80 16.30 FezOa 14.20 12.80 3.94 10 .80 FeO lInO o.19 o.19 0.36 o.26 r{go 4.94 6.95 1.18 3.62 CaO 7.75 9.40 L3.20 10.50 NazO 2.L2 L.74 4 -26 3.26 KaO 1.45 o.63 2.LA 1. L8 o.44 o.38 o.46 E:8:'. 8.90 10.90 9. OO Total 1O1.O1 1õõ-T 101. OO Trace Elements (ppn)

Sc v 26f) 220 230 270 Cr 50 50 50 40 Ni 100 70 60 1l_o Rb 25 4 62 22 Sr 270 410 240 320 Y 40 40 40 40 Zr 270 240 260 290 Nb 20 18 22 22 Ba 380 180 440 410 Ce 70 40 75 60 Nd

Warburton Basin Volcanics from Gatehouse, 1986. Bracket numbers (#) refer to number of analyses. Table 1.3.5: tative Geochenis of l,loralana Vo]-can cs n the Ade a Geosrrncl ne.

Truro Volcanics Irfarburton Basin Volcanics ( 10 ) rÉ-A 189664 189665 189666 Range Uean sio2 63.60 62.40 47 .40 57.50 - 7r.40 65.94 TiO2 2.35 l_.34 1.38 o.35 0.85 o.52 AlzOg 16.40 18.30 16.30 ]-2-ao 18.20 L4.96 FezOa 3.95 2.L5 10.70 o .68 4.15 2-53 FeO o .36 - 3.11 1.40 llno o. 03 o.o2 o.16 o .02 o.10 o.o7 l{go t.20 t-.84 5.55 o .58 2. 50 1.14 CaO 3. 05 o.84 t-o.90 o .13 3. 73 r.67 NaeO 4.20 8. 05 2.80 o .12 4. 54 2.35 KaO 0.96 1.53 L.7L 3 .74 10. 90 5 -46 [:8:r. 9: å3 9:98 9:?8 I :19 : 9: 71 9: tt Total 9A.52 9A.75 98.86 97.47 99.38 9a.24 Trace Elenents (PPn)

SC 10 4 24 v 100 65 80 50 L30 73 Cr 320 100 L20 <5 70 l_5 Ni 20 <4 t4 <2 15 4 Rb 30 80 85 120 290 t_95 Sr 470 330 300 46 230 L22 Y 6 24 20 18 38 24 Zr 190 360 85 160 300 209 Nb 55 100 L2 <4 I4 7 BA 210 105 155 200 2r50 774 Ce 45 95 67 Nd

Truro Volcanics from CSR Ltd. ExpI. Lic.97A nCoonalplm Arearr Open Envelope 4719, South Australia Department of l'tines and Energy. l{arburton Basin Volcanics from Gatehouse, 1986. Bracket numbers (#) refer to number of analyses. Table 1.3.5 continued tive Geochemi of l,loralana Vo

Arrowie Basin Volcanics wt.. * RS-291 RS-292 SiOz 76.rO 59.90 TiOz o.19 o.14 A1=Oa 9.95 l_2.30 FezOo r.32 1. 04 FeO llnO o. 02 o. 04 Mgo o.36 o.28 CaO 2.L8 10.90 NazO o.r7 7.35 KzO a.25 o. 09 E:8:r. 1: Qã 8:9ã Total 100. 01 94.79 Trace Elenents (pPtn)

SC v40 30 Cr 20 10 Ni 30 30 Rb 90 <2 Sr 40 40 Y30 30 Zr 18O 230 Nb 10 30 Ba 1340 60 Ce 70 65 Nd Arrowie Volcanics from S.À.D.!I.E. 6635 RS291-2 (.Amdel Rept= bk. AC.24AO/A5, 198s). Bracket numbers (#) refer to number of analyses- PEA'

@ 0 + l oi^rltÎÊt

@ \ ffi vor.c^r,cs oreenrc liEccrA SPENCER GULF I ) 0 æ ['TT r^*rrerroo o'oup a@ D .\ e LOCAI|O¡ HA? ADELA'OE to H.T. i oLo. o --J___.t o EULF OF a sL vtncENÍ tr v.A" s.Á-

o âr.s.Y,

tI Ylc. Fignrre 2.L. Igneous Rocks of the Adelaide Geosyncline and Kanmantoo Trough. Símplified map of the Adelaide Geosyncline and KanmanÈoo Trough showing locations for major volcanic and plutonic rocks. Highlighted are the locations of kímberlites and major zones of diapiric breccia Èhat contain igneous rocks. Not shown are the igneous rocks of the Padthaway Ridge (southeasÈ of the Kanmantoo Trough). These can be found in-Foden et a7. (l-989). No aÈtempt has been made in this diagram to chronologically sub-divide the igneous units. z þ o00u0 ootorotrl alDos Ê þ sctuDclo^ I

3- slueu¡tpes z ¡-v dnolg DuuDllDC sluau¡tPes Ê þ dno:g DJJng ô DrccaJq cr.ldorg þ

Ê ellrorp 'ctlllqM V Ê z o.rggo0 (Dfey¡) Êì þ +uaujrpes lu¡ceu c

¿ þ e

c c 0 Ê Ê

¿ þ Ê Þ z ) ¡¡ôu DU uD¡nollrn c Ê

r- zo93 a et I crr '¿oeg s

ql!.tl{r.lu . \ s ¿ Derv dD¡l 6- a ftof - I c c Figure 2.7 .L. Geology of a Northern Section in the Willouran Ranges. Geologì-cal sketch map of the igneous and sedimenÈary rocks in the northern lrlillouran Ranges, detailing the locations for samples in table 2.7. Most of the plutonic bodies displayed intrusive contact relations with surrounding sediment. Hohrever, the contact relation of the largest gabbroic body [8520] was covered by recent sediment. Map compiled from personal field data, air photographs, Preiss (1'987) and Murrell (L977). Figure 2.A . Geology of the Margaret Inlier in the Peake and Denison Ranges. PorÈion of the map produced by Ambrose, F]int & Webb (l-981) showing the geology of the central and northern sections of the Margarèt Inlier. This area is the host to the majority of the Bungadillina suite (re. Bungadí7Lina l4onzonite) in the Peake and Denison Ranges. fncluded with the map is the reference key. CEOLOCICAL SURVEY OF SOUTH AUSTRALIA DEPARTMENT OF MINES AND ENERCY

05'

MESOZOIC and CAINOZOIC sediments.

:

z monzonites and syenites, minor diorites. Albitites. Radiometric age c.470-500 Ma À o (Ki Ar-hblde & bio). ô l0' É E o I Diapiric breccia with carbonate matrix. À z É l I o o U É Unnamed siltstone: Red-brown silty shales, grey-green shales, silty dolo z Phr o and grey-yellow dol omites É J óI mites, fine-grained sandstones thin J l E G f t À THORA DOLOMITE: Grey-green and brown dolomites, minor siltstones; o l large festoon surfaces and algal bedding. (,É o IÉ É TAPLEY HILL FORMATION: Laminated grey-green silty shales and silty z Pfl f sandy dolomites, :4 dolomites; basal, thin F É l Unnamed sandstone: Quartzitic sandstones, arkoses, argillaceous sand- t- stonesi red porphyry granules and large scale cross-bedding; minor m icroco n g lo me rates, a t t CALTHORINNA TILLITE: Mixtites; conglomeratic dolomites, laminated ) pale green shales, gritty sandstones, arkoses and quartzites. l5' D i sco nfo rm ity

KALACHALPA FORMATION: Grey-green and brown siltstones and shales, gritty sandstones and quartzites, conglomeratic dolomites, stroma- tolitic dólorñites, oolitic sediments, black cherts; quarlzites and shales at the 1op.

Unnamed unit: Gritty quartzìtic sandstones, stromatolitic dolomites, con- glomeratic dolomites, magnesite conglomerates, black and minor red ðherts, grey shales and siltstones; mudcracks; ripplemarks, cross-bedding.

z SKILLOGALEE DOLOMITE: Basal member comprises quartzites, sand- z E stones, sil le member É Ê dolomites, É É comprises o f minor mag member is l- a predomina ;stromato- lites occur MOUNT MARGARET QUARTZITE: White orthoquartzites, slaty quartzitic 20' sandstones, dark grey sandy siltstones, green-grey silty shales' minor dolomitic sillstoneõ near base; thick orlhoquartzites at top; clay galls' z ripplemarks, cross-bedding. FOUNTAIN SPRING BEDS: Laminated grey dolomit¡c siltstones and u interbedded thick grey quartzites with clay gall laminations, green-grey o (salt grey silty dolomites and a lew quartzites a silty shales casts); minor J near base. U ô Unnamed siltstone: Laminated grey pyritic dolomitic siltstones, green shales, pyritic silty dolomites, fine-grained sandstones, minor grey I quartzites j ripplemarks, cross-laminations, salt casts Undifferentiated blocks (in diapirs and faulted sequences): Sequences I .t_ Y sllty shale ¡nterbeds; arkoses, pebbly dolomites, -purple and grey silty o shales near top; ripplemarks, mudcracks, cross-l aminat¡ons, flute casts N and salt casts. z g z DUFF CREEK BEDS: Laminated olive green silty shales and thin arkose q pale grey yellow É interbeds; flaggy buff weathering and dolomites, minor 25', É dark grey dolomites, flaggy dolomitic siltstones; laminated pyr¡tic fine- o t- grained sandstones; minor quartzitic sandstones; mudcracks, ripplemarks, É clay galls and cross-bedding are common; horizons with abundant salt o casts and gypsum casts; algal Iaminations. z Ê f Nl LPINNA BEDS : Fine-grained cross-laminated sandstones, ripplemarked oJ quartzites (salt casts), grey-green silty shales, minor grey silty dolomites tJ I and greenish arkoses; mudcracks, ripplemarks and salt casts are common. WAR LOAN BEDS:Blue-grey shales and siltstones; dark grey silty dolo- I mites, greenish feldspathic sandstones and arkoses. ROCKWATER BEDS: Blue-grey and black cherts, black dolomitic lime- I stones with black silty shales and grey quartzites. CADLAREENA VOLCANICS: Vesicular basalts and altered doleritesì minor andes¡tes, dacites and rhyolites;tuffs, lapilli luffs; minor lenticular ô z u reddish mudstones and quartzites with red shale interbeds near base and o top. É l o COOMINAREE DOLOMITE: Pale brown and pink stromatolitic dolomites; J gr¡tty 30' tJ dolomites, YOUNGHUSBAND CONGLOMERATE: Basal quartzitic breccias red- purple shales and sandstones at top.

9 o N o Dior¡te and dolerite dykes. Éu //z F o É È granites. U WIRRIECURRIE GRANITE: Coarse-grained, porphyritic Radio J metric age 1648+21 Ma (Rb/Sr-T.R.); 519-1087 Ma (K/Ar-bio), ô ;ô Unnamed metamorphics: Grey quartzites, epidote quartzites, arenaceous schists, rare clinopyroxene granulites; minor amphibolites and pegmatites.

9 BALTUCOODNA QUARTZITE: Greyish-white quartzites and basalts, o amphibolites, minor quartz + muscovite schists, bluish-g rey phy llites, N sillimanite gnelsses, plagioclase a hornblende + epidote calc-sil¡ cates o and calcite marble. 35' uÉ F Unnamed schists: Quartz + muscovite schists, quartz + chlorite phyllites, o É rare sandstone lenses; minor graded bedding and cross-bedding. È J Tl DNAMURKUNA VOLCANICS : Flow-banded porphyritic rhyolites, amyg- É daloidal basalts, rare epidosites and marbles. u Unnamed metamorphics: Quartz + biotite schists, often garnetiferous; muscovite schists, quartz + biotite + feldspar gneisses, white quartzites, rare epidote quartzites; pegmatites and diorite sills common; local migma- tites. Radiometric age 1460-1520 Ma (K/Ar-hblde).

MAIN ROAD,.. GEOLOGICAL BOUNDARY SECONDARY ROAD, OBSERVED .. l::i:, TRACK INFERRED, RAILWAY FAULT WITH SIATION OBSERVED .,. 40, WITH SIDING INFERRED, ... TRIANGULATION STATION Â FOLD IDENTIFIED POINT. ANTICLINAL,,.,, HOMESTEAD, 8UILDING. , ., SYNCLINAL,, ---J---+- Y4RD.,,,,. oYd BEDDING EPHEMERAL STREAM INCLINED ,< as 'FOLIATION WATERHOLE -W.H. INCLINED DAM ..,... VERTICAL I AB BORE, WELL GEOLOGICAL BLOCK DIAGRAM SAND DUNES ,,. TYPE SECTION Þl< tè GEOCHRONOLOGY SAMPLE SITE * tvilNE...... 45' Cu COPPER TECTONIC BRECCIA. . LOCALITY

t290 3 133" t350 1370 t390 4 -.-.-._t I

I ¡ Oodnada I I I 2Bo 280 I

A 300 4

32"

so,, 34" " "*^-4ù PT

36" 36" o /t/

Mt. Gam

129" l3l t33" t350 137" 1390 l4l' )

SCALE l:150000

0 5 t0 l5 5,:

++

I )(J o

i, o (_) + + ü ñ + þ E {ìì, ii 0 tta û j a2 ¡-{;) l':r lir'.--;

a) (, - o Table 2.Lz Geochemis t.rv ofI crneous Rocks in the Adel"aide Geosyncline.

Ref Ä B D E F G H I sio2 49.32 49 .29 47.63 49 .29 49.09 48.46 49 .40 47.75 45.52 TiO= L.96 2 .1,7 o.77 1. Ol_ l_.38 1.53 L.02 L .65 1,.46 Al zO 3 21, . 03 t-8.8L 2]-.94 l-8.41 l_8.03 1"8.76 1,4 .42 1-2.77 14.39 FeeO 3 L.79 3 .57 1.81- 1.00 3.35 6.38 2.75 7 .22 5 .2r FeO 8.3L 7.78 4.59 5 .87 4.56 3.01_ 8 .87 4.38 6.79 MnO 0.08 0.15 0.18 0.08 0.28 o.22 Mgo 2.3L 3 .28 5.81_ 8.68 7 .48 6.94 7 .38 9.92 L2 .68 CaO 10 .91 9 .25 14.08 l_3.03 1-2 .97 5.00 LL.75 5.79 6.22 NaeO 2.97 3.07 L.79 t_. L8 L.7L 3 .44 2.72 3 .46 1.68 KeO o .47 2 .1-O o.28 o .28 o .42 1_.89 0. 38 0.81_ 1.38 PeOs o.L2 0.1"5 o .21, o .21, o.28 0 .06 0.19 0.13 HzO* 0.63 L.O7 0.68 o .67 0.89 3 .55 l_.36 5.79 4.79 o 0.03 0.04 o. o5 o .1,2 ë09- 0.10 Er-20 8:9å 1.98 Sum Tq-32 T0O-9' 9q-.'79 TW7 TOU-Z 99-€ TOUZS TOUf,g rco-77

Ref: J K L M N o P a R

Sio= 47.20 48.11_ 48. O0 49.L7 50.25 76.26 49.L8 46.53 72.34 TiO2 1.80 2.LO 1..83 1- .84 L.92 0.50 3 .82 t.92 0.05 AleOs 1-4.65 15.08 1_3.80 L4.53 15.50 ]2.40 12 .00 L6.70 16.30 FezOo l_1_.55 4.73 L2.1,O *L5.l-9 72.24 L .64 *1_8.40 *11.90 0. o6 FeO 3.7L 8.37 2.80 2.60 o .22 MnO 0.04 o.L2 o.07 o.12 0. l_6 o.22 0.06 0.01 Mgo 6 .6L 5 .87 6.45 7.59 6.08 Èr 4.54 5.34 o.20 CaO 5.39 9.75 4.80 7.3L 9.37 o.28 7.74 3.90 0.50 NaeO 3 .43 3.33 4 .60 3 .28 3.42 6.27 2.80 5.00 5.26 KzO 2.76 L.45 t_. L8 o.70 1-. 15 0.41 0.35 4.L8 ' 3.97 PzOs o .37 o .21, 0 .16 0.19 tr 0.43 0.59 0.13 HzO* 2.46 o.72 2 .60 o.02 0. l_9 r.99 L.25 HzO- o.49 o.17 0.14 o.L2 2.LO 0.07 COe 0.08 o .44 l_.19 Sum m-z. ffi73 Tg.zg ø-æ lffi 1oo5 Ñ m'ã' 100.36

Ref: S T U vvü sio2 75.36 76.90 49.38 62.L8 50.40 TiOz o. o3 2 .22 ) o.79 AlzOa 1,4 .64 ]-3.75 20.40 ) r_6 .91 L4 .91, FezOe 0.35 0.34 2.70 8. l-9 9 .2J. FeO o.L7 l_.60 3.29 6.92 MnO 0.03 Mgo o .1,2 o.22 8.20 0.68 4.70 CaO o.49 o.20 o.62 o.76 5.94 NazO 5.48 6.26 1.50 7.99 5.L7 KzO 3.25 2.78 9.58 0. L0 t_. l_6 0.34 o.12 H;8+ 8:13 o. l_5 1_.08 o.25 o.47 HzO- 0.05 1.96 0.01_ 0.08 COz 0.31 Sum m-' lñ ToCl4 99.90 lab1e 2.L continued Geochemis ofI eous Rocks in the Adelaide Geosvnc ne; Reference L e ncf.

A: Uralitic dolerite; Rosetta Head, Encounter Bay. Brown, 1-920. B: Olivine Diabase; Blinman Mine, Flinders Ranges. Benson' 1909. Basic dyke; Woodside, Mount Lofty Ranges. Alderrnan, 1-931-. D: Basic dyke; Mount Barker, Mount Lofty Ranges. A1derman, l-931-. Eì. Basic ayfe; Mount Barker Junction, Mount Lofty Ranges. A1derman, I93L. Íì. Melaphyre; lrlooltana Volcanics, Flinders Ranges. Mawson, L926- l¡eta-¿õterj_te; Wirreatpa Head Station, Flinders Ranges. MaÌ¡/son, L926. H: Olivine diabase; Wooltana Volcanics, Flinders Ranges. Mawson, L926. I: Ophitic olivine diabase,' Wooltana Volcanics. Mawson L926. I,lètaphyre; Oraparinna, Flinders Ranges. Mawson, L942.' K: Ooleiite; Blinman Dome, Flinders Ranges. Howard | 1-95L. Ranges. Coats L964. lJ¡ Melaphyre; Blinman Dome Diapir, Flinders ' M: ooleiite; Patawarta Diapir, Flinders Ranges. HaII, 1-984' N: Basalt (non-amygdaloidal) ; Patawarta Diapir. HaII, L984. o: Quartz Ceratophyre; Cathedral-rock, Mount Remarkable. Thiele, t-9r6. D. Gabbro; Rieschbeth Complex, VÙillouran Ranges. Farrand & Parker, l_986. a Lamprophyre dyke; lrlíllouran Ranges. Murrell I L977. R f,euóograñi-te TZIZS)¡ Giant's Head, Flinders Ranges- Mawson, L945. S Leucogranite (2876)i Giant's Head, FJ-inders Ranges. Mar¡/son, 1-945- T Leucograníte (51-53); The Pinnacles, Flinders Ranges. Mawson, L945. U Tourmalinized biotitic rock; Blue hole dep., Robertstown. King, L96L. V Albite syenite; Soda-rich stock, Boolcoomatta Hil1s. Segnit, 1949. W Essexite; Soda-rich stock, Bool-coomatta HiIIs, OIary' Segnit, 1949. * Total iron as FezOo. ) AlzOo and TiO= are combined. Table 2.3.2= Geochemistry of the Anabama Granite.

!ùt. å EE I72 173 L74 L79 L32 L45 L46 L48 sio2 65.26 64.43 64.78 6L.84 63.78 66.40 50.7L 66.66 6l-.50 TiO= o.5t_ o .66 o.32 o.79 0.65 o.9L 1.51_ o .62 0.68 AIzOs 15.13 L7.L2 18.67 1,7 .55 17.56 L4.95 l_9.39 1,5 .47 L8 .26 FezOo 2.32 )c4.22 *2.95 )c5.26 *4.11 ',c4.73 rr9.L7 *4.39 *4.77 FeO 3.12 MnO o.07 o.07 o -07 0.09 0.07 0. 09 0. l_4 o.07 0.08 Mgo l_.59 L.67 7.23 2.O9 L.75 l_.81_ 3.88 r_.68 1.92 CaO L .67 4.09 4 .67 4.05 4. 30 2.85 4.90 3 .63 4.36 NazO 2.6r 4 .6L 5.25 4.45 4.4r 3.32 3.73 4.01 4.73 KzO 4 .89 1_.63 l_. L3 2 .1,6 2.52 3.90 3 .84 2 .39 2.08 PzOs 0. l_5 o.20 0. l-o o .23 0. l_6 o .24 0.39 o. 18 0.19 HzO* 1,.43 0.63 0.48 0.86 0.66 0.61 1-.75 0.56 o.75 HzO- 0.04 COz 0.03 Sum 100.l-t- 99.33 99 .65 99.39 99.97 99.7L 99.42 99.64 99.33 Trace Elements (ppm)

F c1 SC LL 8 13 t_ t_ 5 36 1,2 1l_ V Cr Ni 19 L2 30 26 6 65 I 2 Ga Rb 500 69 44 r27 98 LB7 238 109 1t_5 Sr 3 000 533 964 468 228 343 509 404 446 Y 36 6 49 25 35 79 4T 32 Zr 268 t_53 25L 1,99 226 489 27L 342 Nb 22 3 23 20 26 60 25 20 Ba 4r3 278 492 74L LIL9 386 601_ 504 Ce Nd

Y: Slightly altered granite; Anabama. Morris, l-981-. Zz Altered granodiorite; Anabama. Morris' l-981-. AA: Altered porphyritic granodiorite; Anabama. Morris, 1981-. BB: Altered granodiorite with potassíum alteration,' Anabama. Morris, l_981_. CC: Greisen i Anabama. Morris, l-981- . DD: Dacíte; Anabama. Morris, L98l-. LL: Greisen (average of nine samples); Anabama. Richards, 1980. EE: Granite breccia; Anabama. Morris, L98I. L32-179: Unaltered granite; Anabama. Richards, L980.

* - Total Fe as FezOg Table 2.3.2 I continued'l : Geochemis of the Anabarna Granite. wt. å t_51 L52 LL ].56 Y z AA BB sio= 6r.43 70.69 74.46 60.53 59.60 60 .44 62.08 75.25 Tio2 o.77 o.25 0.20 0.85 0.89 0.83 o.7 4 o.26 AlzO 17.85 16.11- 1-3.40 L6.96 L7.53 L7.O2 17.I8 t_1.98 Fe20 *5.84 tc2.20 tc 4 .39 t 6.57 1- .28 r.29 1.30 0.61 FeO 3.93 4 .25 3.L4 1.13 MnO o.07 0.04 0. o3 0.07 o.07 0.07 0.06 0.04 Mgo 2.49 0.86 0.55 2.79 2.70 2.6L 2.LO 0.63 CaO 4.28 2.70 0. o3 3.96 5.08 4.L7 4.38 0.59 NazO 4.6t 5. L9 0.10 3.96 4.1-3 4.00 3.97 2.06 KzO 2.44 L.52 4.7L 2.7 4 2.33 2.48 2.72 5.24 PzOs o .25 0.08 0. o3 o.29 o.29 o.26 o.2 0.07 o .67 0.40 2.14 o.72 H=Bt t:32 [:62 t: tå t: ô9 COz 0.09 0.l-0 0.1_o 0.01- Sum TU0-r3 TO]Îrc.'3 TUOT'I Ts-.34 99-O TT34 TT.2T, 995.0' Trace Elements (PPn)

F c1 Sc 5 L4 t-5 V Cr Ni 7 t4 L2 32 Ga Rb 86 96 1,54 70 70 40 Sr 546 6L7 467 500 800 200 800 Y 8 20 28 Zr 270 l-19 268 Nb t-3 5 1-8 Ba 35L 552 5L88 Ce Nd

L51-l_55: Unaltered granite; Anabama. Richards, 1980. y: Slightly alteréd granite; Anabama. Morris, L98l-. Zz Attãred granodiorite; Anabama. Morris, L981" AA: Altered forphyritic granodiorite; Anabama. Morris' L98L' BB: A1Èered lr.ioåiorite with potassium alteration; Anabama. Morris, 1981-. LL: Greisen (average of nine sarnples); Anabama. Richards, 1980' Table 2 .3 .2 conti nued): Geochemistrv of the Anabama Granite. wt. ? cc DD

SiOz 79.09 70.90 TiOz o .24 o.25 t9:)Z t8: Èå 38 13 FeO 0.56 t.4L MnO 0.0L 0.02 Mgo o .42 0.85 CaO 0.03 2.47 NazO 0.10 4.86 KzO 3.37 t_.59 PzOs 0.02 0. 08 HzO* 1,.54 0.90 HzO- 0.06 0. 06 COz o. ol_ 0.05 Sum 101.53 100.l-8 Trace Elements (ppn)

F c1 Sc v Cr Ni Ga Rb 20 Sr 800 t_00 Y Zr Nb Ba Ce Nd cc : Greisen; Anabama. Morris, l_981. DD : Dacite; Ànabama. Morris, L98L. Table 2.52 of Earlv Adelaidean Volcanics in Diapirs.

Enorana Diapir (13) Arkaba Diapir (4) lrt. ? SiOz 46.10 - 53.70 49.97 49.20 50.12 49.66 TiO2 1. 10 5.64 2.32 1.50 L.7a t_.61 ÀIzOg 9.45 - L5.74 13.89 L4.T4 14.98 L4.42 FezOg Lt-25 - 2L.64 L4.95 13.34 14.65 13.96 FeO I'InO o. 04 o.47 o.20 o.L7 o.25 o -2L t{go 3.40 7.96 6.33 7.09 a.20 7.47 CaO 2.92 5.99 4.r7 6. 08 - 10.16 8.33 Nazo 2.92 5.99 4.r7 2.50 4.42 3.76 KzO o.32 2.LA 1.11 0.20 1. 08 0.55 PzOs o.11 o.48 o.24 o.13 o.r7 0.15 L.O.I o.55 8. 05 2.O9 2.96 2.96 2.L7 Total 99.88 -100.35 100.1-2 100. o1- t-oo.29 100.12 Trace Elements (PPn) Sc 36-59 43 36 43 4T v 204 - 506 357 300 404 360 Cr <5 259 101 150 206 1-75 Ni 23 98 67 98 135 1lL Rb 677 4L 4 57 27 Sr 35 - 309 138 384 696 532 Y 22-65 33 22 2A 26 Zr 64 3r2 L54 77 ro2 91 Nb 322 11 6 I 7 BA 49 520 196 26 939 361 Ce 22 76 45 2I 38 30 Nd 7-49 2l 9 15 13

Volcanic rafts in diapirs from Gum, I9A7. Bracket numbers (#) refer to number of analyses- Table 2.5 continued tative Geoclremis of Earlv Diapt_rs.

Oraparinna Diapir (3) wt. 3 SiOz 48.95 - 49.53 49 -27 TiO2 r.57 - 2.30 1.85 AlzOs 13.63 15.6L L4.56 FezOs 13-62 - 14-40 13.89 FeO llnO o-25 - o.46 o.34 Dfgo 6 .18 8. OO 6.44 CaO 4 .86 9.29 7.55 NazO 3 .29 - 5.40 4.38 KeO o 72 1.66 L.L2 PeOs o 15 o -24 o.18 L.O.I. 1.40 - 4.63 3 -4r Total 99.82 -100.20 99.99 Trace Elements (ppn)

Sc 39 46 43 v 294 395 335 Cr 1-O2 326 247 Ni 65 r25 t_o3 Rb L4 58 30 Sr 35 204 135 Y 24 34 27 Zr 86 I46 LO7 Nb 4 10 6 Ba 77 275 194 CE 20 39 27 Nd 4 15 9

Volcanic rafts in diapirs from Gum, f-9A7 - Bracket numbers (#) refer to number of analyses- Tab1e 2.7.2: Geochemis of the Int,rusive I ous Rocks of the Ar a on rom Teale & rmoser 1 wt. å 7669 7675 7676 7680 768L 7684 SiOz 78.I2 75.L5 75.29 72.22 7L.87 75.2L TiOz 0.03 0.0L 0.04 0.02 0. ol_ 0.03 ÀIzOo L3.46 t4 .25 L4.28 1-6.36 1_6.38 L3.93 FezOa 0 .65 0.16 0.48 o.73 0.30 0.48 FeO MnO 0.05 0.0L 0.02 0.05 0 .1_4 o.a2 Mgo o.23 0.14 0.1-8 0.19 0. 05 0.t3 CaO 0.06 L.22 o.L7 0.33 0.50 o.L2 Na¿O 5.10 6.22 4.44 8.79 8.99 5.84 KzO 1.55 2.L6 4.24 o. l_5 o.28 3 .05 E:8:r. 8:81 8:9å 8: l? 8:39 8:3? 8:1E Tota1 100.13 l_00.07 99.77 99 .46 99. 35 99.29 Trace Elements (ppn).

F 200 t_00 L1-00 400 300 200 c1 Sc V Cr Ni Ga 2L 20 2t 24 21, 30 Rb 40 l_ 38 4L8 5 9 481, Sr 29 29 3 9 6 5 Y 19 t4 7 L7 10 4 Zr Nb Ba t-L49 69 25 L7 1- l- 30 Ce 20 <20 <20 20 <20 20 Nd

Neither precise locatj-ons nor specific tithologies v¡ere recorded for these sarnples, described by Teale & LotÈermoser as tt2 mica granj-tes, quartz albítites, quartz-albite-alkali fetdspar (+/-tourmaline, +/- garnet) , granites and aplitesrt. However, samples 7680, 768L and 454 are believed to be albitites due to very high NazO and very low KzO content Þ. Table 2.7 .2 continued : Geochemis of the Intrusive I s Rocks of the Ar roo a on Tea ô termoser, L987). wt. å 1,729 L73r l_l_80 454 456

SiO= 74.89 75.44 75.65 7t.7 4 75.8r TiO= 0.03 0. o3 0.05 0 .01 0.02 1_3.41 l_6. l_5 1_3.54 Ä,1 =Oa L4.39 14.2I FezOa 0.53 0.50 o .62 o.23 0.33 FeO MnO o.2t 0.01 o.2r 0.08 0.19 Mgo 0.34 0.41_ 0.09 0.1_5 0.09 CaO o.L2 o.22 0. l_0 o .44 o .28 NaeO 5.48 4 .62 5 .23 9 .05 5.08 KzO 3 .4L 4.18 3.30 0.33 3.76 PeOs 0. 09 o. o8 o.07 o.32 o.2L L. O.I o.25 0.48 o.37 o .46 o .47 TotaI 99.74 1oo J8' 99. L0 98.96 99.78 Trace Elements (ppm).

F 1000 L800 300 1_900 ct Sc V Cr Ni GA 35 21, 25 3l_ 22 Rb 640 397 504 L8 709 Sr 3 2 6 L4 3 Y <2 <2 5 4 <2 Zr Nb 99 64 ]-45 LO2 85 Ba l-8 13 25 9 29 Ce

NeiÈher precise locations nor specific lithologies were recorded for these sainples, described by feale & Lottermoser asrr2 mica granites, quartz atËitiúes, quartz-at¡ite-atkali feldspar (+/-tourmaline, +/- farnet), granites ãnd aplitesrr. However, samples 7680t 768L and 454 àre betieved to be albítites due to very high NazO and very low KzO contents. Tabl-e 2.82 Geochemis of Intrusive f eous Rocks of the W llouran Ranges. wt. å 8507 8508 851_ 3 85L9 8520 428 SiOz 47.59 47.35 46.08 46.45 47.57 48.30 TiOz r.27 l_.6L 3.59 L.44 L.42 L.47 AIzOa L9.22 L5.37 l_4.81 15.86 21-.06 14.90 1,2.40 F86o= 3:t9 à:Z? Å:17 ?:EZ 2:22 MnO 0.19 o.20 0.16 o .20 0. L6 0. L0 Mgo 4.L7 8.70 4.49 8 .47 3.20 8.20 CaO L2 .54 1-2.82 7.20 to.78 9.55 7.60 NazO 4.15 2.52 4.45 3.0L 4.L6 3.72 KzO 0.69 L. 05 3.03 o.97 2.66 0.35 PzOs 0.14 0.40 L.1,0 o.2L 0.30 o.L2 L.O.I 2.53 o.87 L.68 l_.19 2 ,53 3.26 Total 98.72 98.99 98.42 98.57 99 .47 L00 .40 Trace Elements (PPn)

F L40 2LO 300 1_60 270 c1 L2660 4620 8085 12300 6345 Sc 3t_ 40 26 30 15 v t_89 260 406 2Lt L98 360 Cr 47 L23 <5 3L5 36 2LO Ni 15 89 1_0 153 31 l_60 Ga 13 L5 L7 L7 L7 Rb 1_6. 3 32 90 20 .4 9L L2 Sr 589 435 l_59 381- 658 r-80 Y L6.7 20.2 34 1-9 .6 1 6.5 20 Zr 63 94 l_85 r_05 1,1,2 50 Nb 14.2 33 78 L9.9 50 I Ba 4L2 522 834 366 ]-260 270 Ce 22 45 75 36 54 Nd 7 23 37 1,7 l2

8507: Albitized gabbro. 8508: Altered gabbro. 851-3: Altered gabbro or diorite. 851-9: Altered gabbro. 8520: Ältered gabbro. RS#6438 4282 Altered Gabbro

No.s 8507-8520: Analyses by R.S. Morrison, The University of Adelaide. No.s 42g-433, Rs #ø+1e: enàlyses by Àndel for the South Ä,ustralia DepartmenÈ of Mines and Energy. Courtesy of Dr. B. Forbes. Table 2.8 (continued): Geochemistry of the Intrusive lgneous Rocks of the lilillouran Ranqes. wt. å 429 430 43L 432 433

SiOz 49.30 48.30 55.50 47.60 47 .40 Tio= L.76 L.67 1 .60 L.57 I.28 A1=Oo L2.90 20.70 L6.00 1_5.30 L9.20 FezOs 12.80 7.30 2.28 9.75 7.30 FeO MnO 0. l_0 o. l_6 0. 06 0.18 o .1-7 Mgo 6.55 4.42 o.34 8.55 4.42 CaO 9.50 L0.70 7.75 L2.60 Ll_.50 NazO 3.56 3 .68 8.40 2.58 3.92 KzO o.34 L.34 L.47 1_.06 o.94 PzOs o. L3 0.33 0.50 0.36 o .22 L.O.I. 2.58 L.70 6.30 L.O7 3 .1,6 Total 99.50 1oo. 3o L00.20 99.60 99.50 Trace Elements (ppm)

F CI SC V 410 r_90 20 230 l_60 Cr 70 90 <10 L20 40 Ni 80 30 20 90 20 Ga Rb 7 44 29 36 t_o Sr 190 500 90 420 520 Y 20 20 20 20 20 Zr 60 70 3 t-0 90 30 Nb 8 40 L25 36 20 Ba 2LO 770 400 480 470 Ce Nd

RS#6438 429 A1t,ered gabbro. RS#6438 430:= Altered diorite. RS#6438 43L'. Diorite. RS#6438 4322 Altered gabbro. RS#6438 433 2 Albitized diorite.

No.s 8507-8520: Analyses by R.S. Morrison, The Uníversity of Àde1aide. No.s 428-433, RS #6438: Analyses by Arndel for the South Australia Department of Mines and Energy. Courtesy of Dr. B. Forbes. g trf gune "2. n B GllassÍ f Íeat lon of the llnt rusÍves of the treake and Denfson Ranges, Qua rIz

60Í Granite Alkali GranÍte Gr anod íor i te TonalÍte Quartz Monzonite Ouartz Alkali Syenite Quartz Monzodiorite Suartz Syenite Quartz Diorite MonzonÍte .Syenite Monzodi or i te AIkali Syenite DÍ or ite \1ka1i feldspar Plagioclase Syenite @ MonzonÍte MonzodiorÍte Alkali Syenite Ia DÍ or ite

35X Syenogabbro Monzogabbro

65Í

Âfter ûsmigon & iÍoôan ( t SrS)"

TotaI mafics Fignrre 3.2.L. Classification of the Bungadiltina Suite. Diagramatic representation of plutonic classification from modal analyses of representative samptes of the Bungadiltina suite. Classification scheme follows that of Streckeisen (L976) and Sorensen (L974) (c.f. TerminoTogy, Nomenclature and CTassifícation). A complete tabulation of modal analyses is recorded in table 3.2. See also appendix A for petrographic report on samples specified in tabLe 3.2.

Plate 3.1: Igmeous Intnrsives of the Peake and Denison Ranges.

Top Left: Syenogabbro showing massíve, homogeneous and equigranular to slightly porphyritic texture on fresh surface. Note small black euné¿rai ärnplriËofe crystals in plagioclase (dark green-grey and a]-kali feldspar (pink). Location: Map F (samPle [9541]). Bottom Left: Aplit,ic dyke 6cm wide intruding (left to right) porphyritic atkalí syeñite. Alkali syenite has flow-lineated alkali tefasþar phenocrysts up to 4cm in length oriented from bottom to top of pnotograpn. Note possible rounded monzonite xenolith to the lower left of lens cap. Location: Adjacent sample locality 17546 I (Map F). Top Right: Prominent tors of monzonite of the western zoned pluton of fUaþ a. Note l-m tong hammer handle for scale to lower right of photograph. Location adjacent northeast margin. AIso note steeply ãippiñq èchlieren from top left foreground to boÈÈon right background (fõõXiñg south). orientation of pluton is roughly para1lel to Èhe surrounding strata, suggesting passive emplacement. Centre Right.. SiII swarm of Maps B and B', looking northwest. These siIls, prãdominantly composed of monzonite, form prominent ridges striking north. Sills intrude a sequence of siltstone and shale sandwicñed between massive quartzite beds (Mount Margaret Quartzite) in foreground'and on horizon. Distance across sill swarrn is approximately 1-.4km. Bottom Right: Hammer (handle is 0.42m in length) rests on a 0.5m wide monzonite-sitl intruding interbedded siltstone and quartzite (Mount Margaret euartzite), Iooking southeast. SilI represents the southern extremity of the sill sr¡/arm of Maps B and B'. Location: Map C (sanP1e 930L).

Plate 3.22 Contact Relations of the Bqngadillina Suíte.

Top Left: Contact between syenogabbro pluton. (at head of 9.8n long hammer and above) and diapiric breccia. Diapiric breccia is composed largely of buckled Burra Group shale; possibly representing stage 3 (c1ástisupported) breccia. Hote felsic dykes which become more irorninent-Lowards margins of mafic,plutons. These fetsic dykes are Lruncated at the contáct with diapiric breccia' suggesting that' brecciation postdates dyke intrusion. Location: ÄdJacent sample locality 19542, 95201 (Map F)' Botton Left: Typical contact between Bungaditlina suite pluton and Burra croup snäfe with interbedded carbonate. Contact is at the base of the pholograph. Hammer handle is 0.42m in length. Note leucocratíc atbitizèd O.em ;riae margin of pluton. Albitization is restricted to tne pluton itself, and unlike ienitizatíon, does not extend into surr-ounding sediments. Less alÈered monzonite is present towards top of photográph. Albitized margins can be brecciated along contacts with aiaþiric-breccia. In such cases, the albitite forms angular clasts witñin an albitite natric suggesting localized brecciation occurred during emplacement. Location: Map E; adjacent sample [9558]. Top Right: Contact zone between rnonzonite and surrounding sediments. Hote pássive inclusion of Burra Group sediments (mudstone with interËedded carbonate) into intruding igneous material. Sedinentary material appears to include diapiric breccia, but the precise stage of brecciation is uncertain. Location: Map F; adjacent sample locality [9528]. Middle Right: Detailed contact margin of (albitized?) monzonite (above Iens cap)-and host Burra croup shale (beIow lens cap). Note passive character of intrusion with little distortion of surrounding strata. Note also small late-stage felsic vein oriented top to botton of photograph immediately tõ tne left of the lens cap. Vein continues as ä tinú siff into the Èurra Group sediments. Bluish colouration is courtesy of Kodak PtY. Ltd. Location: Edith Spring Creek (Map I). Bottom Ríght: Albitized contact margin of a monzogabbro. Monzogabbro is towards the top of Èhe photograph. The contact extends from left to right. Albitite is the líghter coloured rocks. Note Burra Group sedíment (mudsÈone) incorporated in albitite. Contact between Burra Group mudètone and'albitíLe is i¡nnediately belor¡r the xenoliths. White patcires on albitite are calcite. Tan coloured fractures within ät¡itite are filled with calcite. Hammer head is l-7.5cn in length. Location: Map F; adjacent sample l952Ll. t

lLr 4.t ! Plate 3.3: Xenoliths within tlre Bungadillina Suite-

Top Left.. Subangular doleriÈe (top of photograph) a1q gabbroic xeäoliths (base of photograph) within a monzonite siII. Xenoliths may represent the chilled margin of parental cognate material to the monzonite which has been re-incorporated into the rising magma. Hammer head is l-7.5cm in length. Location: Adjacent sample l77OO I (Map B'). Bottom Lett: Rounded (centre of photograph) and elongatg (ri9ht of photograph) xenoliths of foliated (tonalitic?) gneiss wiÈhin ãungaaittina suiÈe monzonite. Both xenoliths are white and speckled witñ mafic minerals. Photograph demonstrates the involvement of Middle to Early Proterozoic crustãl material within the Bungadillina suite. Rounded nature of these xenoliths suggests partial assimilation into the Bungadiltina suite magma. Note dark grey coloured subangular doleritic and gabbroic xenoliths. Ä,lso note hammer head to bottom right of photograph for scaIe. Location: Àdjacent sample l73o2l (Map B'). Top Ríght: Accidental Burra Group quartzite (Mount Margaret Quartzite) xe-nofiLn along imnediate margin of al-bitite pluton with Mount Margaret Quartzite, inðorporated into pluton during intrusion. Locatíon: Northwèst Map F, north of sample tocality 1951.2l. Centre Right: Small gneissic (melanosome) Yenolith in quartz monzonite-. The incluéion of gneissic xenoliths is a very minor component of the xenolith poþulation, suggesting Iinited assimilation of ünderlyíng Earty to l,tidáIé proterozoic crust. Note equigranular texture of quartz monzonite with pink a1kali feJ-dspar, white plagioclase and finer grained intérstitiat arnphibole and biotiÈe. iocátion: Western Map B' and eastern Map A; adjacent sample locality I e5e]- I . Bottom Right: Rounded syenogabbro (hornblendite?) cumulate xenolith 6- 8cm in diáneter within lnonzónite. Note abundant, coarse grained euhedral amphibole crystals. Xenolith is considered to have formed by the re-in"o-tpor.tion óf ferromagnesian rnineral-rich cumulate material into the intruding monzonitic magma. Location: Adjacent sanple locality l77oÙ I (Map B').

Plate 3.4: Dykes and Sills of tlre Bungadillina Suite-

Top Left: Monzodiorite dyke 2Ocm wide intruding monzogabbro. Hammer na-nAte (O.42rn in length) is parallel to dyke strike. Note prorninent chilled'margin of dyÈe, suggesting emplacement after cooling of monz ogabbro. Location: Adjacent sample locality 193221 (Map F'). Bottom Left; Al-kali syenite siII 25cm wide intruding Burra Group quartzite (Mount Margãret Quartzite?). Hammer handle is 0.42m in length ánd parallèI to dyke strike. Note flow lineated alkali feldspar phenócrysts within dyke and lack of any prominelÈ contact iretamorþnisrn. Note also rounded quartzite xenolith immediately above hammer head. Location: Southeast of sampte locality 17337 I (Map I). Top Ríght: Monzonite dyke intruding homogeneous.syenogabbro. Probably a tetsic late-stage fràctionate. Fine para1le1 jointing patter indícates continuóus fracture rnobilizaLion during emplacement. White patches represent horizontol portions of calcite veining. Hammer handle is 0.42n in length. Location: Adjacent sample locality 1732Ll (Map F). Centre Right: Biotite lamprophyre dyke, 7clm wide, intruding. (left Èo right¡ noñzogabbro. l,ampróphyré dyke also cross-cuts sinusoidal 2-3cm wiáe ielsic áyke (top right to botton left). The.felsic dyke probably a late-stage Êelsic þnasé of the ¡nafíc pluton. Biotite lamprophyre is a common but minor cómponent of the intrusives of the Peake and Denison Ranges. Location: Adjacent sample locality 19627 I (Map F). Bottom Ríght: Thin dykes of monzonite intruding monzogabbro adjacent rnargin of monzogabbrõ pluÈon. Represent late-stage magmatism, with residual felsic magrmatic fluids being squeezed out of crystal mush rich in ferromagnesian minerals, forminq a marçtinal felsic dyke network. Compare also with the fronticepiece. Location: Adjacent sample locality 195421 (Map F). plate 3 .5: Cumrlate and Assorted Featr¡res of tlre Bungadillina Suite. Top Left: possible primary rnagmatic layering.showing alternating na'fic-tí.ch and felsic-ricñ UañAs 5 to socm wide oriented left to ríght. This sample is composed of strongly altered nonzogabbro. Loõation: Adjacent sarnple locality [9901-] (Map H). Top Righlc: PossÍble primary rnagrmatic layering in largely.homogeneous qluiartz- syenite. Minerat lineation is oriented from top right-lo. Ëotton fétt of photograph. Note rounded xenolith (pyroxenite?) in the centre-right of photograPh. Location: Àdjacent sample lg92Ll (Map F'). penultímate to Top Left: Two green coloured pyroxenite xenoliths in quartz syenite. these pyroxenite xenoliths are considered to represent f-erromagñesian minerallrich crystal cumulates which have become re- incorpoiated into the more felsic phase of the Bungadillina magma. Location: Adjacent sample locality 19023) (Map F'). penultímate to Top Right: Zone of cognate (cumulate?) xenoliths within syenogabbro. Zone varies in width from 20 to SOcm and contains rounded fãrroñagnesian-rich (pyroxenite and hornblendite) xenoliths. May represeñt volatife-ctiäiged emplacement of cumulate-rich material during the latter stages of maqma crystallization. Location: Adjacent sample locality 195661 (Map F). penultimate to Bottom Left: Contact metamorphosed Burra Group sediments imnediately adjacent to the western nargin of then largest pluton of the Aungadilfiña suite (l[ap G) . These a]-tered siltstones of Lhe Mount Margare€. euartzíEe have unãergone extensive silicification and are charaðterized by locally abundant mica. This is Èhe only Iocality where contact rnetamorpñisn is well preserved in the contiguous sediments. Location: Adjacent sample localiÈy l77o4l (Map G). penultimate to Botton Right.' Veinlets of light brown coloured calcite within light pink colourèd albitite. Calcite ís a common.product of áiniti-r"tion, and calcite veinlets are often found associated with albite. CalciÈe veins are also observed within Burra Group sediments, and are considered to be associated with low-temperature hydrotherrnal alteration. Location: Adjacent sample locality 17329 I (Map F'). Bottom Left.. Syenogabbro, showing fresh surface colour and texture in contrast to weãtheied surface. Note abundant euhedral amphibole crystals. This material is considered to represent ferromagnesian mineral-rich cumulate. Location: Adjacent sample locality t75751 (Map I). Bottom Ríght.. Syenogabbro cumulate-rich xenolith in syenogabbro. Xenolith is conéiaeied to represent a more cumulate mineral-rich phase of the host syenogabbro. Note similar texture. Contact of these to phases is witñin ãm of this xenolith locality. Note also wèak jointing planes filled by calcite. Location: Adjacent sample locality 17703 I (Map F). a.rtoæ ooo¡O3 ,l .lrr3

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Geochemi stry/Petro logy :

Sample Site 75Ol ¡ Track z+È¡-sr-=-==: SÍte of BHP-Utah Pty. LÈd. exploration camp.. trt trrtr¡ Ëllo R.ef ererÌce f or ÈIr.e Geol- oçÍ ica.f- YIa-E)s of ÈI:-e Pea.I

llesozoic and Cainozoícz

9 Cover sediments. Earlv Pa]-aeozoic: Br¡ncladillina Intrr¡síves. Biotite larnprophyre (t). Alka1i syenite (As), with mínor albitite.

+++++++{ AlbitiÈe (A), minor quartz al-bitite. ¡+++ + + + Quartz syenite (aS¡. + + + Syenite (S). Syenogabbro (SG).

x x x Quartz monzonite (aM). x x I I Monzonite (M) wíth minor monzodiorite. I Monzogabbro (MG).

Late Proterozoic¿ Adelaidean. I Diapiric breccia and strongly contorted Adelaidean strata Torrensian - hliTTouranz Burra Group Sediments. Dolomite. 7 Skillogalee Mount Margaret 6 Quartzite. Fountain Springs Beds, undefined siltstone member. 5 shales, siltstones and quartzites. 4 Undifferentiated úrIiTTouranz Ca1lanna Group Sediments and Volcanics. Cadlareena Volcanics. 3 Younghusband Conglomerate 2 Earlv Èoterozoic: Peake lletamorphics.

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t { + \ + + -b r.95?2 @ ++ ++ QS I <¡Þ ? +++ ++ æ s + +t + ç o9OÊ! + 2 .9O¿8 .7?Oa + + l o tlo M6 + + a \ w.t70a I '7l, ++ ç aa t?2 + G + a 6 a -< + + + + 0 2Co 2C'- + + + +

+ + + + + + + 6 + + + + + + + + ++ +++t!a.oa'+ + + + + + 3 Þ o) T o¡ t\\ t\ . .c. ol rO { .o o É3t..' -t- (¡ ¡. . \t. + a\ a =ê- a .o.(¡ \t .a... o ++ ++ aaaaa l¡o q a o (ll . I .lS.o. . Þ .{.a. +++ ++ + + .¡ {o a C' ta{ a a ++++ ++ + + oÞ I a a 3 aaaaaa.a .aaaa a aaaaaa. ol a t++++ ++ + + aaaaa aaaaa' aaaa. aaaaa aaa.a aaaaa a aaaaa .t X ....4 aaaaa a aaaa' ++++++ ++ + ++ .aaa' aa.aa a aaaaa a .aaaaaaa .aaaaaa ++++++++ ++ + +1 aaaaaaaa aa.aaaa aaaaa'aa .a..a¡a aa" ol aaaa aaaaaaa + + ++++++++ ++ + ++ aaaaaa

aaaaaa \ aaaaaa +++ + 3 ++ ++ + ++ Þ aaaaa' ! +++++ + ++ + +++ ....4 G) a.aaa +++++++ + ++ +

f++t+++++ + ++ + { lì' / a þ; -+- {- + (t¡ ++++++++ orst f +f+ o c .o' a aù ¡'l . { ++++++++++ + + + +++f++++ (¡ 9 2ao21 40c 5 lo. 5

/ I \ , I MA P 'H' I I I 9 I I t Soola l:l6,000 + I nalru t+ , o 3(,() 600 atat a+tt I 5 a+Òa tt .l t 4 t t + t a I I t .¡ t+a I + I 3ã t + + I + + + zÛo ì + a ¡¡õ A \ I I - ¡ +

I a 4a a \ t 5

a 5 æ.

ì À I I 5 5

4 at 5 \ a I t t a \ a + t 2a. a a t I a t 9 961t. I I a 5 a t ? a t t 4, a ,ì'.L o a a a 5 5 I

5 8 . + I ot' Ita. OOg OOt OOA O -¿lr OOO.||lrt atros

¿ rI. dv¡r ,o2 + - L ot "y + x I q >\

9ÊÊ¿

\.(

t3 ,9OceÊl v \ tt 9 I I 99 \ 9 I I t dvlr I t r!r ">\. Tab1e 3.22 Percen Modal- Mineral ies of resentative fntrusives the Peake an Den son S.

SampJ-e: eooL 9005 901-2 901-3 90t4 9015 9023 9024 9028 Quartz: 0.8 5.8 0.6 L.l- 0.8 0.2 4.8 o.2 l_.3 Plaqrioclase: 43.2 40.9 L9.9 l-5.6 15.8 47.5 21-.2 25.O L6.3 K-FeIdspar: 35.8 44.7 25.6 36.8 39.0 32.5 65.9 5t_.0 58.5 Anphibole: 7.4 5.5 28.3 6.6 1-4.L L.4 Pyroxene: ,_u 6 7 32.3 9.5 23.2 Biotite: 0.l_ 1 4 o.2 9.0 t_l_.6 Garnet: Epidote: 3.4 0.4 5.4 o.7 3.1 2.3 Cal-cite: 3.0 0.3 0.1 4 5 6 .1, 5.4 Chlorite: l_.5 '-n 1. l_ 2.J, Sericite: o.7 4 I 3.3 2.8

Sphene: l_ o 0.6 4 3 2.L 2 5 1_.5 0.5 Apatite: 0 6 0.3 3 2 o.7 2 0 0.4 0.8 1_ 3 1 l_ Zírc'onz 0 4 oxides: 2 0 0.6 0.1 o l_ 0 2 o.7 3 5 3 6

Sample: 931-l- 9327 9402 9403 9501 9502 9503 9507 9508 Quartz: L.6 2.O 0.4 9.6 L.2 4.9 4.8 1.5 Plagioclase: 2L.4 35.0 25.3 L7 .8 25.8 44 .6 40.7 41, .4 44 .4 K-FeIdspar: 67.2 35.0 28.8 46.7 42.O 3L.0 39.8 33.0 3I.2 Amphibole: 5.8 30 .2 0.3 Pyroxene: 1.5 L6.6 l_.0 Biot,ite: L2.O n-, 4.7 2.3 Garnet:

Epidote: 0.9 l_ 4 0 4 2.O Calcite: 0.3 l-0.0 0 3 4 I e] rrls 4.0 Chlorite: o.7 o.2 5.0 Sericite: 5.0 3.0 9 5 t_0.9 2.O 2.8 L9 .4

Sphene: o.7 0 4 o.2 1 0 0 6 Apatite: 0 9 2 0 1.5 0 9 t:t o.7 o.4 0.2 Zircon: 0 3 Oxides: l_ 6 5 0 5.2 3.9 t-.8 3 3 o.2 2.3 0.7 9004 : Monzoni-te 93Ll_: Syenite porphyry 9005 : Quartz monzonite 9327 z Lamprophyre (visual estinate) 90L2 : Syenogabbro 94O22 Monzonite 901-3 : Syenogabbro 9403: Syenite 901-4 : Syenite 9501_: Quartz syenite 90L5 : Monzonite 9502¿ Monzonite 9023 : Quartz syenite 9503: Quartz monzonite (albitized) 9024 : Syenite 9507 z Quartz monzonite 9028 : Syenite (albitized) 9508: Monzonite (albitized)

1_ Table 3.2 continued : Percenta e Modal Mineralo ies of resentative Intrus ves n P Den son Rancfes. Sample: 95L2 951-4 95L7 9521 9526 9528 9530 954l. 9543

Quartz: 3.0 0.3 0. t_ o.2 0.5 2.9 l_.1 2.O 8.6 Ptagioclase: 56. 3 1,2 .6 t_8.6 L2.9 1_9.8 25 .6 29 .2 1,L.7 56.5 K-Feldspar: 38.8 29.5 45.8 45.5 48.3 43.0 42.O 26.7 25 .3

Anphibole: 33.4 25.6 L8.0 L3.2 L5 .2 11.1 Pyroxene: o:t Biotite: 2.3 9.6 2.5 6 2 25.7 Garnet:

Epidote: 1- 7 0 2 L.9 Calcite: l_9.5 0 2 +.t 4 1 7 7 o.4 L7.7 Chlorite: 0 2 1, .9 0 7 l_.1 Sericite: 1 6 2 I 2.7 5 F 8 0 5 8 9 6 Sphene: 2.O 0.5 0.6 1.3 o.4 Apatite: 2.7 0.8 t:, 0.6 0.9 0 4 0.8 0.1 Zircon: 0.1 Oxides: 0 3 1 3 3.2 3 3 2 5 3 9 2 I 0.1

Sample: 9548 9553 9558 9560 9563 9565 9566 9570 9574 Quartz: o.7 0.3 1.8 0.9 l_.0 2.7 0.4 t_.0 0.8 Plagioclase: 82.O 32 .6 37.7 45.2 5.4 LT.2 45 .2 1,4 .3 24.O K-Feldspar: 8.6 30 .6 46.2 32.7 68.1_ 36.0 L3.2 49 .5 37 .4

Arnphibole: 0 3 3.8 38.5 5.2 14.7 5.0 Pyroxene: 4.7 10.3 1,O.7 Biotite: 18.3 l_ 6 2.1, 1,9 .6 u.n Garnet: 4.9

Epidote: 1_.3 0.6 2 1 0.6 Calcite: 6 7 6 6 5.4 11.5 4.I u_, 10.3 t_ 3 Chlorite: 4 2 1_.8 1,.2 Sericite: 0 I 4 0 3.7 7 3 r.7 10.6

Sphene: 0. t_ 0 4 0 5 0.3 l_ 1 t_ I Apatite: o.2 0.8 0 4 t_.8 0 5 L.4 0.6 1 0 0 9 Zircon: Oxides: 1.0 2.5 o.7 0.6 o.7 2.4 2.O 4 9 2.O 95L22 Monzonite 9548: Diorite (albitized) 95L4 z Syenogabbro 9553: Monzonite 95L7 z Syenogabbro 9558: Syenite (trace fluorite) 952L2 Syenite 9560: Monzonite (albitized) 9526: Monzonite 9563: Alkali Syenite (trace fluorite)

9528 z Monzonite 9565: Syenogabbro 9530: Monzonite 9566: Monzodiorite (albitized) 9541,2 Syenogabbro 957O2 Syenite (trace fluorite)

9543 z Monzodiorite ( albitized ) 95742 Monzonite Tab1e 3.2 continued : Percen Modal Mineral ies of Re sentative trus ves n the Pe D son Ranges.

Samp1e: 9580 9582 9585 959L 9594 9595 9596 960L 9608 Quartz: 1.5 o.7 8.3 L.2 L.0 0.6 9.0 Plagioclase: 23.O zsl,z 34.2 30.0 37 .2 28.7 2L.4 55.0 30.6 K-Feldspar: 26.9 36 .6 42.3 54.2 40.5 43.2 36.7 26.9 68.0

Àmphibole: 7.4 4.5 o.2 2.O 1_l_. r_ 9 4 21- .6 Pyroxene: 20.5 11.3 LI.2 2.9 6 0 8.8 Biotite: 7.O t:' l_.0 o_, o 5 0 t_ Garnet: '-,

Epidote: 0 5 L.7 0 2 0 5 3 2 2.9 Calcite: 0.4 0 4 1.8 l_ 0 5.4 Chlorite: 0 2 0.5 0 5 0 9 l_.5 Sericite: 3 3 0.4 0 3 L.l_ 0.8

Sphene: 2 I 2.2 1_.6 0.9 L.6 2.O 2.5 0 3 0 1 Apatite: 2 2 0.6 o-n 0.1 o.7 0.8 L.4 0 1 0 l_ Zircon: oxides: 8.2 3.3 3.6 0.8 3.1 3.3 3.8 0 6 o.4

Sample: 9625 9630 9636 9703 Quartz: l_.8 0.6 2.O Plagioclase: 27.7 L8.2 L3.9 LO.7 K-Feldspar: 45.0 62.5 3L.6 23.O Amphibole: L2.9 59 .2 Pyroxene: Biotite: 32.3 0 .4 Garnet: Epidote: 4.6 Calcite: o:u L3 .8 t_, Chlorite: o.4 Sericite: 3.1 0.9

Sphene: 2 0 0 5 Apatite: 0 l_ 0 I L 4 0 3 Zircon: 0 6 oxides: 0 1 0.l_ 4 0 0 6 9580: Syenogabbro 95822 Monzonite 9630: Syeníte (albitized) 9585: Monzonite 9703 2 Monzogabbro ( xenolith) 959L: Quartz monzonite 9595: Monzonite 9594'. Monzonite 9601_: Quartz monzonite (albitized) 9596 z Syenogabbro (trace fluorite) 96252 Monzonite (albitized) 9608: Monzonite (atbitized) 96362 Syenite Table 3.2 (continued) : Percentage Modal Mineralogies¡rf Representative fntrusives in the Peake and Denj-son Ranges. Notes: (a) Modal analyses are based upon thin section point-counting of generally equígranular lithologies with 1-2 mm grain size on a 10 mm= grid with 0.L nm grid spacing. (b) Anphibole count records total hornblende and/or actinolite. (c) Significantly metasomatized (ie. albitized) Iithologies are noted. (d) Sericite includes muscovite. (e) Groundmass porportions in 9563 (3.52) and 9625 (22.22) are not included. (f) See text for proposed system of nomenclature. I t .1

1tutu ÐJ l*t 'l (- t ?¿ a. * g :l

,!

(, ( O ¡ 3 ,.I ìl ,¡ a t.. ¡ tlT' f I

a 1

G,'

Tt Plate 4.Iz Mj.neralogy and Petroqraphy - Textures.

(A) 17324f '. Syenite. Hiatial porphyritic with strongly zoned orthoclase phenocrysts in a fine grained felsic Aroundmass. Note euhedral zoned hornblende. Minor sphene. P1ane polarized light, 8mm.

(B) l7324lz Syenite. Crossed polars, 8mm

(C) [9598]: Syenogabbro. Equigranular to poikiolitic with large euhedral hornblende, smaller euhedral- zoned clinopyroxene and biotite in large water-clear orthoclase. P1ane polarízed light, 8mm.

(D) [9598]: Syenogabbro. Crossed polars, 8mm

(E) [9583]: Monzonite. Equigranular slightly zoned plagioclase and orthoclase with smal-l euhedral clinopyroxene, biotite and magnetite. This naterial was used for (erroneous) lJ/Pb (zircon) geochronology. Note chloritized biotite. Plane polarized light, 8mm.

(F) [9583]: Monzonite. Crossed polars, 8mm

(c) 17575)z Syenogabbro. Equígranular to slightly poikiolitic with prominent euhedral zoned amphiboles and smaller euhedral clinopyroxene and magnetite in an orthoclase mosaic. Note amphiboles have actinolite cores and hornblende rims. This rock is considered to be a ferromagnerian rnineral-rich cumulate. Plane polarized fight, 8mm.

(H) l7575lz Syenogabbro. Crossed polars, 8mm.

Distance in nillimetres refers to widÈh of field.

--33)¡i33-- '$tr

n r s-.\. l.

I

?'- Plate 4.22 Miner alocrv and Petroqraphv - Litholoqies.

(A) [9003]: AIkaIi syenite. Hiatial porphyry with strongly zoned órtnoòtase phenocrysts. Minor epidote to upper left corner, minor actinolíte. Note partial albitization around rim of one alkali feldspar phenocryst. Crossed polars, 14mm.

(B) [9565]: Monzogabbro. Flow lineated euhedral accicular hornbl-ende ðhadaðrysts iñ water-clear orthoclase crystals creating a ghost poikioTitic texÈure. Crossed polars, L4mm.

(C) [7503]: Syenite. Syenogabbro xenolith of euhedral hornblende in finer-grained felsic aroundmass within a hornblende syenite. Note gradational contact and j-dentical mineralogy between the two lithologies. Plane polarized Iight, 8mm.

(D) [9007]: Monzogabbro sitl. Sma1l euhedral accicular hornblende õrystáts flow lineated around hornblendite xenolith. The xenolith is-considered to represent ferromagnesian mineral-rich cumulate material of the Bungadiltina suite. Note partial actinolitization of hornblende and inprecise xenolith contact, suggesting xenolith vras incorporated as ã crystal-rich mush. Plane polarized light' 8mm.

(E) 17327lz Biotite larnprophyre. Zoned phenocrysts of biotite in a iine grained felsic groundmass with magnetite and apatite. Plane polarized light, 8mm.

(F) 19524lr Syenogabbro porphyry. Large euhedral- hornblende þfrenoðrysLs witn albite rims in a finer grained biotite- and ðfinopyioxene-rich felsic groundmass. Plane potarized light, 8mm.

(c) 17329lz Alkali syenite. Seriate porphyritic with weakly zoned órtnoðIase phenocrysts and haematiÈized hornfels xenolith to right of field. Minor plagioclase and hornblende. Crossed polars, l-8mm.

(H) l77Otl3 Syenogabbro xenolith. Strongly actinolitized hornblende ånd sèricitizea feldspars. NoÈe small euhedral apatite crystals in secondary haernaÈite. Plane polarized light, 8mm.

Distance in millimetres refers to width of field. ** **o**** ''--

i o T 7 r ,

{. Þ 3 , i' r¡b ¿r

5r¡

- Plate 4.3: Mineraloqv and Petrosraphv - Mínerals.

(A) l7575lz Syenogabbro. Finely zoned hornblende mantling large euhedral actinolite. Small euhedraL magnetite, sphene (top right) and clinopyroxene (paIe green) in orthoclase. Plane polarized light, 2.3mm.

(B) [73L8]: Monzodiorite. Seriate porphyritic with strongly zoned euhedral hornblende and zoned plagioclase (Iabradoríte cores, andesine rins). Crossed polars, 2.3mm.

(C) [7558] : Syenogabbro. Euhedral cl-inopyroxenes showing prominent oscillating zones from core to rim. Crossed polars, 2.3mm.

(D) 17577lz Monzoníte. Hiatíal porphyritic with euhedral phenocrysts of slightly zoned plagioclase and clinpyroxene. Note corroded rim of pyroxene, partially rnantled by hornblende. Snall euhedral biotite (orange) and anhedral epidote (top right). Plane polarized líght,8mm.

(E) [9563]: Atkali syenite. Cluster of euhedral zoned garnets with schorlomite cores and andradite rims in coarse grained alkali feldspar. PaIe yelIow and olivine green biotite, bright green turquoÍse clinopyroxene (aegirine-augite¡ . Plane polarized light, 2 . 3mm.

(F) [9563]: A,lkali syenite. Large clinopyroxene crysÈaI composed of salite core mantled by green aegirine-augite in alkali feldspar. Note purple fluorite (middle left), orange garnet (top teft) and sphene (centre). Plane polarized light, 2.3mm.

(c) [7508]: Syenite. Hiatial porphyritic with strongly zoned euhedral orthoclase phenocrysts in a fine grained felsic Aroundmass. Note weakly zoned plagioclase phenocrysts (oligoclase-albite), small (orange) biotite. Crossed polars, 18mm.

(H) l73O7l: MonzoniÈe. Seriate porphyritic with weakly zoned plagioclase (oligoclase-albite). Subhedral xenocryst of fine grained hornblende nantled by orthoclase (left), strongly altered feldspar phenocryst (right). Small (orange) biotite and (yellow) sericite alteraÈion. Crossed polars, 8mm.

Dístance in millimetres refers to width of field. --ol*[o-- .ll, -(} .e '-'f='.j J,¡

-.\ Ha I

. :..f +'. ttt ) 'a ¿ f¿

* il I l.à \

I '' '. '¡ t*. -t I .t ìG

t\ \ ,r- ,¿ 1 :tr'

-'t':tl ^'a ¿ - F- ,3r.ll . -'. -.¡. . Plate 4.4: Mineraloqv and Petrography - Alteration-

(A) [750].1: euartz monzonite. Large euhedral dark green-brown ñornblende crystals with thin margins that have been altered to pale qreen actinotite. Plane polarízed lighÈ, 2.3mm. (B) 17504)z MonzoniÈe. Sudhedral amphibole crysta] wiln.dark green hornblende core exhibiting more extensive actinolitization around the margin. Note complete al-teration of arnphibole to anhedral- actinolite to lower left and top centre. P1ane polarized. light, 2 . 3mm.

(c) [7306]: Monzodiorite. Hiatat porphyrytic with euhedral green ñornblende phenocryst, the rim of which has been replaced by biotite. This style of alteration is not considered to have occurred after complete crystallization of the magma, but as a Iate-stage volatil-e-induced reaction from increased water and potassium activities. Note zoned plagioclase phenocrysts landesine-oligoclase). Plane polarized light, 8mm.

(D) 17306lz Monzodiorite. Biotite euhedral pseudomorphs after ámphibole. Rectangular biotite crystal is partially replaced by light green chlorite. Plane polarized light, 2.3mm.

(E) [9596]: Syenogabbro. More extensively altered with anhedral äctinófitè (IlqhÈ green) and euhdral sphene (with thin dark brown rim). EpídoÈe ieplãcing core of feldspar crystal (centre right). Minor smalt euhedral apatite. Plane polarized light, 2.3mm.

(F) 195621: AIkaIi syenite. Large orthoclase laths in a sericiÈized and carbonatized groundmass. Crossed polars, 1-4rnm.

(c) [9051-]: euartz syenite. AlbiÈized, with feldspar cores replaced Ëy seiicite and ðalcite. Atbite forming around rims. Crossed polars, 8mm.

(H) [9532]: Albitite. Complete replacement by albite, some crystals ñot displaying multiple twinníng. Veinlets and patches of calcite throughout. Crossed polars, 2.3mm-

Distance in nillimeÈres refers to width of field.

--xxXxx-- 75 Nd (ppm) o a o O o O o 50 o o oo O tT.oo o o 25 o o

O o

150 Ce (ppm) o o b o o ao a o 10 ¡ o .I o o J r1 a t oo o 5 o oo o o O o o o o

0 t 0 1 TaOz wt.o/o 2 Figure 4.3.a a¡rd 4.3.b. Whole-rock Geochemistry for the Bungadillina Suite. hthole-rock geochemistry showing the concentrations of Nd (a) and Ce (b) relative to Tio=. Note the positive sub-linear relation for the euniaáiflina suite. As sphene is the doninant titaniferous mineral of the suite, the positive relation indicates thaÈ the light rare earth elements (IREE); Nd and Ce, are preferentially partitioned into sphene. Figure 4.4 o 10 T¡O2 wt.o/o A O Melanite & Schorlomite (9563) I lnclusions in cpx (9563) o a Xenolith (7901)

5 o o o o

¡ I Ca O wt.o/o 0 0 5 10 15 20 Andradite B o O Metanite & Schortomite (9563) ¡ t lnclusions in cpx (9569) o o o O Xenotith (7goi)

o(}

Grossular ¡ I Almandine Figure 4.4. Mineral Chemistry for Garnets of the Bungadillina Suite. Figure 4.4 .A. Relative concentrations of titaniurn and calcium in garnet. This diagran íttustrates difference between the Ti-rich melanite and schórlomite igneous garnets in atkali syenite [9563] and the Ca-rich Early proteroãoic (?t metamorphic garnets from a xenolith [7301]. Figure 4 .4 .8. Garnet chemical classificaÈion ternary diagrarn for igneous and metamorphic Aarnets within the Bungadillina suite. Andradite : cao(Fe*- rTi)zSi-orz. Grossular = CaeAl=Si-Or-=. Alrnandine : Feg*=AIzSigOr= . trf,gune 4"5"n: Fytr@xene G]lassÍffeatfon fon the llgneous llntrusf,ve Rocks of

lFhe treake and DenÍson Ranges "

CaSi 03 A SaI ite Ferrosal ite Diopsi rle Hedenberglte

<\ ^.-Ã.Ã.) f o òø

,o ð Augite Fer roaugi te o

Subcalcic iv AugÍte Subcalic Ferroaugi

Pigeonite

MgSi 03 FeSi 03 Cl inoenstati te Clinoferrosilite

Note: cross-hatched area represents zone of pyroxene composÍtions; aegirine-augite compositlons are not included. Figure 4.5.1. Pyroxene Classification for the Bungadillina Suite- Pyroxene ctassification diagram from Deer et a7. (L978) showing the composition for the pyroxenes of the Bungadillin Suite. Not' depicteã are the sodic pyioxenes (aegirine-augit,e) as their hiqh Na content relative to Mg and Ca would erroneously plot within the ferroaugíte field. A more detailed rendition of Ca-Mg-Fe inter- crystalline variations is presented in figure 4.5.4- 10(, 6 753 I 7539 7 539 7550

eo 1

00 t

7 2

60 I

õo o

roo 7558 9013 9520 õ 90 9570 a 80 t .70 2

00

o

roo 9570 958 2 9595 970õ t

eo a 80 t

70 2

oo I

60 o

7324 9583 9563 ô

too 1 9570 00 t

80 2

70 I

o CORE + FIX õo

ao /// Aa2ot (ß 30 ./ *"ru" Foxtoo 20

10

o COBE->¡¡¡ COßE COßE _> FIH ->Bttr Figure 4.5.2. Pyroxene Zoning (core to rin) Chenícal Variations. Microprobe analyses of individuat concentrically zoned crystal-s from core to rim. The number of analyses is dependent on the number of zones present as well as the size of each zone. Most crystals have three or less identifiable concentric zones. Few are strongly zoned (e.g. t75391). Distance from core to rim varies from O.2rnm t,o 0.05mm. preóisé meaéurements of this distance $tere not recorded. Zoning represents an inverse relation between aluminium content and Mg number lVtg/(Mg+Fe) I for most samples. Hohtever, the opposite relation áemonstraÈed in [9563] may correspond to sodium enrichment towards the margin, where the crystal is manÈled by aegirine-augite. FIGURE 4.5.3.

o¡

A ZO¡ID ?LU?OII IA? A

Xa ta ao a ra D l¡aLt tar ao Dlat la. o.t aaa a ¡il|. a O GOT .ttt:. aa a otr ] lue+rrror ^f,h. ¡ otrll ooo a a a aa 5 t la' aa + a I '¡ .'t I ¡ J 0¡ F.. a W o¡ ot o¡ I {t. î \ ztt¡allt.

B A loulH tl.ulo¡ IAt O ¡ Drr! lraral o laotl-al ¡ oÌtr  ¡ A A a ô A ¡ T. A A --J-ç, o ol t a at r o c.l o E ¡ ¡ ¡'¡ oo o ¡1. o' o-D oå A òDA o¡ ê OO |rtilr- l{rl. oo'!o ¡ tao^o o^a ^ a a-a a ^ I o.o c¡ ot o¡ ca I t|. oE o.t o Etr c . ltao¡ loa, o a ltatal ! o?lllt

o.al¡ ta C. aa lo

1l¡

a ^ a ^ I t a¡ ¡l ¡lt a A ¡ II âa tl¡ ot o¡ oa o¡ ¿?. Fignrre 4.5. 3 . Sodiurn Contents of the Pyroxenes of the Bungaditlina Suite. The sodium and total iron (Fe-* + Fe2*) contents of individual microprobe analyses of pyroxenes is represented by the cati-on proportion of ¡¡ã on the basis of a six oxygen total with a maximum four cation total. The sodium content is generally low (Iess than 0.1), but with some notable exceptions (t97061: pyroxenite cumulate xenolith, and 17326lz alkali syenite dyke). Most analyses record a general positive relation between sodium enrichment and iron enrichment. Figure 4.5.3.D demonstrates the zoning character and the Na enrichment óf [95631 and t9570]. The variation diagrarn showing Ca versus the Mg numÈer is also presented for other zoned pyroxenes in figure 4.5.4. The diagram demonstrates that pyroxenes with ferroaugite composiÈions are actually aegirine-augite (c.t. Fig. 4.5.L). FTGURE 4.5.4.

zo¡{ED F!U10t{ IAP A zot{ED ÞLU10X r^t A a oo ao aa¡1t. a.lll.

l

a E a + t¡ o + I ¡Ð o o E I I /

to A B j at (aooa+ lo t¡rtt a3 (rltat ao

arlll. Olot.lao a cott aallt. o it¡ ¡ olxti

D a J lrllt. + Ð torca¡flt. ¡ tta o Ð + ry ¡ ¡Ð /¿ o 4 t Faarcaallta

c D

aa ao laor r-a) aa to

toullt PLUIo¡ naP a Dlcr.la. a.lll.

a a + lù o + t to Ð I Ð t ¡ ll

a coit o it¡ ¡ ofHtt

E F al to C. at C¡ to Figrure 4.5.4. Detailed Classification and Chemical Zoning in Pyroxenes of the Bungadillina Suite. Displaved are þvroxene cation proportions of Ca:Mg:Fe¡e.oc.; presenteã iñ an x-y^ðliagram as oppoSed-to the usual Èernary diagrarn (Fig. 4.5.L). This provides a more accurate presentation of subtle chernical variations in the pyroxenes. Top Left and Top RighÈ: Zoned lriestern Pluton; Maps A and A'. Centre Left: [9005 & 7575]. Centre Rightz 173261. Bottom Left: [9012-3] Bottom Ríght: Southern Pluton Maps F', G & f. Tie lines are between contíguous phases or zones. Such zones may be within cores or rims, or nay be between cores and rims, âs depicted. Detailed classification of each analysis is outlined in each diagrarn. Note Èhe ferroaugitic rim composiÈion in 173261 corresponds to excessive Na (c.f . Fig. 4.5.3.8) . 1.0 Pyroxene N[g/Mg*Fe 96304 rt 7513c ou) 9012s o ot o) @ 9520F ¡ft õ o¡ 1.,. N u) ç ¡.. 75394 rO I 93114 o) + 75414 -n 95984 (o-a 9570F 7557s c U' .a @ 0.5 tO o lo ]t 95954 ¡ ('tsn

95t63F Whole Rock Mg/Mg*Fe

0 0.3 0.5 0.7 0.9 Figure 4.5.5. Comparison of hihole-Rock and Pyroxene Mg Numbers. Range of Mg numbers (Mg/Mg+Fe(È.oË.)) from pyroxene microprobe. analyses-comparéd to their iesþective whole-rock Mg number. The wide range in pyròxene chemistries in the alkali syenite [9563] corresponds to larying-concentrations of Na (c.f . Fig. 4.5.3.D). NoÈed is t'he general sinitarity for the Mg number range of all.pyroxenes regardless óf the variations- in the whole-rock chemistry. This índicat'ions pyroxene crysta.Il ízed. in similar chernical conditions, divorced f rom their present whole-rock associations. .J3 fo to .J3 Cro to ro co t tþ;,o Irooo E w \rv o oo t vE ttf" oo 3 Q-E OE o ' tO o oi o B-€ o of o o t? t t.'lo o

Ot o Elv t E uñ rY'

o o aolo lla¡O r o la¡a¿l lt¡o o llt¡o t o (r3a¿t r¡^o o ô l3-l¡O, o Lo¿a, llrno¡tr e lC-lrot o o I o dvt xotn.la H¡no3 0 av¡r xo¿n1d H¡no3 ¡ fo .J¡ .J3 ro to l'o Jo Jro co co o:fo# o o o^o oæ ' o oö^ "ooo o o o Çot o oo E t I ô o g'd OO ro o ot o CD oooo¿ È t'o o o o l¡ll E o rvl

E

acro E E to o v (l¿t¿, la¿a¿l lrooa aoa¿t t lot¿rv" Íad lÉra, o (3aaa, o o o lotaa o¿aat o c arro ro .Jt .t' f0 ro co ro ro co a a a a a a a I a aa at' a a ¡û0 o a a ¡'o a a a a a ún a I a tYt a loo a to

I Y avï xo¡n1d o¡iloz v Y av¡r xo¡n1d o¡¡oz TO Figrure 4.5.6. Pyroxene Chemistry Variations: 41, Mn and Fe(ÈoÈ.). Most samples record a positive relation between A1 and Fe, The enrichment of Fe relative to ÀI and Mn in [9563] (Figs. c and D) corresponds to high Na concentrations (c.f. Fig. 4.5.3). Noted is thaÈ the cumulate pyroxenite xenolith 19706l (fig. n) and the cumuLate rock L75751 (Fig. C) are strongly depleted in Ä1. All pyroxenes are also depleted in Mn, with the exception of the alkali syenite dyke 173261 (Fig. F). Concentrations are cation totals based on six oxygtens. Figure 4.6.1

Na+k<0.50 1.0 '.'f;i ).' ."î ocO t.tl .€3+ ' | , ¡.oo ,!lr. o oa Actinollte ù o^ 0.5 . Actino¡lt¡c-hornblcnde

0 Na+K)/=0.50 Fe3+

+ Edenlte Ferroan hornblende ôt a o o IJ. o o OO a + a o) a a oo 0.5 a a Gummingtonitc I =o) a O

Ferroan ornblende

0 Na+K>/-0.50 Fe3+>Al(Vl) 1.0 Magnesio-has

oo oa Edenltc o o nesian hastl a o O o t3. a oo O lr' o oo o o a -- I o Ll.)^t I Edcnltlc hornblende - ¡ o o o.t a o O a o

Magnesian ha ngsitlc b

0 ¡ &0 %0 6.0 Si per unit formula Figrnre 4.6.L. Ärnphibole Classification for the Bungadillina Suite. Arnphibole classification scheme after Leake (I978) based on microprobe analyses. The stoichiometry of the anphiboles l¡/as determined utilizing a FORTRÄN programme by Spear & Kinball (1984). Arnphiboles are mostly actinolite and ferroan hornblende with minor inèursions into the fields of hastingsite and edenite. Two anomalous cummingtonite analyses r¡tere also recorded. FIGURE 4.6.2

cor{cEitlRtc zot{tÎ{c a.o coilcE¡{lRtC ZOliltrc

rg T¡

a coat a cott ot¡ otr A I 1.O ¡.t a.o ¡t ,.o t.o ¡¡ F. t.o a.o a.o coxcExlFtc zoiltf{o coNcE¡{lFlC zof{lf{o

llg Ig

¿.o

c l.o D l.a a.o tl 7.O r.o t.o F. !.o a.o

tinEoutai PAIC|{Y zoNtxo IRNEOULAB PAÎCIIY ZOXIXO

\ \ ,2 Tg -a Il

a cott o tr F t.o t.t ¡t 7.O a.o ¡¡ F. t.o a.o

nvñFeLEr9E/ | tIULt fË ^9 HOnll!tEiloE/ ACltilOLtlE

Íl Ia

\

o r.o t{ t.6 t.o t'o al a.o 2.O t.o f. a.o Figure 4.6.2. Anphibole Chernistry Variations for the Bungadillina Suite. Arnphibole chemístry variations (cation proportions) of Mg versus Si (Figs. A, C, E & G) and Mg versus Fe¡c.oc.¡ (Figs. B, D, F & H) - The top four diagrams show variations in crystals displaying concentric zoníng. Figures E and F demonstrate variations in crystals displaying paÈchy or irregular phases. The bottom two diagrams show chemical variations between contiguous hornblende and actinolite. Tie lines are between core and rim, core-middle-rim, or contiguous phases. FIGURE ¿1.6.3.

3.O co¡tcEl{TRtc ZOf{t¡{O coxcEr{litc zo¡t]{o

a co[ o r --rc -o

2.O '!

C. ^t

't.a a co¡! o t

A B 6.4 ¡o tt t.o a.o t¡ a.o 3t r.o t.o ¡.o co¡{cEfllFrc Zorltrlc co¡rcENTRtc ZoXtXO a coil a coE or o tf

AI C¡

c D t.Ë t¡ ?¡ l.o t¡ a¡ a¡ t.o !¡ 'l tiiEouLAR PAlCltY ZONTXO

¿.o

Cr ^t

riiloul.^i PAlct{Y ZOfitNO E F

5.õ c.o alf.O a.o ¡¡ a.o ¡r 7.O l.o AClrfioLtll/t{onx¡L!rDE

a

-a C. ^t .¡

ACltt{OLtlE/r{ORil!tENDE G H 'l.a 3.6 c.o t.o a.o !l a.a a.o at t'o ¡.o Figrnre 4.6.3. Amphibole Chemistry Variations for the Bungaditlina Suite. Amphibole chemistry variaÈions (caÈion proportions) of AI versus Si (Figs. A, C, E & G) and Ca versus Si (Figs- 8,.D, F & H). The top foui diagrarns show variàtions in crystals displaying concentric zoning. figures E and F demonstrate variations in crystals displaying patchi or írregular phases. The bottom two diagrams show chemical iariaLions between contiguous hornblende and actinolite. Tie lines are between core and rim, core-míddle-rim, or contiguous phases. 1.0 Amphibole Mg/Mg* Fe'* lO 75414 ot 9012S 75394 9565 F rf) c) o, 95824 +' o) 96304 @ ø 9520F CD !L @ (> rO o) (t) rO fr 9023s or t¡t + OD gt, @ 73018 rO ô ôt 9541F -tl 1.,- ç o t¡t ç (o-. ¡'- ot 0058 0.5 J -lc frll I o 'll 95984 .À P dt ôt à ct 73038 ¡..

7513F

Whole Rock Mg/Mg* Fe'* 0 0.5 1.0 Fignrre 4.6.4. Comparison of Amphibol-e and Whole-Rock Mg Numbers. Range of Mg nurnbers (NIg/Mq+Fe(È.oÈ) ) from amphibole microProbe analyses-comparéd to their iêsþective whole-rock Mg number. Like pyroxenes (fig. 4.5.5), the arnphiboles display a wide range of Vtq¡y1g+fe values in comparison with respective whole-rock Mg numbers. fñerè may exist a stight increase in mean anphibole Mg numbers f9t whole roóf numbers frõm 0.5 to O.7, but for the most part, especially from rocks with higher Mg numbers, there is no variation in the amphibole values witn inðreasing whole-rock values. As amphiboles cornmonly reflect the chemistry of the rock from which t{t"y crystaliize, this indicates that the arnphiboles formed in similar chãrnical conditions, divorced from their present whoLe-rock associations. Figure 4.6.5

Concantric Zoning o Concentric Zoning T ¡ T¡ A B Zon.d Pluton Map A 'ð o Sill¡ ^ o Sllls Mep B

0.2 o o 0.2 o PlutonB Mep F Plutons M¡p ov eo 1 Soulh Pluton MBp G Pluton Map c

.t .q Ouertz Monzonltg ðð o e o 8 Na+K o Na+ K

0.4 Patchy Zoning 0.4 Patchy Zoning/Alteration Ti T¡ c Plutone uç F ab D Pluton¡ Mrp F t o o

"ie 0.2 o o o å o Zoncd Ptuton urp et o Slll. M¡p I ðo o o o South Pluton no' ¡ Mtp G

o oå Na*K o Na+K 0.¿ 0.8 12 0.ô 0.8 1.2 AI AI Concentric Zoning Concentric Zoning

Slll! Mrp B MrP B ( E Slll¡ F

ts6E3l

MlP

South Pluton Mrp G

Zon.d Pluton U.p t ? Zon.d Pluton M.p A Na Mg/Mo*Fe Na Ma/l4a+Fe AI AI Patchy Zoning Patchy Zoning/Alteration

G Slll! M.p B H b ¡ tP o rP Ouertz Monzonite o o South e oð o Plutonr Map F ão tJ

3 o Zon.d Pluton Map n -B

Na Mg/Mg*Fe Na Mg/f4glFe Figure 4.6.5. Amphibole Chernistry Variations Between Dífferent Plutonic croups in the Bungadillina Suite. This series of diagrams disptays variations in anphibole chemistries between different plutonic groups (zoned pluton of Maps A and A,; large southern pluton of Maps F' , G and I; sills of Maps B and B'ì plutons of Map F; IiSZS)¡ [9563]), with respect to different types of airphibole zoniñg (concentric, patchy or alteration). The top four diagräms show variations of Ti versus Na+Ki the bottom four show variations on the ternary plot of AI-Na-Mg/Mg+Fe(.o-)..Although specific regions can oftãn be identifiêd, the wide variations in amphibofe córnpositions are generally present throughout the different, plutonic regions. FtGUnE 4.7.f.

2.1 o o o r zo¡lD tluto¡ I¡t l Ðlt q al.ta I^" a I oow o a (tat¡+a¡ail I EO Eot Þ o (aaaa) rt¡¡ttr o vo v toult ^Lf¡Ltttutox llt o I "o^o t.t ;':å; 9a a a a a o I o o K a o F. oo OE :, . t.¡ I l. I "-ttí a^ ¿ :." ltolflE - - tHloooptÎÊ A B IJ t.s c.a a.l t¡ 8t 2.O ¡lg t'o a.o

¡.o o.c o ¡tolttE PHLOOO'T1E o o I ¡toTrlE I ÞHLOOOPIIE o ¡ I I I a I o ¡lr I o ¡ I .l 2.' f,r t¡ I o.a .J t. I L Ð t ' orv a J ril' I I to O vw EAI E qr¡ I ?r oo- a sl I ov t ooior ll ¡ I ooo l. a I a Fo ' o o o 2.4 T o ": a I I I o ooå a a o ta oo 1 I ¡ a a I a I a o c 'l D I 2-l lo OJ lo to to ao to rgll¡+F. H9llr9+F. Figrure 4.7.L. Biotite Chemistries and Classification. Presented are chemical variations of biotite for different samples/regions of the Bungadillina Suite (zoned pluton of Map A and A'ì silts of Map B and B'; Iarge southern pluton of Maps F', G and I; 19525 & 954L1ì and t95631). Analyses based on electron microprobe iesults utilizing a cation total from twenty-t\^io oxygens. Figure A (K versus Si) shows that bíoÈite from 19525 & 954L1 is most Si-rich, biotite from the zoned pluton of Maps A and A' is Si-depleted, and biotite from the siLls of Maps B and B' is most K-rich. Fígure B (Fe versus Mg) shows thaÈ biotite from [9563] (alkali syenite) is iron- rich and Mg-poor in comparison wiÈh biotite from other samples. Figure C (AI versus Mg number) shows that [9563] and the sills of Maps B and B, have similarly hiqh aluminium concentrations in biotite Èhan other samples. Figure D (Ti versus Mg number) shows that zoned pluton of Maps A and A, have the highest titanium concentrations in biotite. Thus unlike the amphiboles (Fig. 4.6.5), there are more clearly identifiable biotite composiÈions between different plutonic regions of the Bungadillina suite. 0.8 7558s Biotite Mg/Mg* Fe2* 9563F 9541F

959 3Q 95824 75018+ 75414 'n 73018 75424 (o-a I 9595A c ++ 95984 .a 95884 79128. + 7557s o + 731s8 .s J ]U

Whole Rock Mg/Mg*Fez* o.2 0.5 0.75 Figure 4 .7 .2. Comparison of Biotite and hlhole-Rock Mg Numbers- Range of Mg numbers (Mg/Mg+tê6=o.¡) from biotite microplobe analyses-comparéd to Èheir iespective whole-rock Mg number. The much more linited range of biotite compositions is in contrast to either pyroxenes or amphiboles (Figs. 4.5.5 & 4.6.4). Also note t'hat many of tñe biotite cornþositions have a positive linear relation for their whole-rock conpõsitions (from O.5O to 0.63, and from 0.60 to 0.75). The sinitarities in biotite - whole-rock chemistries indicate Èhat, unlike pyroxene or amphibole, biotite crystatlízed in situ, and thus reflect Lhe whole-rocÈ composition. The two separate positive linear trends may correspond to two separate pulses of magma; one more Mg- rich than the other.

Figure 4.8.1. Plagioclase Variations in Zoned Crystals. Core to rin compositions obtained from microprobe analyses are presented. The nunber of analyses from core to rim is.dependent on the èize of the crystat and the number of zones present within the crystal. Note that few samples display a continuous increase or deórease in the anorthite (An: CaAIeSi=Os) component from core to rim, but many display an overall decrease in the anorthit,e component from core to-rim.-Coies of many of the more anorthite-rich zoned plagioclase crystals have often been sericitized or albitized. roo

A B c D E

eo TI (o-. c -l b o o to .5 P lu to

7503 93tI 95C3 e5c3(bl to CORE -+ ilt COiE + ¡tt CO¡E it¡ CORE it¡ COit _+ it¡ -> --> 0J mm 0.1 mm 0.3mm 0.3 mm 0.05 mm Figure 4 .A.2. Alkali Feldspar Variat,ions in Zoned Crystals. Core to rim compositions obtained from microprobe analyses are presented. The numbei of analyses from core to rim is dependent on the ãíze of the crystal and the number of zones present within the crystal. Note Lnat few samples display a continuous increase or deðrease in the orthoclase (Or: KAlSi.Oe) component from core to rim, but rnany display a strong oscillating pattern. Or

Or

Or

b a

a An ¡at o ¡ a An a Ab An Figiure 4.8.3. Feldspar Ternary Di-agrams. Feldspar ternary diagrams showing compositions for both alkali feldpar and plagioclase. Apicies are Ab (albiÈe: NaALSi.O.); An lanorthite: CaAl=Si'O.) ; and Or (orthoctase: KAISÍ3oe). Opel_circles represent rin and coexisting compositions of ptagioclase, filled ciicles represent core and middle compositions of plagioclase and a1kali feldspar compositions, and filled squares represent whole-rock normative compositíons. Tríangle rrarr is f or the f eldspars of Map B and B, sills, and norrnative compositíons of [7301 , 7303, 73L2, 7315 and 7SO3lì triangle trbrr for the feldspars of the southern pluton of Maps F,, é and I, and normative compositions of [7558]; and trianglg rrcrr is for the feldspars of zoned pluton of Maps A and A', and normative composiÈions of 17539, 7542, 9528 and 95881. FIGURE ¡r.1O.1.

2+ t. +t. t+ ra2t + Fa¡t*r¡ ct

PtEUDOf HUNIXOITE

THURINGITE

DAtHttlE

¡r GLIXOCHLOFE lnuxEYrorlE CHATOSITE a¡

o PEXXtXTtE ¡¡ Y¡tt¡Îa DIAIAXT¡1E tnl. n¡¡atat

t.o DELESSITE TALC.CIILORTTE

¡¡ o¡ ¡¡ a, tt, ta 2t + Fa¡* Figure 4.10.1. Classification of Chlorite from the Bungadillina Suite. Chl-orite mineral compositions determined by electrom microprobe on the basis of thirty-tr¡ro oxygens. Classif ication scheme is after Hey (1954). Bottom x-axis is Fe(e-c.) i top x-axis is Fe ( coc. ) /Fe ( c.oe ) +Mg; y-axis is Si . Note two anonamously Fe-rich chlorite analyses may be associated wíth haematite. Table 4.8.l-: Co-existi Feldspar Geothermometrv. Analysis 73O3a 7303b 73O3c 7303d 7303e 73O3f 73L2a 73L2b AIkaIi Feldspar Ab 4.8 2.6 1t_.5 2.5 9.6 22.6 6.5 2.5 An 0.6 0 0 0 0 0 0 0 Or 94.6 97 .4 88.5 97.5 90 .4 77 .4 93 .5 97 .5 Plagioclase Ab 65.8 69.9 79.6 75.O 77.8 78.6 79.8 79.3 An 30.4 27.7 L7.5 L9.5 L9.5 L7 .3 18.3 L9. 3 Or 3.8 2.4 2.9 5.5 2.7 4.r L.9 I.4 Temperature oC a) 363 296 446 28L 425 563 372 276 b) 408 344 494 329 47L 637 41,7 324 c) 359 297 446 282 425 563 372 276 d) 3]-7 243 426 225 400 586 3 31_ 21,8 Analysis 731,2c 73L2d, 75oLa 750Lb 7503a 7503b 75O3c 7503d Alkali Feldspar Ab l_1.6 7.9 3 .1- 3.7 3.0 9.9 6.4 L4.L An 0 0 0 0 0 0 0 0 Or 88.4 92.L 96.9 96.3 97.O 90.l_ 93 .6 85.9 Plagioclase Ab 72.4 90.9 88.6 89.1_ 82.O 87.9 88.4 86.7 An 26 .6 8.3 10.0 9.8 L6.6 t_0 .9 10. 3 1-2.O Or l_.0 0.8 L.4 l_. l_ L.4 L.2 l-. 3 l_. 3 Temperature oC a) 466 375 284 299 289 408 356 458 b) 5l_3 42L 332 347 337 455 402 510 c) 467 375 284 300 289 408 356 458 d) 459 329 223 240 232 37L 307 437 Analysis 7503e 75O3f 75O3f 75039 7503h 7539a 7542a 7542b Alkali Feldspar Ab L6.4 l_3.5 3.7 2.4 5.1 4.8 2.8 5.7 An 0 0 0 0 0 0 0 0 Or 83.6 86.5 96.3 97 .6 94.9 95.2 97 .2 94.3 Plagioclase Ab 86 .6 82.5 97 .4 65.l_ 87.9 92.3 85.5 95.0 An t_1. 3 L5.7 L.2 33.5 l_0.8 7.O L2.9 3.7 Or 2.L 1.8 t.4 L.4 t-. 3 o.7 L.6 1_. 3 Temperature oC a) 48L 462 290 292 332 320 278 334 b) 536 5L3 338 339 379 367 326 381 c) 48r 463 290 292 333 32L 278 334 d) 466 446 227 235 279 263 2L8 278 Table 4. 8. L (continued) : Co-existinq Feldspar Geothermometry.

Analysis 7542d 7542e 7542f 7558a 7558b 7568a 7568b 7568c Alkali Feldspar Ab 4.3 4.5 l_0.1 6.0 8.0 6.7 3 .1_ 7.L An 0 0 0 0 0 0 0 0 Or 95.7 95.5 89.9 94.O 92.O 93.3 96.9 92.9 Plagioclase Ab 97 .5 70.8 60. 3 75.5 91.8 66.8 64 .5 68.7 An L.2 27.3 36.l_ 22.9 6.8 30.9 34.2 29 .4 Or L.3 L.9 3.6 L.6 1-.4 2.3 1-. 3 r.9 Temperature oC a) 303 346 482 370 375 402 318 405 b) 3 51_ 3 91_ 525 4l_5 422 446 364 449 c) 304 346 482 370 376 402 318 406 d) 242 302 477 332 329 373 265 377 Analysis 7568d 757Oa 757Ob 757Oc 757Od 93LLa 931-1b 957Oa Alkali Feldspar Ab 6.2 4.1, 7.9 2.8 6.9 1-9.9 22.L 4.8 An 0 o 0 0 0 6.0 0.9 0 Or 93 .8 95.9 92.L 97.2 93 .1, 75.9 77.O 95.2 Plagioclase Ab 70.o 97.L 99 .2 65.l_ 97 .4 74.1, 70.4 7L.9 An 28.7 2.2 0 l_8. L L.5 L9.6 27.O L9 .6 Or 1.3 o.7 0.8 L6.8 1.1 6.3 2.6 8.5 Temperature oC a) 385 299 363 306 351- 556 596 3 51_ b) 429 347 4l_0 353 397 62r 669 397 c) 385 300 363 307 351 550 586 352 d) 351_ 238 3t_1_ 258 297 575 633 309 Analysis 9574a 9582a 9588a 9588b 9588c 9588d 9588e 9588f A1kali Feldspar Ab 1-2.4 L.2 L2.L r.7 3.8 2.3 6.7 2.7 An o 0 o.2 0 0 0 0 0 Or 87 .6 98.8 85.9 98.3 96 .2 97.7 93.3 97 .3 Plagioclase Ab 87 .4 97.7 6L .2 93 .8 92 .2 94.O 90.5 87.2 An 9.2 1,.4 36.0 4.7 7.L 4.9 8.7 Lt_.1 Or 3.4 0.9 2.8 L.5 o.7 t_.1 0.8 r.7 Temperature oC a) 438 202 5t_0 230 298 253 357 273 b) 488 253 556 280 346 302 404 322 c) 439 203 493 230 298 253 358 274 d) 409 133 495 L62 238 r87 308 2r2

Geothermometric calculations at lkbar pressure based on:

a ) Stormer J.C., 1-975. b ) Storrner J.C. & hlhitney J.4., L977. c ) Powell M. & Powell R., L977. d ) Haselton H.T., Hovis G.L., Hemingway B.S. & Robie R.4., l-983. Figure 5.2.1 AI A x Figure 5.2.2 o o o A o K2G o I o o 8 o o (D o@ I o oo o o ooo--o ôo o oo o o o o o$ 8.3 o11o"o P"P- $s AtKaNno o o Ca+Mg Na+K 8.9 þ F oo o 5.9 oo

B e o o 2.1 1.0 o B o o 2O+d( 84" oo o o I c 0.8 oog 3o o o oo oo o o o o o o oo oo o o 0.6 o oo o o o o oc 3fJ" o o 0.4 A M o o o Norm. Quartz o.2 o c 45 55 65 75

oo Na 20 oo o Norm. Albite oo 8 Norm. Alkali o o o o o o c" o o oo o o o o Feldspar 10 o ot$ "s o o o $ao o o I y. s o o o o o o@ o A ".1" oo o o o o o oo o o B

100K20/Na2O+KãO Norm. Nephellne 0 0 20 40 60 80 Figrnre 5.2.L. Classification of the Bungadillina Suite. A) Classification of the Bungadillina suite after Shand (L927). Speckled area shows range of compositions, demonstrating the Bungadill-ina suite to be metalumínous. x:peraluminous y:metaluminous 2=pêtdlkaline B) A-F-M ternary plot for the Bungaditlina suite. A = totaL alkatis, F = total iron, M : magnesium. Lines represent various trends: a = tholeiitic, b = alkalinet c = caLc-alkaline. Circles (non-atbitized) and diamonds (al-bitized) represent the Bungadillina suite. Albitized samples have Na2O/Na2O+KzO<0.76. Non-albitized samples have NazO/NazO+K2O>0.76. C) Normative double quadrilateral diagram for quartz-albite- nepheline-alkali feldspar. Circles (non-albitized) and diamonds (albitized) represent the Bungadillina suite. Albitized samples have Na2O./Na2O+K2O<0. 76. Non-albitized samples have Nazo/Naao*Kzo>0. 76. TñIs'alãéräm-demoñstiãtes Lñat, the Buhgadillina suite is both nepheline normative and quartz normative.

Figrure 5.2.2. A) Alkaline subalkaline classification of the Bungadillina suite, after Miyashiro (L972). Circles (non-albitized) and diamonds (albitized) represent the Bungadillina suite. Albitized samples have Na2O./Na2O+K2O<0.76. Non-albitized samples have Nazo/Nazo+K2o>0.76. TñÏs' äiãéräm-aèiroñstlãtes tñe ãtfalinè character of' the Bungadillina suiÈe. B) fdentification of albitization (sodic metasomatism) in the Bungadillina suite. This diagram demonstrates the presence of an apparent miscibility gap for Na=O-rich samples (dianonds) at aþproxinately Na2O/Na2O*KzO = O.76. Note that sodium enrichment is independent of silica content. C) Igneous field (B) as defined by Hughes (L972). Note that all of the albitized samples of Èhe Bungadillina suite (dianonds) plot outside of the igneous field, while most of the non-albitized samples (circles) plot witnin tne igneous field. Syrnbols for Èhe Bungadillina suite have been designated from figure 5.2.2.8 (above). Figure 5.3.1

22 o 12 4t203 A o CaO B @ o o o "- o 16 "": ' o o o o 8 oo o o o o 10 o 4 o oo (D o8 o o o og o 4 o oo oo oo3o 0 - 12 o I Fe203 c FeO o D

o I o o so oooo o 4 o 6æ o o o (D o o o o 4 o g ú o o o o.o oo o þ oo oo oo o o o og o o ogo o o 0 o o o 0 ot o 12 12 Na2O

^@o o o8 Uo 4 o ooo 4 o tflo o o o o oo ooo I o oo o oo oo8o3 o o o o 8 0 ooô g 45 0 55 65 75 45 55 65 75 S¡O2 wt.% SiO2 tul.o/o Fignrre 5. 3 .1. lilhole-Rock Geochemistry of the Bungadillina Suite. Major oxide variation diagrans for the Bungadillina suite. Circles represent non-aLbitized samples (NaeO/NazO*KzO < O.76). Diamonds represent atbitized samples (Nazo/Nazo*KzO > Figure 5.3.2

0.8 o MnO t¡'t'L.o/o A MgO t¡,tt.o/o B

o 0.4 oo oo o o oo 5 o o o8 o o o o ds"fs o 8o oæ d o o o o (Þ o o o oJdj oo o! o o o oo 0 2 T,O2 t¡'tl.o/o o c o D P2O5 r¡,tt.o/o o o 1.2 o o o 1

o 0 o oo "'a1"" o i 0 0 bL 50 F ppm 4000 E Cl ppm F

o 00 o o o o o o o o o o 2000 o o o o o 8 500 q o o o t o o o 8o o g o oæ g o 8 o o o oo þ 0 oto o ; o 75 55 65 75 SiO2 t¡,tl.o/o S¡O2 w¡..% Fignrre 5.3.2. Whole-Rock Geochemistry of the Bungadillina Suite. Major oxide and Èrace element variation diagrams for the Aungadillina suite. Circles represent non-albitized samples (Na2O/NaeO*KzO < O.76). Diamonds represent albitized samples (NazO/NaeO*KzO ) O.76). Figure 5.3.3 1.0 Na20/K2O+Na20 8 Mgo o A o o@ B o o 0.8 trl ¡o o 4 tr tr_ o -8 0.6 utrotro o tro-o o o #og o o tr

tr 0 10 Na2O 11 FeO* o c CD I o o o o o o 9tr o o 6 v tr o o f o tr 4 J.Aão o 1 7 K20 20 Ar203 E F È o o 5 eo o -64' tr 16 o o zK: o 3 /.tr' o tr o o 1 o 12

10 CaO 1.2 Tio2 G tr o tr tr o-o trtr o ofu o oo 6 o o o.7 tr Ìrt-: oto o o'a tr o t e a 2 o.2 50 70 2 SiO2 wl.o/o CaO wt.o/o Figrure 5.3. 3. Whole-Rock Geochernistry of the Bungadillina Suite. Major oxide variation diagrams for the plutons of Maps A and A' (after Morrison & Foden, 1989). Circles represent the quartz monzonite body present in both Maps A and B'19590-31. Squares represent non- at¡itized samples (NazO/NazO-FKzO < O.76) . Diamonds represent albitized samples (Na=o7¡tazo*Kzo > non:albiÈized' samples in each. diagram. Figure 5.3.3 (continued) o 160 0 o Zr ppm o o o 130 o o o o o o o 40 Sc ppm 100 o o 30 I o

70 o B 14 o 20 Nb ppm o o o tr 10 go 11 o o tr

o o o o 8 o o V ppm o 400 o o o o 5 o 260 o Y ppm 50 o o o o 6 o6 120 o o o 2 6 10 30 o cao wt.o/o o o o o

10 2 o CaO wt.o/o 10 Figure 5.3.3 (continued) . Whole-Rock Geochemistry of the Bungadillina Suite. Major oxide and trace element variation diagrams for the plutons of Maps A and A, (after Morrison & Foden, 1989). Circles represent the quartz monzonite body present in both Maps A and B'[9590-3]. Squares represent non-albitized samples (Na2O/Na¿O*KzO < O.76)., Diamonds rebresent albitized samples- (Nazo,/Nazô+K=O > o.76). Best-fit, lines are prèsented for the non-albiti2ed sãnp1es in each diagran. Figure 5.3.4 I 10 a Na20 A Na20 B aa a a I .:. a

a a ao a ¡. t a a .t'

a

a

0 0

6 I Kzc. oa Kzc o D a a a c a a .t a a a a a a a aa a a ¡ a t

a ¡¡ ¡¡ ¡ ¡a 0 0

I 12 E Cao F ¡ CaO a a o a a to t. a I aa r¡. a a a I

¡ a - a a' a 0 0 (south) 50 S¡O2 wt.% (sills) 70 50 S¡O2 wt.7o 70

20 19 At203 t¡ H a a a a ¡ ¡ At203 a !¡ ( a a o¡ o¡ ¡¡ aa a a a

a a 12 4 0 CaO wt.% (sills) I 0 CaO vvt.o/o (south) 12 Figrure 5. 3.4. hlhole-Rock Geochemistry for the Bungadillina suite. Major oxide variation diagrams for the intrusives of Maps B and B', and the southern plutons of Maps F', G and I. For Maps B and B'; circles represent siI1s, squares represent plutons and diamonds represent xenoliths (figures A, Ct E & c). For the southern plutons (Maps î, , c & I); circles represent undifferentiated samples, squares represent xenoliths and cumulates (figures B, D, F & H). Lj-nes ttTough tné diagrams are the chemical trend lines for identical comparative diagrams for the western plutons of Maps A & A' (c.f. Fig. 5.3.3), after Morrison & Foden (1989). Note the close placement of most samples with respect to the lines. Figure 5.3.S

12 20 *FeO A *FeO B

ta ' aa l¡o o a a o¡ ¡ a a I a a a a a t ¡¡ a 0 0

5 15 a Mgo c Mgo D

a a a

oo oo 1tt¡ ' a ¡ a ¡ a a ol I a a 0 0

50 50 Sc ppm E Sc ppm F

a

a oo a o a aa a a a a a a I - a a ¡ a a a 0 0

350 ô00 V ppm t¡ V ppm H

a ¡ a a a a a a ( ¡ ¡ ¡o a t a a a a I ¡ t 50 0 0 CaO wt.o/o (sills) I 0 CaO wt.% (south) 12 Figrure 5.3 .5. hlhole-Rock Geochemistry for the Bungadillina Suite. Major oxide and trace element variation diagrams for the intrusives of Maps B and B', and the southern plutons of Maps F' , G and f. For Maps B and B'; circLes represent sills, squares represent plutons and diamonds represent xenoliths (figures A, C' E & G). For the southern plutons (Maps F' , G & I); circles represent undifferentÍaLed samples, squares represent xenoliths and cumulates (figures B, D, F & H). Lines through the diagrams are the chemical trend lines for identical comparative diagrams for the western plutons of Maps A & A' (c.f . Fig. 5.3.3), after Morrison & Foden (1989). Note the close placement of most samples with respect to the lines. Figure 5.3.6

2 TO2 A Ti02 B

a a a ¡ a

a ¡ a a ¡ tt,/' a oo a I a

a a a a

0 0

200 400 Zr ppm c Z¡ pgm (t D a a a I a a a a a a a aa I o a o¡ a o a ¡ a l' a a a 100 0

40 55 Y ppm I L Y ppm F

¡ ta' a a a aa a t a t f . a a a aa a ! a

0 10

14 't2 a H Nb ppm ti¡ Nb ppm a t a

a a t a a a a a a a .t' at o a a a 4 3 0 CaO v'¡t.% (sills) I 0 CaO wt.% (south) 12 Figrure 5.3.6. lilhole-Rock Geochemistry for the Bungadill-ina Suite. Major oxide and trace element variation diagrams for the intrusives of Maps B and B', and the southern plutons of Maps F' , G and I. For Maps B and B'; circles represent sills, squares represent plutons and diamonds represent xenoliths (figures A, C, E & G). For the southern plutons (Maps F' , G & I); circles represent' undifferentiated samples, squares represent xenoliths and cumulates (figures B, D, F & H). Lines through the diagrams are the chemical trend lines for identical comparative diagrams for the western plutons of Maps A & À' (c.f. Fig. 5.3.3), after Morrison & Foden (l-989). Note the close placenent of most samples rrith respect Èo the lines. ppm. A Rb Figure 5.4.1 400

o o o 300 200 o Cr ppm B oo go o o@ o oo o o 200 o $ So o o o æ a $ 0 o 2000 o o o Sr ppmo o c 100 o o o o8 o o d-oo oo o o o ooo o oB o o s o o I ooo o o% oo o "To-o 0 1000 { o oo I 80 o o å-" &€oo oo o D o s'3 to o o o 33 tooo oo o o e oo o o o$o o Ni ppm o o o oo o o o i" tr o oo o þ @ o 0 40 o o 3000 o o 6 o o Ba ppm o E oot o o o 2000 00 o o o o $ o 55 65 75 oo ooo I o oo S¡O2 t¡,tl.o/o o I s o o (D I o o 1000 o6o o o88o b 8 o t ""tï"- o o o 8 o o oo8 o o o o o o

o

200 ""7 "" o oo oQo 0 oo o eËffi oc 1" ô o o oo o o O^ o .g ¿3 0 14 (ppm) Nb o o c 60 Sc (ppm) oo o o o o * o a oo oooo ã"g o 80 o' r 88 40 8o o o a gtr* o cpo 7 å aoo . o o æ I o o o ooJ".oo-o' ooo o oo o I o 20 ooo o oI o o

o o a"8

o ooo 8 ooo@oo 40 o o $ o SosRÞooQB 06& g o 20 o oooGrb@@(Þæ@æoo o ooSB9ooo$oo ooóEDo ó o o ooo oo o o o oooæo o o oo 20 oo oo i o o E-o 10 E oo o o o o o 0 0 45 55 65 75 45 55 65 75 S¡O2 t¡,tl.o/o SiO2 wl.o/o Fign¡re 5.4.2. hlhole-Rock Geochemistry of the Bungadillina Suite. Major oxide and trace element variation diagrans for the Bungadillina suite. Circles represent non-albitized samples lNa2o/NazorKzo ( 0.76). Diamonds reþresent albitized samples iua=O7¡¡azorKeo. > Note albitiãed-samples have sirnilar trace èlemeht concentratr-onsO.76\. as non-alþrELzect sampres. 0.730 sbrratr 0.715 8?sr Total Rb-Sr lsotope Dala pluton A Zoned Map A x, Carbonate B + Albltlte o

o c o o --E C¡ c c o c c o c oot ooo t+ oo þ3{ c I tnoftr 0.700 Etnoft, 0 o.700 0.8 0 0.6 0.715 Etsrfbt 0.7t5 Slll Swarm Map B sbrftr plutons c South Maps G&H oo D o o o o o o

87nofb, 0.700 87n¡fbr 0 0.700 0.8 0 0.6 Fignrre 5.6.1. Rubidium - Strontium lilhole-Rock Isotopes of the Bungadillina Suite. presented are the results of whole-rock Rb-Sr isotope analyses for selected areas of the the Bungaditlina suite. Figure A displays all Rb-Sr isotope data. Figure B displays data from the zoned pluton of Maps À & 4,. Figure C displays data from sills of Maps B and B'. Figure D dísplays data for the southern pluon of Maps F', G and I. The stiaight line tñrough the data points in each of the diagrams.is.not an isõchron, but delnonstrates, by inspection, the extreme variability of the data; rendering any attempts at geochronology useless. Figure 5.7.1

Average Syenite A o c G tr 100 Auerage Syenogabbro >@ .E.H

À o E. 10 E (ú U) Average Albitite

I lrl I I 1 RbKNb Ce Nd Zr Ti Y Ba Sr

rage Alkali Syenite B o c al E 100 o .E

È Averag e Albitite (D o- 10 E ct CD Average Quartz Syenite

1 Rb K Nb CE NdZT TÎ Y Ba Sr Figrure 5.7 .L. Comparative Trace-Element Diagrams Within the Bungadillina Suite. Comparative ltspider-gramsrr for average values of various lithologies in the Bungadillina suite. Absolute values are presented in Table 5.1. Note sinilar values for differing lithologies, with the exception of albitite, which shows consistantly low LIL (large-ion lithophile) element concentrations. Figure 5.7.2

rage Alkali SYenite A

@ y 100 ¡- d E Average Syen abbro o P E E ï o- 10 o o- Average SYenite E cl CI'

1 Nb a"rr*O Zr Ï Y ^Or"*

B o Average Quartz SYenite € Ê 6 E 100 Average Lachlan l-TYPe o .Ey

È o CL lu E qt U) Average Lachlan- A -Type

1 Rb KNb La Sr Zr ï Y Ba CE NCI Fignrre 5.7.2. Comparative Trace-Element Diagrans Within the BungadilLina Suite, and with Average ttType,' Granj-tes from the Lachlan FoId BeIt. Comparative trspider-gramsrt for average values of various lithologies in the Bungadillina suite (figure A). Absolute values are presentèd in Table 5.1-. Note similar values for differing lithologies, (c.f. Fig. 5.7.L). Figure B compares the average quartz syenite trace element chemistry (Bungadillina suite) with average 'rI-typerr and rrs- typett granite values from the Lachlan Fold Belt (after White & Chappell (L983). Note demonstrably different values for most elements between the Bungadillina quartz syenite and Lachlan Fold Bel-t granites. Quartz syenite was chosen for comparison as it has a silica content closer to Lachlan Fol-d Belt granites than other Bungadillina average lithologies. Table 5.1: Summary of the Geochemistry of the fntrusíves of the Peake and Denison Ranses.

Quartz Syenite (3) Quartz Monzonite (5) Range Mean Range Mean

Sio= 62.94 63 .70 63 .4L 63.23 67 .1,O 65.03 o.27 0.33 0.31_ o.23 0.34 0.30 liga= ]-6.42 t_ 6.82 L6.59 1-6.54 l_8.02 L7.22 FezOa l_.58 2.L6 1.86 0.90 L.90 1.53 FeO 0.58 0.83 o.72 o .47 r.25 0.80 MnO 0.05 0.06 0.05 0.04 o.07 0.05 Mgo 0.49 0.86 0.63 o.37 0.85 0.53 CaO 2.06 2.70 2.29 2.37 2.58 2.50 NazO 5.22 5.61- 5.39 5.38 I .24 6.01- KzO 6.20 7.L9 6.73 2.50 5.81_ 4.37 PzOs 0.08 0. L1- 0.1_0 o.07 0.1_0 0.09 HzO* 0.9r_ L .66 1- .37 0.53 L.50 L.01_ Total TUSZ - 99õr TTST ggrz - 9v-õ' 99Ã4

F 3l_ 0 360 335 60 400 225 c1 250 330 282 90 l_50 L27 Sc 5.3 6.2 5.7 4.9 6.6 5.8 v 76 99 88 50 86 65 Cr <5 <5 <5 <5 5 <5 Ni 1 4 3 1_ 6 4 Ga l_8 20 L9 L9 20 L9 Rb I84 21-2 L97 30.2 1"48 ],04 Sr 11_l_6 L21,2 116 3 79L L470 1081- Y 16.1 18.4 L7.3 1_3 .5 26 .1, L6 .6 Zr L43 186 166 L1,7 136 r29 Nb 8.7 10 9.2 6.7 8.L 7.3 Ba LL94 L250 L224 8L9 1053 857 Ce 53 64 58 36 49 40 Nd 1_4 19 L6 1,2 20 L4

Major oxides as weight percent. Number of analyses for calculations in brackets (#). Trace elements in parts per rnitlion. Table 5.L (continued): Summary of the Gqochg¡qislry qf the Intrusives of the Peake and Denison Ranges.

A1kali Syenite (5) Syenite (9) Range Mean Range Mean

SiOz 52 .82 6I.96 57.55 51_.95 64.43 58.88 Tioz 0. 34 0.85 o.52 0. 35 0.83 0.54 AlzOo l_5.40 18.11 L6.93 l_5.43 18.70 16.68 FeeOo 2.92 5.98 4.09 1-.77 4.93 3.27 FeO 0.06 3. l-9 l_.39 0.55 3.29 L.58 MnO 0.03 o.t0 o.07 nil 0.09 0.05 Mgo o.75 2.22 1,.2L 0.59 4.86 L.82 CaO 0.59 4.94 2.76 0.68 7.2L 3.78 NazO r.70 4 .89 3.74 4.39 6.2r 5.22 KzO 8.13 l_0.93 8.7L l_. l-9 6.93 5 .22 PeOs 0.13 0.41_ o .23 0. l_l_ o .67 o.29 HeO* L.32 3.23 2.LO 0.48 4 .66 1_.98 Total 9T.T7 - 9v_'8 9930 99;Ir5 9v3(' TT32

F L20 870 460 200 950 437 CI 260 71,O 455 t_55 680 390 Sc 6.4 22.1, L2.7 6.l_ 36 16.9 V L16 258 1,69 73 274 161 Cr <5 I7 9 <5 52 I6 Ni 5 13 I 4 L7 9 Ga 15 2L 18 L7 22 L9 Rb L76 448 288 55 209 L37 Sr 970 L920 1,461, 466 1,2LT 796 Y 9.9 26 .6 1_9.3 L4.3 36 23 Zr 134 L76 L46 l_04 L79 L46 Nb 8.8 l_0.1- 9.5 6.9 L2 8.8 Ba L357 2582 1897 2L7 L758 LL22 Ce 56 LL2 85 40 t_05 66 Nd 1,9 57 32 l_3 44 25

Major oxides as weight percent. Number of analyses for calcul-ations in brackets (#). Trace elements in parts per nillion. Table 5.l- contínued S of the Geochemist of the Intrusives of the Peake an son Ranges.

Monzodiorite (5) Monzonite (40) Range Mean Range Mean

SiOz 55.96 58.45 57.59 51.91 66.85 59.3L TiOz 0.56 0.80 0.66 0 .2r 1 o2 o.57 AlzO- 1 6.50 l_8.65 ]7.65 l_ l_ .0L 1_8 56 L6.68 FezOo 2.96 4.08 3 .60 0 .72 5 57 3.l_3 FeO 1-.77 2 .49 2.L5 0 .1-9 3 74 L.66 MnO 0.08 0.1_3 0. l_l- 0 .0L 0 L4 0.07 Mgo I.28 2.3L L.83 0 .48 3 93 2.OO CaO 4.7L 5.99 5.28 1 .05 7 30 4.25 NazO 4.45 5.33 4 .89 4 .L4 8 90 5.77 KzO 3 .46 4 .45 3 .86 0 .60 5 55 3 .55 PzOs o.22 o.34 o .29 0 .08 0 60 0.31_ HzO* 0.54 3.39 1_.33 o .53 9 59 2.04 Total 9E:"9g - 99-A 9U.ZJ 9gã3 -TUII;[T' 9T34

F 360 760 494 80 l-t_50 400 c1 l_1_s 370 274 90 940 32L Sc 1_l_. l_ 1-8 .4 L4.3 4 33 L5 v 1_05 L66 l-40 59 251, L42 Cr <5 L9 9 <5 70 15.5 Ni 5 1_ l_ I 3- 2L 1L Ga L8 22 20 L2 23 l-9.5 Rb 63 L23 96 9.2 l_58 82 Sr LO67 LL4], Ll_1_l_ L96 1-402 620 Y L6 34 26 7.2 35 22.4 Zr t_1,9 152 L35 87 L87 L37 Nb 7.8 1,2 9.6 5 1 0.8 8.4 Ba 669 l_046 790 l-58 L489 767 Ce 54 72 63 39 t27 62 Nd L9 37 26 9 61 25

Major oxides as weight percent. Number of analyses for calculations in bráckets (#). Trace elements in parts per nillion. Table 5.1- (continued): Summary of the Geochemistry of the Intrusives of the Peake and Denison Ranges.

Monzogabbro (5) Syenogabbro (20) Range Mean Range Mean

Sio= 50.80 55.79 52.87 48.55 55.36 51, .67 TiO= 0.70 0.9L o.76 o.77 1,.94 r.02 AIzO¡ 1,4.89 1,6 .40 t_5.55 4.78 1,6 .57 ],3.52 FezOs 3.83 8.58 5.L7 1,.70 l_1.39 5.60 FeO l_. t-6 3 .51. 2.89 1.90 7.OO 3.97 MnO 0.03 0. l_l_ 0.09 0.05 0. t_9 0. L3 Mgo 3.34 4 .87 3.96 2.4L 8 .47 4.97 CaO 5.43 7.1,5 6.39 5.54 L2.98 8.39 NazO 3.91- 6.56 5. l_6 r.40 5.76 4.05 KzO L.0l_ 5.23 3.15 0.39 7.32 3 .41- PzOs 0.45 o.74 0.59 0.39 L.63 o.78 H=O* o.78 4.80 2 .62 0.53 5.79 L .69 Total 9v;ft6 - 9q30 TTZT. 9s-9 - 9933 9gß

F 390 780 61,4 260 t_ 380 73L c1 205 930 503 200 t-390 473 Sc 23.L 35 28.4 2L.8 64 34 .5 v 206 270 234 t_85 589 292 Cr 33 47 40 <5 20L 45 Ni 1,6 26 2L 9 74 22 Ga l_8 L9 l_8 t_0 22 L7 Rb 34.4 L62 97 8.7 272 97 Sr 659 957 783 l_90 L770 990 Y 23.t 31_.8 26.8 L6.4 53 3L.4 Zr 1_06 I48 L1,9 45 20L t-09 Nb 6. t_ 8.8 7.5 3.7 tt.8 7.7 Ba 252 1-637 787 1_08 2383 878 CE 57 72 64 34 L46 82 Nd 2L 36 28 22 75 40

Major oxides as weight percent. Number of analyses for calculations in brackets (#). Trace elements in parts per rnillion. Table 5.1- (continued): Summary of the Geochemistry of the Intrusives Déni son Ranges.

Albitite (L7 ) Biotite Lamprophyre Range Mean 9327 9627

SiOz 57.08 7 1- .1-5 63 .68 49 .86 50.58 TiOz 0. t_0 0.81 0.41 l_.00 o.92 AleOa 2L.38 L6.L9 L7.97 l_3.33 13 .44 Fe¿Oo 0. l_0 4.80 l_.53 4.27 5 .28 FeO 0 .04 t.42 0.48 3 .50 3 .90 MnO niI 0.09 0.03 o.07 0.04 Mgo níI 2.L3 o.76 4 .47 5.70 CaO o.22 4.38 2.2L 7.56 6.26 NaeO 8 .44 t_0.69 9.30 5.18 4.L7 KzO o.24 2.1,5 o.79 3.40 4.68 P 2 Os o.02 0.33 0.l_6 o.72 0.84 H 2 o* o.32 5.L4 2.L4 6.09 3.31_ Tota 1 gE:-qg . TTÆ T9-6 gTÃ5 9Fr0

F 80 L820 330 460 340 c1 t-05 9L0 277 975 760 Sc L.3 18.9 7.9 38 4r.5 V l_8 l_38 85 273 275 Cr

Major oxides as weight percent. Number of analyses for calculations in bráckets (#). Trace elements in parts per million. Table 5.6.1-: Rb-Sr Isotopes for Intrusives of the Peake and Denison Rancres. Sample Rb (ppn) Sr (ppm) ttRb,/ttSr e7 Sr /'63r Western Zoned Pluton, Map À. 7525 9.68 1,229 .68 0.32181_ o.70872 753L l_08.23 896.33 0.3431_l_ 0.7091_0 7539 9.90 639.83 0.0461_3 o.70739 7540 60.13 1,277.OO o.L4075 o.707BL 7540 (R') 60. r-3 L277.OO o .]-407 4 o.70726 7540 (R= ) 60. L3 L277.OO o .]-407 4 o .707 44 754L 51.65 86L.75 0.l_7658 o.707L7 7542 L24.68 843.2L o .43026 o.70939 7550 58.17 L346.L7 o.L27L3 o.70729 9582 24.97 L21-6.73 0.06006 o.70697 e582 (R) 24.e7 L216.73 0.05936 o.70499 9583 1,OO.92 L247.7L o.23379 o.70802 9588 9L.36 l_070.50 o.24949 o.70842 9590 rL9.40 801.81_ o .43173 o.71,OI9 9592 Ll-4.83 LO37.93 o.32247 o.70907 9593 LO7.77 984.l_5 0.32086 0.70884 Si1Is, Map B. 7300 t_03 .78 689.7L 0.43540 o.70866 7301, 9L. L0 767.30 0.34360 0.7101_1 730L (R) 9l_.l_0 767.30 0.34360 0.71_006 7303 LL8.23 LO2L.36 o.33494 o.70842 7303 (R) 1L8.23 LO2L.36 0.33495 o.70845 7304 ]-08.26 645.34 0.48556 0.711_59 7306 L23 .86 Lr26.47 0.3181_4 o.70789 7309 L40 .47 554.26 o.73362 o.7L238 73r2 94.68 870.86 o.3L463 o.70984 731,6 103 .54 666.87 o .44939 o.7rL66 7318 LOz.32 LL62 .62 o.26707 o.70706 7320 23]- .67 994.20 o .67 445 0.71_108 Southern Pluton, Maps F& (¡. 7558 L22.30 L793.91, o .1-97 26 o.708L7 7582 63.51 1690. 39 o.Lo872 0.70800 9011- L2.59 789 .48 0.04616 o.70907 9012 L4.99 490.Lr 0.08851_ o.7LO28 9022 L82.45 l_208.03 o .43709 0.71005 9023 2]-]-.27 1l_L8.17 o.54686 0.71_095 A1kali Syenite. 7547 460.43 L978.35 o.67386 o.7L504 9303 L79.83 L524.L6 o.34204 0.70888 9563 326.72 1632.18 0.581_93 0.71_389 ^Atbitite. 9000 L6.73 660.94 o.07321, o.70624 9018 8.45 97.O2 o.25208 o.7l_ot_5 9545 7.55 20L.55 0.1_0835 0.70809 T e 5.6.1-: Rb-Sr I for rntrusives of the and Denison S con nued

Sample Rb (ppm) sr (ppm) a'Rb/'6Sr eTsr/a6sT Carbonate - Vein and Breccia. 7597 0.20 L95.42 o.oo294 o.72541- 7598 0.03 1-2s.83 o. 00065 o.71-597 Tab1e 5.6.22 Carbon and Oxyqen Isotope Geochemistry for Carbonates of the Peake and Denison Ranges.

Sarnple: d13c daso d13C/PDB d18O/PDB

Vein Carbonate 175971: +5.L67 +9.L76 l_.1_1_6 -11_.936 Breccia Carbonate [7598] : +5 .257 +8.865 r .206 -1,2.24L

Albitite [75L6]: +o.263 +5 .826 -767 -L5 .2L7 Albitite 175641: +2.573 +6.O22 -r.467 -L5.O24 Albitite Ie54L]: +2.L69 +4.095 -t.870 -l_6.911_

Carbonate Xenolith l97O7lz -L.767 +7.L54 -5.790 -13.916

Magmatic Carbonate Breccia L72OOI (Zoned P1uton; Map A): -4 .677 +1_2 . 005 -8.688 -9.L66

Carbon and oxygen isotope analyses htere conducted on whole- rock samples with varying calcite and/or dolomite concentrations. Samples r^rere digested in L00å phosphoric acíd and the resultant carbon dioxide gas was coll-ected f or analysis. It is assumed that rnost all of the analysed COz represents that which had been acquired from carbonate mineral-s. Carbon dioxide in ftuid inclusions is assumed to have been liberated during pulverization of the sample. Any other carbon accidently incorporated (e.9. from biotite) is considered a negligible component.

PDB : Chicago PDB standard (be1emnitella americana) from the Cretaceous Peedee Formation, South Carolina.

Conversion factor from PDB oxygen to SMOW (standard mean ocean water): d-SMOW = L.03037 * d-PDB + 30.37

Analyses conducted in duplicate by K. Turnbull (University of Adelaide) on a þIicromass 6O2-E mass spectrometer at the Waite Agricultural Research Institute, Adelaide. Figure 6.2.1

10 10 x 3 A O6 9 B o o o o o x o¡ o o¡ tr o .E + Y nO "r""> Y & tr + l" ,'.*oÑ + o ooo o a o o 4 4 O¡ o¡ '*oo* (\¡ + + (u o z(ú o I z

st' s o t ,.iGÎ

0 0 75 40 75 40 SiO2 vt.7o S¡O2 Yt%

I I o D c o o o o xx x o o @ + I o o + o + * K20 coaP @ t K2 o o a o Yi.c/o !. Vl.t/o ta' ss' ot x ttr-a oo a o tr o o o o o s o o o & 8 0 o o o 'qf 0 0 80 45 SiO2 yt 7. 80 45 SiO2 wt.7o

10 10 o E & F tr g I

o þ3'"3 o aa L' e80 a Na20 ottr Na20 , o o ¡ vl.'/o o f;u1trl xxrI tc-l.'l¡ troo + nao o o I

0 0 80 45 SiO2 rt.7o 00 45 Si02 vt.7o Figrnres 6.2.1-3 a¡rd 6.3.1-3. Cou¡nrative lflhole-Rock Geochenistryr for the lgrneor¡s Rocls of the Ädelaide Geosymcline, Kannantoo llough and r$1petr Granites of the Lachlan FoId Belt and South Pacific. FignrresArC&E: Sr¡mbol: Litholoqical Group: o Intrusives of the Peake and Denison Ranges. o The Anabama Granite. + Syn-tectonic Granites of the Kanmantoo Group. x Post-tectonic Granites of the KanmanÈoo Group. ¡ A-type Granite Àverage: The Lachlan Fold Belt. (} S-type GraniÈe Average: The Lachlan FoId Belt,. a I-Èype Granite Average: The Lachlan FoId Belt. I M-type Granite: Uasilau-Yau Yau Complex, New Britain.

Figrnres Br D & F: Sunbol: Litholoaical Group: o Intrusives of the ltlitlouran Ranges. o Intrusives of the Arkaroola Region. o Canbrian Volcanics. I Port Pirie Volcanics. a Volcanics of the Callanna Group. o Volcanics of the Callanna Group: Rafts in Diapirs. I Gairdner Dyke S$tarm.

Data from Tables 6.L, 2.7, 2.6, 2.2. Kanmantoo Granites data from Foden et, a7. (L999). lrl-rr, rrs-rr, rrA-rr and rrM-typerr averages from û{halen et a7. (L987 ) and l{hite & Chappell (L983). These include both ¡uaf ic and felsic averages. Intrusives of the Peake and Deni.son Ranges include data from the zoned pluton of Maps A and A', the sj.Ils and plutons of Maps B and B', and the southern plutons of Maps F', G and I. Data for igneous rocks of the Adelaide Geosyncline from this work and as documented in chapter two. Figure 6.2.2

6 12 o o A B o a a o O+ do o o'o o Mgo 8t oo M I oo ut.o/o ulP/o l6 sì o ++ + o if x o oo 0 0 10 Al2Og vl.oh 20 10 Al2O3 yt 7" 20

12 't5 c o D E o o o o o o tro o o CaO o o CaO . "jg vf./" vll/" O¡, <) a o I o o x x o a 0 im o 10 0 Al2O3 20 10 rt 7" Al2O3 Vl."/o 20

't2 20 o E oo F o os + a 9o ,l.Fe oa :*Eaô tro vI.oh yì."h o x

T o O9 l::{+ o o 0 0 10 20 Al2O3 u¿l.o/o 10 Al2O3 vt 7" 20 Fignrres 6.2.L-3 a¡rd 6.3 .1-3 . Cou¡nrative llhole-Rock @ochenistry for the lgmeous Rocks of the Àdelaide Geosyncline, Kannantoo 1?ough and Itllyperr Granites of the Laclrlan Fold Belt and South Pacific. FigruresArC&B: Svmbol: Litholoqicat Group: o Intrusives of the Peake and Denison Ranges. o The Anabama Granite. + Syn-tectonic Granites of the Kanmantoo Group. x Post-tectonic Granites of the Kan¡nantoo croup. t A-type Granite Average: The Lachlan FoId BeIt. a S-type Granite Average: The Lachlan FoId Belt. o I-type GraniÈe Average: The Lachlan FoId BeIt. I M-type Granite: Uasilau-Yau Yau Complex, New Britain.

FiguresBrD&F: Srnubol: Litholoqical croup: o Intrusives of the willouran Ranges. o Intrusives of the Ar]

Data from Tables 6.L, 2.7, 2.6, 2.2. Kanmantoo Granites data from Foden et, aJ. (L988). rrl-rr, rrs-tr, rrA-lr and rrM-typerr averages from Irlhalen et, a7. (L987 ) and lithite & Chappell (1983). These include both mafic and felsic averages. Intrusives of the Peake and Denison Ranges include data from the zoned pluton of Maps A and A', the sills and plutons of Maps B and B', and the southern plutons of Maps F', G and I. Data for igneous rocks of the Adetaide Geosyncline from this work and as documented in chapter two. Figure 6.2.3 2 o 4 A B "5 o o + o o T¡O2 o o o T¡O2 v l.'/o ul.l/o tr o

+ x o 0 0 o 45 SiO2 wt.7" 80 45 SiO2 vt.7" 80

5 2 o o c D o a o P2 o P20 oh o ut o vt.'h o o oo p oooS o o oo o o a o I +6@ o oo ¡ tr% 9O 0 0 H, 45 SiO2 vt 7' 80 45 SiO2 vt 7. 80

550 I 400 o E F o x o o o tr x I o Zr + o dB oo x o PPM + +8 pPm o a o å --o x- é .8' x I o x s o6"d+sffit 0 0 45 SiO2 wt o/. 80 45 SiO2 yt.7o 80 Figrnres 6 .2.1-3 and 6. 3 . 1-3 . Conparative lllrole-Rock Geochenistry for the lgmeous Roclrs of the ^âdelaide Geosymcline, Ka¡¡¡antoo ltough and rrllperr Granites of the LachJ.an FoId BeIt afid South Pacific. FiguresArCtE: Svmbol: LÍtholoqícal Group: o Intrusives of the Peake and Denison Ranges. o The Anabarua GraniÈe. + Syn-tectonic Granites of the Kanmantoo Group. x Post-tectonic Granites of the Kanmantoo Group. ¡ À-type Granite Average: The Lachlan Fold Belt. a S-type Granite Average: The Lachlan FoId Belt. o I-type Granite Average: The Lachlan FoId BeIt. I M-type Granite: Uasilau-Yau Yau complex, New Britain.

FígnrresBrD&F: Sy¡nbol: Litholoqical Group: tr Intrusives of the wiltouran Ranges. o Intrusives of the Ärkaroola Region. o Cambrian Volcanics. ¡ Port Pirie Volcanics.

Data from Tables 6.L, 2.7,2.6,2.2. Kanmantoo Granites data from Foden et, a7. (L988). rrl-rr, rrs-rr, rrA-!r and rrl,f-typerr averagtes from Whalen et, al. (L987 ) and lfhite & Chappell (1983). These include both ¡naf ic and felsic averages. Intrusives of the Peake and Denison Ranges include data from the zoned pluton of Maps A and A', the sills and plutons of Maps B and B', and the southern plutons of Maps F', G and I. Data for igneous rocks of the Adelaide Geosyncline from this work and as documented in chapter two. Figure 6.3.1 2000 1500 o A o x B o a oo + x o o o a I o Ba o tr oo 9O o o o ppm oo ppfir 8"oB * o8 o o o tr o ry o qc o + o o I þtn 50

2000 1500 o c D x I o o o o It o o ooo a oo o Ba o o o + Ppn + + t o oo ¡b r o O + a + ri 50 x x I a 0 0 Rb ppn 400 0 Rb ppm 800

2000 700 oo E F o ooo Sr Sr o Pprr o ptrn o o o o 5 o

13 t 0 + a a o 0 0 Rb ppm 400 0 Rb ppm 000 Fignrres 6.2.1-3 and 6.3.1-3. Couparative lûole-Rock Geochenistr'1r for tlre Igmeous Roclrs of the Adelaide Geosymcl.ine, Kannanrtoo ltough a¡rd rTlpen Gra¡rites of the Lachla¡r FoId BeIt a¡rd South Pacific. FigruresArC&E: Svnbol: Litholoqícal Group: o Intrusives of the Peake and Denison Ranges. o The Anabama cranite. + Syn-tectonic Granites of the Kanmantoo Group. x Post-tectonic Granites of the Kannantoo Group. ¡ A-type Granite Average: The Lachlan Fold Belt. a S-type Granite Äverage: The Lachlan Fold BeIt. o f-type Granite Average: The Lachlan Fold BeIt. I M-type Granite: Uasilau-Yau Yau Complex, New Britain. FigruresBrDtF: Svnbol: LÍtholoqical Group: o Intrusives of the litillouran Ranges. o Intrusives of the Arkaroola Region. o Canbrian Volcanics. ¡ Port Pirie Volcanics.

Data from Tables 6.L, 2.7, 2.6, 2.2. Kanmantoo Granites data from Foden et a7. (1988). rrl-tr, rrs-rr, rrA-tr and rrM-typerr averages from ûilhalen et a7. (L987) and White & Chappell (1983). These include both ¡uaf ic and f elsic averages. Intrusives of the Peake and Denison Ranges include data from the zoned pluton of Maps A and A', the sills and plutons of Maps B and B', and the southern plutons of Maps F', G and I. Data for igneous rocks of the Adelaide Geosyncline from this work and as documented in chapter two. Figure 6.3.2

60 150 x A o B x

o ¡ x Nb x x Nb x PPO {l + PPN o x tr

o o d o o OO oo@ 0 ¡rr 0 0 2 0 TiO2 vt."/" 1iO2 ut.o/" 4

60 150 x c tr D x

o x Nb x x o x x Nb x tr IFI PPm + ft- PPn o o x + J x + x tr + tr B o o ogo o tr Etr l'o o 0 0 0 550 Zr ppm 0 h pp^ 400

100 50 x x I oso F x E t tr I x x <Þ x x o o to

FigruresBrD&F: Svmbol: Litholoqical Group: o Intrusives of the willouran Ranges. o Intrusives of the Arkaroola Region. o Canbrian Volcanics. I Port Pirie Volcanics. .O Volcanics of the Callanna Group. o Volcanics of the Callanna Group: Rafts in Diapirs. I Gairdner Dyke Swarm.

Data from Tab1es 6.L, 2.7, 2.6, 2.2. Kanmantoo Granites data from Foden et a7. (L988). rrl-rr, rrs-lr, rrA-rr and rrM-typerr averages from ltlhalen et al. (1,987) and White & Chappell (L983). These include both mafic and felsic averages. Intrusives of Èhe Peake and Denison Ranges include data from the zoned pluton of Maps A and A', the sills and plutons of Maps B and B', and the southern plutons of Maps F', G and I. Data for igneous rocks of the Adelaide Geosyncline fron this work and as documented in chapter two. Figure 6.3.3 45 60 o o A B o o I oo€o. ooo o o + Sc t o oobo g Sc tr I ppm ppm o

tr o x I äffi1 o 0 0 0 TiO2 2 vl."/" 0 TtO2 vl."/" 4

600 600 c D

a tr ao V ø o V l'"t pPm o 60 o ppm o + o o oE o o o d,Ë: o B 0 @ 0 tr 0 1iO2 ul.o/o 2 0 TiO2 vt t."/" 4

75 200 E o F o o a

Ni a Ni o o pPm o o J¡ 9Pm o o o trf 3..P o a (D 9O o % ø o x 8o o 0 e'B 0 o 0 TiQ2 2 vl."/" 0 TiO2 vl."/" 4 Figrnres 6.2.L-3 and 6.3.1-3. Comparative lllrole-Rock Geochemistry for tlre fqmeous Rocks of ttre Ädelaide Geosyrncline, Kanmantoo Trouglr and rrlly?err Granites of the Lachlan FoId BeIt and South Pacific. FignrresÀrC&E: Srr¡nbol: LíÈholoqical croup: o Intrusives of the Peake and Denison Ranges.

tr The Anabarna Granite. + Syn-tectonic GraniÈes of the Kanmantoo Group. x Post-tectonic Granites of the Kanmantoo Group. ¡ A-type Granite Äverage: The Lachlan FoId Belt. (} S-type Granite Average: The Lachlan FoId Belt. o I-type Granite Average: The Lachlan Fold Be1t. I M-type Granite: Uasilau-Yau Yau complex, New Britain.

FigruresBrD&F: Symbol: Litholoqical Group: tr fntrusives of the Willouran Ranges. o Intrusives of the Arkaroola Region. o Cambrian Volcanics. ¡ Port Pirie Volcanics. a Volcanics of the Callanna Group. o volcanics of the Callanna Group: Rafts in Diapirs. I Gairdner Dyke Swarm.

Data from Tab1es 6.L, 2.7, 2.6, 2.2. Kanmantoo Granites data from Foden et a7. (L988). rrl-rr, rrs-rr, rrA-rr and rrM-typerr averages from I¡lhalen et a7. (L987 ) and hlhite & Chappell (1,983). These include both mafic and felsic averages. Intrusives of the Peake and Denison Ranges include data from the zoned pluton of Maps A and A', the sills and plutons of Maps B and B', and the southern pJ-utons of Maps F' , G and I. Data for igneous rocks of the Àdelaide Geosyncline from this work and as documented in chapter two. Figure 6.5 1000

WPG 0 tr 100 I tr Nb ppm

10 tr

VAG + syn-COLG ORG

1

1000 syn-COLG WPG 00 0

100 trtr Rb ppm 0 f tr 10 tr 0 E 0

VAG ORG

1 1 10 100 1000 Y+Nb (ppm) Figrure 6.5. Comparative Geochemistry: Tectonic Discrimination Diagrams. Tectonic discrinination diagrams after Pearce et al. (1-984) for the intrusives of the Willouran Ranges (squares) and the intrusives of the Arkaroola region (ovaIs). lfPG = Within-plate granites. VAG = Volcanic arc granites. syn-COLG = Syn-collision granites. oRG : ocean ridge granites. Note that neither intrusive group coincides with a specific tectonic environment. Data is from Table 2.7.2 (Arkaroola Region) and Table 2.8 (9{illouran Ranges). r-tgure 6.6.1 4 500 M wt.o/o A ppm Zr B

o o a 2 o o 300 oot a .O a a a o SiO2 wt.% a 0 100 a MgO wt.% 50 60 70 0 10 4 Fe2O3+FeO 250 wt.% c Rb ppm D 200 a O a o a 5 a a ß- a 100 a a o o a a o MgO 0 wt.% MgO wt.% 0 0 4 0 o 4 \wl.% 1000 E Sr ppm a oo F o a o a 4 o o a o 600 o a c a 2 a' a O a a MgO wt.% MgO wt.% 0 200 o 0 4 4 4 KZO wt."/" o 80 G Y ppm H

3 a a a a 40 o a taa oa 2 a o o o a a MgO wt.% O a MgO wt.% 0 4 0 1.8 60 4 Ti 2 wt.% ppm Nb J o

1.2 40

o a 'ao oa 0.6 to o o 20 OO o a

MgO wt"% o MgO wt.% 0 0 a 0 2 0 2 Figure 6.6.1. Geochemistry of the Anabama Granite. Selected Harker variation diagrarns for the Anabama Granite. Data is from Table 2.3.2. Figure 0.G.2

F AI

Peraluminous M

I I a I a I "1, I Metaluminous I I PEralkaline

A M Ca+Mg Na+K

2000

A B

c a fl! rooo frf I I D

F

E G

0 0 1000 2000 3000 R1

1000 1000 syn-COLG WPG WPG 100 I a 100 ¡l Nb (ppm) Rb (ppm) a 10 VAG+ . 10 VAG syn-COLG ¡ ORG ORG I

10 100 1000 10 100 1000 Y (ppm) Y+Nb (ppm) Fignrre 6.6.2. Geochemistry of the Anabama Granite. Top left: The Anabama Granite plotted within an A-F-M diagrarn. Top right: Classification of the Anabama Granite using Shand's (L927 ) schene. Note that the Anabama Gran ite is slightly more peraluminous than the Bungadillina suite, although both plot in the metaTuminous f ield (c.f . Fig . 5.2.1.4) . Centre: Tectonic discrinination diagram after Batchelor & Bowden (1985) applied to the Anabama cranite. A : Mantle fractionates. B : Pre-ptate collision (ca]c-alkaline and trondhjernitic). C : Post-collision uplift. D = Late-orogenic (sub- alkaline monzonitic). E : Anorogenic (alka1ine and peralkaline). F - Syn-co1lisíon (anatectic) . Note the Ànabama Granite is nearly all restricted to the post- collision uplift field (c). Bottom right and left: Classification of the Anabama Granite using tectonic discrímination diagrams after Pearce et a7. (1984). WPG = I,rlithin-plate granites. VAG = Volcanic arc granites. syn-COLG : Syn-collision granites. ORG : ocean ridge granites.

Note that the Anabarna Granite ploÈs through both the VAG and WPG fields. Figure 6.7

A o Average Post-Delamerian Granite yc (ú I ç 100 Average o Syn-Delamerian ( .E Granite o- (D E. 10 E al Average CN Quartz Syenite

1 Rb K 'Nb La Sr Y BaC eNd Zrï

1000 B .o ËL Yardea Dacite 6 100 bE ö P b b 10 o- o l- fÀ ,rYqragg---^-- ts G' Quartz Syenite CN 1

Hiltaba Granite

0.1 R%"^ Nb tt"sLo ZrT Y Fignrre 6.7 . Comparative Trace Element Diagrarns. Multi-element comparative geochemical diagrams ("spidergramsrr) for the Bungadillina suíte, represented by average quartz syenite values, compared with Kanmantoo Group granites (figure A), and Middle Proterozoic volcanics (Yardea Dacite) and granites (Hiltaba Granite) from the Gawler Craton (figure B). Average Kanmantoo Group granite values are from Foden et a7. (L989). Middle Proterozoic chemistries are after Jagodzinski (L985). Note the similar values for the Middle Proterozoic and post-Delamerian (Kanmantoo Group) igneous suites. Note also the contrastíng values for the Bungadillina (quartz syenite) suite. Figure 7.4.1

Normative Quartz Plagioclase effect zone

o

10 t o

o o o o oo o o o o t o o o o oo o o Anorthosite o t' o D.l. 0 +++++ o ++ + o +++ ++ + + lnitial o x, o iliquids Amphibole resorption zone o o o c la o o o o o o I o o o ( I o o o l. o 10 I \ Normative Nepheline \ o

40 60 100 Figrure 7.4.L. Silica Saturation versus the Differentiation Index (D.I. ).

Samples frorn the zoned pluton of Maps A and A', sills from Maps B and B', and samples from the largest pluton of the Bungadíllina suite (Maps F', G and I) plotted on normative variation diagrarn. The x-axis is the differentiation index (D.I.). This is the sum of the normative percentages of quartz, orthoclase, albite, nepheline and leucite. More felsic tithologies plot towards the right of the axis (100å). The y-axis is both normative percentage quartz (towards the top) and normative percentage nepheline (Èowards the bottom). The series of arrorrs, marked with an rrxrr , corresponds to a primary basaltic magma fractionation trend. Using this diagram, Bonin & Gíret (l-985) identified a plagioclase effect zone, a cumuTate zone and an anphiboTe resorption zone for alkaline ring complexes in Africa. In contrast, the Bungadillina suiÈe never develops into a suite with high normative nepheline and high D.I.. This may be that, in contrast to the alkaline ring complexes, amphibole in the Bungadillina suite formed a cumulate phase and was not resorbed into the melt. Figure 7.4.2

R2 1

a 2

3

b d c 4 6

5

R 1 Figrure 7.4.2. R1 - R2 Tectonic Discrinination Diagram. Tectonic discrimination diagram after Batchelor & Bowden (L985) using multicationic parameters or RL-R2. R1 = 4 si 11 (Na+K) - 2 (Fe+Ti) R2=4Ca+2Mg+Ã,1 More mafic rocks plot towards the top-right, quartz-rich rocks pJ-ot towards the bottom-right, and alkaline-rich rocks plot towards the bottom-Ieft. The line Rl-:R2 corresponds to silica saturation. The different tectonic fields are as follows: l- = Mantle cumulates. 2 : Pre-plate collision (ca]c-alkaline and trondhjemitic). 3 : Post-collision uplift (high potassic calc-a1kaline). 4 = Late orogenic (sub-alkaline monzonitic). 5 = Anorogenic (alkaline and peralkaline). 6 = Syn-collision (anatectic). Sample fields for the Bungadillina suite shown are: a = Zoned pluton of Maps A and A'. b = Si1ls and plutons of Maps B and B'. c : Quartz monzonite and quartz syenite. d : AIkaIi syenite. Arrows indicate increasing silica. NoÈe most plot into the late orogenic field. Figure 7.6 Zoned Pluton Map A 11 CaO wl.o/o 754 61% Hornblende A 217o Albite 36"/o 17% Diopside

I 9598 40ToDiopside 30%Albite 17o/" 18%Biotite 9%Magnetite 7543 o/cHornb 5 1 ToAndesi ne 43 lende 3"Ã 9588 5 2o/o S9ToAndesine 5%Magnetite 7542

2% 77c/o Ho¡nblende 1oo7o [75411 2% 7522 52% Andesine 187oK-Feldspar 1% 14% Biotite 9%Ca-Pyroxene 9590 2 10 15 Al2O3 wl.V" 20 Sills Map B

I 7702 CaO wl.o/o 28lo Ca Pyroxene B 27lo lls¡¡þlende 59% 337o K-Feldspar 87o Magnetite 4% Apat¡te

o 7314

51% 82%Hornblende 17%Biotite 1nr'.

41% 79%Labradorite 4

7315 TOlolZlOZl 35% 5 1% Biotite 3TToHornblende 3o% BiotiteÕú^^

7312 2 14 Al2O3 wt.o/o 16 18 Figure 7 .6. Least Squares Fractionation Modelling. Least squares fractionation modelling proposed for the zoned pluton of Maps A and A' (figure A), and the sills of Maps B and B' lfigure B). A complete listing of least squares fractionation calculations is recorded in appendix M. Tie-lines connect calculated compositions. Numbers to the left of the diagram correspond to the total percentage of míneral- crystallization and extraction from the liquid is required between eaõh calculated composition. Numbers on the right is the equivalent proportion of rock and minerals requires to be extracted from the melÈ for the same change in cornposition. Amounts of individual minerals required to crystallize are shown adjacent tie-Iines. Figure 7.7

40 A Sc ppm

Cumulate

a o

40% Hornblende o o 407o Plagioclase o 17Yo Pyroxene 20 o 3% Magnetite o a o a 10 60% Plagioclase O 307o Hornblende o 57o Pyroxene o 5% Magnetite v ppm

0 100 200 300 400

Sr ppm a B o o o 1200 \o o o o o o Cumulate o o o o o o /o o a c . 800 a a o

o 60% Plagioclase 40% Hornblende 30% Hornblende 40% Plagioclase a 57o Pyroxene 17% Pyroxene 5% Magnetite 3% Magnetite 400 o Rb ppm

0 50 100 150 200 Fignrre 7.7. Trace Element FracÈíonation Modelling. Trace element fractionation modelling Èrends and actual analyses (circles) for the Bungadillina suite. Figure A shows results for Sc and V fractionation. Figure B shows the results for Rb and Sr. Cumulate composition trends for the fractionated mineral trace element concentrations are also presented for each diagram. The models are based on 5Z interval crystallization of given mineral suites. Mineral partition coefficients are from GiII (l-98L) (c.t. Table 7.7). Note relatively close approximation for Sc and V, whereas significant scatter is recorded for Rb and Sr. Figure 7.10

1.5 Ai CNK A R2 o B o S-Type o o 1.1 A-Type oæo a o 3 o I o q o o f000 o ooo o æo o oo 8o o 0.5 oo o o o o o o S¡O2 wt.% 0 0 45 55 0 R1 60 600 Na20+K ppm CaO c f' D

o 40 o 400 o o o o oo 20 o 200 o o € go oo ooo o o o a o I oooo rtg /At 0 6a/At 160,000

100 1000 WPG ts o F o WPG I syn o VAG+syn COLG COLG I r00 o o o o o 't0 ooo do6o VAG o o ô o oo oo I o o o ORG 10 o oo ORG o o o! o

1 10 1 10 100 Fignrre 7 .LO. Geochemical and Tectonic Classification of the Bungadillina Suite. Figure A: A/CNK (A:-=O=/CâO*NazO*KzO) versus SiO= diagram showing the ffinIinebeÈweeni'S.type'|andllI-type|'granitecIassif1cation. Note that the Bungadillina suite trend approaches the line, but never crosses into the "S-typerr fie1d. Figure B: Tectonic discrinination diagram after Batchelor & Bowden (fses) using nulticationic parameters or R1-R2. RL = 4 Si l-r. (Na+K) - 2 (Fe+Ti) R2=4Ca+2Mg+AI More mafic rocks plot towards the top-right, quartz-rich rocks plot towards the botton-right, and alkaline-rich rocks plot towards the bottom-left. The line R1:R2 corresponds to silica saturation. The different tectonic fields are as follows: B = Mant1e cumulaÈes. A = Pre-p1ate collision (calc-alka1ine and trondhjenitic). B = Post-cotlision uplift (high potassic calc-alkaline). C = Late orogenic (sub-a]kaline monzonitic). D = Anorogenic (alkatine and peralkaline). E = Syn-collision (anatectic). Sarnple fields for the Bungadillina suite shown are: 1 : Zoned pluton of Maps A and A'. 2 = SiLls and plutons of Maps B and B'. 3 = Biotite lamprophyres. 4 = Quartz monzonite and quartz syenj-te. 5 = Alkali syenite. Fiqures C and D: Variation diagrams with Ga/àI. High gallium with respect to Al is considered a hallmark for rrA-typerr granites. In comparison with average rrA-typett values (filled oval), the Bungadillina suite has 1ow GalAJ-. Figures E and F: Classification of the Bungadillina suite using tectonic discrimination diagrams after Pearce et a7. (l-984). WPG = Within-plate granites. VAG = Volcanic arc granites. syn-COLG = Syn-collision granites. oRG = ocean ridge granites. Note the majority of samples plot within the VÀG fie1d. Flguro 7'fl: Sehomat[e ßfl0dd[o Gambnlam Gnustal Gnoss Soet[onr o0 tho Poako amd Dom[sout Ramgos, o ÉE iá Posslblc cocval ll{lddlc C¡rbrl¡n?l bhod¡l Ë volcanlsn (c.9. thrburton Volcantc¡1. IÞ o unbcrat¡ne Oroup and prob.blc Hevkcr Oroup t cqulvalentr I a glll E Eurra Oroup Bungadllllna Sultc: lnJcotlon, +l 9ub-volcanlc plutont¡r. l@ ovcr- a ¡aturatlon. blotltc oryatrlllzrtlon. FI groundvetcr o altcr¡tlon. Èyrtrl E Callanne Oroup cu¡ulatc laycrlng tnd poaalblr 3-t4+ k¡ cauldron ¡ubsldencc. Brlttle-.lactlc oru¡t¡l rhcology Crust¡l ugf lft accoapanlcd Î,{lddlc Proterozolo crust by ¡ deposltlon¡l hlrtu!. lÐpor Grr¡¡t c.g. Ttdnaaurkana Volcanlcs (clrcr 1650 fht lllrrlccurrlc Oranltc (clrca 16OoM¡t l{oblcnok Ou¡rtzltc fclrca >t6SO Mal. þpcr crustal ragna pondlng: 2O-21 k¡ ltzo situretlon: hrornbland. .nd rndcrlnc cryrtal llzatlon: cryctal c-triulato! forrlng. Ductllc-plastlc cru¡trl rhcology P¡rtlal a¡¡hll.atlon of cru¡t. .' t lra Lovcr Proterozolc to Arch.san crult? d Cru¡tal rtrctchlnr¡. ?Kararl a Fault rceobtliz¡tlon- L a Loror Gru¡t Y

Lovcr crust: lt2o tndcr¡rturetad: Labrrdorltc. Fc-Tl. oxldc ¡nd ollnopyroxtnr crystalllzatlon. Ollvtnc and chrorltc 9O-4O kr fractlonatlon. lÞpcr ¡antl.: ¡agil¡ upvolllng ylthout F-IFS corplexlnq: hlgûr oxygcn fugaolty; 4lO-60 kr tracc clenent concentratlon = bulh r¡antl¡. lÐpor too¡tlo Figrure 7 .LL. Schenatic Cross-Section of the Mant1e and Crust for The Bungadillina Suite Intrusion. Diagramatic representation of the crust and upper mantle zones for generation and crystallization of the magma for the Bungadill-ina suite. Noted are tentative locations/depths for fractionation and/or cumulation of major mineral phases in the melt. Note period of magna residency in the vicinity of change in crustal rheology between the upper and lower crusts. IFf,gure V "1,22 Sclhemaû[c Cross-secûûonn flon lPnelDelamenf,amr lEmplaaememû ofl lllhe ltsumgadf,lilf,nna Suf,'ûe.

Skl Il Ilogalloo Dollomf to South Pluton: Maps F', G and I

a Brlttle deformatlon (klnk \ ë folds) ln strata Albltlzed pluton top East € caused by evaporlte dlaplrlsm. Provldes a Xenol lths €N zone of least reslstance for lntruslon of t the Bungadllllna Sulte Ouartz syenlte € zone \ East I Sllls, Maps B and B' Pluton; Map C ë .' a East È. oe È Syenlte zone g t{est ë E Ð !{est o Syenogabbro Zone of Contact E cumulate zone lúest Metamorphl sn Zoned plutont Maps A and A'

and plutrrns Sllls snall South East Maps F and F'.

o Albltlzed pluton top E e @ E) North I Monzonlte pluton body ÉE --' eÈ @ Ê Fe-Mg cumulate-rlch +l Snall Fe-Mg cumulate-rlch gabbrolc plutons € gabbrolc pluton ln ë core and base. zone dlsrupted by evaporlte dlaplrlsn. Ê z @ l{est !L Zone of Contact Metamorphlsm * * Small felslc (monzonfte, syenttel plutons ln zone dlsrupted by evaporlte dlaplrlsm. Figure 7 .L2. Schematic Cross-Section For BungadiLlina Suite Emplacement in Adelaidean Strata. Diagramatic representation of pluton configuration with najor inter-pJ-utonic variations for the Bungadillina suite. Orientation assumes pre-Delamerian emplacement with horizontal Burra Group strata. Cross-sections of plutonic groups are represented by a dashed Iine with arrohrs indicating up direction. Areas for contact metamorphÍsm of conÈiguous sediments are indicated by solid stars. Note that tops of plutons have been greatest effected by groudwater al-teratíon leading to al-bitization. Pl-uton bases are Èhe location for ferromagnesium mineral-rich cumulates. General orientation of entire diagrarn is from the northwest (sil1s Maps B and B') to southeast (south pluton Maps F',GandI). Note zone of diapiric disturbance in centre of diagram. This zone hosts both mafic and fel-sic anhedral plutons. The plastic nature of this zone has allowed the formation of separate bodies for each successive magma pulse, whereas larger zoned pÌutons rnay have incorporated separate pulses into the single pluton, causing pluton swelling and leading to caldron collapse. Table 7 .7 z lfineral Pa¡tition Coefficients For ltace El-enent ltodelling.

Plagioclase Ca-Pyroxene Hornblende Magnetite Rb 0.07 0.02 0.05 0.01 Sr L.8 0. 08 o.23 0. oL v 0.0L l_.1, 32 30 Sc 3 3 Lo 2

Data from ciII (1.98L) pp.?OO-2OL. Table 8.4. Igneous Activity in the Adelaide GeosynclÍne. This Èable provides a succinct summary of the major characteristics of the most of the najor igneous occurrences, both volcanic and plutonic, in the Adelaide Geosyncline, including the Kanmantoo Trough and the Padthaway Ridge. Unfortunate absences from this table are Èhe igneous occurrences within (Mudnawatana Tonalite and British Enpire Granite) and around (Arkaroola Region) the Mount Painter fnlier. The former is not present due to the lack of data available, and the tatter from insufficient identification of specific samples and uncertain chronostratigraphic associations. The table is constructed from a geochronological basis, with Precambrian occurrences in one section, and Cambrian to ordovician occurrences in the other. Information for the construction of this table has been synthesized from appropriate sections in this thesis, and from research currently being undertaken on the Kanmantoo Group Granites and Padthaway Ridge Granites by S.P. Turner and J.D. Foden at the University of Adel-aide (pers. comn. ). IFabllo @ "4: Ilgne@us Aet lvf ty iln the AdellaÍde Goosynell flne, Gllrrono¡trrtlgrophy lúl I I ouran Torrenslan

Lf t0¡ort mtlgre@ry Callanna Group Burra Oroup unberatana Group lgnoour &¡lto Galrdner Dyke Svarn Cadlar€ena. Port Pfrle túantape I la túooltana. tloranda Fla¡toorlclVoleorf c Plutonlc Volcantc >> plutonlc Volcanlc Volcanlc ]'laf lc/Felslc /Bl¡¡odal / l,laflc l,bflc >> Fclstc tlaf Lc l"bflc Interredlrtc Rock Âr¡oclettomr Dyke Svar¡ Flood Basalts and Basalt BasaIt Mlnor Pyroclastlcs Âf,t¡n¡tlo¡r * Lov Orade Scapolftc Lov Orade gcapollte Lov Grade Potasrtc Lov Grade +/- t *t Hlgh Grade Xoorcl lthr N/A ?Mlnor t N/A t N/A @ont¡ct llot¡norp0¡bn rt Mlnor N'A N/A * N/A o a Roglonel lloteoorp0rtrn E Oreenschlst Or¡enschl ct>AnphlboI f te Greenschlst J ?Greenschlst ! -a Fol l¡t¡d/llr¡¡lv¡ - Masslvc ?Masslvc N'A N/A L =b lgnoour Lryrnlng o ?NO Yes l.lo o ?NO õ' No 1.¡o No r Fognrtltor . I l.lo lll¡lor¡l $¡lto t Ollvlne Pscudororphs Ollvlne Pseudonorphs Ollvlne Pseudonorphs t Labradorlte t* and Pyroxcne and Pyroxene and Pyroxene t Rb-Sr lrotopor t 975 t{a &to Ha N/A t N'A IR = 0.7034 IR = 0.711

slû2 42-55 vt.l ¿lfl-55 vt.t 42-52 Yt.l 4,2-46 vt.l

Gooctrorlrtry ileh 7r. Tl, Ca, Y Tl . Sc, Nt . f,lC Fe. Tl. K, V. Rb Tt, P. Zr. Sc

Lov Na+l( Ca. ¡ù Mg, l.la, Sc Rb. v. Cr, Nt Fot rogonot tc Go¡¡t rolr Pr lnltlve Prlnltlve Thotetltlc Prlnltlve Tholelttlc Prh¡ltlve Tholelltlc Tholelltlc Magm¡ l.{agna vlth Mlnor l,lagma vlth Mlnor l,hgna Felslc Fractlonate Felslc Fractlonate Enplrcou¡nt Stylr Crystalllne Baserent Renobtllzed Fault- Renoblllzed Fault- Renoblllzed Fault- Fault-Control led Controlled Flood Controlled Floocl Controlled Flood Dyke Svarm BasaIt BasaIt Basalt and Dykos llolt Soc¡re¡ tþper Mantle Lþper Mantle þper Mantle tþper Mantle

T¡etoorlc Blvlroouont Tenslonal Brlttle Crystalllne Bas6ment Crystalllne Basenent Tenslonal Rtftlng Rlftlng of Rlftlng. Extruslon Rlfttng. Extruslon OId Fault Crystalllne Basement lnto Palaeo-basln lnto Palaeo-basln Renobll lzatlon ìFabllo Ilgno@uts Aet f vil (eomtÍmuod) E,4I: ty l¡r tho Adollaldo Goosyørellümo " Ghrono¡trrt I grrphy Canbrlan Ordovlcian Ll tho¡tf f tlgf ephy Nor¡anvllle e H'vk'r opg Kanilantoo Gp Delanerlan Orogeny Post-Ðelanerlan Ignrour Sul tO tÚarburton Bungadllllna 9¡1to Anabaila ând Encountcr Bay Black Hlll Truro Bendlgo R€edy Cr.ôk Mannuì Arrovle B¡¡ln Pal¡er Padthauây

Plc¡toe¡lolUolc¡¡¡lc Volcanlc >> Plutonlc Plutonlc Plutonlc Plutonlc Plutonlc > volcrnlc l'laf lc /F¡l ¡lc/Bhod.l / Bl¡odal tnt¡r¡odltt¡ lnternedlate Felclc clth B1¡odal lnterlcdl¡t¡ to Felsic Mlnor l,leflc Ourrtz gyenlte Rock Basalt e Tu?fr Crânodlortte Ton¡llt¡. Orrnlte Oranlt.. l,lorlto, A¡roclrtlonr to l,lonzogabbro to Oranlto Mfgnattto Fsl¡fc Volc¡nlo¡ Altorrtlon Lov Grado Sbdlc Lov Orrd¡ Sodlc H19h Orade Potasslc Mlnor Nll Xo¡rollth¡ ? G¡bbro, Monzonlt¡ ? Varlcd l.{tnor Dolerlt¡

@mtret llotrrorphln ? N/A l.lo Yes Ye! ¡nd l,¡o ? t Roglomrl lrtrrorphln t Greenschtrt Gr.enrchlrt Greenschlst Anphlbolttt Anphlbollt¡ Foll¡todllh¡rlvo * ? l.{r!!lv. > Fo¡l.t.d Follâtêd Foll.t.d > llrs¡lv¡ Masslve ta Ignoot¡¡ Lrtorlng a Yes Y.! No No Ye!

Pogretltor Ì.lo No Yes Ye! No =ob a Labradorlt¡ Cl lnopyroxeno. Blotlte Blotttr Cl lnopyroxrnr. lllnorel $¡lto Pyroxana Blotlt¡, And.rln.. Plagloolase Plaglocleco Ollvtnc, Al¡nlt¡ Phenocryrtr Hornbl.nd. Flornbl.nd. Rb-tr lrotogor N/A ¡t92-698 H. ¿164-473 M¡ ¡075-515 lL ¡f51-¿186 H. IR = O.705-O.707 IR = O.7O5-O.7074 IR = 0.711-O.716 IR = 0.70¿l-O.7Ot sl02 57-71 yt.¡ 17-7L vt.l 50-79 tt.¡ 55-70 vt.¡ 67-8O vt.I Al. Gooclro¡lftrt Hrsh Tl. Cr. P. Al . ¡b{{(, Al . Fe{+{g. C.. Al . t'19 l.L{K, Y. lù. Y, Sr Sr, Sc. V 11, Z¡ Sr. 9c Oa/Al Lov Na+l(. V. Rb Tl , t{g*Fr. Zr, }û P. Nar{ 9c K. Y. lù. Zr 41. Ci. Sc. V. Tl Potrogolrotlc Go¡¡teol. Alkalt Tholollttc Htgh Proaaur.. dry Yot l.lelt vlth tlet l,lelt vlth Lov Prcsauro. Dry vlth l'laJor Fractlon¡to. vlth Felglc Blotlte- Fllgfr Prcsruro Helt, llypcrrolvuc Fractlon¡to MaJor l,laflc rlch Fractlonate Frrctlon¡t¡ Fractlonat¡ ylth Conponent û¡¡uIato¡ F-ÈFS Co¡pl¡xlng

Erplrooront tttlo Flood Baerlt¡ ¡nd HlOh L¡vol. Forceful > Ptsslve Forceful. ylth Dleplrlo, ctoplng; Assoclatod Sub-volcanlc, Volatlle-rlch Anatexl¡ po6slbly forcoful. Pyroclâ9tlc! Passlvc > Forc.ful Htgh Level Iott Eourco þper l.,lantle vlth (þpor l,Lntlc to tDper lhntle to Lover Lovrr Cruot¡l tþper l{entl. ?Crustal Co¡ponont Lover Crustal. Crustal. l-type ylth tlth tlaJor tþp.r A-typc A- tnd l-types, l.{lnor 9-type Coilponont Crultâl Corponent Toctonlo B¡vlro¡uont Tensfonal Tenslon¡l Stretchlng Conpresslonal - Old Conpreaslonal - Orogenlc coll.pe.: Stretchlng Kan¡antoo Trough Fault Renoblllzatlon Cru3tal Thfckcnlng Conpresstonal For¡atlon Relêâs.

(Parent - Minerals = Daughter)

Parent: 175421 Daughter: l't5221 Sun of Squared Residuals = 0.138 Parent Daughter Daughter tleighted Components SoI'n tCumulate ït.t .Analysis Analysis Calculated Res iduals

175421 1.000 Si0z 61.04 62.L6 62.t6 0.00 Sphene -0.001 2.48 Ti0z 0.59 0.49 0. 48 0.01 Salite -0.006 12.00 AI¿ Oo L6.97 17.33 L7 .39 -0 .06 Magnetite -0.002 3.75 *FeO 4.85 4.09 4.09 0.00 Hornblende -0.040 76.59 llnO 0.09 0.08 0 .08 0.00 Apatite -0.003 5.t7 Mgo 1.81 L.42 L.42 0.00 175221 0.948 CaO 4. 51 3 .90 3 .90 0.00 Naz 0 4"41 4.88 4.54 0.34 K¿O 4.43 4.45 4.59 -0.14 PzOe 0.28 0.18 0.18 0.01

(Parent - Minerals = Daughter)

Parent: Ie5 8 8] Daughter: 175421 Sun of Sguared Residuals = 0.784 Parent Daughter Daughter lleighted Components SoI'n tCunulate llt.t Ànalysis Analysis Calculated Res iduals

Is588] 1.000 S iOz 58.58 61 .05 60 .94 0.11 Sphene -0.008 2.60 TiOz 0. 68 0.59 0 .55 0.04 Andesine -0.277 88.58 Alz Oa L8.74 t6.97 15 .97 0.00 Magnetite -0.015 5.25 *Fe0 4.94 4.85 4 .85 0. 00 K-FeIdspar -0.011 3 .57 !lnO 0.13 0.09 0 .19 -0.10 Í't5421 0. 587 Mso L.29 1.8L 1 .82 -0.01 CaO 5.43 4.5r. 4 .68 -0.17 Naz O 5.36 4.4L 5 .15 -0.7 4 KzO 3.64 4.43 4 .85 -0.43 Pz O¡ 0.22 0.28 0 33 -0.04

(Parent - l{inerals = Daughter) Parent: [7s43] Daughter: Ie5 88 ] Sun of Squared Residuals = 0.151 Parent Daughter Daughter Ifeighted Conponents Sol'n tCunulate I{t.t Analysis Analysis Calculated Residuals

[7 543 ] 1.000 SiOz 56 .65 58.5? 58.48 0.08 Àpatite -0.003 2.23 1i0z 0.81 0.68 0. 80 -0.L2 Andesine -0.072 50.67 A1¿ Oo t8.62 18 .74 18.89 -0.L2 llagnetite -0.005 3 .61 *FeO 5.83 4.93 4.93 0 .00 Hornblende -0.061 43.49 !lnO 0.08 0.13 0.07 0.06 Ie588] 0. 859 Mgo t.7 6 t.29 1.35 -0.06 CaO 6.06 5.43 5.44 -0.02 Na2 O 5.29 5. 36 5.4'l -0.11 K¿0 3 .50 3 .64 3.93 -0.29 Pz O¡ 0.30 0.22 0.20 0.02 (Parent - Minerals = Daughter)

Parent: Ie5 e8 ] Daughter: [7543] Sun of Squared Resiiluals = 0.378 Parent Daughter Daughter ïeighted Components Sol'n tCumulate l{t.t Ànalysis Analysis Calculated Residuals

Ie5 e8 ] 1.000 Si0¿ 52.8L 56.58 56.',l6 -0.07 Àpatite -0.014 2.66 1i0z 0. 8? 0. 81 0.81 0.00 AIbite -0 .157 30.37 AI¿ Os 13.39 18 .63 t8.29 0.34 Magnetite -0 .048 9.23 rFeO 9. 50 5 .84 5.84 0. 00 Sphene -0 .002 0.36 MnO 0.t2 0 .08 0.23 -0.15 Diopside -0 .204 39.53 Mgo 5.65 1 .76 L.62 0.14 [7 543 ] 0 .484 CaO 8.57 6 .07 6.00 0.07 Naz 0 4.44 5 .30 5.47 -0. 17 Ke0 2.85 3 .50 3.92 -0.41 Pz O¡ 0.77 0 .30 0.40 -0. 10

(Parent - Minerals = Daughter) Parent: [7s41] Daughter: Ie5e8] Sun of Squared Residuals = 1.455 Parent Daughter Daughter lleighted Conponents So1'n tCunulate I{t. t Ànalysis Ànalysis Calculated Res iduals

[74s1] 1 .000 Si0z 50.09 52.80 52.7 4 0.06 Apatite -0.006 1 00 Ti0z 1.08 0. 87 0. 55 0.2L Albite -0.133 20 66 AIz 0¡ 11. 81 13.39 13 .45 -0.06 Hagnetite -0.003 0 45 *FeO 11.05 9. 50 9. 50 0.00 Hornblende -0.390 50 70 !ln0 0.08 0.t2 -0. 14 0.27 Diopside -0.110 L7 18 Mgo 7 .96 5.65 6.39 -0.7 4 te5e8l 0.484 CaO 10.56 8.57 8 .17 0. 41 Na2 0 4.07 4.44 4.7 1 -0.28 KzO 1.54 2.85 2.3 5 0.50 Pz Oo 0.74 0.77 1.3 1 -0. 54 Sills Map B: Mineral and rock chenical conpositions used in calculations:

Wt.t Hbld-1 Labradorite Biotite Apatite Sphene Magnetite HbId-2 Salite K-Feldspar t77021

S iOz 40.13 53.70 39.34 42.36 52.92 64.40 52.94 TiOz 2.05 2.68 31.45 0.67 0.83 Alz 0s 11.88 28.60 15.85 2.24 t2.03 0.35 L7 .93 13.57 ¡FeO 2t.60 0.29 19.13 L.25 96.52 L5.72 9.2t L0.62 l,ln0 0.53 0 .16 o. oz 0.62 0.36 0.20 Mgo 7.79 0.15 Ll.26 0.10 0.22 LL.44 11.59 4.52 CaO 11.75 11.09 56.34 29.04 t2.40 24.56 8.23 Na2 o 2.09 4.7 9 0.1? 2.20 3.26 Kz0 2.L8 0. 36 t0.52 1.75 16 .48 4.70 Pz 0c 42.43 1.13

(Parent - Minerals = Daughter)

Parent: [7315] Daughter: 173121 Sun of Squared Residuals = 0.084 Parent Daughter Daughter I{eighted Corrponents Sol'n tCunulate I{t.t Analysis Analysis Calculated Residuals

[731s] 1.000 SiOz 62.82 66 86 66.84 0.02 Labradorite -0.011 8.15 TiO¿ 0.50 0 27 0.24 0. 03 Biotite -0.072 51.41 Alz Oo 16.39 16 .72 17.70 0.02 Hbtal-l -0.051 36.78 *FeO 4-34 2 .20 2.L7 0.02 Àpatite -0.005 3 .66 I'fno 0.08 0 .04 0.05 -0.01 t73t2l 0.861 Mso 1. 95 0 .84 0.88 -0 .03 CaO 3 .3? 2 .68 2.75 -0.05 Naz O 4.62 4 .98 5.20 -0.23 K¿0 4.68 4 .31 4.45 -0.14 Pz O¡ 0.22 0 .09 0.01 0.08

(Parent - Minerals = Daughter)

Parent: [73 1 5] Daughter: t73!21 Sun of Squared Resiiluals = 0.084 Parent Daughter Daughter lleighted Components Sol'n tCunulate llt.t Analysis Ànalysis Calculated Residuals

[7315 ] 1 .000 SiO¿ 62.82 66 .86 65. 75 0.11 177021 -0. 141 10.41 TiOz 0.50 0 .21 0.29 -0.02 Biotite -0.059 29.53 Alz Os 16.39 16 .72 17.05 -0.33 17 3L2l 0.799 rFeO 4.34 2 .20 2.t6 0.03 !lnO 0.08 0 .04 0.05 -0.01 t{gO t.96 0 .84 0.83 0.02 Ca0 3.37 2 .68 2.78 -0.10 Na2 o 4.62 4 .98 5.24 -0.27 KzO 4.68 4 .31 4.28 0.03 Pz O¡ 0.22 0 .09 0.08 0.01 (Parent - l{inerals = Daughter) Parent: [7304] Daughter: [73151 Sunr of Squared Residuals = 0.165 Parent Daughter Daughter lleighted Components So1'n tCumulate I{t.t Ànalysis Analysis Calculatecl Res iduals

[7304] 1. ooo Si0z 59.84 62.79 62.83 -0. 04 Labradorite -0.153 ?9.31 liOz 0.69 0. 50 0.35 0. 15 l,f agnetite -0.014 7 .51 åle Os L7 -70 t6. 39 L6.25 0. t4 Hbld-l -0.008 4.42 *FeO 5.15 4. 34 4.34 0. 00 Apatite -0.006 3.23 l{n0 0.15 0. 08 0.16 -0. 08 Sphene -0.011 5.53 Mso 1.54 1. 96 t.79 0. 16 [7513] 0.808 CaO 5.32 3. 37 3.52 -0. 15 Naz O 4.53 4. 62 4.66 -0. 04 KzO 3.74 4. 68 4.52 0. L6 Pz 0¡ 0.28 0. 22 0.02 0. 20

(Parent - Minerals = Daughter)

Parent: [? 3 14] Daughter: [7304] Sun of Squareil Residuals = 0.920 Parent Daughter Daughter Ifeighted ComÞonents Sol'n tCunulate I{t.t Analysis Ànalysis Calculated. Residuals

[7 3 14] 1.000 Si0z 56.90 59.83 59.80 0.03 HbId-2 -0.119 82.31 TiOz 0.67 0. 69 0.41 0.28 Magnetite -0.001 0.55 AIz Os 16 .87 L7 .69 17. 58 0.0L Biotite -0.025 17.08 *FeO 6.80 5. 1s 5.15 0.00 [7304] 0.856 MnO 0 10 0.15 0.L2 0.03 Mgo 3 29 1. 54 1.95 -0.41 CaO 5 73 5.32 5 .01 0.31 Naz 0 4 .7t 4.53 5.22 -0.69 K¿O 3 .44 3.74 3.49 0.25 Pz Or 0 .41 0.28 0.48 -0.20

(Parent - Minerals = Daughter)

Parent: 11102) Daughter: 173L4l Sum of Squared Resiiluals = 1.061 Parent Daughter Daughter lf eighted Conponents SoI'n tCunulate I{t.t ånalysis Analysis Calculated Residuals

17702) 1 .000 SiO¿ 52.40 56.92 56.93 -0.01 Hbld-l -0 .110 26.62 Ti0z 0.82 0.67 0.93 -0.26 Magnetite -0 .0 33 7.93 A1¿ Os 13 .43 16. 88 16 .58 0.30 Salite -0 .1 L7 28.30 *FeO 10.51 6 .80 6 .80 0.00 K-FeIdspar -0 .1 38 33.35 l{nO 0.19 0.10 0 .13 -0.03 Àpatite -0 .0 15 3.75 l{gO 4.47 3.29 3 .92 -0.63 [73141 CaO 8.15 5.7 4 5 .43 0.30 Na2 O 3.23 4.7L 5 .L2 -0.41 KzO 4.66 3.44 3 .73 -0.29 PzOr L.L2 0. 41 0 .81 -0.40

All coresponding mineral chenistries are also recorded in Appendicies C - L. *FeO: total iron expressed as FeO. Least squares mixing calculations based on flright & Doherty (1970). September 30, 1-987 .

A ZONED MTDDLE CAMBRIAN PLUTON IN THE PEAKE AND DENISON RANGES, SOUTH AUSTR.A,LIA. By: Robert S. Morrison & John D. Foden c/- TI:^e Department of Geology and Geophysics The University of Adelaide G.P.O. Box 498 Adelaide South Australia 5001 AUSTRALIA [,fith ]-3 figures and 2 tables.

ÀBSTRÄCT A suite of monzonitic rocks, including quarEz monzonite, syenite, alkali syenite, monzogabbro, syenogabbro, âs well as their altered equivalents, intrude Burra Group sediments of the Adelaide Geosyncline in the northern section of the Margaret Inlier in the Peake and Denison Ranges, S.4.. The style of emplacement of these plutons and the nature of their alteration, in particular marginal albitization, suggest they v/ere intruded into a thick sedimentary pile in the presence of a circulating meteoric water system. The petrography and chemistry of the pluton indicate that initial crystallization and progressive fractionation was controlled by clinopyroxene and hornblende, and subsequently by calcic plagioclase. Trace elernent trends support the involvement of two different stages of fractionation. Rb/Sr and U/Pb geochronology of the zoned pluton imply that this magmatism may coincide with late Early to Middle Cambrian volcanism in the Àdelaide Geosyncline and thus pre-date the Delamerian Orogeny. Key words: Hypabyssal anorogenic Aranites, geochemistry, Adelaíde Geosyncline, Delamerian orogeny, albiÈization.

1. Introduction. The Peake and Denison Ranges consist of a series of Adelaidean and Mid Proterozoic inliers 200kn northwest of the lrlillouran Ranges. The northern section of Èhe largest inlier, the Margaret Inlier, is host to a suite of intrusive bodies up to 3km in diameter collectively referred to as l-}:'e BungadiTTina Iúonzoníte (Ambrose et aI 1-981-) (Fig. f-). K-Ar geochronology conducted on this suíte by Anbrose et al (l-981) recorded variable ages rangíng from 679-469 Ma, but Èhey suggest that the date of emplacement was broadly synchronous with the Delamerian Orogeny. The Bungadillina suite is unique in the Àdelaide Geosyncline as it is composed of lithologies ranging from quartz monzonite and quartz syenite to monzogabbro and syenogabbro with minor alkali syenite and biotite lamprophyre. They inÈrude slightly folded Burra Group sedimentary rocks. The intrusives have undergone varying degrees

L of alteration, mosÈ notabty partial to complete albitization and the associated formation of leucocratic albiÈite bodies. The most westerly exposed pluton of the Bungadillina suite is Iargely composed of monzoniÈe, buÈ is unusual in that it has distinctive syenogabbro cores, some monzogabbro margins and smal1 relatively silica-rich areas of quartz monzonite. A smaller homogeneous quartz monzonite pluton is exposed to the immediate northeast. This paper presents the petrology and geochernistry of these plutons from the Bungadillina suite and presents new isoÈopic data for their age and genesis.

2. Fie1d Relations. The most westerly exposed pluton of the Bungadillina suite (Fig. 2) has an irregular shape roughly 4km by 2km and passively intrudes Burra Group (Willouran-Torrensian) sittstones and quartzites of the Fountain Spring Beds and Mount Margaret Quartzites (Ambrose et al l-981). Atthough Ambrose et aJ.. (1-981-) cited Èhe presence of feldspar porphyroblasts in dolomite as evidence of low greenschist facies metamorphisrn in the northern Denison Inlier, there is no such indication of regional metamorphism in the sediments of the northern section of the Margaret Inlier. Within the margin of the pluton, many larger host Burra Group xenoliths retain orientations similar to that of the inrnediate strata. The beds are generally undeformed, and like most other intrusions of the suiÈe, lack any evidence of contact metamorphism. To the souÈheast, the pluton intrudes distorted chaotically oriented beds commonly referred to as diapiric breccia. A small oval-shaped pluton roughly 60Om in diameter intrudes Mount Margaret Quartzite beds to the imnediate northeasÈ. In contrast to the passive nature of intrusion of the larger body, this massive, coarse grained and homoçteneous pluton intruded forcibty as evident from the bowing apart of the surrounding beds (Reyner l-955). A series of sub-parallel a1kali syenite and syenite dykes up to 4n wide intrude the both the northern section of the zoned pluton and the host sediments. These dykes represent a separate late-stage atkaline magmatic event, and are equivalent to aegirine-augite-bearing ultrapotassic intrusives of Èhe Bungaditlina suite found elsewhere in the inlier. fn the zoned pluton, the most northern of these dykes show extensive albitization. A small zone of meta-siltstone breccia hosted by atbite-carbonate outcropping near Èhe centre of the pluton is the only indication of late-stage magrmatic volatite activity. There.are no assóciated pegmatites, but a narrow elongate megacrystic monzonite zorre within the pluton is composed of feldspar phenocrysts grading up to 8cm in length.

3. Petrology and MineralogY. The larger zoned pluton varies from a coarse grained poikiolitic monzoçtabbro ánd syenogabbro to a medíum grained equigranular monzonite and quartz monzonite according to Sorensen's (L974) classificaÈion scheme. In this scheme the definitive components are the nodal

2 concentration of; f-) the nafic constituenÈs (hornblende, clinopyroxene, biotite, sphene and magnetite), 2) a1kali feldspar, 3) plagioclase and 4) quartz (Fig. 3). The contact between the gabbroic and more felsic lithologies in the zoned pluton are gradational over a narrohr distance of chromite. Minor alteration to haematite exists along fractures and margins. TiOz and CrzOs ârê less than O.2O wt.å, MnO and MgO less than 0.282, AlzOa less tham 0.35 wt.å and VzO¡ up to O.5l- wt. å. C7ínopyroxene forms early 0.2-l-nm euhedral pale green prisms, often with slight concentric normal zonation from diopside to ferrosalite or irregular patchy subsolidus zonation from Fe- to Mg- rich compositons (Fig. 5). No exsolution lamellae are present. Of the minor constiuents, TiOz is usuallv in low abundance (<0.5 wt.?), but AlzOa and NazO cañ be as hiqh as 4.S wt.å and l-.5 wt.? respectively with acmite and Ca-Tchermakíte components no greaÈer than 2.52, anõl jadeite

3 less than this. The application of hornblende geoÈhermometry on the basis of Ti content would be erroneous as the early crystallization of magnetite indicates melts of high oxygen fugacity which strongly Iowers the Ti content of hornblende (HeIz 1973; Otten L984). Biotite is locaIIy a major phase occasionally forming in preference to arnphibole as the sole ferro-silicate phase in more felsic lithologies. In some cases it replaces hornblende, probably in response to decreasing temperature and increasing potassium activity (Vüones & Gilbert , L982). It is cornmonly partially altered to either actinolite or more often to chlorite and has a restricted composition ranging between phlogopitêes-ânniÈe.= and phlogopitesa-anniteo, (Fig. 5). Sphene occurs as the main Ti-bearing mineral phase, crystallizing early as euhedral prisms showing slight yttriun enrichment within some cores from electron microprobe analyses of zoned crystals. Sphene is also occasionally found associated with anatase and calcite which are considered to be alÈeration products, or as a minor secondary nineral replacing clinopyroxene. Like sphene, apatite is a IocaI1y abundant ea-Iy accessory phase and it also occurs in secondary calciÈe-epidote patches. This may inply some phosphate mobility during alteration. Substantial nobitity of high-field strength elements (Ti, Y, P, Zr and Nb) has been noted as the result of greenschist facies metamorphisn in the presence of a COz-bearÍng phase (Hynes l-980; Murphy & Hynes l-986). This-may have been a significañt factor during the Delamerian Orogeny. Zircon is a minor phase occurring as tiny stubby prisms and quartz, when present, occurrs as small anhedral grains. Alteration of the pluton also includes locallized and patchy recrystallization of calcite, epidote, chlorite, sericite, albite and actinolite. ÀIbite-epidote-calcite form subspherical patches up to O.5m in diameter. Such assemblages are those of the lower greenschist facies of metamorphism (e.g. Miyashiro L979). A1teraÈion involving albitization is more prevalent along pluton margins with small leucocratic albítized dykes noted along the western margin. Albitite occurs along the northern margin and syenogabbro altered to monzogabbro along the eastern, northern and western margins. In contrast, the quartz monzonite pluton has undergone líttle al-bitizaÈion.

4. Geochemistry. [ühole-rock major and trace element geochernistry was conducted on 29 samples from the pluton (Tab1e f-). Sample numbers refer to a rock identification code at the University of Àdelaide. AIl elements lvere determined by XRF at the University of Adelaíde wiÈh the exception of sodium (atomic absorptioñ), fluorine (specific ion electrode) and ferric iron (titration). The plutons have a strong metaluminous calc-al-kaline character (Fig. A & 7) with silica contents ranging from 48-67 wt.å. The Harker diagrams of the alkali oxides demonstrate that some sarnples have undérgone extensive sodic metasomatism (albitization) and in these Na2O./Na2O+KzO>0.8 (Fiq. 8). This process inYolves !he-progresçive -r:eFtâcêmènt-óf -x-nù ñá as'well as'the conspicuous deplètión of the

4 large ion lithophile elements Rb and Ba, and to a lesser extent Sr. The average Ba concentration in albitized samples is commonly 600 ppm less than the unaltered equivalent (91-0 ppm vs 300 ppm), and Rb has experienced depletions of a similar rnagnitude (94 ppm down to 19 ppm; Fig. 11). Other incompatible trace elements (e.9. Zr or Nb) and the halogens appear to be unaffected by albitízation (Fig. 9). Such alteration is noÈ noted in the innediate surrounding sediments and is in keeping with the interaction of Iow-temperature saline groundwater and the cooling pluton (e.9. Baker L985), and does not involve rnagmatic volatile fluids as in the case of fenitization (e.9. Kresten & Morogan 1986). Iron may also have been mobilized during albitization reflected in haematitization and general Fe depletion. The abundance of secondary calcite in albitized lithotogíes indicaÈes that Ca2* v/as liberated as part the alteration reaction but immediately recrystallized by inÈeraction with COz. One albitized sample [9630] has ielatively high incompatible trace element concentraÈions. This is a marginal felsic differentiate located directly adjacent to the equally albitized more mafic main lithology [9585], and is the only eüiAenðe for late-stage REE enrichment. The Harker diagrams for the alkali oxides of relatively unaltered samples.show.a.general linear trend of increasi!9 Na=O and K=O with increasing silióa as would be anticipated in a fractionating system. Calcium is only slightly effected by alteration and shows a negative Iinear correlation with silica. These trends, in conjunction with the positive correlaÈion of Fê, Mg and Ca, reftect the progressive fractionation of hornblende and pyroxene. AIeOs is generally very high (>16 wt.å) and shows an initial negative correlation with CaO in more mafic samples (CaO>5 wt.å) indicating fracÈionation of prinarily hornblende and to a lesser degree pyroxene. For rocks with <5 wt.å CaO, the inverse holds true suggesting incorning and fractionation of calcic plagioclase. Incompatible trace elements have low concentrations in comparison to silica-saturated alkaline anorogenic intrusives and A-type granites, and are more in common with f-type granites (e:9. Bedard et ál LIBT; Whalen et aI L987). Variation diagrams of the high field strength incompatible elements (Zr, y, Nb) against CaO show enrichment with initial CaO-depletion followed by depletion once CaO has dropped to <5.52. The small quartz monzonite body (Fig. 2) has a composition which always places iÈ at the most fractionated end of the compositional spectrum shown by Èhe main monzonite-monzogabbro body (e.g. Fig. 8, 9 & 1O). This suggests it is sinply a separate intrusion of a batch of the same magrma. The incompatibte elements Ba and Sr are generatly in greater abundance than in Èypical I- and A-type granites. Furthermore, by comparison with typical I- or S-type suites from the LachLan Fold BeIt (e.g. Chappell & White L974), this suite shows much more extensive continuity towards relatively rnafic end-members. In this sense, there is some similarity with the Boggy Plain Suite recently described by û{yborn et al (1,987). Sc and V variations are consistãnt with fracLioña1 crystallization (Fig. 10), showing initial rapid depletion with falling CaO, but with an inflection in the trend at about 5? CaO. Ni and Cr concentrations show exponential depletion from quite hiqh values in the most mafic rocks (e.9. 754L, Table 1) to very low valuès in the quartz monzonites (e.9. 9593, Table f-). This variation again is consistent with fractional crystal-lization. Nd and Ce generally decrease in concentration with increasíng silica content

5 v/ith about 12pprn in the quartz monzonites and over 50 ppm and 40 ppn respectively in the syenogabbros. Ga occurs in concentrations comparable to A-type granites (Collins et a7 L982). This reflects the generalty higher aluminíum contenÈ, possibly reflecting enrichment during early Fe-Mg silicate fractionation.

5. fsotope Geochemistry. Whole-rock Sr isotope geochemisÈry was conducted on a Thompson mass-spectrometer and detailed whole-rock Rb concentrations rdere determined by XRF aÈ the UniversiÈy of Adelaide, analyses of which are summarized in Table 2. The resultant isochron records a Model 1 age of 52L+/-35 Ma with an initial ratio of 0.70648+/-O.0001-4. The Model 3 isochron displays a severe error range of +/-LL4 Ma with little variation in the error range of the initial ratio. Extensively albitized samples hrere not included as the preferential loss of Rb over Sr would erroneousty shift resultant points towards the eTSr/a6Sr axis. In conjunction with the South Australia Department of Mines and Energy, lJ/Pb zircon geochronology was conducted for one sample [9583]. Samples from the same site r¡/ere responsible for a K-Ar date of 679 Ma (Àmbrose et aI 1981). The broad error range of the resultanÈ ísochron of 525+/-35 NIa (Fanning pers. com. 1"987) was incapable of defining Èhe age of the intrusion as pre- or syn-Delamerían, but it possibly iñAicates that the K-Ar daÈe is erroneous while supporting the Rb/Sr results. These dates suggest that the intrusion may predate the Delamerian Orogenic ages assumed for the suite (circa. 495 Ma) by Ambrose et aL (198L). Instead are they more equivalent to an age obtained from lJ/Pb dating of zircons in a 1n thick sequence of late Early to Middte Cambrian tuffaceous volcanics in the Arrowie Basin in the f'linders Ranges (532+/-L2 Nla, Fanning L987). This volcanic event corresponds with the formation of the Kanmantoo Trough along the southern and eastern rnargins of the Mt. Lofty Ranges. The Truro Volcanics in the Mount Lofty Ranges, the Mount Wright Volcanics of the Barrier'Ranges and the Mooracoochie Volcanics in the l{arburton Basin in northern South Australia represent a s1ight.ly earlier period Early Cambrian volcanism (Preiss, 1987; Gatehouse, L986). The initial ratio obtained (0.7065) is similar to that of the Änabama Granite (0.705) of the Nackara Arc, and the Pal¡ner Granite (0.7068-0.7O7L) of the southern Mount Lofty Ranges, but much less than that of the Encounter Bay suite (Milnes et al I9?7). The Black Hitl norite body has virtually the same ratio (O.7066) as the Peake and Denison intrusives (Milnes et al L977). Figure 12 illustrates age-initial 67sr/e69r relationships for granitið rocks in the Gawler Craton and southern Lachlan Fold Belt in Ñ.S.W., Victoria and Tasmania. The South Australian Delamerian and Peake and Denison data are also included on this diagram. The Bungaditlina monzonite has a lower initial "Sr/"Sr value than aII S- and most l-type granites from the Lachlan FoId Belt in N.S.W., Victoria and-iasmania. It is stilt however, markedly more radiogenic than the mantle growth curve at this tirne. fn South Australia, the Iast major pre-Aáelaidean phase of crustal growth and evolution took place during and irnmediately after the Mid Proterozoic Kimban Orogeny (circa. L700-1400 Ma).

6 Age-inítia1 ratio data from hiebb et a7 (1986) are shown on Fig. 12. These data extend from very radiogenic samples to some which are very close to the mantle growth curve. The Gawler Range Volcanic province (e.9. Blissett L986) is shown to be bimodaL with both crustal and mantle inputs. The Yardea Dacite for instance, has recently been demonstrated to be pigeonite-bearing, geothermometric results indicating extrusion temperatures of the order of 1L00'C (R. Creaser, pers. com. ). This suggests major emplacement of mantle-derived melts in the lower crust at this Èime. Though the Sr evolution diagram (Fig. L2 ) only places linited constraints on Èhe evolution of the Bungadill ina suite, it does pernit the following source models: 1. An origin by re-melting of mafic rocks with moderate Rb/Sr ratios (0.05) emplaced in the lower crust during the Mid Proterozoic (Kirnban Orogeny) . 2. An origin by partial melÈing of anomalously enriched contemporary 1-ithospheric mantle. 3. Àn origin by partial nelting of contemporary mantle, the composition of which is close to the mantle evolutionary trend, and subsequently contaminated by more radiogenic crustal material.

6. On Emplacement. Unlike other plutons intruding Àdelaidean strata such as the Anabama and Bendigo granites (B1issett & Reid 1-973; Langsford 1972), the western-most exposed pluton of the Peake and Denison Ranges has neither a contact metamorphic aureole nor a dyke network intruding into the surrounding host beds. In contrast to the granites of the Kanmantoo Trough, the Bungadillina intrusive suite has no associated migmatites and does not occur within a zone of high-grade metamorphism (Fleming & WhiÈe, L984). The contrast between strongly zoned euhedral minerals such as pyroxene, hornblende and plagioclase in low-temperature oikiocrystic feldspars suggests initial crystallization at a greater depth than that of finat emplacement. The presence of large rafts of sediments along the larger pluton margins indicate passive stoping as the main mode of intrusion. The local site of these intrusions may be partly determined by zones of weakness as dictated by the presence of diapiric breccia. SmaIt circular quartz monzonite enclaves in the monzonite pluton may represent stoping of earlier formed narginal facies of the pluton. Although not in the area of immediate concern, monzonite and monzogabbro sills occur within tight, steeply dipping Delamerian folds immediately northeast of the largest single pluton of the Bungadillina suite, indicating pre-orogenic emplacernent. Similarily, a siIl sr¡rarm inÈruding less competent shales interbedded in massive Mount Margaret Quartzite to the imrnediate northeast of the area of study suggests that emplacernent was not dicÈated by regional Delamerian structural weaknesses, but is straÈigraphically controlled. The shallow intrusion of a hot magma may have been expected to cause contact metamorphic aureoles, yet none are present around most

7 intrusives of the Bungadillina suite, the exception being the western side of the largest single body. In order to prevent the formation of a contact metamorphic aureol-e, there must be an effective dispersal of the latent heat of the magma body. This may be made possible by circulating meteoric water. The interaction of water, especially if it is bearing Na* ions, could also provide the mechanism for localized albitization (e.9. Baker 1985). If the intrusion occurred during the Delamerian Orogeny, much of Èhe fluid conÈent of the country rocks may be expected to have already been squeezed out due to increased heat and pressure. Thus emplacement probably occurred prior to orogenic activity, intruding a wet sedimentary pile. Up to 15km of sedi-ments nere deposited into intracratonic basins and lat,er in a continentaL shelf environment comprising the Adelaide Geosyncline (Preiss & Forbes l-981). The subsequent Delamerian Orogeny, although not intense enough to significantly deform the intrusive bodies, did cause patchy Iow grade metamorphism as evident from abundant epidote nodules (Snith L977 ) as opposed to syn-intrusive epidote veins (Marzouki et aI L979). Mafic anorogenic magmas originating in lower crust can be readily emplaced to hígh levels via fractures due to crustal isostatic readjustments (Castro 1986). In the Peake and Denison Ranges, the area of plutonism in the northern section of the Margaret Inlier has been postulated to coincide with a major east-urest shear zone, the Kararí fauTt Tineament, sporaticatly active since the Early Proterozoic (Anbrose et aI l-98L; Flint & Parker L982; Rankin et aI L987). Yet there is no evidence to indicate the presence of any such structure in the Late Proterozoic strata. If a major crustal shear zor.e does exist, it must occur between the Margaret and Denison Inliers and is thus not exposed. The zoned nature of the pluton is best explained by autointrusion of a fractionating diapir (e.9. Nabelek et aJ L986). Crystallization and fractionation would have occurred at depth prior to emplacement. The expanding diapir model- invoking reverse zonation would develop in response to a denser more mafic core collapsing into a felsic intruding rnaglma from a progressively fractionating source. This style of emplacement by cauldron subsidence is typical in anorogenic environments (Castro 1987). ReLict mafic margins are preserved on both sides of the pluton as more altered monzogabbro, the margins being more accessible to the netasomatizing effects of circulating meteoric water.

7. Conclusions. V/Pb and Rb/Sr isotope systematics in conjunction with the nature of emplacement, alteration effects and regional metamorphism, indicate that the intrusion predates the Delamerian Orogeny. It is probably more closely associãted with late Early to Middle Cambrian volcanic activity of linited extent within the Àdelaide Geosyncline, occurring in respónse to a renewal of extensional tectonism. This magmatism must have either involved a contemporary input from the mantle or possibly partial fusion of nafic rocks from the lower-most crust. Cambrian Litting probably provided the basin into which the Kanmantoo sediments ltrere deposited and was also associated with the intrusion of pre-tr'r mafic ayfes in the Mount Lofty Ranges (Flerning 6r White l-984). This extensional phase was terminated by compressíon at the onset of the

I Delamerian Orogeny.

AcknowTedgements . XRF analyses hras presided over by J. Stanley,' wet chemistry directed by P. McDuie; aid in mass-spectrometry, D. Bruce; aid in isotope preparation, P. Macdonald & J. Cooper. Original manuscript was imrnensely irnproved by M. Sandiford. Fieldwork completed with financial and togistical assistance from Union Oil DevelopmenÈ Corporation and the Regional Geology Division of the South Australia Department of Mines and Energy under the authority of Dr. A.J. Parker.

REFERENCES Ambrose G.J., F1int R.B. & Webb A.W. L981-. Geology of the Peake and Denison Ranges. GeoTogical Survey of South AustraTia BuTTetin 50, L-71,. Baker J.H. 1985. Rare earth and other trace element rnobility accompanying albitízation in a Proterozoic granite, W. Bergslagen, Sweden. ILineraTogical Itlagazine 49, LO7-LI5. Bedard J.H.J., Ludden J.N. & Francis D.M. 1987. The Megantic intrusive complex, Quebec: a study of the derivation of silica- oversaturaÈed anorogenic magmas of atkaline affinity. JournaT of PetroTogy 28, 355-388. Blissett A.H. 1986. Subdivision of the Gawler Range Volcanics in the Gawler Craton. QuarterTy GeoTogicaT Notes of the GeoTogicaT Sunrey of South Austral-ia 97 , 2-1,1,. Blissett A.H. & Reid J.A. 1,973. Geological survey investigaÈion of the Anabama copper and molybdenum prospect, O1ary, Wadnaminga. South AustraTia Department of Flines and Energy Report book 73/4 (unpubl. ) . Castro A. L987. On granitoid ernplacement and related structures. A review . GeoTogische Rundschau 76/t, Lo1,-1,24. Chappell B.!{. & White A.J.R. 1,974. Two contrasting granite types. Pacilic Geology 8, L73'L74. Coltins W.J., Beams S.D., !{hite A.J.R. 6. Chappell B.!{. L982. Nature and origin of A-type granites wiÈh particular reference to southeastern Australia. Contributions to l,[ineraTogy and PetroTogy 80, 189-200. Fanning C.M. 1987. ffndel report G 6988/107 & G 6677/86. South Austalia Department of þIínes and Energy enveTope 5530 (unpubl.). Flening P.D. 6, White A.J.R. L984. Relationships between deformation and partial rnelting in the Palmer migmatites, South Australia. Australian JournaL of Earth Sciences 3L, 351--360.

9 Fli nt R. B. & Parker 4,.J. L982; Tectonic map of South AustraTia 1-: 2 ,OoO,OOO. Geological Survey of South Australia, Adelaide, S.A Gatehouse C. L986. The geology of the Warburton Basin in South Äustralia. AustraTian JournaT of Earth Sciences 33, 161-l-80. Hammarstrom J.M. & Zen E. l-986. Aluniniun in hornblende: An ernpirical . igneous barometer. Anetícan MíneraTogist 7L, I297-L31-3. HeLz R.T. L973. Phase relations of basalts in their melting range at pHzO=5 kb as a function of oxygen fugacity. Part 1. Mafic phases. JournaT of PetroTogy L4' 249-302. Hollister L.S., Grissom G.C., Peters 8.K., Stowell H.H. & Sisson V.B. Ig87. Coniirmation of the empirical correlation of A1 in hornblende with pressure of solidification of calc-silicate plutons . American MineraTogist 72, 23L-239 - Hynes A.J. l-980. CarbonatizaÈion and nobility 9f Ti, Y and Zr in Ascot Formation metabasalts, S. E. Quebec . Contributions to ItlineraTogy and PetroTogy 75, 79-87. Kresten P. & Morogan V. L986. Fenitization at the Fen complex, southern Norhtay. Líthos L9, 27'42. Langsford N.+. L972. Kia-Ora-Southdam project. BURRA Iz25O,00g sheet reconnatssance drilling. South AustraLia Department of [4ines and Energy Report book 72/I3L (unpubl. ). Marzoukí F., Kerrich R. & Fyfe W.S. L979. Epidotization of diorites at AI Hadah, Saudi Arabia: fluid influx into cooling plutons. Contríbutions to lLíneraTogy and PetroTogy 68, 28L-284. McCulloch M.T. & Chappelt B.W. L982. Nd isotope charasteristics of S- and Ï-type granites. Earth and Planetary Scíence Letters 58, 5l-- 64. Milnes 4.R., Compston [rT. & Daily B. 1-977. Pre- to syn-tectonic emplacement of Earty Palaeozoic granites in southeastern South AuËtralia. Journal of the GeoTogícaL Socíety of AustraTia 24, 87- L06. Miyashiro A. Lg7g. Iletamorphism and metamorphic beTts (4th edition). George Allen & Unwin Ltd., London. Mongkoltip P. & Ashworth J.R. 1986. Anphibolitization of metagabbros - in the Scottish Highlands. Journal of Metamorphic GeoTogy 4, 26L- 283. Murphy J.B. & Hynes A.J. 1986. Contrasting secondary nobility of Tf, - þ, Zt, Nb, and y in two metabasaltic suites in the Appalacians. Canadian Journal of Eatth Scíenees 23, l-L38-1144. Nabelek p.I., Papike J.J. & Laul J.C. l-986. The Notch Peake granite stock, Útanl origin of reverse zoning and petrogenesis. Journal of PetroTogy 27, 1035-1069.

10 Otten M.T. L984. The origin of brown hornblende in the Artfjallet gabbro and doleriÈes. Contributions to ILíneralogy and PetroTogy 86 , 189-l_99. Powell R. & Powell M. 1977. Plagioclase-alkali feldspar geothermometry revisited. ILineraTogicaT l[agazíne 4t, 253-256. Preiss W.V. (compiler) L987. The Adelaide Geosyncline. GeoTogicaT Survey of South AustraTia BuTTetin 53 , 1--438. Preiss lil.V. & Forbes B.c. l-98L. Stratigraphy correlation and sedimentary history of the Àdelaidean (Late Proterozoic) basins in Australia. Precambrjan Research 15, 255-304. Rankín L.R., Martin A.R. & Parker A.J. 1987. Identification of a major crustal shear zone, northwest Gawler Craton, S.4.. South AustraTia Department of Mines and Energy Report book 87/3O (unpubl. ) . Reyner M.L. 1955. The geology of the Paeke and Denison region. GeoTogicaT Suntey of South AustraTía Report of Investígations 6, 1-16. Richards J.R. & Singleton o.P. 1-981. Palaeozoíc Victoria, Australia: igneous rocks ages and their interpretation. JournaT of the GeoTogicaL Society of Australia 28, 395-422. Shand S.J. 1,950. The Eruptíve Rocks, their genesis, comPosition, cTassilication, and their reTatíon to ore-deposjts with a chapter on meteorites (4th edition), Thomas Murby & Co., London. Srnith R.E. 1977. Petrography and geochernistry of epidote alteration patches in gabbro dykes at Matagami, Quebec: discussion. Canadian Journal of Earth Sciences 14, 505-507. Sorensen H. (ed.) 1974. The ATkaline Rocks, John Wiley & Sons, London. Webb 4.W., Thomson 8.P., Btissett 4.H., Daly S.J., Flint R.B. & Parker A.J. l-986. Geochronology of the Gaw1er Craton. AustraTian Journal of Earth Sciences 33, IL9-L44. hlhalen J.8., Currie K.L. & Chappell B.w. 1987. A-type granites: geochemical characteristics, discrimination and petrogenesis. Contributions to lLineraTogy and PetroTogy 95, 4O7-4L9. lithitney J.A. & Stormer J.C. L976. Geothermonetry and geobarometry in eþizonal granitic intrusions: a comparison of iron-titanium oxides and co-existing feldspars. American lLineraTogist 6I, 75L- 76L. !{ones D.R. & Gilbert M.C. L982. Amphiboles in Èhe igneous environment. In (Verblen D.R. & Ribbe P.H. eds. ) Amphiboles: Petrology and experimental phase relations. lllineraTogicaT Society of Anerica Reviews in ltineraTogy 98, 355-389. Wyborn D., Turner B.S. & Chappell B.W. L987. The Boggy Plain

t_1 Supersuite: a distinctive bel-t of l-type igneous rocks of potential significance in the Lachlan Fold BeIt. AustraTian Journal of Earth Sciences 34, 2L'43.

FIGURE LEGENDS Figure 1: LocaÈion map for figure 2 of the Peake and Denison Ranges shõwing general outline of the Adelaide Geosynclj-ne. Figure 2z Geology map of the western intrusives of the Peake and Denison Ranqes. Figure 2Az Legend for Fig. 2. Figure 3: Modal mineral porportions of quartz, alkali feldspar (F), plagioclase (P) and total (*) mafics for selected rocks of the Bungadillina suite in the Peake and Denison Ranges. Symbols: a : quaitz syenite, b - quartz monzonite, c - quartz monzodiorite, d - áf*afisyenite, e syenite, f-monzonite, g -monzodiorite, h- syenogabbro, i - monzogabbro. Figure 4z Selected feldspar compositions for the western intrusives. riÍfea circles represent cores, open circles represent ri¡ns. AIkaIi feldspar compositions presented co-exist with rirn plagioclase. Figure 5: Compositional variations for pyroxene, amphibole and Uiótite. Nu¡nbãrs in brackets refer to number of individual microprobe analyses. Figure 6z û{hole geochernistry utilizing Shand's (L95O) classification scñemei a-peraluminous, b-metaluminous, c-peralkatine. Squares represent ãnalyses from larger zoned pluton, circles from smaller quartz rnonzonite pluton, diamonds from albitized (Na=O/K=O+Na2O>0.8) samples in zoned pluton

Ficrure 7z A (NazO+K=o) F (Feo*Fezoo). M lMclo) diaqram for intrusives; a-ÉholeiiÈic' trend, b:calè-alkaline Èreùaí ó-alkáline trend. Syrnbols as in Fig. 6. Figure 8: Selected Harker diagrams. Syrnbols as in Fig. 6- Figure 9z Selected trace element variation diagrams. Dashed line represents 5 wt. å CaO. Syrnbols as in Fig. 6 . Figure t-O: Selected trace element variation diagrams. Symbols as in Fig. 6. Figure 11: Rb and Sr systematics. Symbols as in Fig. 6. Filled circles represent analyses from relativeJ-y unaltered samples (Tab1e 2). fn-itiat ezgr_¡eêgr ratio for linear regression is O.70648. Figure L2z fllustration of age-initíal aTSr/e6Sr relationships for gránitic rocks in the Gawler Craton and southern Lachlan FoId BeIt in éornparíson with the South Australian Delamerian granites and the Bungadillina intrusive suite. Data from Blissett (1986), McCulloch & Cha[pe1t (IgB2), Milnes et aI (I9?7), Richards & Singleton (]-98L) and

L2 Webb et a7 ( l-986 ) .

t_3 F igure 1.

s Peake and Denison b Ranges $ q

2go

o 100km

Denison Inlier

Fig. 2 .a Margaret lnlier I i& 1 2go3o'

a

s o

20km 1360 Ð LEGEND

Mesozoic and Cainozoic sediments MID CAMBRIAN TO EARLY ORDOVICIAN ++ + Alkali syenite dykes Øo xx x Ît xx x Quartz monzonite L- c Megacrystic monzonite (ú E + + E'= + + Monzonite ct + + co f co Monzogabbro

Syenogabbro ADELAIDEAN

D Diapiric breccia ct = Lo Mount Margaret Quartzite o, (ú L L Fountain Spring Beds o= \

I I , I lt I tt I ++ I ll I ++ I I I + x \l I ì t\ t + + + xxxxxxxx I I I + \ 54' lr I ++++ + I xxxxxxx I ,l I + + + + , ++ \ xxxxxxx I *4***./4 + + +++ + + \ x x x x I \ x ++ + + \ x x x x x 280 29', + + + + + x x + + + + + + + + + + I + + + + I + + + + + I + + + + + + + + + + + + + + + +++ + + I +++++ + +++ + + ì I +++++ + + + + +++ + + + + + + + + + + + + ++ ++ + :i + + ++ + + + ... + ++ + + + ++ + + + + ++++ + + + + + + + + + + + + + + + + rl + + +++ + + + + + + + + + + + + + I + + + + + \ ++ + + + + + + + D + + + + + + + + + + + + + + + + \ ++ + + + + + + +++ + t I +++++ + + + + + + + + + +++++ + + + + + + + + + iÌ: ++++ + + + ::0: { 7 2' + + + + + + + + + t +++++ + + + + + + + + + + I ++++ + + + + + + + + D "t I + + + + + + + + + .1 I + + + + ++ + + + + :l I + + + + + + + + + I + + + + ++ + + + I + +++++++ + + +++++ ++++ + +++ + + I ++++++++ + +++ + + + D I +++++ + + + + + + + + I +++ + + + + + + + + I ++ + + + + + + + + + o I ++ + + + + + + + + + 28 24' I + + + +++ + + + I ++ + + + + + + + D D D I + + ++ + + + + + + I + I + + + + + + + I I + + + + I + + + + + I + + + + + D D D I I + + + + , I I + + + + I I I + + I I + + I I + c I I + ++ I +++ + l , + ++ + + D D D I I ++ +++ + I +++ + ++ + + I + +++ + I + + + + + + I +++ ++++ + I +++ + + D D D D D I ++ +++ + + + ++ +++ + + +++ ++ +++ + + ++++ ++ + + + + +++ + + D 0 D

600m 2go D D 2s' 135o s7' 1 3505 Quartz Fis ure 3.

20

P F a a a o a o a a a t o o ,t. tf e 35 o oi o h 65 *Maf ics

AI 60

50

40

Ca Na+K

F Fígure ó.

a F igure 7.

c otr E b

o

o o o A M F ìgure 9. o 160 o B Zr ppm o o o 130 o o tr o o 40 Sc ppm o o 100

o 30 o o I tr o 70 a,/gr-r tr 14 o 20 /" Nb ppm o o tr 10 oo 11 o o o o o I o o o v ppm tr o 400 o o o o þ o o 260 o tr 50 Y ppm o o o o o o E og 120 o tr o 30 2 6 10 o cao wt./o oo o o F igure 10.

10 2 6 10 cao wr.Yo Figure 8. Na20/K20+Na20 I Mgo ô o oo oo ::[

o 4 tro o .8 0.6 tr otr o o tro o e # o e o 0.4 o 0 €p 10 Na2O 11 FeO* o o I o o o o 0 o 6,tr o 6 tr v tr o o of B o 4 J-Aão- o 1 7 K2c. 20 At203 o Ê ô o 5 go o 6{ o tr 16 tr o o B o 3 tr o OFl- o o 1 oo, l- ' oó__J 12 o o 10 CaO 1.2 T¡O2 tr o tr cEl tr o o El- o o o{ oo o o o o.7 --"i tr o o o o oìO e 2 0.2 50 70 2 S¡O2 wt.o/o CaO wl.o/o r300 o B o o o oo o tr Sr ppm tr tr tr o o o o o tr tro 800 o o o o Rb ppm 300 100 200

0.711 87sr/8Qsr a

a 0.7091 \TA o A1/\

o a o oO o.707 initial ratio = 0.70648 87Rbl8ôsr 0.705 0 o.2 0.4

Fiqure 11. + Bungadillina d o Anabama a O Palmer 0.?15 a 0 Encounter Bay X Black Hill o Lachlan Fold Belt S-Type ¡ Gawler Craton O

a a a o l-Type û; o,7og a ìO o o0 Gawler Range Volcanics g o ttt o [. 3\ oo o o fiQ9 =g.05 Carnot Gneiss . Rþ, ST

285 a / Sr=0'0 0.703 Gurve Rb Gr owth a a Mantle

o

2500 2000 1500 1000 500 0 AGE (Mal

F igure 12. ?ròh 1: lhjor alrl Trac.816!.at csocbe¡irtry - ta.rt6r! I¡trurlv.. of tb. p.¡¡. r¡d D.Bj,ror R.Dgc..

llajor clo[€Dte iu reight D€rcer¡tage

Selple 752L 7322 ?523 7525 ? 531 ?533 753{ ?537 ?539 75¿0 ?5{1 7312 ?5{3 75{{ ?550

Si0¡ 58.71 6¡. {3 53.92 51.0? 61.10 59 .06 5?. 53 51. 91 62.31 {E. 55 {9.23 60. 68 55. 96 5{.23 60.50 TiO¡ 0.59 0. {8 1.02 L.26 0. 53 0. 78 0. 67 1. 02 0.55 1.07 1.06 0.59 0.80 0.92 0. {7 À1¡O¡ L7.22 1?. 13 Lt.71 1{. 0? L1.37 15. s8 18.00 15. 78 1? .09 t5.29 11.61 16. 8? 18. 39 L6.52 L7.28 fe¡ O¡ 5. ¿1 2.83 6.02 6. E9 3.05 {. 97 J .7l 5. 57 0.72 6.92 6.7{ 3.35 {.08 5.18 3.L2 FeO 1.37 1.50 3.2r t.47 1. {3 1.60 2.03 3.7{ 0. {6 {. 58 rl. 80 1. 81 2.09 2.98 L.26 ll¡0 0.11 0. 08 0 .L7 0.1? 0. 09 0. 0{ 0.08 0. tl 0. 01 0.0? 0.08 0.09 0.08 0 .11 0. 0? Hco 1. 75 t. {0 3 21 {.08 L.42 3. 2l I .86 3.71 2.97 5. ¡¡8 7.82 1. 80 1. 7{ t.09 1.59 CaO 3 .61 3 .85 7 01 8. 8E 4.25 3. 20 5.29 1.23 6. 11 8.51 10.38 {. ¿8 5. 99 6.53 t.22 O lla, {.90 {. 82 3 62 {. ¿{ {.87 7. 20 {. 88 {. 31 8 .07 {. 55 ,{.00 t.38 5.23 {. {6 5 .59 K¡0 {. 15 {. {0 5 3{ 2.57 ¿.35 1. 33 3 .61 3.96 0.59 1. 6? 1. 51 {. {0 3.{6 3.61 3 .78 P¡O: 0. 29 0.1E 0 55 0.59 0. 19 0. ¿5 0.29 0. 56 0.30 0. 79 0.73 0.28 0. 30 0. {9 0.25 H¿0t L.75 1. aE 0 65 0 .65 0. 76 2.01 1.08 L.2l 0. 67 1. 38 t. 1l 0. 59 0.77 1. 08 0.53 1o3¡l 99. 86 99.58 99. 58 99.21 99. ¿1 99. 16 99.16 99.20 99. 8E 98. 86 99.10 99.32 98. 89 99. 20 98.86

Îr¡ca €IoloDÈr iû Drrtr 9rr liLlloa

F 220 220 510 ?00 330 310 {10 700 2r0 800 660 ?00 500 650 200 c1 220 180 {50 310 {10 350 370 265 585 290 385 225 315 370 125 sc 13.7 11.0 22.7 27.1 11. 1 23.0 13.5 21. 0 11.5 29.7 {2.0 13 .5 L2.5 23.5 10. 3 v 135 90 266 3{0 101 186 133 236 10? 31? 323 L20 13{ 208 101 (5 Cr 6 51011 l0 (5 30 {5 35 20L L2 (5 18 9 Ni 5 391{ ö 11 5 16 LZ 27 7l 8 7 1{ 6 Ca 20 20 l8 2L 20 19 2t 22 19 22 t7 2L 22 2J 19 Rb 83 111 153 79 106 32 95 88 10. 3 61 52 L2l 63 70 58 Sr ¡,098 859 1178 1218 89{ 3t2 1103 1189 646 L254 852 83{ 11{1 L062 1J 20 Y 21.9 22.L 33.0 {{.0 2t.8 25.3 27.7 29.1 25.0 28.5 21.7 22.8 3r.0 29.1 22.L ZÊ l3r 13E Lzt 106 1{6 135 130 87 r62 84 1t 13{ 150 10¿ 107 ilb 8.6 E.3 9.8 10.8 8.6 7.2 8.{ 8.5 10.3 5.8 5.{ 8.7 L2.0 8.? 8.0 BA L270 905 1t6? 998 910 420 83{ 669 196 56{ 313 893 10{6 680 11¡09 Ce 60 55 59 98 50 69 55 12 ¿6 72 61 {9 60 70 74 ild 1E 1? 33 55 1.6 29 23 37 31 35 t2 20 23 2l L7

llaJor olelcott ia trigàt ¡,rrca¡t¡g!

Salglc 9311 9313 9582 9583 9585 9588 9590 9591 9592 9593 9595 9598 9599 9630

SiO¡ 63. t9 62.69 55.69 55. ?3 58. 92 58. 28 67.10 63.23 6a. 9{ 6{. 98 55 .16 51. 98 59. 73 61.09 TiO¡ 0.35 0. 7l 0.83 0. 86 0. 6¿ 0.68 0.23 0.33 0.29 0.29 0.80 0. 86 0. 76 0.65 À12 O¡ 17.35 18. a5 16.92 16.66 1? .51 18.65 16.5{ t1.26 17.18 17.11 16.95 13 .18 L7.t7 18. 19 Fez 0¡ 2.5L 1.00 3 .96 t.39 3.61 r.t9 t.29 1.88 1. ?0 1.90 t.28 5.55 2.03 0.63 Feo 0.77 0.7? 2.2' 3.06 2.00 t.11 0. 73 0.83 L.23 0. 70 2.3L {.36 1. 0? 0.73 llDO 0. 05 0.03 0.0? 0.1r 0.05 0.13 0.01 0.05 0.07 0. 05 0-07 0.L2 0. 05 0.03 xgo 0. 7{ 1.34 3 .09 2.78 ,.. 9? L.28 0. 37 0. {5 0. {{ 0. 55 2.61 5. 56 2.26 2.07 CaO 2.62 2.91 1.02 6 .29 l. t5 5. ¿0 2.37 2.66 2.38 2.53 6.29 8. ¿¿ 6.26 5.71 lla¡O 5.30 9.31 6.72 t. 6? 8.06 5.33 5. {3 5. ¡8 5.51 5.{? 5.98 t.37 7.1L 8.15 K¡0 5 .51 0.69 1.33 3.87 1.01 3.62 t. 13 5. 81 {. 5{ l. 66 2.1{ 2. 81 0. 60 0.81 P¿O¡ 0. 11 0.2L 0. {0 0. {2 0.25 o.22 0. 0? 0. 09 0.08 0.09 0.39 0. 76 0. 36 0. 30 8¡O' 0.48 L.22 1.39 0. 7{ 0.70 0. 5{ 1.06 1. 50 0.81 1.13 1. 93 1. 02 0.83 L.0z Totrl 99.27 99. {0 99.6? 99. 57 99.1? 99.39 99 .56 99. t6 99.22 99. {6 98. 97 99 .03 99. t3 99. 39

lrrc. ¡I.t.¡tr ia grrtt 9rr lillioo F 200 100 580 6{0 tlo rao z4o D¡ roo cl 165 e0 r6s Jlo 2ro 60 ?oo {so ¡50 180 sc iL 15o 135 i¡- lls 155 270 r3o 265 ?'3 r0.5 18-r 21-3 11-5 -ióad:i 5.0 6.6 a.¡ 6.2 z'.o v ?3 106 1e3 17s L47 50 E6 61 28.6 17.5 13.1 cr 10 6 2t zo 19 -(a (5 (5 63(5 181 253 138 10{ xi 6|L7L7g32561113695 a lt 1oo 10 L7 C¡ 20 21 ¡1 2L 2t 21 19 t9 20 nb L23 le.8 25-2 1or 19 20 16 19 20 Ss 22-r ,a 118 ri¡ d¡ 108 13 L2tL 510 1zr{ 1250 80. lo6t ?el riri 1õ¡i 10{ rJ.e s.2 r t8'e 22-1 3t.2 30.5 e?r e68 ro1{ eol Boe 27.t ii.s 13.5 15.3 it:s rr.¡, 3o.e s6 ZE 1f0 156 121 120 138 La2 133 1r? -ii¡ 21.1 31.3 ilb E.l t3.e 10.t e.5 e.o tr.t 7.2 12E 116 112 133 lro 8. 10{8 286 {0r 678 i.¡ 6:i ?.0 e.3 6.3 lo.3 s.2 Cê 276 ?90 ?36 lo53 ¡;; 820 t2s7 eJ3 3oo 51 {E 77 7l 50 66 36 {9 ¡ó 37 218 [ô 19 20 36 31 26 2E 7L 82 73 69 L2 la 13 13 2t 39 35 51 Table 2: Rb-Sr Isotope tfhole-Rock Data for rilestern Intrusives of the Peake and Denison Ranges. Sanple Rb (ppn) sr (ppn) B?Rb/86Sr 87sr/86Sr

7525 79.68 L229.68 0.32181 0.70812 7531 108.23 896.33 0.34311 0. 70910 753 9 9.90 639.83 0.04613 0.70?39 7540 60.13 L217.00 0.14075 0. 70781 7540 (R1) 60.13 L277.00 0.14074 0.10126 7540 (R2 ) 60.13 L271.00 0.14074 0 .707 44 754L 51.65 861.75 0. 17658 0.701L7 7542 L24.68 843.2t 0.43026 0.70939 7550 58.17 L346.L7 0.12?13 0.70129 9582 24.91 r2L6.73 0.06006 0.70697 9583 L00.92 L247 .7L 0.23319 0.70802 9588 91.36 1070.50 0.24949 0.70842 9590 119.40 801.81 0.43173 0. 71019 9592 11{. 83 103?.93 0.32247 0.7090? 9593 L07.71 984.15 0.32086 0.70884 TECßOÑIC II{PLICATIOIS OF DET,AIÍERIAIT IIAGITATISIÍ IlT SOIIIÏI AUSIRAÍJTA ÀlID TIESTERTÜ VIETORTA' J.D. Foden, S.P. Turner and R.S. lforrison Department of Geology and Geophysics, University of Adelaide, GPo Box 4981 Ade1aide, South Australia, 5001

ABSTRAC:I A comparison of the early Palaeozoic igneous hÍstory of the GIeneIg Metamorphic Complex in western Victoria wiÈh that of the oelaneiian rockË in souLhern South Australia, supports the suggestion that they are part of a single province. In both areas, Early ordovíciãn, syñ-tectonic, t-typè diorite-granodiorite-granite magmas intrude Cambrian metasediments. f{ith these syn-Delamerian intrusives, a younger Ordovician series of high-Ieve1, silicic A-type granites and acia võIcanics occur across S.E. South Australia and into western Victoria. This post-tectonic phase of Ordovician f elsic magmaÈism l¡tas associated with-mafic dyke emplacement and the intrusion of.large rnafic plutons in a proOãnle extensíonal environment. The highly fractiónated, felsið, post-Delamerian magmas are enriched i! F, Gã, Nb, LREE and y. These were generated in á second-stage rnelting event as the products of re-melting of the same ¡nafic lower crustal source that pròduced the syn-tectonic granites. This resulted from the rise of post-Èectonic, mantle-derived, mafic plutons. Canbrían sedimentation before the Delamerian orogeny was assoçiated with contemporary basaltic to trachytic volcanism and the intrusion of mafic si1Is. Cãmbro-ordovician magmatísm in this rrDelamerian provincerr therefore records a tectonic history of extension, collision and then further extension. In a reconstructed Gondwanaland, the Delamerian granites of South Australia and western Victoria form part of an extensive bett which extends through western Tasmania and the eastern part of the f,rlilson terrane in Victoria Land. Key lrlords: Delamerian Orogeny, geocheuristry, A-type granite, I-type granite, syn-tectonic, post-tectonic. Running Tit1e : Delamerian Magrmatisn-

Introduction: A number of recent studies, including those of Von der Borch (1990), Jenkins (1986, 1988) and C1arke & Powell (L987 ) have promoted à criúicaf appraisat of the tectonic character of Èhe Àdelaide FoId BeIt. This f-oiA belt has a sedimentation history extending fron the Adelaidean through to the Late Cambrian (Daily & Milnes, L972) and experienced the éffects of the Delamerian Orogeny in the Late Cambrian to Early Ordovician. This orogenic event resulted in complex, polyphaSe deforrnation (e.g. Máncktellot'r, 1980) and a Barrovian-style inetäinorphism extending at the highest grade zones to upper amphibolite

l_ facies (offler & Fleming, 1968; oliver et ãf., 1988). Von der Borch (1980) proposes that Adetaidean sedimentation proceeded in a developing rift. This tensional environment continued into Èhe Cambrian wheie the Kanmantoo Group, ât least in part, developed an open marine character with some sand-silt units probably represènting pioxirnal turbidites. By this stage, in the southern part of the fold bett, accretion of some oceanic crust may have occurred to the east. The extensional phase was arrested and reversed by the Delamerian Orogeny in the Early ôrdovician and hle propose that following this eveñt,-minor lithosþheric relaxation and slight crustal extension followed during the Middle ordovician. In western Victoria, the GIeneIg River Complex (úIells, L956i Vandenbêîg, Lg78) is considered a possible easterly extension of the South Ausùralian rrDelamerian provincetr. Unfortunately the intervening areas in the southeast of South Australia, Èo the east of the Murray River, are covered by Cainozoic and Mesozoic marine and terrestrial sediments. The onty basement outcrops are small, resistant exposures of mainly granitic rocks and more rarely, acid volcanics (Fig. l-). Syn- and post-Delamerian igneous activity is recorded by felsic and naiic intrüsions which ouÈciop to the east of the sinusoidal axis of the Adelaide FoId Be1t. Carnbrian pre-tectonic nagrmatism also occurred, resulting in syn-sedimentary volcanism and probable early siIl injection. These igneous rocks have been the subject of relatively few studies. It ís the airn of this paper to present new reconnaissance data and to provide a synopsis of that already existing. It_has been recognísed fõr some tine (e.g. Milnes et ã7. , L977; Mancktellow, L979) that the South Australian Palaeozoi.c granite suites included both syn- and post-tectonic associations. In this paper r¡re intend to discuss the timing and compositional relations of Early Palaeozoic magrmatis¡n in the sõuthern Aäelaide Fotd BeIt as a means of assessing the tectonic model described above.

Geological Set'ting of tlre lgmeous Rocks- 1. üt. IoftY Ranges. In the southern Mt. Lofty Ranges, most intrusive igneous rocks are restricted to the Kanmantoo Group. Granitic intrusives occur at palmer, Reedy Creek, Monarto, in the Victor Harbor area (Encounter Bay Granites) and at Cape Wiltoughby and Remarkable Rocks on Kangaroo Is1and (fig. i.). fñere are álsõ smaller intrusions in the Tanunda Creek and Cookås Hill areas north of Palmer and at Long Ridge, Mannum and Murray Bridge in the Murray Valley, just to the east of the Mt- Lofty Ranges. The Rathjen Gneiss (Fig. r-) (white, Ls66) i" a highly foliated, sheet-Iike boáy of strongly deformed granite in the Palner Area. It nãs a prominenL north-trending lineaÈion and is very like the granitic gneiss at Tanunda Creek (Chinner, l-955).

2 The Black Hill Norite (!{egrnann, L98O) is a major, but poorly exposed mafic intrusion to the east of the Mt Lofty Ranges north of Mannum (Fig. 1). No contacts are exposed, but it is thought to be ernplaced in Kanmantoo Group metasedimentary rocks. Diamond drilling here has intersected several granitic or tonalitic bodies (lVegmann, L98O), some of which cross-cut the norite and others with strong deformational fabrics, which may be roof septa or xenoliths. The Black Hill Norite is not metamorphosed and observed deformation is restricted to discrete shear zones. We therefore regard this body as effectively post-tectonic. Though almost all the Ca¡nbro-Ordovician igneous rocks in the southern part of the Adelaidean Fold BeIt are restricted to the Kanmantoo Group, the pegrnatitic Mt. Crawford granite is an exception. This íntrudes Lne aaelaidean rocks close to the contact with a Mid- Proterozoic crystalline basement inlier, the Barossa Complex (Mills, L973). Mafic inÈrusive rocks occur in the southern Mt. Lofty Ranges mainly as sub-alkaline, dolerite dykes many of which are post- tectoñic. These form swarms mostly orientated NI¡I-SE, and are weII represented in the MÈ Barker - hloodside area and near Mt. Kitchener soutn of the Barossa Valley. Likewise, the strongly foliated Reedy Creek granodiorite, the much less deformed and cross-cutting Reedy Creek diorite and Èhe post-tectonic Mannum granite are all cut by Iate-stage, undeformed mafic dykes. These mafic dyke rocks are apparently confined to the Canbrian Kanmantoo and Normänville Groups. Even where the Adelaidean is adjacent to dyke-rich Ca¡nbrian sequences (as in the !ùoodside area) thèse dykes do not intrude the Proterozoic rocks. Many of the amphibotite bodies however appear to be deformed and have Fr or Fz fabrics (Flening & l{hite 1994) - Some of Èþese syn- õt-pÏ:e--teêtõñic-dikéé-õõcùr in tÉe Cookes'HiIl' área south of Springton (Abbas , Ig75), and they are also observed in the Monarto area where Èhey are cut by pegrnatitic Aranite (Hoesni, 1-985). Likewise, in Èhe Tungkilto area to the west of Palmer, numerous amphibotite bodies uþ to 3 m thick, are conformable with the host mela-sediments and have suffered aII the same deformations as these. These must therefore either be early siIls, or basaltíc lava flows. Clear evidence of pre-tectonic magrmatic activity is provided by the basaltic to trachytic Truro Volcanics (Forbes et a7., L972). These are conformably interÈedded with shales and sandstones which form part of a sequence which is equated which the Normanvil-Ie Group. (Jago pers. coÍtm. ). The volcanic roCks indicate shallow water deposition. They are highly vesiculated, have brecciated flow tops and display ballistic-bomb-sag features. This magrmatic acÈivity is broadly contemporaneous witn extensive volcanism in western Tasmania (Varne & Foden, Lg87) and with hígh level rnonzonite to gabbro intrusions in the Peake and Denison Ranges in the northern Adelaide FoId Belt (Morrison, 1989; Morrison & Foden, L989).

3 2. South Easterrr Souttr Australia. From east of the Murray River to the Victorian border, the only occurences of Palaeozoic rocks are scattered outcrops of graniÈe and very rare acid volcanic rocks, protruding from Quaternary sedirnents. parLicular localities include Mt. Boothby, hlitlalooka, Gip Gip Rocks, Marcollat, Mt. Monster, Christmas Rocks and Kongal. This series of isolated outcrops forms a linear S.E.-trending ridge including the Sedan and Mannurn granites to the north and the Dergholn granite in Victoria to the south-east. Thís basement high is known as the padthaway Ridge (Rochow, tgTL). The granite at Taratap, near Kingston, lies to the south of this belt and differs petrographically from those granites. Most of the rrsoutheastrt granites are siliceous, post- tectonic bodies, though that at Taratap (Fiq. 1) is a biotite granodiorite with a nica-defined fabric. Post tectonic volcanic rocks óf rhyolitic or dacitic composition (Henstridge, L97O) outcrop in close proxinity to the Padthaway Ridge granites, suggesting that comagmatic granites are high 1evel. Some sub-surface drilling at various localities on the Padthaway Ridge suggests that between the Adelaide FoId BeIt and the Casterton district in western Victoria, there is an extensive concealed tract of Early palaeozoic nafic to fetsic magrmatic rocks and associated meta- sediments (e.9. Parker, 1986).

3. I'he Glenelg tletanorphic Complex. The GIeneIg Metamorphic Conplex represents the most westerly exposure of Palaeozoic rocks in Victoria (Fig. l-). The geology of the region has been studied by Vilells (1956) and more recently by Turner (1õ86). Here a metasedimeñtary sequence of pelitic Èo psammo-pelitic èornposition has suffered polyphase deformation under low pressure, anpñiUolite facies conditions. Pre-, to syn-tectonic _igneous. intrusive suites include the Wando Granodiorite and a series of gabbroic dykes or sil1s. The I-type Wando Granodiorite is compositional-Iy like the Reedy Creek granodiorite in the Mt Lofty Ranges. In the same area, the Harrow rnigmatiÈic granite is also syn- tectonic. However, this is an S-type intrusion which contains numerous metapelitic xenoliths (Fig. L). The GIeneIg igneous-metasedimentary sequence is in faulted contact with ultralnafic rocks (the Hummocks Serpentinite). These have harzburgite compositions and relict textures suggestive of olivine- orthopyioxene piínary mineralogy. Cr-spinels from these rocks are the same äs ttrose irom tñe tectonitã-narzburgite zone of ophiolites. Intruding this sequence is a post-tectonic pluton, the Derqholm Granite which is texturalty as well as composiÈionally similar to the post-tectonic Delamerian granites to the west- The metasedimentary rocks in the Glenelg Metamorphic Complex Ef,îE"iXS iåãåIuåã"tliåÊ'r53å$="Hå'3.fi3,"ä+3*Iptñiil¿'?"33åi:'fiñå:å' structures are ¡nuch more like the Delamerian structures exhibited by the Kanmantoo Group in the Mt. Lofty Ranges, than those of the

4 Benambran Orogeny seen in Ordovician rocks further east in Victoria (in the Bendigo area for instance; Vandenberg, L978i King, 1e8s).

Geochronologty and Isotope Geoloçry. Webb (L976) provides Èhe most comprehensive review of isotopic and geochronological studies carried out on Delamerian granitic and volcánic rock fiom South Australia. Other studies of specific plutons include those of Milnes et a7. (L977) (Encounter Bay granites) and Irthite et a7. (L967 ) (Palmer Granite). The only data available are those for the K/Ar and RblSr systems. As discussed by Milnes et al. (IgZ7) Rb /Sr dating of the syn-tectonic granites (Encounter Bay and palmer) are complicáted by resetting. The general conclusion is that the syn-tectonic granites (Palrner, Encounter Bay and Taratap) record slighlly greater ãges (515-475 Ma) than the post-tectonic aranites and volõanics (479-460 Ma). Significantly, the initial t'==./t'=r râÈr-oã or È1-rê ¡)oE€-teeÈonl-e grroutr) are v€r]¡ 1ow

Petrology. 1. S1m-Tectonic Granites. The syn-tectonic Aranite suites such as l{ando and Reedy Creek show wide óornpositional ranges from dioritic end members throuqh tonalite and granodíorite to granite (Fig. L). The more mafic end members are pÍagioclase (Ansa-An,-o) - quartz hornblende - biotite quartz dioriles. Sphene, zircon and apatite are important accessory fna="s, together with epidote. Felsic end-members of the syn-tectonic èeries are composed of meso-perthitic microclinê, quartz, plagioclase (oligoclase), bioÈite, sphene, magnetite and apatite and range frorn granóaiorite (Reedy Creek) Èo quite siliceous true granite (the Encounter Bay granites) . The syn-tectonic granites show development of biotite-defined foliation. At Reedy Crãek this fabric is strong in the^granodiorite and quite weak in Lne younger diorite which cuts it. Milnes et a7. (L97i) describe strongl gneissic fabrj-cs in the margins of granites at Victor Harbor. The syn-tectonic granites contain xenoliths of diorite and arnphibolite as well as metapelitic ones derived IocaI1y from the Kanmantoo GrouP. Geological rel-ationships between the dioritic and more felsic end members of these suites are some times complex. At Reedy Creek, the diorite intrudes the granodiorite, thouqh they exhibit good compositional continulty (e.g. MoeIIer, L98O and Fig. 2), suggesting they are related nagrmas. Àt gncounter Bay, there are extensive rafts of Quartz diorite iñctuded in the felsic granite. At Wando Va1e, tonátite and granodiorite are deformed and support the early, regional

5 fabric and are intruded by the more felsic Í,Iando Granodiorite. The most nafic Wando granitoids include diorite which is hornblende- (ca 30:Mg 40:Fe 30, MglMg+Fe 0.45-O.59, TiO2 O.7-L.2 wL.z) and plaqiocÌase- (Anso) bearing and.of cumulate.gfiqin. In boÇh the Reedy [!eék-ãña-wanàô ãÍñ-Ëéðtõñíc suités, compositioñaI evolution from tonalite or diorite to granodiorite, is controlled by plagioclase - hornblende crystallization. Mineralogically and geochenically these granites are I-type according to the criteria of Chappell & hlhite (L974, t982). Mafic end rnembers áre hornblende-bearing while even very felsic granites such as the Encounter Bay series are magnetite-sphene bearing. Aluminous phases such as cordierite do not occur and most rocks are metalurninous. Mafic end members of the syn-tectonic granite spectrum have high FeO, MqO, CaO, TiO= and Àlzo" (Fiq. 2). Their Mg/Mg+Fe values are ófóée- É,o'0.50'and Sc, Ni and V'leúe1s are also high. These rocks have moderate KzO contents and Low KzO/NazO ratios as well as high Sr and moderately hiqh Ba contents. Their Rb/Sr ratios are basalt-like (<0.25) (Figure 3). Granodíorite in this province (e.9. Reedy Creek or TaraÈap, table l-) is very similar in composition to the average Lachlan Fold Belt I- type granite (e.g. Chappetl & White, L982ì hlhalen et a7., L987). These aré quite calcic, sodic aranodiorites, with silica contents between 62 and Og wt.å. and MglMg+Fe ratios about O.37-O.47 (Fig- 2) - Concentrations of Ni, V, Sc and Ti are much lower than those of associated diorites, but are still fairly high. Likewise, Sr levels are lower, but still quite high, and Rb/Sr ratios are quite low (< 1.0). garium concentràtions aie high, and BalRb ratios are very high (Fig. 3). The incompatible element patterns of Èhese granodiorlles are .ierf siinitar to thaL of the average Lachlan Fold Belt l-type (Fig. 4). The granites in the Encounter Bay area (Victor Harbor, Cape lrtitloughby) , the Palner granite and those in the Monarto area Èo the west oi lturray Bridge, aie very felsic members of this syn-tectonic (tabte granites SiOz (73-75 wt.å) suite 1). These are true with high ' tão¿Xe;9"ñEEi8Írì0l¿.18H.9"ßa.,Ës?o*89 SFo"ßådnYåfiå,IsH Ë8lUgf,Es ãf,Er"= higher Rbrzsr and BalSr values than the granodiorites (Fig. 3). Their inðornpatible trace element patterns are very sinilar to that of the average felsic Lachlan Fold Belt l-type granite (Fig. 5) given by Whaleñ et a7. (1987). By comparison with the granodioritic members of the syn-tectonic group,-thesè felsic granites have lower Ti contents and similar or depleted Nb, Zr and Y. By comparison with Èhe post-tectonjc granites, which are also very siliceóus, these fetsic syn-tectonic granites are less depleted in ãr, are marÈedly more Ba-rich, have much lower Rb/Sr ratios and have rnuch lower t¡bl Zr and, Y contents. These contrasts are illustrated in figure 6b. They have lower Fe/Mg ratios and have lower F and Ga contents.

6 2. Erridence For Local S1m-tectonic llelting. Migmatite and pegmatite is abundant in the highest metamorphic grade zones of the Mt. Lofty Ranges. These are derived by partial nelting of pelitic and feldspathic units of the Kanmantoo or Normanville Groups (White, L966). The generation of such melts spans the deformationat nistory of the belt from the deformation of earliest miqmatite leucosomes by Fr, throuqh to the formation of tourmaline- rióh. post-F= pecnnatiËe (Fleminq-& White, 1984). AÈ Reedy Creek, the iõfiáteä granõdioÉíte croès-cuts-the migmatite.'There is évidence that this rnigrmatite underwent some remelting during intrusive of both the granodiorite and the diorite. The granodiorite and diorite at Reedy õreek are also cross-cut by later pegmatite-, aplite- and leucogranite veins. In the Mt. Lofty Ranges, the suggestion made by C1arke & Powell (L987) that the Kanrnantoo Group was emplaced as a hot allochthon has interesting inplications for the generation of rnigmatiÈe. lrlas this local rnelting due entirely to thermal ef f ects, or v/as it also prornoted by fluid flux from the adjacent cold and hydraÈed autochthon? The syn-tectonic granites also include the Harrow Granodiorite, a nigmatitic-granite which occurs near Èhe Wando area (Fig. 1). This is an S-type granite, apparently derived by melting of the local metapetites. The grañite contains abundant biotite-rich schleiren which are the residue of thÍs rnelting. In contrast to most other granites considered in this paper, the Harrow Granodiorite has A1=OelCaOrNazO*KzO > 1.1. The biotite-that compositions are also dlfferent ï¡õm-tñoèe-'ðñ-täã-othei-.irãñités-iñ tney are much more aluminous. They contain about 3.5 atoms of AL/formula (/22 oxygens) while the other (I-type) granites contain < 3 (tabte 3). Amongst the very felsic Encounter Bay granites there are some that have AL=O=/CaO+NazO+K=O ratios slightly greater than L.l-. As White et a7. (1996) point out this is nõt a necessary indication of S- type character. Metaluninous melts may evolve to become peralgminous ciðse to their solidi in equilibrium with hornbtende (e.9. El1is & Thompson, 1986). Furthermore, there is a strong possibility that the Encoünter Bay granites have become contaminated by digestion of Kanmantoo eroup metasedimentary country rock. This suggestion is both supported by f-ield observation and Sr-isotope data (Milnes et a7., Le77).

3. lltre Post-Tectonic Granites. Members of the post tectonic group are all very siliceous, true granites. They are oiten very homogeneous with interlockÍng, ienomorphic-gianular textures. Some are one feldspar granites (e.9. Marcollát, tãnte 2) and all are alkali feldspar-, quartz-rich and relativeli plagiocÍase-poor. Plagioclase is often included in alkali feldspar. tñese granites are characterised by smokey quartz. The alkali-feldspar is very coarse perthite, in which the abundant albite exsolution is often contiguous with albite rims- The late-stage granites are magnetite-bearing generally with Fe- rich biotite, attnough some (including the Marcollat granite) are

7 amphibole (ferro-hastingsite) and even hedenbergite-fayalite-bearingr. rnèir ferro-magnesian siticate phases have very high Fe/Mg ratios (Èable 3). arnpñiboles and biotites have low A1(tota1) and high. ÀI.t->/AL(va) ratios. Biotite, amphibole and apatite a1I contain significant fluorine contents while those in the syn-tectonic suite are F-free (table 3). Accessory phases comprise apatite, sphene, zircon and fluorite. Zircons are lárge, euhedrãI and apparently unzoned. Zoned allanite is also a common accessory mineral. Some even have other minerals as cores (p1agíoclase). High fluorine concentrations in these magmas have resulteã iñ nign zircon solubility, probably elininaÈing inherited populations. The post-tectonic aranites are siliceous (73-77 wt-.å-9iO=),. relativel? al=Oo-þoor, áIka1i-rich rocks. They have markedly higþer K=O./NazO iatíos (1 to 2.5) than the syn-Èeclonic group. and {Iave IohI 'Cãó'äñã-vãiy-Iõw'ttgo-cõnténtsl Mg/Mq+' Fe values aÉe ektremely Iow (< 0.35) and are much lower than those of the syn-tectonic group. Chromium, Ní, Sc and V concentrations are aII extremly low. Sr concentrations are very low and Rb/Sr ratios are very high (Figs.-3 and 6). By comparison witn tne syn-tectonic granites they are deplet'ed in Ba (Fiós. g and 6) and have lower BalRb ratios, whilst Gâ, Nb, Zr and Y conõentrations are considerably enriched. The trend of evolution towards one feldspar magrmas indicates fractionation at Iow pressures where the feldspar solvus does not intersect the solidus (they are hypersolvus granites). This implies in addition that they have already fractionated plagioclase, a fact demonstrated by their very low Sr contents and Ba depletion. These must have been dry magmas by comparison with the syn- tectonic group. For example the Marcollat granite (Fig-l-, table 3) shows good evidence of añ extended history of plagioclase fractiónation which would have enriched the water content of the residual melt. Even so it still crystallised alnphibole and not biotite and olivine and clinopyroxene relicts are still present. The parent magmas of this series-must have been very dry. By.contrast, the syn- teétonic suites show evidence of higher water activiÈies with the replacement of hornblende by biotite in quite mafic, alkali-poor maç[mas. These post-tectonic suites are classical A-type granites_on the basis of thä criteria of Collins et a7. (1982) and White et al. ( r.e82 ) . The syn-tectonic suites show differentiation trends of Y, Zr and Nb depletiän. This is not the case in the post-tectonic aroup (Fiqs. 3,5,6 and 7). û{hite et al. (1982) have discussed the influence of hígh F/oH ratíos on the crystállisation history of granite magmas. fhéy rãcognised that Nb, Zi and Ga probably formed rnagrmatic alkali- fluðro coñplexes and Èhat these delayed saturation of for instance, zircon. In the syn-tectonic magrmas with higher a!I=O,.the earl'12 ããt,tràtion of ziicon, sphene añd hornblendè results in depletion of these high field strength elements. pearce et a7.'s (L984) tectonic discrininant diagrams (Fig. 7)

I provide support for the syn- and post-tectonic subdivisions of the Delamerian granites. The post-tectonic group without exception fall- into the within-plate granite field. The syn-tectonic group faIls into the volcanic-arc/ syn-co1lisiona1 field on figure 7a whereas on figure Zb, where this field is divided into syn-collisional and volcanic-arc fields, these graniÈes falt into the volcanic-arc field. Mineralogical and geochenical factors lead to the following conclusions about the origin of the post-tectonic granites or Èheir magrmas: 1-. They are highly fractionated. 2. They have evolved from quite dry parent magrmas. 3. They have been emplaced at high crustal levels. 4. The magnnas from which they crystallísed hlere relatively hot.

Discussion. 1. source Rock and Tectonic Implications. Data presented here suggest a close sinilarity between both the nature and sequence of granitic magmatism in the Glenetg Metarnorphic Complex and in the southern Mount Lofty Ranges. In both localities the intrusion of syn-tectonic diorite-granodíoriÈe-granite suites (I-type) are followed by post-tectonic A-type granites. The early Palaeozoic igneous history of this belt implies a sequence of: (1) Cambrian extension (pre-Delamerian), (2) Early Ordovician compression (Delamerian) and then (3) Iater Ordovician extension (post-Delamerian). Mafic magmatism is associated with both of the extensional phases, but the post-Delamerian period was bi- modal, with A-Èype graníte intrusion and rhyolitic volcanism accompanying (spatially and temporatly) mafic intrusion.

i. Sym-tectonic llagrnatism During the compressional phase associated with the Delamerian orogeny, mafic magmas rrtere excluded from the upper crust. The suggestion that the Kanmantoo croup is allochthonous (Clarke & Powell, LggZ) promotes the question: l{here was the contenporary locus of syn- pelameiian crustal fusion? C1arke & Powell (1,987) considered the thrusting may have taken place early and from the east. In this case' some of tne syn-tectonic plutons may have been emplaced before folding and faulting produced crustal thickening. On the Rb vs. Nb+Y discrininanÈ diagram (Fiq. z) the syn-tectonic granites faII into the Itvolcaníc arc granit,ett field which is the field óe granitic rocks formed at sites where a significant mafic source component is present, usually during continent-ocean collision. In Èhe Casterton areá, the Hummocks Serpentinite, provides some evidence for the developrnenù of oceanic crust, a consequence of the pre-Delamerian extensional phase. It is also a strong possibility that an extensive lower crustal or upper-mantle mafic layer (underplate) had already developed beneath

9 the Adelaide Fold BeIt before the Cambrian extensional phase. This mafic layer, rây have begun development during phases of nafic magrmatism at the start of the Adelaidean (e.9. the Depot Creek Volcanics, the Beda Volcanics, the Gairdner Dyke Shtarm and the T,{ooltana Volcanics) (Crawford & Hi11yard, l-988). The existence of this underplate is supported by low initial è7St/'65.r ratios determined for the pre-Delamerian monzonítes of the Peake and Denison Ranges (Morrison & foden, L989). l{e propose that the syn-tectonic granites developed by melting of this underplate material as a result óf heat input during the pre-Delamerian extensional phase. These magmas moved up into the upper crust during the compressional stages of the orogeny and suffered some conta¡nination there. As there is a considerable varíation in the degree of tectonic fabric development in the syn-Èectonic Aranites in the Adelaide FoId Belt (Rathjen Gneiss very strong, Reedy Creek Diorite very weak) this delivery of melts froln tne sõurce to their emplacement site probably continued over a protracted period of the orogeny. ft is not expected that.these types óf granite would result from rnelting of evolved Proterozoic continental crust.

ii. Post-tectonic llagrnatism. The Sr-isotopic characteristics of the post-tectonic aranites are consistent with a source that inctuded even less evolved crustal material than the syn-tectonic series. Their relationship to source- rock chemistry is difficult to assess because of their extensively fractionated character. The very high levels of some trace elements nay reflect enrichment during extreme fractionation rather than particularly high leve1s of these elements in the source region. Ho!,rever, the post tectonic source must have lower water contents than the syn-Èectoàic. This is consistent with the sequential derivation of syn- and post-tectonic Aranites from the same source. Restites or cumulates left by first stage f-type magmatism could include biotite, hornblende, magnetíte, apatite , zircon, sphene and allanite. These have a collective capacity to host many of the trace el-ernents enriched in the post-tectonic magmas. An initial melting event may have fractionated the OH/F ratios of the residue after which second stage, relatively F-enriched, high-temperature melts vtere produced. These hrere able to rise and fractionate much more before freezing. Several features support the hypothesis that the post-tectonic maglmas hrere relatively hoÈ and were therefore able to be enplaced at nién crustal levels. ineir association with vol,canic rocks in fact suqcrests that some mav have been subvolcanic. Having low aHzO levels IñÍËIãIIy-i'ioufã-äfsö-äfrõw-thérn- to fractionate exteñsively at the granitic-minimum without reaching water saturation. The terrains that host these post-tectonic granites therefore represent shallower Ordovician ðrustal levels than those in which the syn-Èectonic granites are exposed. O1iver et a7. (L987) have suggested that in the Mt. Lofty Ranges, the Dz deformation with upright folds 4nd a near yertical stretching iïñeaEloñ-h'ãs-ñãit--oË-ã--cfüétãï -tñiõkening event. The post-tectonic granites hrere énplaced after this at a stage when lithospheric

10 extension followed on from crustal overthickening. This extenSional phase also produced mafic intrusion and Èhere is evidence that mafic and felsic magmas hlere in close spatial and temporal proximity. The quarry at Mannum, for instance, exposes the Manñum A-type granite which hosts swarms of mafic xenoliths. These xenoliths ènow-extensive signs of digestíon and hybridisation with the host granite. Some show dissaggregating, tear-drop shapes. There is also évidence of block-stoping of a chilled marginal granite phase. These features suggest maçfma mixing is taking place, perhaps during turbulent flow as-the magrna ascended a conduit. The post-tectonic graniÈes generally have very low Mg and Fe contents and.high Fe/Mg iatios. rñis is rèflected in the very low Mglyg+ Fe ratios of ferromagnesian silicates in these rocks. By contrast, the Mannum granitel a mernber of this group, has very magnesian bíotites (Mg# > OO, table 3), as a reflection of the magma mixing observed. In his study of the post-tectonic mafic intrusion aÈ Black HiII, Wegman (19g0) has shown that a component of magmatic differentiation inúolves large -scale potassium enrichment towards monzo-norite. Many of the norités contain biotite and orthoclase. It is probable that this potassium enrichment is a resulÈ of the combined effect of assi¡nilation of locaIIy formed crustal melts and fractional crystallisation. A speculative conclusion may be that the A-Èype gránite plutons are high level reflections of deeper-seated, hot, ñafic Ooãies, Iike the Black HilI intrusion. Some mixinq of these systems occurs, âS at Mannum, a situation which is promoted by lithospheric extension. Although Èhe post-tectonic suite can be explained by re-nelting of the syn-Éectonið source due to heating by contemporaneous mafic magmas, 1t is not possible to entirely discount an origin by direct fractionation f rom these maf ic magrmas.

2. Tlre Delamerian Granites and the east Gondwanaland Reconstruction. The reconstruction of Gondwanaland places eastern Antarctica, southeastern Australia and Tasmania in close, pre-Mesozoic proxirnity However, there is some controversy over the detailed nature of this fir. fn eastern Victoria Land, Cambro-Ordovician I- and S-type granites intrude the [¡lilson Terrane (Vetter & Tessensohn, L987; Stump ét a7., L9B6). The eastern I¡lilson Terrane is composed of metamorphosed, probable Ca¡nbrian sediments (e.9. FÍndlay, 1987). Those granite-s which intrude closest to the boundary between the Wilson and Bowers Terranes to the east are mainly l-type. In Tasmania the l-type Darwin and Murchison granites are enplaced in the Cambrian Mt. neaá-Volcanics and the Dove Granite intrudes Adelaidean basement. Each of the eastern Antarctic, Tasmanian and South Australian- Victorian Delamerian granite terranes is flanked to the east by areas of deeper-water, Ordovician, sedimentation. lite equate the three Delamerian granite terranes and would

11 therefore favour a reconstruction which a1lows them to form a single belt in the then eastern margín of Gondwanaland. In this respect, Baillie,s (1985) reconstruction which moves Tasmania to the west with respect to'Australia and which places Victoria Land south of Tasmania, is iavoured (see Bail-lie, L985; Figs. : and 4). The South Australian- western victòrian trDelamerian provincerr on this basis is equivalent to the eastern hlilson Terrane.

Conclusions. The conclusions of this study are as follows: l-. Simitarities in the structural and magmatic histories of early palaeozoic terrains in western Victoria (The Glenelg Metamorphic Complex) and in the southern Adelaide Fold Belt suggest that these are part of a single province. 2. Three distinct phases of Cambro-Ordovician magmatic activity are recognÍsed. These cómpriset (a) an at least partly syn-sedimentary, pre-ãeformational phase, (b) a syn-deformational phase, and (c) a post-tectonic extensional phase. 3. The pre-deformational magmatic activity is do¡ninantly rnafic, the syn-tectðnic period is nainly one of I- type granite _generation and tñe post-tectõnic phase is oñe of combined mafic- and A-type granitic magmatism. 4. The syn-tectonic phase is also associated with crustal melting producing- migrmatite, pegrnatite and S-type granite. The tectonic cycle implied is one of; (1) rifting, (?) collision and uplift and (3) post-cóffisional extension. This continental marginäI tectoniè ácLivity formed a Delamerian terrane which is also preéerved in western Tasmania and eastern Antarctica.

Acknowledgenents. The authors thank Mr. J. Stanley and Mr. P. McDuie at the Department of Geology and Geophysics, University of Adelaide, for tnèir vital role in iock analysis. We also acknowledge helpful comments provided by Drs. R. Both, R. Oliver, M. Sandiford, J. Parker, J. Jago, c. Gatehouse and two anonlrmous reviewers'

References. Abbas S.A.F., LTTS: Granitic and nigrnatitic rocks of the Cookes HiII area, South Australia, and their structural setting. University of Adelaide Ph.D. thesis (unpublished). Baillie p.W. , Lg85: À Palaeozoic suture in eastern Gondwanaland. Tectonics 4 (7 ), 653-660. Chappell B.hl. & hthite À.J.R., Lg74: Two contrasting granite types. Pacific GeoTogY 8, I73-L74.

L2 Chappetl B.hf . & hlhite A.J.R., Lg82: I- and S-type granites in the Lachlan Fold BeIt, southeastern Australia. In: Geology of granites and their metallogenic relations. Proceedings of the Ínternational Synposium, Nanjing University, China, p.87-1-01. Chinner G.A. , Lg55: The granitic gneisses of the Barossa Ranges. university of Adelaide B.sc. Hons. thesis (unpublished). C1arke c.L. & Powell R., L988: Basement-cover interaction in the Adelaide Foldbelt, South Australia: the developrnent of an arcuate foldbelt. Tectonophysics (in press) - Collins W.J., Beams S.D., White Ã,.J.R. & Chappell 8.W., L982: Nature and origin of A-type granites with particular reference to southeastern Australia. Contríb. þIíneraL. PetroT. 80, L89-2oo- Crawford A.J. & Hilyard D., 1-988: Geochemistry of the Late Proterozoic tholeiitic ffoõa basaits, Adelaide Geosyncline, South Australia. In: Brian Daily Mem. VoI. Geo7. Soc. Aust. (this volume). Daity B. & Milnes A.R. I Lg72: Revision of the stratigraphic nomenclaÈure of the Cambrian Kanmantoo Group, South AusÈralia. J. GeoL. Soc. Aust. L9(2), L97-2O2. Ellis D.J. & Thornpson 4.B., 1986: Subsolidus and partial rnelting reactions in the quartz-excess CaO+MgO+AIzOa*SíOz*HzO sysÈem under water-excess and water-defìcient conditions to l-okbars: Some irnplications for the origin of peraluminous melts from mafic rocks. J. PetroT. 27, 9L-L2I. Findlay R.H., Lg87: A revier¡r of the problems important for the iñterpretation of the Cambro-Ordovician palaeogeography of northèrn Victorialand (Antarctica), Tasmania, and New Zealand. In: Gondwana Six: Structure, Tectonics and Geophysics. Geophysícal lfionogtaph Seties 40, Amer. Geophys. Uníon (Ed. G.D. McKenzie), 49-66. Fleming p.D. & hthite A.J.R., Lg84: Retationshíps between deformation aña partial rnelting in the Palmer migTrnatites, South Australia. Aust. J. Earth Sci. 3r, 351-360. Forbes 8.G., Coats R.P. & Daily B., Lg72: Truro Volcanics. O. IVotes Geo7. Surø. S. Aust. 44, L-5. Henstridge D.4., LTTO: The petrology and chemistrY of the upper souùheast granites, Soütn Austialia. University of Àdelaide B.Sc. Hons. thesis (unpublished). Hoesni M.J., 1995: The granitoids and migrmatites of the Monarto area, South Australia. Uñiversity of Adelaide B.Sc. Hons. thesis (unpublished). Jenkins R.J.F., L986: Ralph Tate's enigrrna- and the regional significance of thrust faulting in the Mt. Lofty Ranges. In: 8æ-. australian Geological Convention, Geo7. Soe. Aust. Abstr. 18.

t3 Jenkins R.J.F., 1988: The Adelaide Foldbelt: tectonic reappraisal. In: Brian Daity Mem. VoI. (Èhis volume), Geo7. Soc. Aust.. King R.L., 1985: Ba1larat )-:25Or000 geological rnap explanatory notes. GeoL. Surv. Victoria Rept. 75. Mancktelow N.S., L979: The structure and meÈamorphism of the southern Adelaide Fold Be1t. University of Adelaide Ph.D. thesis (unpublished). Mills K.J. , lg73: The structural geology of the hlarren National Park and the western portíon of the Mount Crawford State Forest, South Australia. Trans. Roy. Soc. S. Aust. 97(4), 28L-3L5. Milnes 4.R., Compston ht. & Daily 8., 1,977: Pre- to syn-tectonic emplacement of Ear1y Palaeozoic granites in south-eastern South Australia. J. Geo7. Soc. Aust. 24, 87-106. Moeller T., 1980: The petrology and geochemistry of the Reedy Creek granitoids and mígmatites. University of Adelaide B.Sc. Hons. thesis (unpublished). Morrison R.S., 1989: Igneous intrusive rocks of the Peake and Denison Ranges within the Adelaide Geosyncline. University of Adelaide Ph.D. thesis (unpublished) . Morrison R.S. & Foden J.D., l-989: A zoned Middle Canbrian pluton in the Peake and Denison Ranges, South Australia. In: Brian Daily Mem. VoI. , GeoL. Soc. Aust. (this volume). offter R. & Fleming P.D. , L968: A synthesis of foldinq and metamorphism in the Mt. Lofty Ranges, South Australia. J. GeoL. Soc. Aust. L5(2), 245-266. Oliver R.L., Sandiford M., Mills K.J. & Allen R., 1987: Cordierite paragenesis in the Delamerian Orogeny as evidenced by the Springton area, South AusÈralia. In: Brian Daily Mem. Vol. , Geo7. soc. Aust. (this volume). Parker A.J., 1986: Tectonic development and metallogeny of the Kanmantoo Trough in South Australia. Ore GeoL. Rev. L, 2O3-2L2. Pearce J.4., Harris N.B.W. & Tindle 4.G., L984: Trace element discrilnination diagrarns for the tectonic interpretation of granitic rocks. J. PettoT. 25(4), 956-983. Rochow K.A. , L,TL: NAR.ACOORTE, South Àustralia. Explanatory notes, Lz2ïo,ooo Geological Map Series. Geo7. Surv. S. Aust-- Stump E., hlhite A.J.R. & Borg S.G., 1986: Reconstruction of Australia and Antarctica: evidence from granites and recent rnapping. Earth Planet. Scí. Lett. 79, 348-360. Turner S.P. , Lg86: Early Palaeozoic plutonism in western Victoria and eastern South Australia: implications. University of Adelaide B.Sc. Hons. thesis (unpublished).

L4 Vandenberg A.H.M., L978: The Tasman FoId Bel-È system in Victoria. Tectonophysics 48, 267-297. Varne R. & Foden J.D. , !987: Tectonic sdtting of Cambrian rifting, volcanism and ophiolite formation in western Tasmania. Tectonophysics L40, 275-295. Vetter U. & Tessensohn F., 1-987: S- and I-Èype granitoids of North Víctorialand, Antarctica, and their inferred geotectonic setting. GeoTogísche Rundschau 76(L), 233-243. Von der Borch C.C., l-980: Evolution of Late Proterozoic to Early Palaeozoic Adelaide fotdbelt, Australia: comparisons with post- Permian margins . Tectonophysics 70, LL5-l-34. Webb, 4.W., L976: Geochronology of the granitic rocks of southeastern South Australia. AmdeT Rept. lto. 1138. ürtegmenn D., 1980: Pre-Tertiary geology of the Black Hill region in the western Murray Basin of S.4., with speciat emphasis on the petrology and geochemistry of the gabbroic rocks. University of Adelaide B.Sc. Hons. thesis (unpublished). [rlells 8.E., Lg56: Geology of the Casterton district. Proc. Roy. Soc. Victoria 68, 85-LL0. lilhaLen J.8., Currie K.L. & Chappelt 8.W. , L987: A-type granites: geochemical characteristics, discrimination and petrogenesis. Contríb. MineraT. PetroT. 95, 4o7-4L9. lrlhite A.J.R., 1966: Petrology and structure of the Rathjen granitic gneiss of the Palmer region, South Australia. J. Geo7. Soc. Aust. L3, 47L-489. hthite A.J.R., Lg66: Genesis of migmatites from the Palmer region of South Australia. Chem. Geo7. L, L65-2OO. White Ä.J.R., Compston W. & Kleeman A.l{., 1967: The Palmer Granite - a study of a gianite within a regional metamorphic environment. J. PetroT. 8, 29-50. White A.J.R., Collins lV.J. & Chappell B.I,{. , L982: Influence of melt structure on the trace element composÍtion of granites. In: Geology of granites and their netallogenic relations. Proceedings of thé- Inteinational Symposium, Nanjing University, China , p.737- 75I. hlhite A.J.R., Clemens J.D., Holloway J.R., Silver L.T., Chappell 8.h7. & WatI V.J., L986: S-type granites and their probable absence in southwestern North America. Geleogy L4, 115-LL8.

Fignrre Captions. Figure t. Map showing the location of the Delamerian granitic rocks in thé southern Mt. Lofty Ranges, southeastern South Australia and in western Victoria.

L5 Figure 2. MgO- variatíon diagrams (vs. CaO, AIzOo and SiO=) iliustrating the compositional range of the I-Èype , syn-tectonic suites from Wando in the Glenelg Metamorphic Complex and Reedy Creek in the Mt. Lofty Ranges (Moeller, 1980). Open circles felsic Wando granodioríte, fiIIed circles- Wando tonalite, open squares - Reedy creek granodiorite, filled squares - Reedy Creek diorite. Figure 3a. BalRb vs. ppm Nb variation for average or typícal examples of each of the SouÈh Àustralian and western Victorian plutons for which data are availabte. The analyses plotted in each of figures 2, 3, 4, 6 and 7 are given in tables 1 and 2. Slrmbols: open squares = syn-Èectonic granítès, filled diamonds = post-tectonic Aranites. Figure 3b. Ba,/Rb vs. ppn Y variation for the same typical reþresentative Delanerián granites as in figure 3a. asterix = averaçle l,achlan Fotd BeIt A-type granite, half fitled square = âVêrâ9e Lachlan FoId BeIt l-type graniLe and open círcle = average felsic l-type graniÈe (lilhalen et a7., L987). Figure 3c. Log Rb/Sr vs. ppn Nb variation for the same representative Delamerian gránite compositions from South Australia and western Victoria as in figure 3. Figure 3d. Log îeO/MgO vs. Log Rb/Sr variation. Figure 4. Average continental crust-normalised incompaÈible element variation diagràms, showing; a) lilando granodiorite and the average Lachlan FoId Èe1t l-type graniÈe (Whalen et a7., t987 ) and b) typical tonalític or granodioi-itic members of the South Australian and western Victorian Delamerian province. Figure S. Average continental crust-normalised incompatible element valiation diagram showing the average Lachlan Fold BeIt felsic l-type granite (Whalãn et a7., ßú) and a typical example of a very felsic granite from the Delamerian province (Cape Vüilloughby). Fígure 6. Average continental crust normalised incompatible element variation diagram showing , a) the average Lachlan FoId BeIt A-type granite (Whalãn et al., lgez ) and post-tectonic Delamerian granites irom Mannum and Dergholm, b) a comparison of an example of the felsic syn-tectonic granites (Monarto) and the post-tectonic aranites (Mannum). Figare 7. Trace element discrimination diagrams for Èhe tectonic inlerpretatíon of granites; a) log Nb vs. Iog Y, b) log Rb vs. log y+Nb.: Slmbols repiesent the same rocks as in figure 3. oRG = field of ocean ridge granites, VAG = volcanic arc granites' syn-COLG = syn- cotlisional granites, wPG = within plate granites.

L6 LOCATION l¿J fD

Truro Volcanics GULF @ Seaan ST. ck Rath VINCENT Mt. o aucx Hill Norite Crawford s Gnel!! ul CookE Hill 3 Palmer ù ADELAIDE a /\ 6¡ Mannum Wo 35' ck. Mt. Barker' Monarto G Murray Bridge E (l)F fl t o

KANGAROO ISLAND

Cape Willoughby Remarkable Rocks @ Papineau Rocks I KINGSTON

s7o LEGEND Harrow

Syn-tectonic Granite N Dergholm Wando ++ tonalite Post-tectonic Granite gneiss) Hummocks vv :.:.:.;.: vvv Volcanic or Subvolcanic CASTERTON . Wando Granodiorite Kanmantoo Trough Sediments (incl. Glenelg Metamorphic Complex) - ggo

0 50 1oo

Km

e" t¿0" 141' O a 19 ?ro t o F At2o3 % e to ral fã o 15

e o 65 o o ú I SiO2o/o ¡o 55 I ar t rt tr ¡ 45

I !. t I oor a o I o CaOlo o

o a B 4 o o 0 2 4 o MgOTo 20 20 A B

t T tl I ¡ Ba/Rb ¡ Ba/Rb ¡ 10 10

I ¡l ¡! A õ¡ A A ^ I A t A ro t A ^ 0 0 0 30 60 0 50 100 Nb ppm Y ppm

1.5 A c ^ D A 1.5 A A ^ ¡ A A 0.5 ô A o TA II A a A 0.5 aaqa Log ¡l Log ¡ I^ ö Rb/Sr o Rb/Sr $ -0.5 o ¡ -0.5 I I l¡ I I t ¡ -1.5 -1.5 0 30 60 0 1' 2 Nb ppm Log FeO*/MgO 10 e

Average Lachlan l-type oi, Eborf åE1 \¡coo. EC tUO CDO Wando Granodiorite

0.1

KNbLa rZrT¡ Y Ba Ge Nd

10 Black Hill tonalite b

O t¡, cD= Ebo

åE 1 \¡goo

L.?C,ë Wando Granodiorite 38 Reedy Creek Granodiorite

0.1 î r Ba Ce Nd Average Lachlan felsic l-type 1 0 (D+. (ÚJo,_32 õq¡ <(Ú \C:y oo 1 E-- 6ã CDó \ Cape Willoughby granite

0.1 Rb e dZT T¡ Y Ba Sr a Mannum granite 1 0 Average A-type aØ(D +. I õ= õc)

ìa+J è6 1 ä= 38 0 1

I Dergholm Granite

Nb a r f Ba Ce Nd

b

1 0 t'E Mannum granite !úí õo -.!eb cLC 1 sã

Monarto granite 0.1 a r Ba Ce Nd 1000

WPG 100 A A Log Nb ¡ A {e t A I I 10

..VAG+syn-COLG ORG

1 1 10 100 1000 Log Y

1000 syn-COLG

A A f A+ WPG 100 ¡¡ It t Log Rb

10 VAG ORG

1 1 10 100 1000 Log Y+Nb Table l: Chemistry of selected s1m-tectonic aranites. Sanple L234s 6 7 B 9 l0 ll T2 sio^ s3. s8 62.66 64.45 65.47 68.65 71.59 73.2I 73.39 73. 48 73.5-l 74.60 75.58 rio:. 1.46 0.46 0.73 0.'16 o.74 o.2B 0.2r 0.26 0.41 0.32 0.27 0.26 18.61 IB. OB t6.76 16.6I 14.74 15.48 L5.02 14.30 13.22 14. l0 13. 34 t2.47 iþó, 8.35 4.56 4.46 4. 16 4.27 2.02 1.30 2.26 2.47 1.59 1.83 1.66 MnO 0.14 0.13 0.09 0.07 0.07 0.02 0.01 0.06 0.06 0.o2 0.02 0.04 l4gO 4. 13 2.25 2.3I 1.78 1.51 0.61 0.47 0.94 l.0l 0.61 0.37 0.74 CaO 7.52 5.99 4.76 3.87 2.42 1.93 L.52 1.44 r.32 l. lg 1.49 0.92 Na^O 4. 15 3.67 4. 19 4.43 2.18 4.74 4.39 2.88 3.43 3.99 4.01 2.96 R^6 1.75 2.04 2.00 2.60 5.21 3.24 3.82 4.30 4.52 4.56 4.01 5.40 ,lou 0.50 0. 15 0.25 0.24 0.19 0.08 0.06 0.17 0.06 0.05 0.06 0.06 l|g* 47.00 47.00 49.00 43.00 39.00 35.00 39.00 43.00 42.00 41.00 27.00 44.00 Cr n.d. t9 n.d. n.d. 28 n.d. n.d. 27 n.d. n.d D.d. n.d Ni 3182I19 l6 n.a. fl. â. T2 ll. â. l6 ll. â. n.â. Sc 26 15 t3 12 1l 3 3 t0 6 4 5 5 v 2I5 99 104 82 56 n.a. ll. â. 36 n.a. l6 ll. â. n.â. R) 56 74 73 80 2LO 95 t15 178 189 86 139 314 Ba 79t 474 880 1389 827 1396 1605 654 735 579 253 340 Sr 737 386 7r9 522 r92 592 487 174 ll3 95 66 59 era 20 n.a. n.a. n.a. 2T n.a. ll. ä. 18 Il. â. n.a. ll. â¡ ll. âo

N) 22 I 16 2t l4 16 25 ll t3 22 l4 l5 Zr 229 134 175 304 237 2tL 163 116 tr3 249 15s 112 Y 3t 16 T7 23 34 7 7 26 27 2l 28 58

La n.a 23 n oCI n. a. 50 ll. â. ll. â. 22 ll. â. ll. â. ll. â. ll. â. Ce 56 46 50 87 82 90 B8 35 20 tt5 49 57 30 ñl 15 2L 29 36 ll. â. L7 t3 ll. ä. 43 ll. â. 30

F n.a. r42 lì. â. n a 944 n.a. ll. â. 3sl ll. â. n.a. ll. â. ll. â. Rb,/Sr 0.08 0 t9 0.10 0.15 0.10 0.16 0.24 I 02 r.6g 0.90 2.Il 5 27 Balb 14.02 6 36 1I.99 17.30 3.93 14.62 13.90 3 67 3.89 6.69 l.gl 08 K^O I tfu^o 0.42 0.56 0 48 0.59 2 39 0.69 0.87 1.49 L.32 1.15 1.00 1.82 ceft 1.81 2.89 2 83 3.74 2 38 T2.7I 12.57 1.35 0.74 5.39 1.75 0.98 N)Æ 0.72 0.53 0 91 0.91 0 4t 2.29 3.57 o.42 0.48 1.05 0.50 0.26 l: lgeAY Creek diorite; 2: Reedy Creek Granodiorite; 3: Average l{a¡rdo Granodiorite; f: S1m-tectonic Black Hill tonalite; 5: Taratap granite; 6: South llonarto Granite; 7: tloittr Monarto Granite; á: aveiage nãiror,r GranodiorÍte; 9: S1m-tectonic Black HilI Granodiorite; l0: Cape willouglby granite; l1: pal¡ner öranite; 12í Añ;"g" Etrcounter Båy Granite; n.d. = not detected; n.a. = not analysed. Table 2: Ctrenristry of selected post tectonic Aranites.

Salçle 12345 6 7 I 9 10 ll t2

sio^ 75.40 77.37 77.35 77.87 74.39 72.57 75.56 73.63 73.26 74.t4 rioÍ 0. 19 0.08 0.06 0.09 0.22 0.38 0. 19 0. 19 0.37 0.20 A1^ó- t2.92 12.20 L2.37 I1.68 13.70 13.83 t2.22 13.29 13.58 t2.59 Fá5 t.2I 1.44 1. ll 1.59 1.34 1.93 2.t3 2.6L 2.t4 3.32 MnO o.02 0.01 0.01 0.05 0.05 0.07 0.07 0.05 0.05 0.05 ü9O 0.37 0.01 0.01 0. l0 0.49 0.55 0.08 o.23 0.28 0.lr CaO 0.53 0. 15 0.45 0.56 r.33 0.87 0.59 0.78 L.27 0.94 Na^O 3.45 4.03 3.82 3.32 3.94 4.03 3.77 3.74 3.79 3.87 K^ó 5.92 4.69 4.81 4.73 4.49 5.69 5.36 5.45 5. r8 4.76 nlou 0.01 0.02 0.01 0.01 0.04 0.08 0.02 0.03 0.07 0.03 rþ* 35.00 1.00 1.00 10.00 39.00 34.00 6.00 14.00 19.00 6.00

Cr n.d. lll I 1 2 I n.d. 4 Ni l5 722 4 I 3 5 Il. âo I Sc 4 233 4 5 3 4 6 5 v 4 7L3 l4 2l 2 4 l5 5

R) 188 378 298 347 2lo t97 109 186 279 188 Ba 119 r10 76 69 49s 643 76 384 431 303 Sr 36 ls l0 19 100 136 10 51 94 57 Ga n.a. 29 22 L7 l9 2L t9 19 n.a. 2L

t|] 30 55 30 28 26 49 l9 19 35 25 Zr t97 292 L52 109 159 335 392 246 280 219 Y 90 81 94 70 35 62 38 50 62 73

La n.a. 22 33 41 6t 91 160 to2 n a. n.a. C.e 106 40 69 80 81 I52 25t 166 118 166 ¡ri 59 20 45 41 26 57 119 70 50 79

F n.a. 523 1754 1364 384 714 553 777 n.a. lI22

Rb/Sr 5. 17 25.23 28.74 17.56 2.to 1.45 10 38 3.60 2 97 3.28 Balb 0.63 0.29 0.26 0.20 2.15 3.2s 0 70 2.06 I 55 l.6l K^O tßa^o 1.71 l. 16 I.26 I 42 1.14 I 41 I 42 1.46 1.37 L.23 ceft 1.19 0.49 0.73 I 14 2.3I 2 45 6 58 3.27 1.89 2.27 rtÆ 0.34 0.68 0.32 0 41 0.76 0 79 0 5l 0.39 0.56 0.35

l: Post tectonic Black Hill granite¡ 2¿ Christmas Rocks nicrogranite; 3: Dergholm Granite¡ 4: Kongal Rocks granite; 5: Sedan Graníte¡ 6: llanntnn granite; 7: ltarcotlat granite; 8: llount l,toster Porphyry; 9: tlurray Bridge Granite; 10: l{illalooka granite¡ n.d. = not detected; n.a. = not anallæed. Tab1e 3 Selected electron microprobe analyses

BIOTITE ANALYSES ANPHIBOLE ANALYSES SA¡lPLE 94 90 13 8ó 42 5 5l 088ó5 5l si02 33.44 38.52 36.48 33.08 35.07 35. u 36.30 36,90 40.50 4l .89 44.80 44. OO ïi02 3.53 I .13 2.25 2,36 2,41 2 3l 3,24 2,93 I .5ó o.95 l.lo 0.91 Al 203 14. l9 I I .30 rr.ó8 t 8.31 t5. ol 5 83 15. lo 15.20 6,61 I O.89 9.26 I 37 FeO 2t,57 r 5.99 23.77 20,21 18.25 I 9 30 t8,20 18.70 35. 37 t8.77 t6.20 I I 00 lln0 o,24 o.98 o,62 0 28 0 22 0 86 0. o0 o,2t l.19 0.50 0.1ó 0 35 11so 7,64 15. l5 8.47 7 ,49 il 07 9 46 12.60 t2. to 0.46 8.91 11.80 I I 00 Ca0 o.00 o.00 0.00 o .00 o oo o 00 o.00 o. o0 ro. t4 t1.44 t1.80 I 70 l\20 9 .41 l0.ll 9.0ó 9 .39 9 64 9 95 9,36 9.85 t.20 l.o4 0.64 I 02 Na20 o,24 o.oo 0. oo o .29 o 27 0 00 o, t7 0.00 1,92 I .18 t,32 I 4l TOTAL 90,27 93. t7 92,40 9t .40 9t 94 92 80 94,97 95.89 99.2t 95.58 97,rt 96 95 tlsS 38,7 62.8 38.8 39 8 52. O 46 6 55.0 55. O 2.3 45 .8 56 60 32 00 F 0.45 I 94 1,29 o 237 o.081 n d. n.â¡ lì¡ãr n. e. n .J. n e. n a. Structural Formulae (BaEed on 22 Oxygen) (tsased on 23 0xygen ) Si 5.525 I 5.9701 5 .9104 3,3263 5.5636 5.5575 5 5320 5,5930 '6.6626 6,5122 6,7240 6,6470 Ti 0.4388 o.l3l8 0 .2737 o.2856 o.2872 o,2743 o 37r0 0.3440 0.1935 0.IIl5 0. t 240 0. l 030 AI 2,7641 2,0640 2 .2300 3.4738 2,8072 2.9536 2 .7080 2,7t40 t,2824 0,996t 1,6370 I . óó90 Fe 2.9801 2,0720 3 ,220t 2,72t2 2,4216 2,5544 2 ,3240 2.3ó80 4.8ó60 2,4408 2.03r0 2.2770 lln 0.0340 o.1283 0 .0857 o,0376 0.o291 0.1t52 0 .0000 o.0270 0.1ó54 0.0655 0. 02l o 0.0450 mg r.88r I 3.5004 2 .o444 t.7964 2,6189 2.2315 2 .8530 2,7270 o,tt26 2,0647 2.6450 2.47 tO Ca o. 0000 0.0000 0 .0000 0.0000 o.0000 o.0000 o .0000 0.0000 t.7877 I .9063 I .8980 I .89ó0 K 1,9832 I .9989 I ,8732 1,9293 I .95t I 2,OO84 I .8190 I .9030 o.25t2 0.2059 o. t220 0.1970 Na o.0784 o. oooo o . 0000 o.0902 o.0835 o.0000 o . 0510 o.oooo 0.ót39 0.3564 o. 3850 0.4t40

I :Taratap grenodiorite, 94:llannum grenite, 90:Dergholm Granite, l3:Harrou Granodiorite, 8ó:Uando tonal ile, 422(felsic) Uando Granodiorite, 5:Reedy Creek diorite, 5l:Reedy Creek granodio¡ite, O8:l'larcol lat granite. n.d.=not detected, n.a.=not analysed. 4.8 EÁRLY PÂI.AEOZOIC PLUNOTÍISU I¡f EE PEAXB At{D IIEIÍISOI| BANGES¡ S.A. Robert S. Morrfson Departuent of Geology and Geophysfcs, UnLversity of Adelalde

The Peake and Denison Ranges are a series of north-south trending Adetaidean inliers 120h long and 24kn wide located approxfunately 1000km north of Adelaide. In the northern section of the largest inlier intrudes a suite of more than 30 plutons and associated dykes of Early Palaeozoic age. The largest pluton is Skn in dianeter, but nost are relatively snall (0.5 - 1kn). The granitoids intn¡de a sequence of Late Proterozoic (Burra Group) qr¡artzites and siltstones, and a carbonate hosted'rdiapiriclf breccia consisting of large angular clasts of Burra Group sedinents. They occupy an area roughly cor- responding to the intersection of the westerly trending Karari Fault Linea- ment with the Peake and Denison Ranges. The intrusive lithologies rÍrnge fron pyroxene - hornblende gabbro and nonzo- gabbro to (quartz) monzonite and (quartz) syenite, albitite (alkali syenite), dolerite and larnprophyre dykes. Those plutons which display nineral zoning have gabbroic cores grading to leucocratic nargins. Thin dykes or sills of biotite lanproph¡'re intn¡de or encitcle these plutons. The intrusive relat- ions show progressively nore felsic magm intnrding the parent host. Con- positions of these rocks r¿rnge fron 51-72 wt.en SiO2, 0.5-9 wt.eo Mgg, s-Ll wt.% Na20 and 0.2-9.2 wt.% K2O, representing a mildly peralkaline to metaluninous suite of alkali-calcic affinity. Primary nineralogy consists of hornblende - biotite - clinopyroxene (diopside- ferrosalite, aegirine-augite) - plagioclase (labradorite-albite) - alkali feldspar with varying quantities of nagnetite - sphene - apatite - quartz +/' zireon. Post-en¡lace¡nent netamorphisn has resulted in þartial ¡netasonatic replacenent of nafic conponents by actinolite - epidote - ðhlorite and felsic comPonents by albite - nuscovite - calcite. Such alteration has been attri- buted to the Canbro-Ordovician lþlamerian Orogeny which netanorphosed the igneous suite to a lower greenschist facies. Potassiun-argon daling of mineral assenblages have given figures rangeing fron 680 to 470 tr{a. Ttre vaiiety of dates reflect the effects of lÞlanerian netanorphisur, with the oldest age probably indicating a nore accurate age of enplácement. contacts of plutons are co only characterized by a0.2-5.0n wide zone of leucocratic albitite consisting of over 90% albite plagioclase, but in the easteÍi section of the area of study, albitite occurs as thick sills or s¡nall plugs. Contact netamorphic aureoles are corulonly absent. Distortion or brec- ciation of beds adjacent to contacts indicate ari initial phase of magatism of forceful- enplacenent of plutons i¡to an active circulaling neteoric water systen which quickly disperse the latent heat of the intrusiõn and provided a mechanism for partial to cornplete albitization. The quartz nonzonite-plutons have no albitite, possess a small contact meta- norphic aureole and intn¡de the overlying sedinänts without distortion or brecciation. Intrusive relations indicate that enplacenent of these plutons w¿rs one of the last nagnatic events. Tiro types of '?diapiric'r breccia ¿rre present; a finer grained'rinjectionrf breccia which post-dates a widespread 'rblockrr breccia. ttre pr"señce of pro- bable Delamerian intn¡sive clasts and the tn¡ncation of aplite dykes at injection breccia contacts indicates that the injection Ëreccia-postdates the enplàcenent of intrrrsives, whilst the block bieccia predates ^enplacenent.

138 as Recent seismic sulveys conducted due west of the Îãlges are interpreted salt diapiric activity within-Canbro-Devonian trough ¡tãiðãt¡tg substantiâi the ca¡bonates. Such s"fi aiapirs eiolved f¡on Mid Proterozoic evaporites of equilibriu¡n was õ;ii;;" beds and-wãr" p"i.iodicalty active -uriti-l Lithostatic It is the subsäquent col1âpse of diapirs wtrich developed the earlier block"ãã"fr"¿. breccia. ttre iniection brecciä forned as tne result of either breccia renobilization along it"tt"t of greatest stress during Delanerian defo:mation or by carbonatitic ãclivity or nagtna degassing'

ïhe diapiric breccia was in part controlleil by stnrctulal wealgtesses and nay h;";;ñiãed the path of_leäst.resistance for rapid conduct of nagna to near-surface conditions. Salt

139