Gawler & Curnamona

Table Of Contents

Compiled by Anthony Budd

1 SYNTHESIS 2 MILTALIE GNEISS Miltalie Gneiss 2014 ± 28 Ma

3 DONINGTON GRANITOID SUITE (OLDER LINCOLN COMPLEX) Quartz gabbronorite 1843 ± 2 Ma Memory Cove Charnockite 1818 ± 13 Ma Megacrystic granite gneiss

4 MINBRIE GNEISS Minbrie Gneiss >1800 Ma

5 YOUNGER LINCOLN COMPLEX Middlecamp Granite (syn-KD2) 1738 ± 68 Ma Colbert Suite (between KD2 - K D 3 ) Hornblende granite, Cape Colbert (btwn KD2 - K D 3 ) 1757± 14 Ma McGregor Volcanics 1755 ± 12 Ma Carpa Granite (syn-KD3) 1677 ± 125 Ma Granite at Moody Tank (syn-KD3) 1709 ± 14 Ma Burkitt Granite (?KD3) 1655 ± 61 Ma Bungalow Granodiorite (?KD3) 1601 ± 14 Ma Engenina Adamellite (?) 1641 ± 38 Ma Symons Granite (?) 1700 - 1680 Ma Carappee Granite (?KD3) 1689 ± 59 Ma Granite gneiss Ifould Lake (?) 1667 ± 115 Ma Yunta Well Leucogranite (syn-KD3) Uranno Microgranite (? KD3) Wertigo Granite (? KD3)

6 OLARY PRETECTONIC A-TYPE SUITE Ameroo Gneiss 1703 ± 6 Ma

7 ST PETER SUITE Granodiorite at Point Brown 1620 ± 4 Ma Nuyts Volcanics 1627 ± 2 Ma St Francis Granite

© Geoscience Australia 2001 Gawler & Curnamona 1.i 8 HILTABA SUITE Roxby Downs subsuite Charleston Granite 1585 ± 5 Ma Granophyre at Cultana 1584 ± 3 Ma Roxby Downs Granite 1588 ± 4 Ma Quartz monzodiorite, Olympic Dam area 1590 ± 4 Ma Quartz monzonite, Andamooka area 1593 ± 4 Ma Quartz monzodiorite, Wirrda Well 1593 ± 2 Ma Moonta monzogranite Granite at Hiltaba Granite at Nuyts Tickera Granite Kokatha subsuite Granite at Kokatha Granite at Kingoonya Granite at Kychering Granite at Minnipa Granite at Wudinna Granite at Buckleboo Granite at Tarcoola Undivided plutons Balta Granite Calca Granite Lower Gawler Range Volcanics (dated units only) Tuff at Roopena 1587± 15 Ma Waganny Dacite 1591 ± 3 Ma Childera Dacite 1592 ± 17 Ma Ealbara Rhyolite 1589 ± 16 Ma Upper Gawler Range Volcanics (dated units only) Yardea Dacite 1592 ± 3 Ma

9 OLARY 1590 Ma ASSOCIATION Triangle Hill granite, ‘Regional suite’ ~1590 Ma ‘Gb suite’

10 BABBAGE ASSOCIATION Moolawatana Suite Yerila Granite 1556 ± 10 Ma Terrapinna Granite 1556 ± 4 Ma Wattleowie Granite Prospect Hill Granite White Well Granite

© Geoscience Australia 2001 Gawler & Curnamona 1.ii Box Bore Granite Golden Pole Granite Con Bore Granite Others Mount Neill Granite 1569 ± 14 Ma Petermorra Volcanics 1560 ± 2 Ma Camel Pad Granite Granite at Radium Creek Old Camp Granite Lookout Granodiorite

11 OTHER UNITS/SUITES Myola Volcanics 1791 ± 4 Ma Poodla Hill mafic granitoid, Olary I-type suite ~1630 Ma Spilsby Suite ~1530 Ma Tidnamurkuna Volcanics 1806 ± 27 Ma Wirriecurrie Granite 1793 ± 8 Ma

Compiled by Anthony Budd

1.1 Executive The Gawler Craton underlies the greater part of South Australia. It is defined as that Summary - region of crystalline basement of Archaean to Mesoproterozoic age that has undergone Geology no substantial deformation except for minor brittle faulting since 1450 Ma. The Gawler Craton is subdivided into a number of discrete tectonic subdomains based on structural, metamorphic and stratigraphic character. These include the Christie and Coulta Subdomains which contain most of the exposed Archaean rocks; the Cleve Subdomain which is a Palaeoproterozoic fold belt on eastern Eyre Peninsula; the Moonta Subdomain which, although considered an extension of the Cleve Subdomain, includes stratigraphically younger rocks; the Mesoproterozoic Gawler Ranges Volcanic Province; and the Wilgena, Nuyts and Nawa Subdomains of mixed or complex character. The Christie and Coulta Subdomains are composed predominantly of Archaean or earliest Palaeoproterozoic rocks representing the original protolith on which subsequent tectonic units were superimposed. The Fowler Suture Zone in the southern part of the Christie Subdomain contains voluminous Proterozoic intrusives, whereas there are no Palaeoproterozoic intrusives known in the Coulta Subdomain. Both were deformed to some extent during later Palaeoproterozoic events, and neither contains substantial components of younger Proterozoic metasediments, volcanics or intrusives. At ~2000 Ma, along what is now its eastern margin, the Gawler Craton underwent substantial extension to form a major elongate basin into which a ~1950-1845 Ma mixed shallow-water clastic and chemical sedimentary succession (including iron formation, and carbonates) was deposited. Subsequent deformation of this basin during the Kimban Orogeny (1845-1700 Ma), accompanied by intrusion of large volumes of granite, led to the formation of a broad fold belt or orogen known as the Cleve Subdomain. The Moonta Subdomain is approximately parallel to and east of the Cleve Subdomain, and consists of syn-Kimban orogeny silicic volcanics, chemical and clastic sediments, and earliest Mesoproterozoic granitoids. Unlike older subdomains of the Gawler Craton, the Gawler Ranges Volcanic Province is relatively undeformed and more irregular in its distribution. It overlies and intrudes the older Cleve and Coulta Subdomains. The Province is composed of the Gawler Range Volcanics (GRV) and very restricted contemporaneous sediments (such as the Corunna Conglomerate), and the Hiltaba Supersuite. The Stuart Shelf is not strictly a tectonic unit of the Gawler Craton, but defines the region of Neoproterozoic to Cambrian platformal sedimentation developed upon the existing craton (i.e., underlain by Gawler Craton including GRV and Hiltaba granites). The Curnamona Province crops out in the Willyama, Mount Painter and Mount Babbage Inliers, and is located on the eastern and northeastern margins of the Adelaide Geosyncline. The remainder of the Curnamona Province is poorly known as it is largely mantled by platformal sediments. Drill hole data indicate that the composition of the Craton is similar to the eastern edge of the Gawler Craton. The Willyama Inliers include the Olary and Broken Hill Blocks, which are separated by the Mundi Mundi Fault zone. Three major episodes of granite emplacement occurred during the Proterozoic in the Gawler and Curnamona Cratons, with several smaller events. Granites emplaced syntectonically during the Kimban Orogeny have been divided into two complexes - those of the Donington Granitoid Suite at ~1840-1820 Ma, and those emplaced around 1750-1700 Ma. The Gawler Range Volcano-Plutonic event at ~1590 Ma is one of the

© Geoscience Australia 2001 Gawler & Curnamona 1.1 GAWLER & CURNAMONA SYNTHESIS biggest magmatic events in Australia, and is divided into two geochemical subsuites, each related to a particular style(s) of mineralisation. Possible correlatives of the GRV magmatic event exist in the Curnamona Province. Minor but locally important magmatism also occurred at ~2000 Ma, ~1800 Ma, 1740 Ma, 1700 Ma, ~1625 Ma, 1560 Ma, and ~1530 Ma.

1.2 Executive This compilation has assessed the potential of each granite suite within the limitations Summary - of the existing datasets based on the criteria set out in the Project Proposal. Suites Metallogenic which have been identified as having high potential for granite-related mineralisation Potential are set out below. This project has identified the key differences between two subsuites of granites of the Hiltaba Suite at 1592 Ma, emplaced during the Gawler Ranges volcano-plutonic event, and the implications of these differences on the mineralisation potential for each suite. The Roxby Downs subsuite is host to the giant Olympic Dam Cu-Au-U-REE deposit, and several other Fe-oxide style prospects. The Kokatha subsuite is probably host to Au-Sn-Ag deposits such as those of the Glenloth Goldfield. The Roxby Downs subsuite is more fractionated and more oxidised, and was emplaced at a shallower level, than the Kokatha subsuite. Both suites have high potential for further discoveries. It is most likely that granites of the Hiltaba Suite extend into the Curnamona Province.

1.3 Methods Information Sources: Special mention must be made of Volume 1: The Precambrian, The Geology of South Australia, Bulletin 54 (Drexel et al. 1993), which is an excellent summary of the geology of the Gawler and Curnamona Cratons. In addition, two CD-ROM packages produced by the Department of Mines and Energy Resources of South Australia (now Primary Industries and Resources South Australia) were also used: the SA State GIS (March 1995), and the Olary Region, prepared as part of the Broken Hill Exploration Initiative. The granites map prepared by this project used the 1:1 000 000 map of Flint (1986) as a base map. Published ages are derived predominantly from Bulletin 54 and much of the goechemistry was sourced from the MESA database supplemented with data from AGSO and the University of Adelaide. The AGSO Minloc database, and AGSO magnetics and gravity were also used. Classification of Granites: In this report the granites have been divided into suites (or complexes or associations) based on the age, geographic location, and geochemistry of each pluton. [Note that usage of the term suite in the Gawler and Curnamona report denotes a formally defined stratigraphic unit, whereas the terms association and complex denotes an informally defined unit as subdivided by this project.] Using this method, approximately 15 suites are recognised (Table 1.1). Host Rocks: The country rocks which are thought to be intruded by each suite have been summarised, and classified according to mineralogical characteristics thought to be important in determining the metallogenic potential of a granite intrusive event. Relating Mineralisation: Quite good descriptions have been found for most of the deposits thought to be related to Proterozoic granites in the Gawler Craton.

1.4 References Daly, S.J., Fanning, C.M. and Fairclough, M.C. 1998. Tectonic evolution and exploration potential of the Gawler Craton, Australian Geological Survey Organisation Journal of Australian Geology and Geophysics., 17(3), 145-168. Drexel, J.F., Preiss, W.V. and Parker, A.J. (editors ) 1993. The Geology of South Australia, Volume 1, the Precambrian, Geological Survey of South Australia, Bulletin 54, 242 pp. Flint, R.B. 1986. Geological Map, Gawler Craton, 1:1,000,000 scale, Australian Journal of Earth Science, 33.

1.5 Table 1.1

Chpt Grouping Age Potential Confid Pluton # (Type) (Ma) Cu Au Pb/Zn Sn Mo/W Level Miltalie 2 2015 None None None None None 120 Miltalie Gneiss (Forsayth) 3 Donington 1840 Mod Mod None Mod None 220 Donington Granitoid Suite (Kalkadoon) Memory Cove Charnockite Minbrie 4 >1800 None None None None None 120 Minbrie Gneiss (Unclassified) Younger 1750~ Mod Mod None Mod None 220 5 McGregor Volcanics Lincoln 1700 (Nicholson) Middlecamp Granite Carpa Granite Moody Tank granite/monzonite Burkitt Granite Bungalow Granodiorite Engenina Adamellite Symons Granite Carappee Granite Ifould Lake granite gneiss Yunta Well Leucogranite Uranno Microgranite Wertigo Granite Cape Colbert hornblende granite Olary A-type Undivided metagranitoid, inc. 6 1703 Low Low None None None 111 (Sybella) Ameroo Hill granitoid 7 St Peter 1625 ? ? ? ? ? 220 St Peter Suite Hiltaba? Nuyts Volcanics St Francis Granite 8 Hiltaba 1592 High High Low None Mod 323 Roxby Downs subsuite Roxby Downs Granite Charleston Granite Cultana granophyre Moonta monzogranite Hiltaba granite Nuyts granite Tickera Granite

Chpt Grouping Age Potential Confid Pluton # (Type) (Ma) Cu Au Pb/Zn Sn Mo/W Level Mod High High Mod Mod 323 Kokatha subsuite Kokatha granite Kychering granite Kingoonya granite Tarcoola granite Minnipa granite Wudinna granite Buckleboo granite ? ? ? ? ? Balta Granite Calca Granite Olary 1590 Ma 9 1590 Mod Mod Low Low Low 212 ‘Regional suite’ (Hiltaba) ‘Gb suite’ 10 Babbage 1560 High Mod Mod Mod Mod 212 Mount Neill Granite (Hiltaba) Terrapina Granite Wattleowie Granite Yerila Granite Camel Pad Granite Radium Creek granite Old Camp Granite Prospect Hill Granite White Well Granite Box Bore Granite Golden Pole Granite Con Bore Granite Lookout Granodiorite Nooldoonooldoona Trondhjemite Armchair Granite Myola 11 1791 ? ? ? ? ? 210 Myola Volcanics (Sybella)

Olary 1640Ma Granodiorites and tonalites in the Poodal Hill-Tonga Hill-Alconie 11 I-type 1640 ? ? ? ? ? 110 Hill-Antro Woolshed-Bimbowrie (Hiltaba?) region

Spilsby Porphyritic monzograite to 11 1530 ? ? ? ? ? 110 granodiorite on Spilsby and Sir (Hiltaba) Joseph Banks Group islands Tidnamurkuna 11 1806 ? ? ? ? ? 100 Tidnamurkuna Volcanics (Sybella)

Chpt Grouping Age Potential Confid Pluton # (Type) (Ma) Cu Au Pb/Zn Sn Mo/W Level Wirriecurrie 11 1793 ? ? ? ? ? 110 Wirriecurrie Granite (Hiltaba)

2.1 Timing 2015 Ma

2.2 Individual Primary Ages: Ages 1. Miltalie Gneiss 2014 ± 28 Ma, U-Pb zirco n Source: Fanning et al. 1988.

2.3 Regional The Miltalie Gneiss occurs on the central-eastern Eyre Peninsula, and is interpreted as Setting part of the basement to the Hutchison Group. It may represent a granitoid intrusive into the Sleaford Complex, remnants of which occur nearby between the Plug Range and Cowell.

2.4 Summary This is a small peraluminous, reduced and restite-dominated gneissic unit.

2.5 Potential As a restite-dominated, small, peraluminous gneiss, the mineralisation potential for this unit is very low. Cu: None Au: None Pb/Zn: None Sn: None Mo/W: None Confi dence level: 120

2.6 Descriptive Location: Adjacent to The Plug Range on central-eastern Eyre Peninsula. Data Dimensions and area: Approximately 40 x 5 km.

2.7 Intrusives Component plutons: Miltalie Gneiss. Form: The gneiss is elongated north-south. Metamorphism and Deformation: The gneiss has been highly deformed, with sillimanite and garnet present, presumably indicating amphibolite facies. Dominant intrusive rock types: Granitic gneiss. Colour: Grey, with pink segregations. Veins, Pegmatites, Aplites, Greisens: Pink, coarse-grained pegmatitic segregations make up to 20 % of the rock. Distinctive mineralogical characteristics: The gneiss is medium to coarse-grained, even- grained, well foliated and composed of quartz, perthitic microcline, plagioclase, biotite and minor apatite, zircon, garnet, opaque minerals, sillimanite and hornblende. Pink, coarse- grained pegmatitic segregations and structurally concordant amphibolite sills or deformed dykes up to several metres thick are present throughout. Breccias: None mentioned. Alteration in the granite: None mentioned.

2.8 Extrusives None mentioned.

© Geoscience Australia 2001 Gawler & Curnamona 2.1 MILTALIE GNEISS 2.9 Country Contact metamorphism: None mentioned. Rock Reaction with country rock: None mentioned. Units the granite intrudes: The Miltalie Gneiss may be intrusive into the Archaean Sleaford Complex, remnants of which occur nearby between he Plug Range and Cowell. Dominant rock types: Gneiss at Ullabidinie Creek and ‘Minbrie Springs’ is dated at 2315 ± 175 Ma, and may be intruded by the Miltalie Gneiss. It is described as containing quartz, K-feldspar, plagioclase and biotite, and may be equivalent to the Sleaford Complex. Potential hosts: None.

2.10 Mineralisation None. The mineralisation potential for this suite is very low.

2.11 Geochemical Data source: All data are from the South Australian Department of Mines and Energy Data Resources. Data quality: Unknown. Are the data representative? Possibly, although the samples all come from the southern part of the gneiss unit. Are the data adequate? No. Several elements (U, Th, Pb, Cu, Zn, Ce, F, Ga and Nd) were not determined.

Figure 2.1: His to gram of SiO2 val ues.

SiO 2 range (Fig. 2.1): Ranges from 67.82 to 73.75 wt.% SiO 2 . This is a narrow range, and represents felsic compositions. Alteration (Fig. 2.2): The suite possibly shows some alteration.

• SiO 2: No silicic alteration is evident. • K 2 O/Na 2O: All samples are a little low in sodium, and one sample is anomalously high in potassium. • Th/U: No data available. • Fe2O3/(FeO+Fe2 O 3 ): Almost all values are very reduced, however one sample is oxidised and is probably altered. Fractionation Plots (Fig. 2.3): The gneiss is unfractionated.

• Rb: All values are moderately low, and define a decreasing trend with increasing SiO 2 . • U: No data are available. • Y: Values are moderate, with some scatter. • P 2 O 5 : Values are low, with a slightly decreasing trend with increasing SiO 2 . • Th: No data available. • K/Rb: Values are moderate, with some scatter. • Rb-Ba-Sr: Samples plot in the granite and anomalous granite fields. • Sr: All values are low.

© Geoscience Australia 2001 Gawler & Curnamona 2.2 MILTALIE GNEISS • Rb/Sr: All values are very low. • Ba: Values are moderately low, and define a decreasing trend with increasing SiO 2 . • F: No data available. Metals (Fig 2.4): Only tin data is available; all values are low. • Cu: No data available. • Pb: No data available. • Zn: No data available. • Sn: All values are low. High field strength elements (Fig. 2.5): All HFSE are low to moderate. • Zr: Values are moderate, and show a decreasing trend if the most felsic sample is not altered. • Nb: All values are low, and decreasing with increasing SiO 2 . • Ce: No data are available. Classification (Fig. 2.6): Peraluminous, reduced, Sr-depleted, Y-undepleted, felsic.

• The CaO/Na2O/K 2O plot of White, quoted in Sheraton and Simons (1992): Samples plot in the granodiorite, monzogranite and granite fields. • Zr/Y vs Sr/Sr*: Insufficient data for this plot. • Spidergram: The spidergram is poorly defined for this suite, however, the suite is Sr- depleted, Y-undepleted. • Oxidation plot of Champion and Heinemann (1994): Most samples are reduced, however, one sample is oxidised and is probably altered. • ASI: The samples are peraluminous, and decrease with increasing SiO 2 . • A-type plot of Eby (1990): Insufficient data for this plot. Granite type (Chappell and White 1974; Chappell and Stephens 1988): S-type. Australian Proterozoic granite type: Forsayth type - peraluminous, restite-dominated, ?unmineralised.

2.12 Geophysical Radiometrics (Fig. 2.7): Only potassium data i available, therefore the RGB colour for this unit Signature cannot be predicted. Gravity: Unfortunately, the gravity image is very coarse, however the Miltalie Gneiss has a slightly higher gravity signature than background. Magnetics: The Miltalie Gneiss is within a deep regional magnetic low.

2.13 References Parker, A.J., Daly, S.J., Flint, D.J., Flint, R.B., Preiss, W.V. and Teale, G.S. 1993. Palaeoproterozoic. In Drexel, J.F., Preiss, W.V. and Parker, A.J., (editors) The geology of South Australia, Volume 1, the Precambrian. South Australia Geological Survey, Bulletin 54. Parker, A.J. 1983. Whyalla, South Australia, 1:250 000 Geological Series. South Australia Geological Survey, SI/53-8. Fanning, C.M., Flint, R.B., Parker, A.J., Ludwig, K.R. and Blissett, A.H. 1988. Refined Proterozoic evolution of the Gawler Craton, South Australia, through U-Pb zircon geochronology, Precambrian Research, 40/41, 363-386.

2.2A: Na 2 O vs K2O

NO THORIUM/URANIUM DATA AVAILABLE

2.2C: Fe2 O 3 /(FeO+Fe2 O 3 )

2.3A: Rb vs SiO2

NO URANIUM DATA AVAILABLE

2 .3C: Y vs SiO 2

2.3D: P 2 O 5 vs SiO 2

NO THORIUM DATA AVAILABLE

2 .3F: K/Rb vs SiO2

2.3G: Rb- Ba- Sr Legend

Strongly dif fer en ti ated gran ite

Anoma lous Granit e gran ite

Monzo gran ite Tonal it e

2.3H: Sr vs SiO 2

2 .3I: Rb/Sr vs SiO2

2.3J: Ba vs SiO2

NO FLUORINE DATA AVAILABLE

NO COPPER DATA AVAILABLE

NO LEAD DATA AVAILABLE

NO ZINC DATA AVAILABLE

2.4D: Sn vs SiO2

2.5A: Zr vs SiO2

2 .5B: Nb vs SiO2

NO CERIUM DATA AVAILABLE

Tonal ite

Grano dio rit e

Mon zo gran ite

Granit e Trondhjemit e

NO SR* DATA AVAILABLE

2.6C: Spidergra m SiO2 range: 69.1-69.4%

Strongly oxi dised

Oxi dised

Re duced

Strongly Reduced

2.6E: ASI vs SiO 2

NO CERIUM OR GALLIUM DATA AVAILABLE

2.7A: K2 O% Box-whiske r

Pro tero zoic media n

THORIUM DATA NOT AVAILABLE

URANIUM DATA NOT AVAILABLE

Miltalie Gneiss

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 69 .84 69.42 1 .63 67.82 73.75 11 TiO2 0.6 0 .64 0 .12 0 .36 0 .74 11 Al2O3 13 .07 13.13 0 .52 12.47 14.38 11 Fe2O3 0.68 0 .51 0 .55 0 .23 2 .2 11 FeO 3.82 4 .09 0 .9 2 .31 5 .02 11 MnO 0.04 0 .04 0 .02 0 .02 0 .08 11 MgO 1.68 1 .62 0 .79 0 .57 3 .53 11 CaO 1.26 1 .17 0 .58 0 .36 2 .09 11 Na2O 2.48 2 .27 0 .54 1 .88 3 .12 11 K2O 4.61 3 .56 1 .76 2 .71 8 .49 11 P2O5 0.21 0 .23 0 .03 0 .13 0 .25 11 H2O+ 0.89 0 .94 0 .19 0 .59 1 .18 11 H2O- 0.1 0 .11 0 .05 0 .02 0 .15 11 CO2 0.08 0 .08 - 0 .08 0 .08 1 LOI ------Ba 703.64 720 184.57 300 960 11 Li ------Rb 174.55 170 46.77 120 240 11 Sr 103.18 120 28.31 60 140 11 Pb ------Th ------U ------Zr 416.36 450 106.42 170 520 11 Nb 13.09 14 5.24 20 11 Y 48.73 50 11.25 30 65 11 La ------Ce ------Pr ------Nd ------Sc ------V 28.64 30 13.06 10 55 11 Cr 33.64 25 57.08 200 11 Mn ------Co 2.73 0 .75 5 11 Ni 21.14 15 35.52 125 11 Cu ------Zn ------Sn 2.73 1 .01 4 11 W ------Mo 3.77 3 3 .96 15 11 Ga ------As ------C ------F ------B ------Ag ------Bi ------Hf ------Ta ------Cs ------Ge ------Se ------

(OLDER LINCOLN COMPLEX)

3.1 Timing 1840 Ma

3.2 Individual Primary Ages: Ages 1. Quartz gabbron or it e1 1843 ± 2 Ma, U-Pb 2. Mem ory Cove Char nock ite2 1818 ± 13 Ma, Rb-Sr Sources: [1] Mortimer et al. 1988. [2] Mortimer et al. 1986.

3.3 Regional NOTE: In this report, the Lincoln Complex has been divided into two suites, with the Setting earlier syntectonic granitoids comprising the Older Lincoln Complex (made up dominantly of the Donington Granitoid Suite and discussed as such here), and the Younger Lincoln Complex (which includes the Colbert and Moody Suites–Chapter 5). The Donington Granitoid Suite is the oldest of the Lincoln Complex granites. It comprises a broad spectrum of pyroxene and hornblende-biotite granites ranging from quartz gabbronorite, hypersthene gneissic granite (e.g., Memory Cove Charnockite), megacrystic intermediate granite gneiss, late-stage alkali-feldspar granitic gneiss to retrogressively metamorphosed hornblende-biotite gneiss. Granites and mafic intrusions of the Lincoln Complex occur from as far west as the Nuyts Archipelago, eastwards to the Yorke Peninsula. The best exposures are found on the coastline and on offshore islands, but, the complex is also found along the length of the eastern Eyre Peninsula. The Lincoln Complex is interpreted to have been emplaced syntectonically, and is intrusive into the Hutchison Group and the Sleaford Complex. The Lincoln Complex is divided into several suites, and these show changes in composition and mineral assemblage through time. Mortimer et al. (1988) suggest that the two older suites (Massena Bay orthogneisses and Donington Granitoid Suite) evolved through pyroxene- and plagioclase-dominated crystal fractionation, while the younger Colbert and Moody Suites evolved from hornblende and plagioclase- dominated fractions possibly with amphibole (± garnet) as a residual phase during partial melting.

3.4 Summary This suite covers a broad composition range, and appears to be restite-dominated, with fractionation starting to occur at very felsic compositions. It is metaluminous, and is Sr-depleted, Y-undepleted. Unfortunately, there are no data available to determined the oxidation state of the suite, however, it is most probably oxidised (Wyborn, pers. comm . 1996).

3.5 Potential Parker (1987) stated that, except for uranium, Lincoln Complex granitoids are devoid of anomalous mineralisation. Based on the limited available geochemical data, this suite is similar to the Nicholson Suite (Mount Isa). It has moderate potential for gold, copper and tin in veins. Cu: Mod er ate Au: Mod er ate Pb/Zn: None Sn: Mod er ate Mo/W: None Confi dence level: 220

© Geoscience Australia 2001 Gawler & Curnamona 3.1 DONINGTON GRANITOID SUITE 3.6 Descriptive Location: Rocks of the Donington Granitoid Suite occur as the main rock type along the east Data coast of the southern Eyre Peninsula from Cape Tournefort to Port Neill. They also occur on the southern Yorke Peninsula. Dimensions and area: The Donington Granitoid Suite has an area calculated from mapped outcrop of 840 km 2.

3.7 Intrusives Component plutons: Quartz gabbronorite on Cape Donington, Memory Cove Charnockite, and megacrystic granite gneiss. Form: Batholithic. Metamorphism and Deformation: All rocks in this suite are foliated. The degree of foliation varies from weak to strong. Mortimer (1984) suggested that the metamorphism which affected the Donington Granitoid Suite could be divided into four types based on mineral composition and texture. Type 1 comprised polygonal mosaic plagioclase, orthopyroxene and clinopyroxene; Type 2 comprised coronas of hornblende around pyroxene; Type 3 comprised metamorphic tectonite fabrics with microcline twinning common, and Type 4 comprised inequigranular, interlobate to polygonal plagioclase + K-feldspar + quartz + biotite + hematite. Regionally, there is a general gradation from Type 1 to 3, from east to west as the Kalinjala Mylonite Zone is approached. This suggests that the mylonite zone exerts a strong control on the distribution and extent of retrogression. Type 4 metamorphism is of local extent only, at McLaren Point. Dominant intrusive rock types: Mortimer (1984) suggested that the Donington Granitoid Suite around the Port Lincoln area contained six rock types. They are: the Quartz gabbronorite gneiss, the Ferrohypersthene granite gneisses 1 (FGG1) and 2 (FGG2), the Eulitic alkali-feldspar granite gneiss (EAGG), the Granite gneisses 1 and 2 (GG1 and GG2), and the Alkali-feldspar granitic gneiss (AGG). Mortimer considered that the units GG1 and GG2 were composed of retrogressed FGG1 and FGG2, while the unit AGG was composed of retrogressed EAGG. Colour: The pyroxene granitoids of the Donington Granitoid Suite are dark-coloured, whereas the hornblende-biotite granitic rocks are light-coloured. Veins, Pegmatites, Aplites, Greisens: None mentioned in literature. Distinctive mineralogical characteristics: The Quartz gabbronorite gneiss consists of phenocrysts of plagioclase, orthopyroxene and clinopyroxene, interstitial quartz and K- feldspar, and biotite in part replacing pyroxene, with accessory zircon and apatite. The Ferrohypersthene granite gneiss 1 (FGG1) is composed of phenocrysts of plagioclase, orthopyroxene and K-feldspar, a groundmass of K-feldspar and quartz (+ plagioclase), with some biotite, ilmenite ± hornblende, and accessory zircon and apatite. The Ferrohypersthene granite gneiss 2 is similar to the unit FGG1 above, but has rapakivi-like megacrysts of K- feldspar, no plagioclase in the groundmass, and more hornblende than ilmenite. The Eulitic alkali-feldspar granite gneiss (EAGG) contains phenocrysts of plagioclase, K-feldspar and quartz, has a groundmass of plagioclase, K-feldspar and quartz, and accessory zircon and apatite. The Granite gneisses 1 and 2 (GG1 and GG2) have relict phenocrysts of plagioclase and K-feldspar and relict rapakivi-like megacrysts of K-feldspar. The Alkali-feldspar granitic gneiss (AGG) is composed of relict phenocrysts of plagioclase and K-feldspar. The quartz gabbronorite gneiss and the ferrohypersthene granite gneisses contain a few mafic inclusions or xenoliths. Breccias: None mentioned in literature. Alteration in the granite: None mentioned in literature.

3.8 Extrusives The Massena Bay Gneisses (at Massena Bay near Tumby) are mainly composed of felsic, possibly metavolcanic rocks, with subordinate intercalations of quartzite, calc-silicate and garnet-sillimanite gneisses (Mortimer et al. 1986). This unit is intruded by the Donington Granitoid Suite. Mortimer (1984) suggested that the quartzofeldspathic, biotite-hornblende gneisses of the Massena Bay Gneisses have a major and trace element geochemistry broadly similar to enclaves of orthogneiss and calc silicate rock within the orthopyroxene-granitoids of the Donington Granitoid Suite, and that this may indicate a broadly similar petrogenesis for these two units. However, more recent work (Mortimer and Fanning pers. comm. 1997) indicates that the enclaves at Cape Donington could be of Hutchison Group or possibly Miltalie Gneiss. The gneisses at Massena Bay may be Miltalie Gneiss or possibly equivalents of the

© Geoscience Australia 2001 Gawler & Curnamona 3.2 DONINGTON GRANITOID SUITE Broadview Schist and Myola Volcanics. Correlations with the enclaves within the Donington Granitoid Suite at Cape Donington are uncertain.

3.9 Country Contact metamorphism: None mentioned in literature. Rock Reaction with country rock: None mentioned in literature. Units the granite intrudes: The intrusive relationships of the Donington Granitoid Suite are not clear. On a regional scale, the Lincoln Complex comprises ‘granitic gneiss, migmatites, granulite augen gneisses’ and ‘quartzofeldspathic gneiss relics of older (Archaean) basement complexes’ (Thomson 1980). In the Port Lincoln area, no Archaean rocks were found (Mortimer et al. 1986). The Kalinjala Mylonite Zone obscures the relationship between the Hutchison Group supracrustals and the Donington Granitoid Suite. Nevertheless, Fanning et al. (1986) have correlated granitoids to the north which intrude the Hutchison Group with granitoids in the Donington Granitoid Suite. Near Port Lincoln, the Donington Granitoid Suite is seen to intrude the Massena Bay Gneisses. Dominant rock types: The Hutchison Group west of the Kalinjala Mylonite Zone is composed of basal micaceous and feldspathic quartzite and calc-silicate rock (Warrow Quartzite), overlain by dolomitic marble, banded iron formation (sulphide facies - Middleback subgroup), pelitic schist and amphibolite (Cook Gap Schist), pelitic schist and metasiltstone (Yadnarie Schist) calc-silicate rock and acid porphyry (Bosanquet Formation) and amphibolite. The Massena Bay Gneisses are composed of quartzofeldspathic, biotite-hornblende gneiss; garnet+ sillimanite gneiss; calc-silicate gneiss; granitic gneiss; amphibolite ‘dykes’ and pegmatitic veins. Potential hosts: The basal calc-silicate rock of the Warrow Quartzite is host to significant copper and silver-lead mineralisation in the Cleve Hills, including the Miltalie Mine. The sulphide-facies banded iron formation of the Middleback Subgroup would also make an excellent host to mineralisation, while parts of the marble and amphibolite units may also be suitable hosts. The amphibolites and calc-silicate gneisses of the Massena Bay Gneisses may also be good hosts.

3.10 Mineralisation Parker (1987) states that except for uranium, Lincoln Complex granitoids are devoid of anomalous mineralisation.

3.11 Geochemical Data source: All of the available geochemical data comes from Mortimer’s PhD thesis Data (Mortimer 1984). Data quality: The data is thought to be of good quality. Are the data representative? Possibly not. Mortimer’s study focused on outcrops of the southern Eyre Peninsula, and there are considerable amounts of the Suite which are unsampled. Are the data adequate? No, for the reason above, and also that the oxidation state of iron was not determined, and only a limited number of trace elements were analysed.

SiO 2 range (Fig. 3.1) : Ranges from 55.5 to 78.8 wt.%, but with a gap between 58-64 %. Alteration (Fig. 3.2): There are insufficient data to adequately describe the alteration status of this suite.

Figure 3.1: His to gram of SiO2 val ues.

• SiO 2: No alteration is obvious. • K 2 O/Na 2O: One sample has anomalously high sodium with some loss of potassium. The mafic samples have lower potassium than the rest of the suite. • Th/U: No data available. • Fe2O3/(FeO+Fe2 O 3 ): No data available. Fractionation Plots (Fig. 3.3): Although there are no U or Th data available, it is evident that this suite becomes fractionated at high SiO 2 levels, but is probably restite-dominated earlier in its differentiation history.

• Rb: Values range from low to moderate, and increase linearly with increasing SiO 2 . • U: No data available. • Y: Values range from moderate to low. The general trend is firstly increasing, then decreasing with increasing SiO 2, but with some scatter. • P 2 O 5 : Values range from moderately low to low. For those samples above 65 wt% SiO 2 , values decrease with increasing SiO 2, while the more mafic samples show a flat trend. • Th: No data available. • K/Rb: Values range from moderate to moderately low, with a slight decrease with increasing SiO 2 , although there is some scatter. • Rb-Ba-Sr: The majority of samples fall in the granite field, some plot very close to the Rb apex in the strongly differentiated granite field, and others plot in the monzogranite and anomalous granite fields. • Sr: Values range from moderately low to very low, showing a clear decrease with increasing SiO 2 . • Rb/Sr: Values range from very low to very high, increasing exponentially above 75 wt% SiO 2. • Ba: Values range from moderate to very low. The mafic samples show an increasing trend, but then the more felsic samples show a strongly decreasing trend with increasing SiO 2. • F: No data available. Metals (Fig. 3.4): No data available. • Cu: No data available. • Pb: No data available. • Zn: No data available. • Sn: No data available. High field strength elements (Fig. 3.5): Values are generally moderately low to low, and generally decrease with increasing SiO 2.

• Zr: Values range from moderate to low, with a general decrease with increasing SiO 2. Some of the mafic samples fall below the general trend. • Nb: Values range from moderately low to low, with a general decrease with increasing SiO 2. Some of the mafic samples fall below the general trend. • Ce: Only a few analyses are available, and these range from moderately low to low, with considerable scatter. Classification (Fig. 3.6): The suite is mostly felsic, low Sr, high Y, and metaluminous.

• The CaO/Na2O/K 2O plot of White, quoted in Sheraton and Simons (1992): The majority of the samples plot in the monzogranite and granite fields, with four plotting in the tonalite and granodiorite fields. One (altered) sample plots in the trondhjemite field. • Zr/Y vs Sr/Sr*: Very few samples plot on this graph (few Ce analyses available). Those that do plot are Sr-depleted, Y-undepleted. • Spidergram: Due to the limited range of elements analysed, the spidergram does not plot well. However, it is obvious that the suite is Y-undepleted. • Oxidation plot of Champion and Heinemann (1994): FeO and Fe2O 3 data are not available to determine the redox state of this suite. • ASI: All values are metaluminous, and increase with increasing SiO2 . • A-type plot of Eby (1990): No gallium analyses are available for this plot. Granite type (Chappell and White 1974; Chappell and Stephens 1988): I-(granodiorite) type.

© Geoscience Australia 2001 Gawler & Curnamona 3.4 DONINGTON GRANITOID SUITE Australian Proterozoic granite type: Kalkadoon - restite-dominated until fractionation occurs at high (75 wt%) silica levels, I-type.

3.12 Geophysical Radiometrics (Fig. 3.7): Median potassium values are well above the Proterozoic median. No Signature uranium or thorium analyses are available. Gravity: Part of the Suite occurs on a regional gravity low, whereas other parts of the suite have a signature close to background. Magnetics: The Donington Granitoid Suite shows a strong magnetic high. These rocks are noted in the literature as being ilmenite rather than magnetite-bearing.

3.13 References Fanning, C.M., Blissett, A.H., Flint, R.B., Ludwig, K.R. and Parker, A.J. 1986. A refined geological history for the southern Gawler Craton through U-Pb zircon dating of acid volcanics, and correlations with northern Australia, Geological Society of Australia, Abstracts, 15, 67-68. Mortimer, G.E. 1984. Early to Middle Proterozoic granitoids, basaltic dykes and associated layered rocks of southeastern Eyre Peninsula, South Australia. University of Adelaide, PhD thesis (unpublished). Mortimer, G.E., Cooper, J.A. and Oliver, R.L. 1986. The geochronological and geochemical evolution of the Proterozoic Lincoln Complex, Eyre Peninsula, South Australia. Geological Society of Australia, Abstracts, 15, 140-141. Mortimer, G.E., Cooper, J.A. and Oliver, R.L. 1988. The geochemical evolution of Proterozoic granitoids near Port Lincoln in the Gawler Orogenic Domain of South Australia, Precambrian Research, 40/41, 387-406. Parker, A.J. 1987. Archaean to Middle Proterozoic mineralisation of the Gawler Craton (including Stuart Shelf Region), South Australia, Department of Mines and Energy, South Australia, Report Bk. No. 87/84. Parker, A.J. 1993. Magmatism - Lincoln Complex, in Drexel, J.F., Preiss, W.V. and Parker, A.J. (editors). The geology of South Australia, Volume 1, The Precambrian, South Australia. Geological Survey. Bulletin 54, pp 74-81 Thomson, B.P. 1980 (compiler). Geological map of South Australia, 1:1 000 000 scale. Geological Survey of South Australia, Adelaide.

3.2A: Na2 O vs K2O

NO THORIUM OR URANIUM DATA AVAILABLE FOR Th/U vs SiO2 PLOT

NO FeO OR Fe2O3 DATA AVAILABLE FOR Fe2O 3/(FeO+Fe2 O 3 ) vs SiO2 PLOT

3.3A: Rb vs SiO2

NO URANIUM DATA AVAILABLE

3.3C: Y vs SiO2

3.3D: P2 O 5 vs SiO2

NO THORIUM DATA AVAILABLE

3.3F: K/Rb vs SiO 2

Strongly dif fer en ti ated gran ite

Anoma lous Granit e gran ite

Monzo gran ite Tonal it e

3.3H: Sr vs SiO 2

3 .3I: Rb/Sr vs SiO 2

3.3J: Ba vs SiO2

NO FLUORINE DATA AVAILABLE

NO COPPER DATA AVAILABLE

NO LEAD DATA AVAILABLE

NO ZINC DATA AVAILABLE

NO TIN DATA AVAILABLE

3.5A: Zr vs SiO2

3 .5B: Nb vs SiO2

3 .5C: Ce vs SiO2

Tonal it e

Grano dio rite

Monzo gran ite

Trondhjemit e Gran ite

3.6B: Zr/Y vs Sr/Sr*

3.6C: Spidergra m SiO2 range: 1x57%, 3x~70%

NO FeO OR Fe2O3 ANALYSES ARE AVAILABLE FOR REDOX PLOT

3.6E: ASI vs SiO2

NO GALLIUM DATA AVAILABLE FOR Ga/Al vs HFSE PLOT

3.7A: K2 O% Box-whiske r

Pro tero zoic media n

NO THORIUM DATA AVAILABLE

NO URANIUM DATA AVAILABLE

Donington Granitoid Suite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 70 .4 70 .58 6 .58 55.53 78.81 39 TiO2 0.42 0 .41 0 .27 0 .07 0 .87 39 Al2O3 13 .76 14.01 1 .32 11.81 15.9 39 Fe2O3 ------FeO ------MnO 0.05 0 .04 0 .04 0 .01 0 .15 39 MgO 1.21 0 .56 1 .8 0 .04 5 .95 39 CaO 2.39 1 .97 1 .88 0 .55 7 .02 39 Na2O 2.8 2 .83 0 .6 1 .9 5 .9 39 K2O 5.14 5 .44 1 .33 2 .17 8 .15 39 P2O5 0.11 0 .11 0 .07 0 .01 0 .24 33 H2O+ ------H2O------CO2 ------LOI 0.3 0 .3 0 .12 0 .09 0 .59 37 Ba 590.42 649.5 373.86 3 1281 36 Rb 274.08 273.5 111.03 84 448 36 Sr 114.36 109 69.28 10 240 36 Pb ------Th ------U ------Zr 206 174 84.76 76 380 33 Nb 12.67 13 4.59 4 24 33 Y 35.64 39.5 13.12 7 53 36 La 41.83 44 19.04 10 61 6 Ce 74 70 46.16 14 129 7 Nd 30.33 34 17.64 4 51 9 Sc 9.85 9 8 .51 1 29 34 V 74.86 53 56.74 20 169 14 Cr 11.56 11 5.66 2 23 16 Mn ------Co ------Ni 40.73 20 40.46 11 111 15 Cu ------Zn ------Sn ------Mo ------Ga ------As ------Ag ------Bi ------

4.1 Timing >1800 Ma

4.2 Individual Primary Ages: Ages 1. Min brie Gneiss (>1800 Ma, Rb-Sr ) Source: Webb et al. 1986.

4.3 Regional The Minbrie Gneiss occurs north of Port Neill, between Elbow Hill and Lake Gillies. It Setting is highly deformed, and is interpreted by Parker (1983) to be an early Kimban Orogeny intrusive. Parker also equated it to the Donington Granitoid Suite. However, the geochemistry of the two suites is quite different.

4.4 Summary This suite has a broad composition range, from tonalite to granite, and is restite- dominated. It is Sr-depleted, Y-undepleted. It is probably metaluminous as it contains hornblende in places. However, it has an ASI trend typical of S-type granites, and this may possibly be explained by sodic-calcic alteration, or by the unit not being fully subdivided due to its highly deformed nature.

4.5 Potential This suite is not considered to have any mineralisation potential because it shows no fractionation. Cu: None Au: None Pb/Zn: None Sn: None Mo/W: None Confi dence level: 120

4.6 Descriptive Location: North of Port Neill, between Elbow Hill and Lake Gillies, Whyalla 1:250 000 sheet Data area. Dimensions and area: The Minbrie Gneiss has a mapped outcrop area of approximately 900 km 2.

4.7 Intrusives Component plutons: Minbrie Gneiss. Form: Batholithic. Metamorphism and Deformation: The unit is strongly deformed, ranging from gneissic to migmatitic. It is foliated and banded in places. Dominant intrusive rock types: Augen gneiss, granodiorite gneiss, granite gneiss, ranging from tonalite to monzogranite to granite in composition. Colour: Grey. Veins, Pegmatites, Aplites, Greisens: None mentioned in literature. Distinctive mineralogical characteristics: Augen gneiss is the dominant lithology between Cowell and Lake Gillies. It is composed of coarse-grained, banded, megacrystic augen gneiss and migmatite. It contains scattered relict microcline phenocrysts in a recrystallised groundmass of quartz (25-35%), microcline (25-35%), plagioclase (20-30%), biotite (10- 15%), hornblende and rare orthopyroxene, with minor muscovite, zircon, monazite, chlorite and epidote.

© Geoscience Australia 2001 Gawler & Curnamona 4.1 MINBRIE GNEISS Granodiorite gneiss at Refuge Rocks is medium-grained, even-grained, grey, and composed oflargely recrystallised quartz (25-35%), plagioclase (30-45%), biotite (15-20%), microcline (5-15%) and minor rutile, zircon and chlorite. Rafts and xenoliths of mafic gneiss and Warrow Quartzite are enclosed within migmatitic granitic gneiss containing evidence of multiple deformation during the Kimban Orogeny. Granitic gneiss at Elbow Hill is banded, foliated, medium-grained, grey, and ranges from a granodiorite to monzogranite gneiss. Typically, it contains xenoblastic quartz, feldspar, biotite (5-20%) and minor garnet, zircon, apatite and opaques. Feldspar varies from plagioclase dominant (>35%) to plagioclase (10%) and microcline-perthite (30-40%). Rb-Sr geochronology of these rocks was inconclusive, although consistent with crystallisation of the gneiss during the first phase of the Kimban Orogeny. However, derivation from in situ melting and migmatisation of an older granitic precursor (e.g., Miltalie Gneiss of Sleaford Complex) is possible. Breccias: None mentioned in literature. Alteration in the granite: None mentioned in literature.

4.8 Extrusives None mentioned in literature.

4.9 Country Contact metamorphism: None mentioned in literature. Rock Reaction with country rock: None mentioned in literature. Units the granite intrudes: Hutchison Group, and possibly the Sleaford Complex. Dominant rock types: The Hutchison Group consists of basal quartzite, which is locally calc- silicate-rich at the base and higher up are intercalated with pelitic schist. Immediately overlying the quartzite is a sequence of mixed chemical and semipelitic metasediment ranging from massive dolomite and associated banded iron formation and chert to quartzofeldspathic gneiss and schist. There are numerous conformable amphibolite sills throughout this part of the sequence, but their origin is obscure. The chemical/semipelitic part of the sequence is well developed in the Middleback Ranges, where it is known as the Middleback subgroup. The composition of the iron formations is dominantly quartz-hematite at the surface, but below the weathered zone ranges from quartz-magnetite to quartz-magnetite-amphibole (grunerite- actinolite) ± talc, calcite, sulphide and diopside. Feldspar is absent. The metasedimentary sequence above the iron formation horizons is of pelitic to semipelitic character, including the pelitic schist and amphibolite of the Cook Gap Schist, pelitic schist and metasiltstone of the Yadnarie Schist, and calc silicate rock and acid porphyry of the Bosanquet Formation. The Sleaford Complex (Daly and Fanning 1993) outcrops mainly along the southern and southwestern coast of Eyre Peninsula, with limited exposure inland. It is Archaean in age. The Carnot Gneiss consists of homogeneous hypersthene gneiss, tholeiitic metabasalt, augen gneiss, layered garnet gneiss, magnetite gneiss, biotite-garnet gneiss, cordierite-garnet gneiss, and leucogneiss. The Dutton Suite consists of the massive even-grained Whidbey Granite, the porphyritic, gneissic Kiana Granite, and the Coulta Granodiorite. The Wangary Gneiss is a massive to compositionally layered gneiss. Potential hosts: The iron formations of the Middleback Subgroup may be a good host, particularly for an oxidised fluid. However, it is uncertain whether or not they occur within the proximity of the Minbrie Gneiss.

4.10 Mineralisation Uncertain - although there is substantial mineralisation within the Hutchison Group nearby (e.g., Parker 1993), the geochemistry of this granite indicates that mineralisation is not genetically related to the granite.

4.11 Geochemical Data source: The geochemical data is from PIRSA. Data Data quality: The data is thought to mostly be of good quality, however, several elements were not determined, and neither was the oxidation state of iron. Are the data representative? Probably - the data cover a broad range of compositions. Are the data adequate? No, because of several elements/oxides not being determined.

Figure 4.1: His to gram of SiO2 val ues.

SiO2 range (Fig. 4.1): Ranges from 52.8 to 75.7 wt%, reflecting compositions from tonalite to granite. Alteration (Fig. 4.2): Sodic alteration has occurred in some samples. Also, one sample shows almost total loss of alkalis.

• SiO2: No silicic alteration is evident. • K 2 O/Na 2O: Several samples show sodic alteration, another shows potassic alteration apparently without loss of sodium, and another shows almost total loss of both alkalis. • Th/U: Most samples plot in the normal crustal range, however some are anomalously high. • Fe 2O3/(FeO+Fe2 O 3 ): No data. Fractionation Plots (Fig. 4.3): This suite is restite-dominated, ie not fractionated.

• Rb: Values range from moderate to low, decreasing with increasing SiO 2 . • U: All values are low, and possibly decrease slightly with increasing SiO 2 . • Y: Values range from low to moderate, and are scattered. • P 2 O 5 : Values range from low to moderate. The two most mafic samples are low, then the intermediate samples are moderate, followed by a decrease with increasing SiO 2 . • Th: Values range from very high to very low, generally decreasing with increasing SiO 2 . • K/Rb: Values range from moderately low to moderately high, increasing with increasing SiO 2. This trend shows that this is a restite-dominated suite. • Rb-Ba-Sr: Most samples plot in or near the granite and anomalous granite fields, with one sample plotting near the monzogranite field. • Sr: Values range from low to moderately low, with a generally flat trend. • Rb/Sr: All values are very low. • Ba: Values range from very high to very low, and are quite scattered. • F: No data available. Metals (Fig. 4.4): Values range from low to very high, and show no trends with differentiation. • Cu: Values range from low to moderately high, and are scattered. • Pb: Values range from low to moderately high, and are scattered. • Zn: Values range from very high to moderate, and are scattered. • Sn: Only one sample is available, and it has a moderately high value. High field strength elements (Fig. 4.5): Values are generally low to moderate.

• Zr: Values range from moderate to low, decreasing slightly with increasing SiO 2 . • Nb: Values range from moderately low to very low, decreasing with increasing SiO 2 . • Ce: Values range from moderately low to low, mostly decreasing with increasing SiO 2 . One sample is anomalously high.

© Geoscience Australia 2001 Gawler & Curnamona 4.3 MINBRIE GNEISS Classification (Fig. 4.6): The suite is Sr-depleted, Y-undepleted, restite-dominated and hornblende-bearing and therefore possibly I-type.

• The CaO/Na2O/K 2O plot of White, quoted in Sheraton and Simons (1992): One sample plots in the tonalite field, two plot in the trondhjemite field and the other plot in a trend from granodiorite through monzogranite to granite. • Zr/Y vs Sr/Sr*: Insufficient data available (Nd not determined). • Spidergram: This suite is Sr-depleted, Y-undepleted, and unfractionated. There is considerable variation in some elements, reflecting a broad composition range and possibly some alteration. • Oxidation plot of Champion and Heinemann (1994): There are insufficient data available for the oxidation state of the granite to be determined. • ASI: The samples appear to show a trend of decreasing peraluminosity with increasing SiO 2, which is typical of S-type granites. However, other indicators, such as the presence of hornblende, and a decreasing P2O 5 trend, would indicate that the unit is I-type. As the unit is strongly deformed, and shows some alteration, it is possible that the unit has not been fully subdivided, or that some samples are sodic-calcic altered, making them more peraluminous than they originally were. • A-type plot of Eby (1990): Insufficient data - no gallium analyses. However, the low to moderate HFSE values indicate that this unit is not enriched. Granite type (Chappell and White 1974; Chappell and Stephens 1988): I-(granodiorite) type. Australian Proterozoic granite type: Possibly Kalkadoon type.

4.12 Geophysical Radiometrics (Fig. 4.7): Potassium and thorium are slightly above the Proterozoic median, Signature while uranium is equal to the median. Therefore the predicted RGB colour is yellow. Gravity: The central part of the Gneiss shows a slight gravity high, with outer parts of the unit showing values close to background. Magnetics: These granitoids are in part characterised by a belt of high total magnetic intensity which distinguishes it from the adjacent folded Hutchison Group (Parker 1993).

4.13 References Daly, S.J. and Fanning, C.M. 1993. Sleaford complex, in Drexel, J.F., Preiss, W.V. and Parker, A.J. (Editors) The geology of South Australia, Volume 1, The Precambrian, South Australia Geological Survey, Bulletin, 54, 33-38. Parker, A.J. 1983. Whyalla, South Australia, 1:250 000 Geological Series, South Australia Geological Atlas, SI/53-08. Parker, A.J. 1993. Magmatism - Lincoln Complex, in Drexel, J.F., Preiss, W.V. and Parker, A.J. (Editors) The geology of South Australia, Volume 1, The Precambrian, South Australia.Geological Survey, Bulletin,. 54, 74-81. Webb, A.W., Thomson, B.P., Blissett, A.H., Daly, S.J., Flint, R.B. and Parker, A.J. 1986. Geochronology of the Gawler Craton, South Australia, Australian Journal of Earth Sciences, 33, 119-143.

4.2A: Na2 O vs K2O

4.2B: Th/U vs SiO2

INSUFFICIENT DATA FOR Fe2O 3/(FeO+Fe2 O 3 ) vs SiO2 PLOT.

4.3A: Rb vs SiO2

4 .3B: U vs SiO 2

4 .3C: Y vs SiO 2

4.3D: P 2 O 5 vs SiO2

4 .3E: Th vs SiO2

4 .3F: K/Rb vs SiO2

Strongly dif fer en ti ated gran ite

Anoma lous Granit e gran ite

Monzo gran ite To nal ite

4.3H: Sr vs SiO 2

4 .3I: Rb/Sr vs SiO 2

4.3J: Ba vs SiO2

NO FLUORINE DATA AVAILABLE

4 .4A: Cu vs SiO2

4.4B: Pb vs SiO2

4 .4C: Zn vs SiO2

4 .4D: Sn vs SiO2

4.5A: Zr vs SiO2

4 .5B: Nb vs SiO2

4 .5C: Ce vs SiO2

To nal ite

Grano dio rit e

Monzo gran it e

Trondh jemite Gran ite

INSUFFICIENT DATA FOR Zr/Y vs Sr/Sr* PLOT

4.6C: Spider gram SiO2 range: 52.8-75.7%

INSUFFICIENT DATA FOR REDOX PLOT

4.6E: ASI vs SiO2

INSUFFICIENT DATA FOR Ga/Al vs HFSE PLOT

4.7A: K 2 O% Box- whisker

Pro tero zoic media n

4.7B: Th ppm Box- whisker

Pro tero zoic media n

4.7C: U ppm Box- whisker

Pro tero zoic media n

Minbrie Gneiss

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 68 .11 69.1 6 .82 52.8 75.7 11 TiO2 0.5 0 .51 0 .28 0 .12 1 .09 11 Al2O3 14 .97 13.8 1 .97 13.1 18.4 11 Fe2O3 4.36 4 .36 2 .3 1 .21 9 .5 11 FeO ------MnO 0.06 0 .04 0 .06 01 0.23 11 MgO 1.99 1 .35 1 .82 0 .44 6 .55 11 CaO 1.91 1 .48 1 .89 0 .46 7 .4 11 Na2O 3.19 3 .04 1 .17 0 .71 5 .15 11 K2O 4.6 4 .06 2 .67 0 .7 10.3 11 P2O5 0.17 0 .12 0 .12 0 .06 0 .44 11 H2O+ 0.76 0 .76 0 .13 0 .67 0 .85 2 H2O------CO2 ------LOI ------Ba 868.18 730 551.16 120 2260 11 Li ------Rb 158.44 130 98.48 34 340 9 Sr 169.55 160 52.18 80 280 11 Pb 46 29 26.37 2 90 11 Th 36.91 26 39.39 140 11 U 5.27 4 2 .53 8 11 Zr 242.73 270 85.33 80 390 11 Nb 10.45 10 8.66 30 11 Y 27.73 30 18.35 60 11 La 95.45 90 54.66 30 220 11 Ce 144.55 120 95.04 45 380 11 Pr ------Nd ------Sc ------V 67.27 60 44.29 20 160 11 Cr 74.55 40 77.64 20 250 11 Mn ------Co 65.45 60 13.68 50 100 11 Ni 46.36 40 34.65 120 11 Cu 123.64 50 228.31 20 810 11 Zn 83.64 70 44.33 40 180 11 Sn 42.5 42.5 24.75 2 60 2 W ------Mo 12.73 7 .54 30 11 Ga ------As 17.5 17.5 17.68 30 2 C ------F ------B ------Ag ------Bi ------Hf ------Ta ------Cs ------Ge ------Se ------

5.1 Timing 1757 ~ 1700 Ma

5.2 Individual Primary Ages: Ages 1. Horn blende gran ite, Cape Col bert [1] 1757 ± 14 Ma, Rb-S r 2. McGre gor Volcan ics [2] 1740 Ma, U-Pb 3. Mid dle camp Gran ite [3] 1738 ± 68 Ma, U-Pb 4. Carpa Gran ite [4] 1677 ± 125 Ma, Rb-S r 5. Gran ite at Moody Tank [1] 1709 ± 14 Ma, Rb-S r 6. Burkitt Gran ite [4] 1655 ± 61 Ma, Rb-Sr 7. Bunga low Gra no dio rite [4] 1601 ± 14 Ma, Rb-S r 8. En gen ina Adamel lite [4] 1641 ± 38 Ma, Rb-S r 9. Symons Gran ite [5] 1684 ± 10 Ma, U-Pb 10. Carap pee Gran ite [6] 1689 ± 59 Ma, U-Pb 11. Gran ite gneiss at Ifould Lake [4] 1667 ± 115 Ma, Rb-S r Sources: [1] Mortimer et al. 1986; [2] Fanning et al. 1988; [3] Fanning 1987; [4] Webb et al. 1986; [5] Fanning 1997; [6] Flint et al. 1988.

5.3 Regional The Lincoln Complex occurs on the Eyre Peninsula, and has been subdivided into Setting several suites (Mortimer et al. 1986, 1988) which show changes in composition and mineral assemblages through time. The Donington Granitoid Suite, which is included here in the Older Lincoln Complex, evolved through pyroxene- and plagioclase- dominated crystal fractionation, while the Colbert and Moody Suites, included here in the Younger Lincoln Complex, evolved from hornblende- and plagioclase-dominated fractionates, possibly with amphibole (± garnet) as a residual phase during partial melting. The Younger Lincoln Complex has higher P 2O5, Sr, Ba, Ce and ASI, but lower Y than the Older Lincoln Complex. The Moonta Porphyry on the Yorke Peninsula is geochemically quite similar to the Younger Lincoln Complex, and is about the same age (1740 Ma). The Moonta Porphyry has not been included in this supersuite because it is slightly more enriched in high field strength elements.

5.4 Summary This supersuite is mostly felsic, and appears to be restite-dominated with fractionation occurring in more felsic units. At mafic compositions it is metaluminous, and Sr- depleted, Y-undepleted. Unfortunately, there are no data available to determine the oxidation state of the granites, however, some of the granites are pink, indicating that they are oxidised, while others are grey and less oxidised or reduced.

5.5 Potential There is no mineralisation known to be directly related to granites of the Lincoln Complex (Parker 1987). However, some units of the Younger Lincoln Complex are fractionated; also, some rocks which the granite intrudes have good potential for hosting mineralisation. Based on the limited geochemical data, this supersuite has moderate potential for gold, copper and tin in veins. Cu: Mod er ate Au: Mod er ate Pb/Zn: None Sn: Mod er ate Mo/W: None Confi dence level: 220

© Geoscience Australia 2001 Gawler & Curnamona 5.1 YOUNGER LINCOLN COMPLEX 5.6 Descriptive Location: The Lincoln Complex predominantly occurs in the eastern Eyre Peninsula. The Data Middlecamp Granite occurs to the east of the town of Cowell. Granites of the Colbert Suite occur on Cape Colbert near Port Lincoln, and on the islands of the Sir Joseph Banks Group. The Carpa Granite occurs to the southwest of the Middlecamp Granite. Granite at Moody Tank, the Yunta Well Leucogranite, and the Uranno Microgranite occur near one another in the central southern Eyre Peninsula, southwest of Port Neill. The Burkitt Granite occurs north of the Middleback Range, and the Wertigo Granite occurs west of Whyalla. The Bungalow Granodiorite is found in drillcore, north of Cowell. The Carappee Granite crops out near Darke Peak in the central Eyre Peninsula. The Engenina Adamellite occurs in the Mount Woods Inlier, the Symons Granite occurs northwest of Tarcoola, and some granite gneiss is found in the Ifould Lake region. Dimensions and area: The Younger Lincoln Complex has a mapped outcrop area of approximately 1300 km 2.

5.7 Intrusives Component plutons: The supersuite is made up of several suites and other undivided units. The Colbert Suite includes granite gneiss and hornblende granite at Cape Colbert. The Moody Suite includes the Carpa Granite, the Yunta Well Leucogranite, granite and hornblende monzonite at Moody Tank, the Uranno Microgranite, the Burkitt Granite, the Wertigo Granite, and the Bungalow Granodiorite. Other units included in the supersuite are the Middlecamp Granite, the Engenina Adamellite, the Symons Granite, the Carappee Granite, and granite gneiss at Ifould Lake. Form: Batholithic. Metamorphism and Deformation: Most of the ungrouped plutons and those in the Colbert Suite are foliated. Plutons of the Moody Suite are weakly foliated, and the Carpa Granite is massive, although quartz is undulose and plagioclase is partly recrystallised. This deformation and metamorphism is ascribed to the Kimban Orogeny (Parker 1993) which consists of three main events. These are KD1 at ~1845-1795 Ma, K D 2 at ~1795-1745 Ma and K D 3 after ~1745 Ma. This is reflected in the Younger and Older Lincoln Complexes; the Donington Granitoid Suite of the Older Lincoln Complex is syn-KD 1, the Colbert Suite of the Younger Lincoln Complex is late-KD2 to pre- K D 3 , and the Moody Suite also of the Younger Lincoln Complex is syn-K D 3. Dominant intrusive rock types: Granite, granodiorite, porphyritic or even-grained hornblende granite, monzogranite. Colour: The Middlecamp Granite, granite at Moody Tank, Uranno Microgranite, Bungalow Granodiorite and Engenina Adamellite are all grey. The Carpa Granite, Symons Granite and granite gneiss at Ifould Lake are all pink. Veins, Pegmatites, Aplites, Greisens: The Middlecamp Granite contains numerous narrow pegmatite veins. The Yunta Well Leucogranite also contains pegmatite. Distinctive mineralogical characteristics: The Middlecamp Granite is medium-grained, foliated, and of monzogranite to granodiorite composition. It contains quartz (20-25%), plagioclase (45-60% and 20-30%), K-feldspar (10-25% and 35-50%), biotite (5-10%), titanite, apatite and minor accessories. The Cape Colbert granite is massive, foliated, medium-grained equigranular granite gneiss, with granoblastic quartz, microcline, plagioclase, biotite and accessory titanite, apatite, zircon and opaques. Cape Colbert hornblende granite is a foliated, medium-grained to porphyritic, and is accompanied by minor granodiorite. It contains phenocrysts of plagioclase, orthoclase and hornblende in a groundmass of these plus biotite, quartz, iron oxides and accessories. The Carpa Granite is homogeneous, unfoliated, medium even-grained pink granite to monzogranite. It contains quartz (30-45%), pink K-feldspar (30-60%), plagioclase (10-40%), biotite, muscovite and garnet. The Yunta Well Leucogranite is a variably foliated, medium to coarse-grained muscovite-bearing granite. It contains microcline (55%), plagioclase (15%), quartz (20%), muscovite (10%) and minor garnet, tourmaline and apatite. Granite at Moody Tank is a massive, medium-grained to weakly porphyritic, grey granite to monzogranite, with local coarse-grained segregations. It contains grey quartz (25-30%), microcline (35-50%), plagioclase (15-30%), biotite (2-8%), ± garnet, muscovite and opaques. Hornblende monzonite of the Moody Suite is a massive, coarse-grained monzonite to syenite with phenocrysts of plagioclase, microcline and hornblende. It contains microcline (35%), plagioclase (20%), quartz (5%), hornblende (15%), biotite (14%) and ilmenite, apatite, titanite and zircon. The

© Geoscience Australia 2001 Gawler & Curnamona 5.2 YOUNGER LINCOLN COMPLEX Uranno Microgranite is a fine to medium even-grained grey microgranite, and consists of quartz (10-15%), K-feldspar (35-60%), plagioclase (10-25%), biotite and accessory hornblende, titanite, opaques, zircon and myrmekite. The Burkitt Granite is a massive, medium even-grained hornblende granite, consisting of perthitic K-feldspar (50-65%), quartz (10- 20%), plagioclase (20-25%), hornblende (3-5%), monazite, biotite, opaques and accessories. The Wertigo Granite is a massive, medium-grained, weakly gneissic granite and granodiorite, with quartz (20-30%), K-feldspar (25-40%), plagioclase (20-30%), biotite (5-10%), and minor sericite, epidote and magnetite. Granodioritic rocks contain plagioclase (55-60%), minor K- feldspar (<5%) and hornblende in place of biotite. The Bungalow Granodiorite consists of medium even-grained grey granodiorite, granite and monzogranite, composed of quartz, plagioclase, K-feldspar, biotite (and chlorite), apatite, ± garnet and muscovite. The Engenina Adamellite is predominantly a grey porphyritic monzogranite, with porphyritic granite and granodiorite also present. Tabular to ovoid feldspar phenocrysts 20 mm across are ubiquitous and generally aligned subparallel to the foliation. These include orthoclase, microcline and plagioclase, in which Carlsbad, grid-iron and polysynthetic twinning are common. Small patches of myrmekite commonly extend into large microcline phenocrysts. The biotite content is high (10-15%), and the groundmass of quartz and feldspar shows extensive recrystallisation. The Symons Granite is a foliated porphyritic granite and augen gneiss. It contains large augen of microcline in medium-grained quartz, plagioclase, microcline, biotite and accessories. The Carappee Granite is dominantly a coarse-grained porphyritic granite, with abundant large white K-feldspar phenocrysts consisting of microcline and microcline perthite. Phenocrysts are chiefly tabular, but also ovoid, averaging 2-4 cm in diameter and aligned either oblique or subparallel to the foliation. Quartz and plagioclase are also present. Biotite and muscovite chiefly occur as recrystallised stringers in a well-developed foliation. Granite gneiss at Ifould Lake is medium to coarse-grained, and grades into augen gneiss, with some granodiorite and diorite. It consists of quartz and K-feldspar augen in granoblastic quartz (15-40%), plagioclase (25-45%), microcline (5-35%), biotite (5-10%), muscovite (<10%), hornblende, epidote, titanite, apatite and opaques. Breccias: None mentioned in literature. Alteration in the granite: None mentioned in literature.

5.8 Extrusives This supersuite is geochemically very similar to the McGregor Volcanics, and is of about the same age, and so it is possible that the Volcanics are co-magmatic with parts of the Younger Lincoln Complex. The Volcanics themselves comprise bimodal felsic and lesser basaltic volcanics dated at ~1740 Ma. The base of the unit does not crop out; the lowermost exposed unit is a spherulitic rhyolite which is overlain by porphyritic to even-grained rhyolite, rhyodacite, dacite and minor quartzose sandstone. A thin basaltic andesite occurs at the top.

5.9 Country Contact metamorphism: None mentioned in literature. Rock Reaction with country rock: None mentioned in literature. Units the granite intrudes: The Middlecamp Granite, Carpa Granite, Yunta Well Leucogranite, granite and hornblende monzonite at Moody Tank, Uranno Microgranite, Burkitt Granite and probably the Carappee Granite all intrude the Hutchison Group. Granites of the Colbert Suite intrude megacrystic granite of the Donington Granitoid Suite. The Carpa Granite also intrudes the Middlecamp Granite. The Wertigo Granite intrudes the Myola Volcanics. The Bungalow Granite intrudes the Middleback Subgroup. The Engenina Adamellite intrudes gneiss and felsic granulite of the Mount Woods Inlier. The intrusive relationships of the Symons Granite and granite at Ifould Lake are uncertain. Dominant rock types: The Hutchison Group consists of basal quartzite, which is locally calc- silicate-rich at the base and higher up is intercalated with pelitic schist. Immediately overlying the quartzite is a sequence of mixed chemical and semipelitic metasediments ranging from massive dolomite and associated banded iron formation and chert to quartzofeldspathic gneiss and schist. There are numerous conformable amphibolite sills throughout this part of the sequence, but their origin is obscure. The chemical/semipelitic part of the sequence is well developed in the Middleback Ranges where it is known as the Middleback subgroup. The composition of the iron formations is dominantly quartz-hematite at the surface but below the

© Geoscience Australia 2001 Gawler & Curnamona 5.3 YOUNGER LINCOLN COMPLEX weathered zone ranges from quartz-magnetite to quartz-magnetite-amphibole (grunerite- actinolite) ± talc, calcite, sulphide and diopside. Feldspar is absent. The metasedimentary sequence above the iron formation horizons is of pelitic to semipelitic character, including pelitic schist and amphibolite of the Cook Gap Schist, pelitic schist and metasiltstone of the Yadnarie Schist, and calcisilicate rock and felsic porphyry of the Bosanquet Formation. Megacrystic granite of the Donington Granitoid Suite is a distinctive, dark-coloured, strongly foliated, mafic-rich, coarse-grained granite to augen gneiss. It is characterised by 20-40 mm ovoid plagioclase and orthoclase megacrysts, commonly with mafic-rich cores. The Myola Volcanics consist of deformed felsic meta-volcanics and fine-grained gneiss, schist and quartzite metamorphosed to upper greenschist to lower amphibolite facies. Potential hosts: The calc-silicate rocks, carbonates, and iron-rich formations of the Hutchison Group are all good potential hosts for mineralisation.

5.10 Mineralisation There is no mineralisation known to be associated with any of the granites of the Lincoln Complex (Parker 1987). Base metal mineralisation in the Middleback Subgroup is believed to be of sedimentary-exhalative origin deposited within an upper shelf facies or subtidal carbonate-mudstone sequence with elevated iron and possible tuffaceous or detrital clay input. The sequence has been metamorphosed leading to regional recrystallisation and local migration of metal-bearing fluids, but possible hydrothermal activity associated with nearby Lincoln Complex granitoids, Gawler Range Volcanics or Hiltaba Suite granites may have remobilised metal-bearing solutions.

5.11 Geochemical Data source: Data for the Colbert and Moody Suite granites are from Mortimer (1984). All Data other data are from the Department of Mines and Energy, South Australia, and are published by them on CD-ROM. Data quality: The data quality is considered to be good. Are the data representative? Probably. Are the data adequate? No. Several key elements were not determined in some of the granites, making it impossible to subdivide the granites into suites. Also, the fractionation history and oxidation state are undetermined for some granites.

Figure 5.1: His to gram of SiO2 val ues.

SiO 2 range (Fig. 5.1): Ranges from 58.5 wt% to 75 wt%. Alteration (Fig. 5.2): Some alteration is present in the Middlecamp Granite, the McGregor Volcanics, and the Symons Granite.

• SiO 2: No silicic alteration is evident. • K 2 O/Na 2O: Sodic alteration is present in some samples from the Middlecamp Granite and the McGregor Volcanics. • Th/U: Most samples are normal, however, three samples from granite at Moody Tank are all below the normal range, while some samples from the Middlecamp Granite, McGregor Volcanics, Symons Granite and granite at Moody Tank are above the normal range. • Fe2O3/(FeO+Fe2 O 3 ): Only one sample from the Burkitt Granite was analysed for both FeO and Fe 2O 3. Note that the samples from the Symons Granite which plot on this graph

© Geoscience Australia 2001 Gawler & Curnamona 5.4 YOUNGER LINCOLN COMPLEX only plot because in the database the value of total iron has also been entered in the FeO and Fe2O 3 fields (i.e. the points are useless).

Fractionation Plots (Fig. 5.3): The Colbert and Moody Suites are fractionated at higher SiO 2 levels, although they were not analysed for U or Th, and the McGregor Volcanics are probably also fractionated, although they were not analysed for Rb. The other units appear to be restite- dominated. • Rb: Values range from moderately low to moderate, showing an increasing trend with increasing SiO 2 . The trend steepens at SiO 2 >73 wt%. One sample of granite at Moody Tank is anomalously high. • U: Values are mostly low to moderately low, with no discernible trend. One sample of the Moody Tank granite is anomalously high. The McGregor Volcanics show an increasing trend with increasing SiO 2 , which may be due to fractionation or alteration. • Y: Values range from low to moderate, with too much scatter to discern a trend. • P 2 O 5 : Values range from high to very low. There is a decreasing trend with increasing SiO 2, however there is some scatter about this trend. The undifferentiated samples from the Moody Suite in particular are significantly higher than the rest of the supersuite, but still have a decreasing trend. • Th: Values range from low to moderate. Generally, there is a decreasing trend with increasing SiO 2 , although the McGregor Volcanics increase with increasing SiO 2 . • K/Rb: The Colbert Suite, Moody Suite and Symons Granite all show a decreasing trend with increasing SiO 2, indicative of fractionation. Granite at Moody Tank increases with increasing SiO 2 . Note that no other units plot on this graph, because they were not analysed for rubidium. • Rb-Ba-Sr: Some samples from the Colbert and Moody Suites plot in the strongly differentiated granite field, while the remaining samples plus those from the Symons Granite, granite at Moody Tank, and the Burkitt Granite plot in the granite and monzogranite fields. Other units do not plot. • Sr: Values range from very high to very low, decreasing with increasing SiO 2 . There is some scatter about the trend, however. • Rb/Sr: Values range from very low to moderate. The Colbert and Moody Suites show an exponential increase above 73 wt% SiO 2. • Ba: Values range from very high to very low, generally decreasing with increasing SiO 2 , however, there is some scatter around the trend. • F: No data available. Metals (Fig. 5.4): No data for the Colbert and Moody Suites are available. For the others, the metals generally range from high to low, with no obvious trends. • Cu: Values range from very high to low, with a lot of scatter. • Pb: Values range from high to low, with a lot of scatter. • Zn: Values range from moderately high to low, with a generally decreasing trend. • Sn: Only three groups plot (McGregor, Symons, Carpa) and these range from moderately high to low, with a lot of scatter. High field strength elements (Fig. 5.5): Values generally range from high to low.

• Zr: Values range from moderate to low, with a decreasing trend at higher SiO 2 . • Nb: Values range between low and moderate, with no trend. • Ce: Values range from high to low, decreasing with increasing SiO 2, although there is some scatter. Classification (Fig. 5.6): The Younger Lincoln Complex is I-type, Sr-depleted, Y-undepleted, and mostly restite-dominated but becoming fractionated at felsic compositions.

• The CaO/Na 2O/K 2O plot of White, quoted in Sheraton and Simons (1992): Most samples plot in the granite field, with others plotting in the monzogranite and granodiorite fields. Altered samples (sodic or potassic alteration) plot in the trondhjemite field. • Zr/Y vs Sr/Sr*: Only samples from the Colbert and Moody Suites plot; these are Sr- depleted, Y-undepleted.

© Geoscience Australia 2001 Gawler & Curnamona 5.5 YOUNGER LINCOLN COMPLEX • Spidergram: The Middlecamp Granite and the Carpa Granite are apparently Y-depleted, although they are also Sr-depleted. This may be due to alteration. All others are Sr- depleted, Y-undepleted. • Oxidation plot of Champion and Heinemann (1994): Only the Burkitt Granite can be plotted properly here - other units were analysed only for total iron. The Burkitt Granite is oxidised. • ASI: The general trend increases with increasing SiO 2 , with samples below ~70 wt% SiO 2 having ASI <1.1, and those above ~70 wt% SiO 2 having ASI >1.1. This is the general trend for I-type granites. • A-type plot of Eby (1990): Only one sample from the Burkitt Granite plots - it falls in the Palaeozoic A-type field, although it has low Ga/Al. Predictably, most of the other units would plot near the fractionated granite/Palaeozoic A-type boundary, as these granites have some high Zr, Nb, Y and Ce values. Granite type (Chappell and White 1974; Chappell and Stephens 1988): I-(granodiorite). Australian Proterozoic granite type: Probably Nicholson type - restite-dominated until fractionated at high SiO 2 levels, metaluminous at mafic compositions.

5.12 Geophysical Radiometrics (Fig. 5.7): Potassium for all units is above the Proterozoic median. No Th or U Signature data are available for the undifferentiated Colbert and Moody Suites. Granite at Moody Tank has Th about equal to the Proterozoic median, and U is significantly higher. Its predicted RGB colour is light blue. The predicted RGB colour for the one sample of the Burkitt Granite is greenish white. The Carpa Granite has Th below the Proterozoic median, and U above, giving it a predicted RGB colour of magenta. The Middlecamp Granite has both Th and U higher than the Proterozoic median, giving a predicted RGB colour of white. The Symons Granite has Th and U lower than the Proterozoic median, so has a predicted RGB colour of red. The McGregor Volcanics are slightly higher than the Proterozoic median in Th and U, so have a predicted RGB colour of white. Gravity: The Younger Lincoln Complex mostly shows a background-level gravity signature. Magnetics: The Younger Lincoln Complex mostly shows a high total magnetic intensity signature.

5.13 References Benbow, M.C. and Flint, R.B. 1979. The Engenina Adamellite and Balta Granite of the Mount Woods Inlier, South Australia Geological Survey, Quarterly Geological Notes, 69, 9-13. Fanning, C.M. 1987. U-Pb geochronology of Broadview DDH1, Wangary Gneiss, Carpa Granite and Middlecamp Granite. Amdel report, G7155/88 (unpublished). Fanning, C.M. 1997. Geochronological synthesis of southern Australia, Part II: the Gawler Craton. PRISE (Precise Radiogenic Isotope Services - ANU) Report to PIRSA. Fanning, C.M., Flint, R.B., Parker, A.J., Ludwig, K.R. and Blissett, A.H. 1988. Refined Proterozoic evolution of the Gawler Craton, South Australia, through U-Pb zircon geochronology. Precambrian Research, 40/41, 363-386. Flint, R.B., Fanning, C.M. and Rankin, L.R. 1988. Carappee Granite of central Eyre Peninsula. South Australia Geological Survey, Quarterly Geological Notes, 105, 2-6. Mortimer, G.E. 1984. Early to Middle Proterozoic granitoids, basaltic dykes and associated layered rocks of southeastern Eyre Peninsula, South Australia. University of Adelaide, PhD thesis (unpublished). Mortimer, G.E., Cooper, J.A. and Oliver, R.L. 1986. The geochronological and geochemical evolution of the Proterozoic Lincoln Complex, Eyre Peninsula, South Australia. Geological Society of Australia, Abstracts, 15, 140-141. Mortimer, G.E., Cooper, J.A. and Oliver, R.L. 1988. The geochemical evolution of Proterozoic granitoids near Port Lincoln in the Gawler Orogenic Domain of South Australia, Precambrian Research, 40/41, 387-406. Parker, A.J. 1987. Archaean to Middle Proterozoic mineralisation of the Gawler Craton (including Stuart Shelf Region), South Australia, Department of Mines and Energy, South Australia, Report Bk. No. 87/84.

© Geoscience Australia 2001 Gawler & Curnamona 5.6 YOUNGER LINCOLN COMPLEX Parker, A.J. 1993. Palaeoproterozoic. In: Drexel, J.F., Preiss, W.V. and Parker, A.J. 1993. The Geology of South Australia. Vol. 1, The Precambrian. South Australia Geological Survey, Bulletin 54, pp 51-106. Rutland, R.W.R., Parker, A.J., Pitt, G.M., Priess, W.V. and Murrell, N. 1981. The Precambrian of South Australia. In: Hunter, D.R. (Editor.), Precambrian of the Southern Hemisphere. Developments in Precambrian Geology Series, 2. Elsevier, Amsterdam, 309-360. Webb, A.W., Thomson, B.P., Blissett, A.H., Daly, S.J., Flint, R.B. and Parker, A.J. 1986. Geochronology of the Gawler Craton, South Australia. Australian Journal of Earth Sciences, 33, 119-143.

5.2A: Na2 O vs K2O

5.2B: Th/U vs SiO 2

5 .2C: Fe2 O 3 /(FeO+Fe 2 O 3 )

5.3A: Rb vs SiO2

5 .3B: U vs SiO 2

5 .3C: Y vs SiO 2

5.3D: P2 O 5 vs SiO2

5 .3E: Th vs SiO2

5 .3F: K/Rb vs SiO 2

Strongly dif fer en ti ated gran ite

Anoma lous Granit e gran ite

Monzo gran ite Tonal it e

5.3H: Sr vs SiO 2

5 .3I: Rb/Sr vs SiO 2

5.3J: Ba vs SiO2

NO FLUORINE DATA AVAILABLE

5 .4A: Cu vs SiO2

5.4B: Pb vs SiO2

5 .4C: Zn vs SiO2

5 .4D: Sn vs SiO2

5.5A: Zr vs SiO2

5 .5B: Nb vs SiO2

5 .5C: Ce vs SiO2

Tonal it e

Grano dio rit e

Monzo gran it e

Trondhjemit e Gran ite

5.6B: Zr/Y vs Sr/Sr*

5 .6C: Spidergra m SiO2 range: 61- 77%

Strongly oxi dised

Oxi dised

Re duced

Strongly Reduced

5.6E: ASI vs SiO 2

5 .6F: Ga/Al vs HFSE (Eby 1990)

5.7A: K2 O% Box-whiske r

Pro tero zoic media n

5.7B: Th ppm Box-whiske r

Pro tero zoic media n

5.7C: U ppm Box-whiske r

Pro tero zoic media n

Undivided Colbert Suite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 71 .66 75.82 6 .33 63.35 77.24 10 TiO2 0.56 0 .3 0 .41 0 .16 1 .1 10 Al2O3 13 .16 12.45 1 .53 11.47 15.08 10 Fe2O3 ------FeO ------MnO 0.04 0 .04 0 .03 0 .01 0 .09 10 MgO 0.63 0 .28 0 .59 0 .07 1 .43 10 CaO 1.76 0 .98 1 .4 0 .46 3 .7 10 Na2O 2.46 2 .4 0 .31 2 .08 2 .97 10 K2O 6.02 6 .11 0 .66 4 .94 6 .85 10 P2O5 0.13 0 .04 0 .15 0 .01 0 .35 10 H2O+ ------H2O------CO2 ------LOI 0.39 0 .4 0 .1 0 .24 0 .61 10 Ba 691.5 727 411.04 84 1144 8 Rb 259.22 276 54.89 196 342 9 Sr 100.89 57 72 22 187 9 Pb ------Th ------U ------Zr 295.33 333 75.01 173 411 9 Nb 15.56 17 5.68 7 22 9 Y 37.89 46 14.56 16 53 9 La 66.33 62 7.51 62 75 3 Ce 129.5 129.5 9 .19 123 136 2 Nd 57.33 61 8.14 48 63 3 Sc 8.5 5 5 .5 4 17 8 V ------Cr 6.33 5 3 .21 4 10 3 Mn ------Co ------Ni ------Cu ------Zn ------Sn ------W ------Mo ------Ga ------As ------F ------Ag ------Bi ------

Undivided Moody Suite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 71 .75 73.67 4 .99 58.88 75.73 11 TiO2 0.32 0 .07 0 .43 0 .03 1 .4 11 Al2O3 14 .55 14.46 0 .6 13.76 15.57 11 Fe2O3 ------FeO ------MnO 0.08 0 .07 0 .04 0 .03 0 .14 11 MgO 0.54 0 .37 0 .64 0 .06 2 .31 11 CaO 1.26 0 .73 1 .14 0 .46 4 .28 11 Na2O 3.56 3 .31 0 .52 2 .87 4 .32 11 K2O 4.71 4 .86 0 .63 3 .83 5 .6 11 P2O5 0.32 0 .3 0 .18 0 .08 0 .63 11 H2O+ ------H2O------CO2 ------LOI 0.61 0 .57 0 .18 0 .35 1 .03 11 Ba 473.7 41.5 806.85 1 2471 10 Rb 281.7 283 78.54 164 416 10 Sr 141.1 19 245.72 7 774 10 Pb ------Th ------U ------Zr 154.5 34 170.38 25 464 10 Nb 22.9 25.5 8 .6 8 32 10 Y 19.7 14.5 14.16 6 40 10 La 135.75 103 66.84 101 236 4 Ce 172.5 197.5 154.45 4 418 6 Nd 100.25 81 46.84 70 169 4 Sc 4.5 4 3 .84 1 12 10 V ------Cr ------Mn ------Co ------Ni ------Cu ------Zn ------Sn ------W ------Mo ------Ga ------As ------F ------Ag ------Bi ------

Moody Tank granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 68 .82 71.9 6 .94 58.5 73 4 TiO2 0.46 0 .46 0 .24 0 .2 0 .71 4 Al2O3 14 .58 14.7 0 .32 14.1 14.8 4 Fe2O3 3.95 3 .17 2 .72 1 .72 7 .75 4 FeO ------MnO 0.07 0 .05 0 .06 0 .04 0 .16 4 MgO 2 0.87 2 .51 0 .5 5 .75 4 CaO 2.75 2 .34 1 .47 1 .47 4 .86 4 Na2O 3.46 3 .58 0 .98 2 .22 4 .46 4 K2O 3.45 3 .08 1 .6 2 .06 5 .6 4 P2O5 0.24 0 .09 0 .31 0 .08 0 .7 4 H2O+ ------H2O------CO2 ------LOI ------Ba 597.5 610 279.81 250 920 4 Rb 285 217.5 179.12 155 550 4 Sr 185 185 61.37 110 260 4 Pb 53.75 55 22.87 2 80 4 Th 22 18 16.17 8 44 4 U 19.5 13 19.49 4 48 4 Zr 245 195 139.16 140 450 4 Nb 20 15 13.56 10 40 4 Y 27.5 25 9.57 20 40 4 La 90 85 29.44 60 130 4 Ce 101.25 77.5 52.66 70 180 4 Nd ------Sc ------V 75 35 83.47 30 200 4 Cr 90 40 114.02 20 260 4 Mn ------Co 62.5 60 15 50 80 4 Ni 42.5 25 38.62 20 100 4 Cu 50 40 34.64 20 100 4 Zn 62.5 37.5 77.94 170 4 Sn ------W ------Mo 10 - 4 Ga ------As ------F ------Ag ------Bi ------

Burkitt Granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 60 .55 60.55 - 60.55 60.55 1 TiO2 0.51 0 .51 - 0 .51 0 .51 1 Al2O3 16 .7 16 .7 - 16 .7 16 .7 1 Fe2O3 3.24 3 .24 - 3 .24 3 .24 1 FeO 2.15 2 .15 - 2 .15 2 .15 1 MnO 0.11 0 .11 - 0 .11 0 .11 1 MgO 1.52 1 .52 - 1 .52 1 .52 1 CaO 3.4 3 .4 - 3 .4 3 .4 1 Na2O 4.5 4 .5 - 4 .5 4 .5 1 K2O 5.71 5 .71 - 5 .71 5 .71 1 P2O5 0.37 0 .37 - 0 .37 0 .37 1 H2O+ 0.63 0 .63 - 0 .63 0 .63 1 H2O- 0.35 0 .35 - 0 .35 0 .35 1 CO2 0.03 0 .03 - 0 .03 0 .03 1 LOI ------Ba 2290 2290 - 2290 2290 1 Rb 188 188 - 188 188 1 Sr 970 970 - 970 970 1 Pb 60 60 - 60 60 1 Th 76 76 - 76 76 1 U 11 11 - 11 11 1 Zr 288 288 - 288 288 1 Nb 23 23 - 23 23 1 Y 34 34 - 34 34 1 La 96 96 - 96 96 1 Ce 177 177 - 177 177 1 Nd ------Sc 10 10 - 10 10 1 V 59 59 - 59 59 1 Cr 6 6 - 6 6 1 Mn 945 945 - 945 945 1 Co ------Ni 9 9 - 9 9 1 Cu 22 22 - 22 22 1 Zn 55 55 - 55 55 1 Sn ------W ------Mo ------Ga 13 13 - 13 13 1 As ------F ------Ag ------Bi ------

Carpa Granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 73 .15 73.25 0 .93 71.7 74.1 6 TiO2 0.14 0 .11 0 .12 0 .05 0 .37 6 Al2O3 14 .7 14 .55 0 .45 14.2 15.5 6 Fe2O3 1.24 1 .1 0 .48 0 .84 2 .16 6 FeO ------MnO 0.01 0 .01 0 .01 0 .01 0 .02 6 MgO 0.29 0 .22 0 .2 0 .15 0 .69 6 CaO 0.81 0 .69 0 .46 0 .44 1 .62 6 Na2O 4.12 4 .11 0 .41 3 .46 4 .72 6 K2O 4.52 4 .84 0 .83 2 .98 5 .15 6 P2O5 0.13 0 .13 0 .06 0 .07 0 .19 6 H2O+ 0.57 0 .53 0 .14 0 .47 0 .86 6 H2O------CO2 ------LOI ------Ba 353.33 345 271.27 100 640 6 Rb ------Sr 105 95 95.08 20 225 6 Pb 49.83 45 9.7 40 64 6 Th 14.17 6 .65 25 6 U 8.33 7 .5 4 .08 15 6 Zr 103.83 82 71.93 46 230 6 Nb 12 11 4.38 6 18 6 Y 5 - 6 La 21.67 20 18.07 50 6 Ce 48.33 40 28.05 25 100 6 Nd ------Sc ------V 35 35 10.49 20 50 6 Cr 21.67 15 24.63 70 6 Mn ------Co 95 95 5.48 90 100 6 Ni 14.17 10 9.17 30 6 Cu 50 98.49 250 6 Zn 36.67 35 18.62 20 70 6 Sn 53 60 17.18 2 70 5 W ------Mo 5 - 6 Ga ------As 17.5 15 10.84 30 6 F ------Ag ------Bi ------

Middlecamp Granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 65 .28 65.95 4 .35 59.4 69.8 4 TiO2 0.69 0 .72 0 .29 0 .38 0 .95 4 Al2O3 15 .53 15.75 0 .56 14.7 15.9 4 Fe2O3 4.39 3 .48 2 .69 2 .3 8 .3 4 FeO ------MnO 0.05 0 .04 0 .04 0 .03 0 .11 4 MgO 1.88 1 .29 1 .72 0 .53 4 .4 4 CaO 2.28 2 .29 0 .56 1 .58 2 .94 4 Na2O 4.43 3 .58 1 .85 3 .34 7 .2 4 K2O 3.82 4 .4 1 .99 1 .09 5 .4 4 P2O5 0.19 0 .17 0 .11 0 .09 0 .35 4 H2O+ 0.81 0 .84 0 .14 0 .61 0 .93 4 H2O------CO2 ------LOI ------Ba 705 710 480.38 200 1200 4 Rb ------Sr 295 272.5 104.64 205 430 4 Pb 51 56 14.65 30 62 4 Th 57.5 57.5 30.14 25 90 4 U 8.75 10 2.5 10 4 Zr 341.25 280 157.39 235 570 4 Nb 13 11 4.76 10 20 4 Y 6.25 2 .5 10 4 La 200 180 77.03 130 310 4 Ce 252.5 215 147.51 130 450 4 Nd ------Sc ------V 90 80 43.2 50 150 4 Cr 62.5 35 65.51 20 160 4 Mn ------Co 90 90 8.16 80 100 4 Ni 40 30 28.28 20 80 4 Cu 187.5 200 105.95 50 300 4 Zn 75 50 56.86 40 160 4 Sn 65 65 5.77 60 70 4 W ------Mo 5 - 4 Ga ------As 25 20 10 20 40 4 F ------Ag ------Bi ------

Symons Granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 72 .72 73.6 5 .11 64.3 82 8 TiO2 0.28 0 .2 0 .19 0 .14 0 .69 8 Al2O3 13 .49 13.3 2 .57 8 .6 17.1 8 Fe2O3 1.9 1 .51 1 .12 1 .01 4 .34 8 FeO 1.9 1 .51 1 .12 1 .01 4 .34 8 MnO 0.02 0 .01 0 .02 01 0.06 8 MgO 0.28 0 .14 0 .3 0 .06 0 .96 8 CaO 0.47 0 .22 0 .76 0 .1 2 .34 8 Na2O 2.86 2 .7 1 .12 1 .84 4 .74 8 K2O 5.15 5 .57 0 .94 3 .62 6 .05 8 P2O5 0.03 0 .02 0 .04 01 0.13 8 H2O+ ------H2O------CO2 ------LOI 1.34 0 .98 0 .77 0 .82 3 .08 8 Ba 1018.75 910 425.22 410 1680 8 Rb 216.25 212.5 60.16 100 280 8 Sr 232.88 122 230.48 70 690 8 Pb 9.06 10 3.76 15 8 Th 23.75 15.5 22.12 12 78 8 U 2.5 0 .93 4 8 Zr ------Nb 10.63 10 3.54 7 18 8 Y ------La 81.25 55 67.92 20 230 8 Ce 126.25 70 108.62 30 360 8 Nd ------Sc ------V 14.5 12 9.67 7 34 8 Cr 4.88 4 3 .36 12 8 Mn ------Co ------Ni 5.88 3 .5 5 .38 2 18 8 Cu 7 5 4.78 3 17 8 Zn 35.25 31 16.35 16 62 8 Sn 2.5 1 .41 6 8 W ------Mo 1.5 - 8 Ga ------As 1.13 0 .35 2 8 F ------Ag 0.56 0 .18 1 8 Bi 2.5 - 8

McGregor Volcanics

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 67 .4 65 .1 3 .71 64.1 72.5 7 TiO2 0.65 0 .74 0 .13 0 .51 0 .78 7 Al2O3 14 .41 14.8 0 .94 13 15.3 7 Fe2O3 5.52 6 0 .75 4 .52 6 .2 7 FeO ------MnO 0.1 0 .12 0 .04 0 .05 0 .14 7 MgO 1.58 1 .49 0 .23 1 .37 2 7 CaO 1.85 1 .9 1 .38 0 .37 3 .46 7 Na2O 3.27 2 .76 1 .24 2 .42 5 .85 7 K2O 3.66 4 .02 1 .9 0 .94 6 .45 7 P2O5 0.18 0 .2 0 .05 0 .12 0 .26 7 H2O+ 1.09 1 .02 0 .33 0 .81 1 .74 7 H2O------CO2 ------LOI ------Ba 648.57 880 398.97 110 1020 7 Rb ------Sr 193.43 265 150.74 25 350 7 Pb 41.29 40 12.78 28 66 7 Th 30 25 11.18 20 45 7 U 9.86 10 4.88 15 7 Zr 330 335 41.83 280 380 7 Nb 19.57 20 4.31 14 25 7 Y 31.43 35 15.47 10 55 7 La 92.86 90 29.84 40 120 7 Ce 119.29 120 25.24 75 160 7 Nd ------Sc ------V 66 80 29.01 28 100 7 Cr 27.29 20 17.76 10 62 7 Mn ------Co 59.57 70 18.78 31 80 7 Ni 15 10 10.55 33 7 Cu 442.86 180 711 90 2050 7 Zn 71.14 80 31.28 2 90 7 Sn 32.43 15 21.28 2 60 7 W ------Mo 4.86 0 .38 5 7 Ga ------As 11.86 10 8.38 20 7 F ------Ag ------Bi ------

6.1 Timing 1700 Ma

6.2 Individual Primary Ages: Ages 1. Ameroo Gneiss (me ta grani toid) 1703 ± 6 Ma, SHRIMP Source: Cook et al. 1994.

6.3 Regional Leucocratic quartzofeldspathic gneisses form a significant proportion of the lower part Setting of the Palaeoproterozoic Willyama Supergroup sequence in the Olary Block, South Australia, and have correlatives in the adjacent Broken Hill Block (Ashley et al. 1996, Laing 1996). Field and geochemical data demonstrate that an important, albeit minor proportion of these rocks were originally rhyolitic volcanics and granite, with A-type affinities consistent with magma production during intracratonic rifting. Although the rocks have characteristic high field strength element enrichment, many have undergone extensive pervasive pre- or syn-metamorphic sodic alteration and are typically rich in albite. The Ameroo Gneiss is considered by Ashley et al. (1995) to be part of the lower Quartzofeldspathic Suite and may have ?extrusive/pyroclastic/ epiclastic equivalents. Laing (1996) correlates it with the Rasp Ridge Gneiss in the Broken Hill Domain.

6.4 Summary This suite has a narrow, felsic composition range, and is slightly fractionated, oxidised, and Sr-depleted, Y-undepleted. It is significantly enriched in the HFSE, leading to an A-type classification by Ashley et al. (1996). It is extensively sodic altered by pre- or syn-metamorphic overprinting (Ashley et al. 1995).

6.5 Potential This suite is considered to have little potential for mineralisation, based on its limited size and composition range, and the slight degree of fractionation. Cu: Low Au: Low Pb/Zn: None Sn: None Mo/W: None Confi dence level: 111

6.6 Descriptive Location: Quartzofeldspathic gneisses are well exposed immediately east of Ameroo Hill, Data Doughboy Well mine, Basso mine, Drew Hill and Tonga Bore—Mt Bull region. Dimensions and area: The A-type Suite has an area of approximately 15 km 2 .

6.7 Intrusives Component plutons: This gneissic unit is not divided in the field. Form: Extensively metamorphosed. Metamorphism and Deformation: Extensively metamorphosed, and may have undergone extensive pervasive pre- or syn-metamorphic sodic alteration and are typically rich in albite. Dominant intrusive rock types: Massive to commonly foliated, leucocratic medium grained quartz-feldspar-biotite gneiss (Laing 1996). Colour: Leucocratic, ‘white’ to grey. Locally the volcanics weather to ‘rusty’ red, i.e. faintly gossanous. Veins, Pegmatites, Aplites, Greisens: Magnetite-quartz schlieren and veins occur at Drew Hill.

© Geoscience Australia 2001 Gawler & Curnamona 6.1 OLARY PRETECTONIC A-TYPE SUITE Distinctive mineralogical characteristics: Massive to commonly foliated, leucocratic medium-grained feldspar-quartz rock without crude compositional layering (Ashley et al. 1996). Field relations demonstrate probable intrusive relations with surrounding gneisses. Bodies are extensive (hundreds of metres across) and lack distinct stratigraphic control. Minor disseminated biotite is characteristic and some locations contain disseminations and schlieren of magnetite. This gneiss is dominated by the assemblage albite+quartz, with subordinate to minor microcline. However, there are variations in the plagioclase to K-feldspar ratio and at Drew Hill the feldspars are in approximately equal proportions. The rocks are generally equigranular, but locally contain larger quartz grains up to 3–4 mm across. Scattered biotite flakes define the foliation, interpreted to represent S 1, and there is minor retrograde chlorite, martitised magnetite and accessory zircon (commonly attached to oxide grains). The precursor of this rock type has been interpreted as a granitoid. Breccias: None mentioned in literature. Alteration in the granite: It is likely that the plagioclase content has been enhanced by pre- or syn-metamorphic sodic alteration.

6.8 Extrusives In the ‘Lower Albite’ of the Quartzofeldspathic Suite there are local occurrences of rocks which are interpreted as metamorphosed felsic volcanics and volcaniclastics containing relict quartz phenocrysts. These have been dated at 1699 ± 10 Ma (Cook 1993), and are considered to be comagmatic with the Pretectonic A-type granitoids (Ashley et al. 1995).

6.9 Country Contact metamorphism: None mentioned in literature. Rock Reaction with country rock: None mentioned in literature. Units the granite intrudes: The granite is intrusive into the Quartzofeldspathic Suite. Dominant rock types: The Quartzofeldspathic Suite is dominated by massive to layered quartzofeldspathic rocks, most of which are typically albite-quartz, but there are gradations into types with appreciable, and even dominant K-feldspar. The Quartzofeldspathic Suite comprises the informally termed ‘Lower Albite’ unit of massive to thickly layered albite-quartz (± K-feldspar ± biotite ± muscovite ± magnetite ± pyrite) rocks, the ‘Upper Albite’ unit of commonly well laminated albite-quartz (± K-feldspar ± biotite ± magnetite ± calcsilicates) and the locally intervening ‘Middle Schist’ unit of psammopelitic and pelitic schist and composite gneiss. Minor rock types in the Quartzofeldspathic Suite include quartzite, distinctive quartz + Fe oxide ± barite iron formation and rare amphibolite and tourmalinite (Ashley et al. 1995). Potential hosts: The iron formations may be excellent hosts to mineralisation.

6.10 Mineralisation This suite is thought to have limited mineralisation potential, because of the narrow composition range and lack of extensive fractionation.

6.11 Geochemical Data source: All geochemical data were provided by P. Ashley (pers. comm. 1996), and is Data collected from several honours theses from the Universities of New England, Adelaide, and Melbourne, and also from North Mining. Data quality: The data is considered to be of good quality. Are the data representative? Probably. Are the data adequate? Possibly - although the units may not be mapped out completely.

SiO 2 range (Fig. 6.1): The suite is very felsic, ranging from ~70 wt% to ~79 wt% SiO 2 . Alteration (Fig. 6.2): Sodic alteration has occurred on a regional scale. This is likely to be related to an overprinting metamorphic event.

• SiO 2: It is probable that none of the samples are silica-altered. • K 2 O/Na 2O: There is a trend towards sodic alteration, which reflects a regional sodic overprinting. • Th/U: Many of the samples are anomalously high. • Fe2O3/(FeO+Fe 2 O 3 ): The few samples that plot are mostly oxidised.

Figure 6.1: His to gram of SiO2 val ues. Fractionation Plots (Fig. 6.3): The suite appears to be mildly fractionated, although it has been overprinted by subsequent metamorphism which obscures some of the evidence of fractionation. • Rb: Values range from moderately low to very low, and possibly decrease with increasing SiO 2. • U: Values are low to very low, and are scattered about a flat trend. • Y: Values range from moderate to extremely high (285 ppm), and possibly increase with increasing SiO 2 . • P 2 O 5 : Values range from moderately low to very low, decreasing with increasing SiO 2 . • Th: Values range from low to moderately high, with no clear trend. • K/Rb: Values range from very high to low, and possibly decrease with increasing SiO 2 . • Rb-Ba-Sr: The majority of samples plot in the granite field, however there is considerable scatter due to alteration. • Sr: Values range from low to very low, decreasing with increasing SiO 2 . • Rb/Sr: Values range from very low to moderately low, increasing exponentially with increasing SiO 2 . • Ba: Values range from moderately high to very low, possibly decreasing with increasing SiO 2. • F: No data available. Metals (Fig. 6.4): Generally range from moderate to very low.

• Cu: Values range from moderate to very low, decreasing with increasing SiO 2 . • Pb: Values range from moderate to very low, with no trend identifiable. • Zn: Values range from moderate to very low, mostly decreasing with increasing SiO 2 . • Sn: Only one sample plots; it is low. High field strength elements (Fig. 6.5): The HFSE reach high values, especially Y. • Zr: Values range from moderately low to moderately high, slightly increasing with increasing SiO 2 . • Nb: Values range from moderately low to high, increasing with increasing SiO 2 . • Ce: Values range from low to very high (519 ppm), possibly increasing with increasing SiO 2. Classification (Fig. 6.6): The suite is Sr-depleted, Y-undepleted, felsic, slightly fractionated, mostly oxidised and is an I-type.

• The CaO/Na 2O/K 2O plot of White, quoted in Sheraton and Simons (1992): The samples plot in the granite and trondhjemite fields, reflecting sodic overprinting. • Zr/Y vs Sr/Sr*: All samples are Sr-depleted, Y-undepleted. • Spidergram: The suite is Sr-depleted, Y-undepleted, and shows little fractionation. • Oxidation plot of Champion and Heinemann (1994): Few samples plot; those that do are mostly oxidised, with one strongly oxidised and one reduced.

© Geoscience Australia 2001 Gawler & Curnamona 6.3 OLARY PRETECTONIC A-TYPE SUITE • ASI: The samples are mostly weakly peraluminous (<1.1) to peraluminous, possibly with an increasing trend with increasing SiO 2. However, mafic samples are not available, so the trend is not clearly defined. Other element trends support this suite being an I-type, specifically the decreasing trend of P 2O 5 and the increasing trend of Th with increasing SiO 2. • A-type plot of Eby (1990): All samples plot well within the Palaeozoic A-type field. Granite type (Chappell and White 1974; Chappell and Stephens 1988): I-type (granodiorite). Australian Proterozoic granite type: Sybella type (?).

6.12 Geophysical Radiometrics (Fig. 6.7): Potassium plots well below the Proterozoic median, while U is Signature slightly above, and Th is well above. The predicted RGB colour for this suite ranges from black to green. Gravity: The available gravity data are too coarse to show any useful information. Magnetics: Rocks of this unit mostly have a high magnetic signature.

6.13 References Ashley, P.M., Cook, N.D.J., Lawrie, D.C., Lottermoser, B.G. and Plimer, I.R. 1995. Olary Block geology and field guide to 1995 excursion stops, Department of Mines and Energy, South Australia, Report Book 95/13. Ashley, P.M., Cook, N.D.J. and Fanning, C.M. 1996. Geochemistry and age of metamorphosed felsic igneous rocks with A-type affinities in the Willyama Supergroup, Olary Block, South Australia, and implications for mineral exploration, Lithos, 38, 167-184. Cook, N.D.J. 1993. Geology of metamorphosed Proterozoic playa lake deposits, Olary Block, South Australia. PhD thesis, University of New England (unpublished). Cook, N.D.J., Fanning, C.M. and Ashley, P.M. 1994. New geochronological results from the Willyama Supergroup, Olary Block, South Australia. In: Australian Research on Ore Genesis Symposium, Adelaide, Australian Mineral Foundation, 19.1-19.5. Laing, B. 1996. Stratigraphic subdivision of the Willyama Supergroup–Olary domain, South Australia, Mines and Energy South Australia Journal, 2, 39-48.

6.2A: Na2 O vs K2O

6.2B: Th/U vs SiO 2

6 .2C: Fe2 O 3 /(FeO+Fe 2 O 3 )

6.3A: Rb vs SiO2

6 .3B: U vs SiO 2

6 .3C: Y vs SiO 2

6.3D: P 2 O 5 vs SiO2

6 .3E: Th vs SiO2

6 .3F: K/Rb vs SiO 2

Strongly dif fer en ti ated gran ite

Anoma lous Granit e gran ite

Monzo gran ite To nal ite

6.3H: Sr vs SiO 2

6 .3I: Rb/Sr vs SiO 2

6.3J: Ba vs SiO2

NO FLUORINE DATA AVAILABLE

6 .4A: Cu vs SiO2

6.4B: Pb vs SiO2

6 .4C: Zn vs SiO2

6 .4D: Sn vs SiO2

6.5A: Zr vs SiO2

6 .5B: Nb vs SiO2

6 .5C: Ce vs SiO2

To nal ite

Grano dio rit e

Monzo gran it e

Trondh jemite Gran ite

6.6B: Zr/Y vs Sr/Sr*

6 .6C: Spidergra m SiO2 range: 74.1-74.8%

Strongly oxi dised

Oxi dised

Re duced

Strongly Reduced

6.6E: ASI vs SiO 2

6 .6F: Ga/Al vs HFSE (Eby 1990)

6.7A: K 2 O% Box-whiske r

Pro tero zoic media n

6.7B: Th ppm Box-whiske r

Pro tero zoic media n

6.7C: U ppm Box-whiske r

Pro tero zoic media n

Pretectonic A-type

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 75 .02 75.02 2 .24 69.74 79.18 28 TiO2 0.31 0 .33 0 .1 0 .18 0 .51 28 Al2O3 12 .42 12.49 0 .79 11.1 13.9 28 Fe2O3 2.63 2 .22 1 .14 0 .42 4 .84 28 FeO 0.95 1 .17 0 .32 0 .37 1 .2 7 MnO 0.02 0 .01 0 .01 0 .01 0 .06 24 MgO 0.72 0 .61 0 .38 0 .06 1 .72 28 CaO 0.39 0 .41 0 .23 0 .06 0 .77 28 Na2O 5.38 5 .66 1 .32 3 .08 7 .16 28 K2O 1.93 1 .56 1 .33 0 .24 3 .98 28 P2O5 0.07 0 .09 0 .06 0 .01 0 .24 27 LOI 0.84 0 .41 1 .36 .92 5 .98 22 Ba 500.79 325 521.81 15 1715 28 Rb 77.22 65 49.52 8 .13 216 28 Sr 54.88 57 32.34 11 130 28 Pb 18.6 22 12.87 3 50 26 Th 44.14 40.5 29.32 6 124 28 U 5.37 6 2 .24 1 9 19 Zr 434.93 418 85.99 326 640 28 Nb 56.94 49 19.05 34 93.1 28 Y 153.8 137.5 55.49 70 285 28 La 82 68 45 26 163 9 Ce 210.36 177.5 96.41 66 519 28 Pr 30 30 4.24 27 33 2 Nd 108.92 96 50.25 36.99 286 28 Sc 7.42 8 3 .07 1 .2 12 27 V 12.11 11 8.97 0 .3 35 28 Cr 13.7 7 24.41 1 130 27 Co 35.03 27 20.38 2 86.8 27 Ni 27.52 8 35.25 1 104 25 Cu 14.24 9 15.99 1 60 25 Zn 16.46 9 .5 19.4 2 93 28 Sn 5 5 - 5 5 1 W 1.7 1 .7 1 .84 0 .4 3 2 Mo 2.2 2 1 1 4 20 Ga 24.9 24 4.04 20 35 28 As 4.75 3 4 .31 1 16 12 Hf 11.5 11.5 2 .12 10 13 2 Ta 5.5 5 .5 0 .71 5 6 2

7.1 Timing 1630 - 1620 Ma

7.2 Individual Primary Ages: Ages 1. Gra no dio rite at Point Brown [1] 1620 ± 4 Ma, U-Pb 2. Gra no dio rite at Point Brown [1] 1619 ± 15 Ma, U-Pb 3. Nuyts Vol can ics [2] 1631 ± 3 Ma, U-Pb 4. Nuyts Vol can ics [3] 1627 ± 2 Ma, U-Pb Sources: [1] Flint et al. 1990; [2] Cooper et al. 1985; [3] Rankin et al. 1990.

7.3 Regional The St Peter Suite consists of mafic to felsic volcanics and intrusives in the Nuyts Setting Archipelago and Streaky Bay region. It was initially regarded by Flint et al. (1990) as a part of the Lincoln Complex, but is now considered to be emplaced shortly after the end of the Kararan orogeny ~1650 Ma (Daly et al. 1998). The St Peter Suite is a complex of comagmatic intrusive and extrusive rocktypes, regarded by Flint et al. (1990) as being typical products of mingling and mixing of comagmatic mafic and felsic magmas.

7.4 Summary The St Peter Suite granitoids represent a broad range in compositions, from diorite to granite. These granites show signs of weak fractionation at the most felsic compositions. The Nuyts Volcanics are considered to be comagmatic with the granitoids because of their geochemical similarities, and are even more felsic, and strongly fractionated. The Suite as a whole is I-type, oxidised, and Sr-depleted, Y- undepleted.

7.5 Potential No mineralisation is known to be associated with these granites. Although this suite shows some fractionation, it is not as enriched as the Hiltaba Suite, and is more felsic, sodic, and less enriched than the Cullen Batholith. It is very similar to the Nicholson suite in the Mount Isa Inlier, and so is considered to have moderate potential for gold, copper and tin. However, the mineralisation potential of the suite is difficult to determine, due to insufficient geochemical data to fully characterise the suite, and the lithology of the host rocks is not well known. Cu: Unknow n Au: Unknow n Pb/Zn: Unknow n Sn: Unknow n Mo/W: Unknow n Confi dence level: 220

7.6 Descriptive Location: The St Peter Suite occurs in the Streaky Bay–Ceduna–Nuyts Archipelago region, to Data the west of the Eyre Peninsula. The distribution of the suite in the subsurface on the Streaky Bay 1:250 000 sheet area is extensive (Rankin and Flint 1989). Dimensions and area: The St Peter Suite has a mapped outcrop area of approximately 75 km 2 .

7.7 Intrusives Component plutons: St Francis Granite and unnamed granites (sensu lato ) on Lacy, Evans, St Peter, Purdie, Lounds and Goat Islands, and Point Brown, Smooth Pool, Point Westall, Wittelbee Point, Thevenard, Rocky Point and other outcrops on coast west of Ceduna. Form: Exposed in coastal outcrops and islands.

© Geoscience Australia 2001 Gawler & Curnamona 7.1 ST PETER SUITE Metamorphism and Deformation: Granitoids in the Streaky Bay region are deformed, containing a biotite foliation, and localised mylonite zones. There is no record of metamorphism in the literature. Dominant intrusive rock types: The St Peter Suite consists of a complex of comagmatic intrusive rock types, including granite, monzogranite, granodiorite, porphyritic monzogranite, dolerite, diorite and amphibolite. Colour: Pale grey, to pink to red. Veins, Pegmatites, Aplites, Greisens: None mentioned in literature. Distinctive mineralogical characteristics: Five main phases are evident, although their composition and texture greatly vary within isolated exposures and from one exposure to the next. 1) Pink, fine to medium-grained granite and monzogranite grading to a medium to coarse- grained pink to red granite. Pink to red microcline (<20 mm) is conspicuous. The rock is composed of granoblastic to elongate quartz (25-35%), microcline (25-40%), plagioclase (10- 30%), biotite (5-10%), muscovite, hornblende and minor zircon, epidote, garnet and opaques. 2) Fine to medium even-grained monzogranite to granodiorite, commonly as dykes. Varieties contain up to 10% hornblende, enclaves of dolerite/diorite are common, and magmatic banding is conspicuous along the margins of some dykes. It is composed of granoblastic plagioclase (50-60%), quartz (15-20%), aligned biotite (5-20%), microcline (2-15%) and minor hornblende, titanite, zircon, epidote and opaques. 3) Medium-grained, porphyritic monzogranite to granodiorite with abundant orthoclase and plagioclase phenocrysts. Enclaves of dolerite/diorite are common. 4) Dolerite, diorite and amphibolite are fine to medium-grained and chiefly consist of pyroxene, hornblende and plagioclase. Lamprophyre dykes which contain euhedral hornblende crystals (<15 mm) are present. Generally, these rocks are composed of plagioclase (25-60%), hornblende (5-60%), biotite (5-15%), clinopyroxene (<20%), orthopyroxene (<10%), quartz, titanite, epidote, opaques and garnet. The texture is ophitic to granoblastic, with pyroxene partially to wholly replaced by poikilitic hornblende. 5) A pink medium-grained porphyritic granite containing conspicuous pale pink microcline phenocrysts up to 15 mm. The St Francis Granite is a pale grey to pink, massive, medium even-grained to locally porphyritic leucogranite with quartz and K-feldspar phenocrysts. It contains quartz (30-40%), microcline to perthitic K-feldspar (55-70%) and minor (<2% total) augite, hornblende, biotite and magnetite. It is characterised by graphic intergrowths of quartz and K-feldspar. Breccias: None mentioned in literature. Alteration in the granite: None mentioned in literature.

7.8 Extrusives The Nuyts Volcanics are geochemically very similar to, and are the same age as the St Peter Suite granites and the St Francis Granite, and are probably comagmatic with these granitoids. The Nuyts Volcanics consist predominantly of dark grey and pinkish porphyritic rhyodacite to rhyolite. Phenocrysts up to 5 mm of quartz and feldspar are abundant (10-30%) in a siliceous aphanitic groundmass. Xenoliths are common and include porphyritic and flow-banded rhyolite. Volcanic banding is poorly developed. Three suites of rhyodacite-rhyolite dykes are common. Unusual megacrystic rhyodacite dykes are up to 12 m wide and have very thin chilled margins <50 mm wide. The dykes contain abundant (<50%) feldspar phenocrysts up to 15 mm in an aphanitic groundmass. Dark grey to black rhyodacite dykes are 2-3 m wide and contain abundant, aligned euhedral feldspar phenocrysts (<5 mm). Dykes of the third suite are grey to pinkish rhyolite with distinctive flow- banded margins up to 0.4 m wide. Feldspar and quartz phenocrysts are common but confined to the centers of dykes. On St Francis Island, a grey early granite is intruded by numerous dykes of megacrystic rhyodacite, porphyritic rhyodacite, flow-banded porphyritic rhyolite and dolerite. Rhyodacite, rhyolite and dolerite dykes also intrude the main mass of volcanics. On St Peter Island, younger felsic volcanic dykes are absent, but there are intrusive plugs and dykes of dolerite. A later

7.9 Country Contact metamorphism: None mentioned in literature. Rock Reaction with country rock: None mentioned in literature. Units the granite intrudes: Contacts with basement units are rarely exposed. In the Point Westall–Smooth Pool and Wittelbee areas, granitoid rocks of the St Peter Suite intrude gneissic granite interpreted to be an older intrusive of the Lincoln Complex. Dominant rock types: Unknown. Potential hosts: Unknown.

7.10 Mineralisation None known in the area.

7.11 Geochemical Data source: Data are sourced from the Department of Mines and Energy, South Australia, and Data has been published on CD-ROM. Data quality: The data is considered to be of good quality. Are the data representative? Probably. Are the data adequate? No. Some elements have not been determined in some samples, including FeO vs Fe2 O 3 , and Ga has not been determined at all.

Fig ure 7.1: His to gram of SiO2 val ues.

SiO 2 range (Fig. 7.1): Ranges from about 52% to 79%. Alteration (Fig. 7.2): No obvious alteration is present.

• SiO 2: Some very felsic samples of the St Peter granites may be silicically altered, however, there is no mention of this in the literature. • K 2O/Na2O: Some samples of the St Peter granites are sodic-altered, and some of the St Francis Granite, St Peter granite and Nuyts Volcanics are possibly slightly potassic- altered. • Th/U: Not all of the samples have been analysed, but those that have are mostly normal. Some are lower than normal, while very few are above normal. • Fe2O3/(FeO+Fe2 O 3 ): Samples of the St Peter suite are oxidised, and become more so with increasing SiO 2. Most other samples do not plot properly because only total iron was determined. Fractionation Plots (Fig. 7.3): The suite is restite-dominated until it becomes fractionated at >75 wt% SiO 2, particularly the Nuyts Volcanics.

• Rb: Values range from low to moderate, increasing with increasing SiO 2 . • U: All values are low. • Y: Values range from low to high, increasing with increasing SiO 2, although there is considerable scatter. • P 2O 5: Values range from moderate to very low, decreasing with increasing SiO 2 . • Th: Values range from low to moderately low, increasing slightly with increasing SiO 2 . • K/Rb: Values range from low to high, but show a lot of scatter with possibly a very slightly decreasing trend with increasing SiO 2. • Rb-Ba-Sr: Samples plot in the strongly differentiated granite, granite, monzogranite and anomalous granite fields. • Sr: Values range from very high to low, decreasing steeply with increasing SiO 2 . • Rb/Sr: Values range from very low to very high, increasing exponentially (especially the Nuyts Volcanics) with increasing SiO 2. • Ba: Values range from moderately high to very low, decreasing with increasing SiO 2 . • F: No data available. Metals (Fig. 7.4): Values range from low to high, and most show trends with differentiation. • Cu: Values range from low to very high, with a great deal of scatter. • Pb: Values range from low to moderately high, increasing (exponentially) with increasing SiO 2, although there is some scatter. • Zn: Values range from very high to low, decreasing with increasing SiO 2 , although there is some scatter. • Sn: Values range from low to moderate, and increase with increasing SiO 2 . High field strength elements (Fig. 7.5): Most values are low to moderate. • Zr: Values range from low to moderately high, increasing exponentially with increasing SiO 2. • Nb: Values range from low to moderately low, increasing slightly with increasing SiO 2 . • Ce: Values range from moderate to very low, increasing then decreasing with increasing SiO 2.

Classification (Fig. 7.6): I-type, oxidised, restite-dominated until fractionated at higher SiO2 , Sr-depleted, Y-undepleted, felsic.

• The CaO/Na2O/K 2O plot of White, quoted in Sheraton and Simons (1992): Most samples plot in the granite field, with some samples plotting in the granodiorite field. A few samples plot in the monzogranite, tonalite and trondhjemite fields. Overall, the suite is a little more sodic than normal Proterozoic granites. • Zr/Y vs Sr/Sr*: The Nuyts Volcanics are mostly Sr-depleted, Y-undepleted, with some scatter. Other units do not plot. • Spidergram: The suite is Sr-depleted, Y-undepleted. • Oxidation plot of Champion and Heinemann (1994): The samples that do plot on this graph are oxidised to strongly oxidised, increasing with fractionation. Many samples don’t plot, or plot with Fe2O 3/FeO = 1 because only total iron was analysed. • ASI: The majority of samples have ASI <1.1. • A-type plot of Eby (1990): Insufficient data. Granite type (Chappell and White 1974; Chappell and Stephens 1988): I- (granodiorite) type. Australian Proterozoic granite type: Hiltaba type.

7.12 Geophysical Radiometrics (Fig. 7.7): All units have K higher than the Proterozoic median, lower Th, and Signature median uranium. Therefore, the predicted RGB colour for the entire suite is darkish red. Gravity: The St Peter Suite shows a moderately low gravity signature. Magnetics: The St Peter Suite mostly shows a moderate to moderately high magnetic signature. West of Cednua, PIRSA aeromagnetics show a discrete batholith which was later fractured.

7.13 References Cooper, J.A., Mortimer, G.E., Rosier, C.M. and Uppill, R.K. 1985. Gawler Range magmatism - further isotopic age data. Australian Journal of Earth Sciences, 32, 115-123.

© Geoscience Australia 2001 Gawler & Curnamona 7.4 ST PETER SUITE Daly, S.J., Fanning, C.M. and Fairclough, M.C. 1998. Tectonic evolution and exploration potential of the Gawler Craton, South Australia, Australian Geological Survey Organisation, Journal of Australian Geology and Geophysics, 17/3, 145-168. Flint, R.B., Rankin, L.R. and Fanning, C.M. 1990. Definition of the Palaeoproterozoic St Peter Suite of the western Gawler Craton. South Australia Geological Survey, Quarterly Geological Notes, 114, 2-8. Parker, A.J., Daly, S.J., Flint, D.J., Flint, R.B., Preiss, W.V. and Teale, G.S. 1993. Palaeoproterozoic. In: Drexel, J.F., Preiss, W.V. and Parker, A.J., (editors). The geology of South Australia, Volume 1, The Precambrian. South Australia Geological Survey, Bulletin 54, 51-106. Rankin, L.R. and Flint, R.B. 1989. Geology of St Peter and Goat Islands (Nuyts Archipelago) and Cape Beaufort. South Australia Department of Mines and Energy, Report Book, 89/84. Rankin, L.R., Flint, R.B. and Fanning, C.M. 1990. Palaeoproterozoic Nuyts Volcanics of the western Gawler Craton. South Australia Department of Mines and Energy, Report Book, 90/60.

7.2A: Na2 O vs K2O

7.2B: Th/U vs SiO2

7 .2C: Fe2 O 3 /(FeO+Fe 2 O 3 )

7.3A: Rb vs SiO2

7 .3B: U vs SiO 2

7 .3C: Y vs SiO 2

7.3D: P2 O 5 vs SiO2

7 .3E: Th vs SiO2

7 .3F: K/Rb vs SiO2

Strongly dif fer en ti ated gran ite

Anoma lous Granit e gran ite

Monzo gran ite To nal ite

7.3H: Sr vs SiO 2

7 .3I: Rb/Sr vs SiO 2

7.3J: Ba vs SiO2

NO FLUORINE DATA AVAILABLE

7 .4A: Cu vs SiO2

7.4B: Pb vs SiO2

7 .4C: Zn vs SiO2

7 .4D: Sn vs SiO2

7.5A: Zr vs SiO2

7 .5B: Nb vs SiO2

7 .5C: Ce vs SiO2

To nal ite

Grano dio rit e

Monzo gran it e

Trondh jemite Gran ite

7.6B: Zr/Y vs Sr/Sr*

7 .6C: Spidergra m SiO2 range: 75.2-77.5%

Strongly oxi dised

Oxi dised

Re duced

Strongly Reduce d

7.6E: ASI vs SiO 2

NO GALLIUM DATA AVAILABLE FOR 1000*Ga/Al vs Zr+Ce+Nd+Y PLOT

7.7A: K2 O% Box- whisker

Pro tero zoic media n

7.7B: Th ppm Box- whisker

Pro tero zoic media n

7.7C: U ppm Box- whisker

Pro tero zoic media n

St Peter granites

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 64 .29 65.9 10.19 47.8 78.1 15 TiO2 0.73 0 .56 0 .75 0 .13 3 .04 15 Al2O3 14 .51 14.8 1 .53 11.1 16.5 15 Fe2O3 5.37 3 .78 4 .82 0 .93 16.1 15 FeO 2.69 1 .46 2 .81 0 .18 9 .6 15 MnO 0.12 0 .11 0 .07 0 .05 0 .27 15 MgO 2.16 0 .67 2 .3 0 .09 6 .55 15 CaO 3.39 1 .75 2 .8 0 .3 7 .9 15 Na2O 3.66 3 .92 1 .09 0 .68 5 15 K2O 3.22 3 .44 1 .38 1 .12 5 .5 15 P2O5 0.19 0 .13 0 .17 02 0.64 15 H2O+ ------LOI 1.37 1 .16 0 .67 0 .65 3 .2 15 Ba 866 860 488.7 140 1600 15 Li ------Rb 205.67 150 144.25 48 620 15 Sr 350.33 380 262.53 20 860 15 Pb 6 2.8 15 15 Th 12.27 10 8.84 34 15 U 4.13 4 2 .56 10 15 Zr 180.2 140 89.43 66 330 15 Nb 13.13 11 7.32 5 32 15 Y 28.8 24 18.37 8 70 15 La 36.67 40 20.93 80 15 Ce 67.33 70 34.53 140 15 Nd ------Sc ------V 83.17 35 100.85 320 15 Cr 42.83 5 89.64 350 15 Co ------Ni 26.17 33.58 95 15 Cu 21.67 5 31.33 110 15 Zn 88.33 75 57.68 20 230 15 Sn 3.33 2 .79 12 15 W ------Mo ------As 4.17 3 .09 10 15 Ag 1.03 1 0 .44 2 15 Bi 2.93 1 .83 8 15

St Francis Granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 77 .28 77.16 1 .22 75.3 79.6 18 TiO2 0.16 0 .15 0 .04 0 .1 0 .22 18 Al2O3 11 .79 12.2 0 .76 10.6 12.6 18 Fe2O3 1.15 1 .23 0 .5 0 .21 1 .74 18 FeO 0.93 0 .98 0 .57 0 .19 1 .74 8 MnO 0.05 0 .05 0 .03 0 .01 0 .12 17 MgO 0.1 0 .1 0 .04 0 .04 0 .18 18 CaO 0.19 0 .18 0 .13 0 .05 0 .45 18 Na2O 4.04 4 .02 0 .47 2 .74 4 .76 18 K2O 4.58 4 .5 0 .47 3 .88 5 .45 18 P2O5 0.02 0 .02 0 .01 01 0.04 18 H2O+ 0.32 0 .34 0 .07 0 .19 0 .41 10 LOI 0.29 0 .28 0 .1 0 .19 0 .41 4 Ba 150.47 150 116.47 40 380 17 Li ------Rb 257.33 252 17.62 243 277 3 Sr 26 20 19.04 70 17 Pb 41.07 38 21.37 11 80 14 Th 15 7.07 25 14 U 5 - 14 Zr 294.12 290 165.41 110 610 17 Nb 14.88 14 5.85 4 24 17 Y 27.65 30 9.46 10 40 17 La 44.64 50 21.35 70 14 Ce 63.65 55 23.72 30 100 17 Nd 22 21 7.55 15 30 3 Sc ------V 33.18 40 14.7 3 50 17 Cr 23.47 20 8.63 40 15 Co 120 120 12.47 100 140 10 Ni 19.06 20 9.9 30 17 Cu 326.07 45 624.4 2300 14 Zn 92.14 85 44.75 30 180 14 Sn 52.86 60 12.51 2 60 14 W 897.5 935 130.22 720 1000 4 Mo 5 - 10 As 42.14 50 10.51 20 50 14 Ag ------Bi 5 - 4

Lacy Island granite

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 77 .7 77 .7 0 .28 77.5 77.9 2 TiO2 0.16 0 .16 0 .01 0 .15 0 .17 2 Al2O3 12 .25 12.25 0 .07 12.2 12.3 2 Fe2O3 0.61 0 .61 0 .01 0 .6 0 .62 2 FeO ------MnO 0.01 0 .01 0 .01 0 .01 0 .02 2 MgO 0.11 0 .11 0 .02 0 .09 0 .12 2 CaO 0.2 0 .2 0 .01 0 .2 0 .21 2 Na2O 3.53 3 .53 0 .07 3 .48 3 .58 2 K2O 4.93 4 .93 0 .1 4 .86 5 2 P2O5 0.02 0 .02 - 0 .02 0 .02 2 H2O+ 0.61 0 .61 0 .02 0 .59 0 .62 2 LOI ------Ba 310 310 42.43 280 340 2 Li ------Rb ------Sr 47.5 47.5 3 .54 45 50 2 Pb 39 39 18.38 26 52 2 Th 15 15 7.07 20 2 U 5 - 2 Zr 110 110 7.07 105 115 2 Nb 14 14 2.83 12 16 2 Y 7.5 7 .5 3 .54 10 2 La 50 50 - 50 50 2 Ce 60 60 21.21 45 75 2 Nd ------Sc ------V 45 45 7.07 40 50 2 Cr 25 25 7.07 20 30 2 Co 145 145 7.07 140 150 2 Ni 25 25 7.07 20 30 2 Cu 5 - 2 Zn 25 25 21.21 10 40 2 Sn 60 60 - 60 60 2 W ------Mo 5 - 2 As 40 40 - 40 40 2 Ag ------Bi ------

Nuyts Volcanics

MEANS AND STANDARD DEVIATIONS

Element Mean Median Standard Minimum Maximum Number of Deviation Items SiO2 74 .02 77.08 5 .96 47.74 78.99 75 TiO2 0.26 0 .17 0 .18 0 .05 1 .31 75 Al2O3 12 .45 12.1 2 .66 0 .29 16.69 75 Fe2O3 1.48 1 .25 1 .22 0 .08 9 .89 73 FeO 2.87 0 .72 7 .68 0 .16 29.67 27 MnO 0.09 0 .08 0 .11 0 .01 0 .86 72 MgO 0.42 0 .16 0 .96 0 .03 8 .17 74 CaO 0.78 0 .26 1 .22 0 .01 8 .44 75 Na2O 4.26 4 .13 1 .59 2 .07 13.33 75 K2O 4.49 4 .48 0 .64 2 .22 6 .31 73 P2O5 0.05 0 .02 0 .05 02 0.19 72 H2O+ 0.49 0 .3 0 .4 0 .14 2 .69 64 LOI 1.17 1 .08 0 .43 0 .75 1 .77 4 Ba 589.36 142 677.37 2 1805 73 Li 186 186 - 186 186 1 Rb 196.01 197 45.96 85 320 67 Sr 123.46 27.5 164.18 2 648 72 Pb 34.21 30.5 24.5 2 70 14 Th 16.36 15 8.3 34 14 U 5.36 2 .34 10 14 Zr 324.79 255 161.9 51 680 73 Nb 14.67 14 5.31 2 26 73 Y 36.29 32 17.67 105 73 La 67.14 57.5 57.27 210 14 Ce 72.6 65 50.34 5 260 73 Nd 25.02 20 19.9 1 104 59 Sc 6.87 6 3 .82 2 30 55 V 18.45 9 27.11 216 73 Cr 7.89 10.33 40 35 Co 80.1 80 28.09 31 120 10 Ni 10.89 7 18.3 151 71 Cu 115.89 10 180.7 590 14 Zn 50.64 45 27.45 10 100 14 Sn 18 18.12 2 60 10 W ------Mo 7 2.58 5 10 As 10.35 10 8.73 30 10 Ag 0.63 0 .25 1 4 Bi 4 4 1.63 6 4