Development of the

Development of the 1:250 000 scale Broken Hill Special Metallogenic map, concepts and methodology

By

Peter M. Downes and Joel A. Fitzherbert MinSys NSW group

December 2014

GS2015/0001

1

ABSTRACT A new metallogenic map has been prepared at 1:250 000 scale for the Broken Hill Domain. The map covers parts of two 1:250 000 map sheets areas between Latitude −31o 10′ to −32o20′ and Longitude 141o00′ to 141 o55′. This first edition map includes several key components. These are: (1) only those deposits with past production and/or identified resources as at July 2014 have been given a relative size (small, medium, large, or very large — based on January 2009 commodity prices) and included as a classified deposit on the map face/table of deposits; (2) metallic and metallic-related industrial deposits are classified according to the NSW mineral system classification schema, industrial and construction material sites are grouped by commodity type. The symbol for each deposit indicates the deposit type, its relative value and the generalised commodities present while the accompanying number corresponds to a deposit in the “Table of Deposits” which gives the name of the deposit and an ordered list (major (minor)) of commodities present; (3) selected sites where mineralisation is present but for which there is no size (i.e. occurrences) are shown with a generalised commodity-only symbol. A feature of the map is the inclusion of two 1:500 000 scale metamorphic facies/isograd maps showing the distribution of metamorphic facies and related mineral deposits for both the Olarian and Delamerian orogenies. The map used a composite geological dataset that included the updated 1:100 000 Broken Hill Stratigraphic map combined with data for the Neoproterozoic to Cambrian units and basement interpretation from the interpretive Proterozoic geology data package. PostDelamerian cover sequences including unconsolidated Cainozoic sedimentary units are shown as semi-transparent layers over the Cambrian–Proterozoic basement. This map will add a new dimension to the existing MetIndEx database by providing a systematic classification for important deposits within the Broken Hill terrain. In addition, this project has identified areas of further work where systematic collection of data relating to the distribution of metamorphic facies, the timing of mineralisation and ore forming processes is warranted.

2

INTRODUCTION The Mineral Systems (MinSys NSW) team has prepared a Broken Hill 1:250 000 Special Metallogenic map (Fitzherbert et al. in prep) which is presented and described here. The map covers parts of the Broken Hill and Menindee 1:250 000 scale map sheet areas between latitude −31o 10′ to −32o20′ and longitude 141o00′ to 141 o55′. This map is designed to be used by mineral explorers and help in land-use decision making. In addition, the reverse side of the map includes a brief description of the geological history of the area, its mining history and its unique mineral diversity — making it of interest to a wider audience. The map uses the mineral occurrence/deposit data that has been captured as part of the metallogenic mapping and related projects since the late 1960s. The aim of the project was to:  Update the 1st edition 1:100 000 Broken Hill Stratigraphic map compiled by Willis (1989). That map is now out of print (Figure 1);  Develop a clear understanding of the regional pressure–temperature distribution within the complex, low to high- grade metamorphic terrane associated with the Broken Hill Domain and how it relates to the distribution of mineralisation within the map sheet area.  Review and classify individual mineral deposits within the map sheet area by deposit type according to the NSW mineral system classification schema of Downes et al (2011);  Update the size of metallic and industrial deposits using values based on January 2009 commodity prices (Table 1);  Identify the timing of mineralisation for the major mineral deposit types;  Show the distribution of individual occurrences using a commodity-only symbol — thus highlighting important clusters of sites where metal anomalism has been identified; and,  Add value to the MetIndEx (metallic, industrial and exploration) mineral occurrence database.

Mineral deposits naturally occur in clusters or districts, reflecting a common age and origin. The focus of the Broken Hill 1:250 000 Special Metallogenic map is to show the distribution of deposits where there is recorded past production and/or identified resources and to classify these deposits by deposit type, size and commodity.

The Broken Hill 1:250 000 Special Metallogenic map supersedes the 1:100 000 Broken Hill Stratigraphic map compiled by Willis (1989). That map classified mineral deposits using the schema proposed by Barnes (1988) and focussed on the Palaeoproterozoic units within the map sheet area. In addition, there are four 1:50 000 scale metallogenic maps covering the Broken Hill and Euriowie blocks (Barnes 1989, Bartholomaeus et al 1995, Burton 1999, Raphael & Barnes 1999). That map sheet series again classified deposits using the deposit classification schema of Barnes (1988), used

3

The First Edition of the 1:100 000 scale Broken Hill Stratigraphic map (Willis 1989).

4

commodity prices current in 1967 and focussed on the lithology of the Palaeoproterozoic outcrop — rather than stratigraphic relationships and also largely ignored younger units.

This project is part of the ongoing study into the mineral systems and processes for New South Wales with an outline of that study summarised in Lewis and Downes (2008).

BROKEN HILL 1:250 000 SPECIAL METALLOGENIC MAP Key elements important to the development of the Broken Hill 1:250 000 Special metallogenic map include selection and classification of hard rock deposits and occurrences by deposit type, relative size and commodity, development of an understanding of the metamorphic history and relating deposit types to that history; updating and simplification of the base geology for the map sheet area, revising the time–space plot and the development of a comprehensive legend providing a revised stratigraphic framework for the area. Each of these elements is discussed below.

Mineral deposit dataset All metallic, industrial and construction material sites for the Broken Hill project area were selected from the Geological Survey of New South Wales’ MetIndEx (metallics, industrial minerals and exploration discoveries) database. MetIndEx includes over 30 000 sites (~17 000 related to metallic minerals) and represents a history of systematic data gathering that commenced in the late 1960s (Bowman & Stevens 1976).

Prior to extracting the data for the Broken Hill metallogenic project in July 2014 the MetIndEx database for Broken Hill was updated with production and other selected data from Dickinson (1972) and Lishmund (1982) — as there are significant gaps in the completeness of the database for the Broken Hill–Euriowie area.

There are over 3834 sites in MetIndEx within the Broken Hill project area. Each site was evaluate for inclusion in the metallogenic map with an initial 1720 sites — including those where no commodity was known and those relating to clay, gem and unprocessed construction materials (e.g. road base borrow pits) being discarded from the initial dataset for the metallogenic study. Furthermore, in developing the final map it became apparent that the number of sites (~2110) to be shown on the map face needed to be reduced as the data density was obscuring important details of the regional geology. Thus sites where there was no size (i.e. occurrences only) and no observed minerals of economic interest recorded in the database were removed from the final dataset for the map face. The final dataset for display on the map face and in the “Table of Deposits” included 239 metallic, industrial and selected hard-rock construction material deposits — those with either recorded production and/or identified resources (based on contained commodity — see below). In addition, there are a further 5

1110 sites where minerals of economic interest have been identified are also shown on the map face as a coloured point — with the colour indicating the dominant commodity present. Selected sites from the combined final dataset (1349 sites) were then assigned to either the Olarian or Delamerian orogenies as appropriate for display in one of the two 1:500 000 metamorphic facies/isograd (insert) maps relating metamorphic grade to the distribution of mineralisation present.

Hard rock metallic and industrial mineral deposits shown on the map generally relate to the Paleoproterozoic Willyama Supergroup, the Olarian Orogeny, the Neoproterozoic Adelaide Rift Complex or the subsequent Delamerian Orogeny. The Geological History on the reverse side of the map (Fitzherbert & Downes 2014) summarises the relationship between the stratigraphy and deformational history of the area and mineralising styles and events.

Commodity (metal) endowment The commodity (metal) endowment of a deposit is considered to be the value of past production and value of known resources for that deposit (as at July 2014). Individual deposits were classified by size with deposits having a contained commodity $values greater than $1000 M (based on average commodity prices from January 2009 — Table 1) being classified as very large in size, those with a contained commodity $value between $1000 M and $100 M were classified as large, those with a contained commodity $value between $100 M and $10 M were classified as medium whilst those with a contained commodity $value between $10 M and $10 000 were classified as small. This served both as a reality check as to the importance of many of the smaller workings; excluded many “favourite” occurrences where an economic value had yet to be demonstrated; and de-clutter the final map face. In total 239 deposits are identified on the map face and in the “Table of Deposits”.

The deposits selected for inclusion of the map face/“Table of Deposits” includes: • 180 hard-rock precious, base metal, ferrous and minor/rare metalliferous deposits (e.g. copper, lead, zinc, silver, tin etc); • 40 pegmatite-related deposits that have been important sources of non-metallic-related industrial minerals (e.g. feldspar, fluorite, muscovite); • 15 industrial mineral deposits related to sedimentary processes (e.g. limestone etc) or to non-melt related metamorphic processes (asbestos, garnet, sillimanite etc); • 4 major and/or important sources of hard rock construction materials (i.e. hard rock aggregate).

Deposits shown on the map face/“Table of Deposits” are numbered from top left to bottom right in four bands of approximately 15 to 20 minutes of latitude (−31o 10oo to −31o30oo; −31o30oo to −31o45oo;

6

−31o45oo to −32o00oo; and, −32o00oo to −32o20oo). This change to the band widths for the northern-most and southern-most bands was required to accommodate the extent of the Palaeoproterozoic outcrop.

Table 1

Comparison of commodity (metal) prices used to size symbols for the 1st edition

Broken Hill 1:250 000 metallogenic map (1967 commodity prices — Bowman & Stevens 1976) vs commodity prices used for the 2nd edition Broken Hill 1:250 000 metallogenic map (January 2011).

Commodity

Ag

First edition

Second edition

Commodity prices 1967

Commodity prices January 2009 a

(tonnes of metal)

(tonnes of metal)

46 600

369000

As Au

2200 1 000 000

42 700 000

barite

46.5

Co

3000

6600

Cr

444

1400

Cu

984

4890

Fe

5.90

76

Mo

3300

37 000

Ni

1570

17 600

Pb

235

1765

Pd

7 000 000

Pt

35 000 000

Sb

797

6800

Sn

3000

17 700

W

4410

40 000

Zn

272

1850

Note — a = exchange rate Aus$1 = US$0.65

7

Deposit classification Individual deposits selected to be shown on the map face/table of deposits were classified using version 4 of the NSW Mineral System classification schema (Downes et al 2011 — updated from Downes et al 2008). Mineral deposits naturally occur in clusters or districts, reflecting a common age and origin. The classification of individual deposits within the Broken Hill map sheet area commenced with a detailed review of the principal deposits and districts — with deposit-types being assigned and/or reviewed by the expert panel (Peter Downes, Phil Blevin, Joel Fitzherbert and David Forster). This project build upon the data used previously in the 1:50 000 metallogenic mapping series (Barnes 1989, Bartholomaeus et al 1995, Burton 1999, Raphael & Barnes 1999) and the deposit classification schema of Barnes (1988).

Specific information considered as part of the review process included: •

constraints as to the timing of mineralisation — including age dating, Pb-isotope lead model ages and geological/structural relationships;

•

nature of the ore forming fluids — temperature, oxidised/reduced, acidic/near-neutral etc (evidenced from ore mineralogy, alteration assemblage, fluid inclusion data, geothermometry etc);

•

potential heat sources;

•

potential sources of metals and/or fluids (evidence from metamorphic facies/isograds, Pb- and Sisotope data, etc);

•

potential precipitation mechanism(s) — cooling, boiling, fluid mixing, pH change etc; and,

•

extent, characteristics and intensity of zonation.

Zonation (or its absence) at all scales and attribute-types (alteration, mineralogy, geochemistry, metal zonation, isotopic zonation, etc) is considered to be a key attribute for understanding how individual deposits/systems form and help to constrain the permissible deposit model(s).

In some cases only limited data was available to help constrain the deposit classification (e.g. Mount Robe — where little work has been done in recent years). In these cases the map authors relied on their understanding on how metals are transported in fluids/melts and the presence/absence of specific features common to certain classes of deposit-types.

A simplified version of the version 4 of the NSW Mineral System classification schema (Downes et al 2011) is shown included on the left hand side of the published map. Adjacent to the schema are the symbols used to indicate the deposit type. In some cases the symbol includes a range of processrelated deposit types that have been identified within the map sheet area. For the Broken Hill area, version 4 of the NSW Mineral System classification schema has proved to be remarkably robust, given

8

that it was not designed to cover all deposit variations within a high grade metamorphic terrain. The only additional term required for the Broken Hill 1:250 000 Special Metallogenic map was the inclusion of “feldspar-rich pegmatites” within the Felsic association to cover the presence of metalpoor and feldspar-rich pegmatites in the core areas of the Broken Hill terrain.

Base geology There have been significant changes to the understanding of the geology of the Broken Hill area since the 1:100 000 scale stratigraphic map of Willis et al (1989). Work by Page et al (2005), Stevens (2008) validated the original stratigraphic interpretation of Willis et al (1983) and Stevens (1983), but also led to the reinterpretation of a number of felsic gneiss previously considered stratigraphic units (e.g. Alma and Rasp Ridge granite gneisses, as well as several other granitic gneisses; Silver City Suite of Stevens (2008)) as shallow, sill-like granite bodies that intruded at the base of the Thackaringa Group, and at various levels between the base of the Broken Hill Group to the lowermost Sundown Group. Stevens (1998) also interpreted basic gneisses throughout the sequence as sub sea-floor sills and dykes and Stevens (2006, 2008) suggested they should not be used to define stratigraphic units (i.e. Silver King Formation became Silver King Metadolerites and the Parnell Metadolerites were separated from the Parnell Formation). Stevens and Corbet (1993) formally defined a number of units in the Redan Sub-Block, and the Rantyga Group exposed in this sub-block was named by Stevens (2006), with the upper most Farmcote Gneiss of the Group formally named in Stevens (2008). Age dating of Page et al (2005) and Stevens (2008) suggests the Farmcote Gneiss is a time correlative of the lowermost Thackaringa Group, while the lower most Redan Gneiss of the Rantyga Group is correlated with units if the Olary Domain to the west.

In addition: •

Burton (2001) competed the mapping of the Eurowie Block, which was absent from the 1:100 000 stratigraphic map of Willis et al (1989).

•

Stevens (2011) produced basement interpretation maps of the Broken Hill 1:25 000 series (digital, unpublished versions only). This interpretive maps included areas left blank on the previous Broken Hill 1:100 000 Stratigraphy Map (Willis 1989), namely the Mundi Mundi Plains, the northern Euriowie Block and the extensive soil-covered areas in the east and south. Unlike the previous 1:100,000 map, the new maps show all of the mafic and ultramafic intrusions, and all but the very small pegmatites and post-deformational granites.

•

Cooper et al (1978) mapped the Neoproterozoic units over Tarrowangee-Fowlers Gap 1:100 000 map sheet area. This mapping was extended and revised by The Geological Survey (2009) to include the remaining Neoproterozoic geology over the Corona, Fowlers Gap, Broken Hill and Taltingan 1:100 000 map sheet areas (unpublished digital data only).

9

The new Broken Hill metallogenic map is a merge of two data sources, 1) the combined unpublished 1:25 000 scale Paleoproterozoic interpretation of Stevens (2011) and the 1:100 000 scale Neoproterozoic interpretation of The Geological Survey of New South Wales (2009), and 2) the simplified geology of the 1:100 000 stratigraphic map of Willis et al (1989). These datasets have been modified for the purpose of 1:250 000 scale map production. These modifications include: •

To be displayed at 1:250 000 scale the units of the upper Broken Hill Group had to be amalgamated into the Purnamoota Subgroup (Willis et al 1989), although units that were important for the location of sygenetic mineralisation (e.g. Hores Gneiss and Silver City Metadolerites) are displayed on the Broken Hill 1:250 000 metallogenic special.

•

Member level units could not be shown at 1:250 000 scale. These include the Ettlewood and King Gunnia Calc-silicates and such units have been dissolved back into their formation level host sequences.

•

Mesoproterozoic aged intrusives (syn- to post-Olarian Orogeny) interpreted by Stevens (2011) could not be displayed at 1:250 000 scale over the top of the complex Paleoproterozoic geology. These units have been displayed on Inset 1 along with the Olarian facies/isograds maps (see below). The larger named Mesoproterizoic plutons (Alberta Pluton, Brewery Well Pluton) have also been included on the Broken Hill 1:250 000 Special metallogenic — these does not include the Texas Bore Luecogranite or the Overshot Pluton of Burton (2001).

•

Neoproterozoic to Cambrian aged mafic dykes, sills and plutons interpreted by Stevens (2011) could not be displayed at 1:250 000 scale over the top of the complex Paleoproterozoic geology. These units are shown on Inset 2 along with the Delamerian mineral zone/isograds maps (see below). The larger, named mafic bodies (e.g. Red Hill Serpentinite and Little Broken Hill Gabbro) have been included on the Broken Hill 1:250 000 Special metallogenic.

•

The complex array of Mesoproterozoic to Cambrian retrograde shear zones interpreted by Stevens (2011) could not be displayed over the top of the complex Paleoproterozoic geology at 1:250 000 scale. These complex retrograde schist zones are shown on Inset 2 along with the Delamerian mineral zone/isograds maps (see below). A modified version of these retrograde schist zones was merged with the original, simplified version of Willis et al (1989) for the Broken Hill 1:250 000 Special metallogenic. Coding for ‘precursor known’ retrograde schist zones (Stevens 2011) could not be displayed at 1:250 000 scale. These retrograde schist zones are included as unattributed retrograde schist zones on the Broken Hill 1:250 000 Special metallogenic. Many of the thin schist zones had to be converted to lines for display purposes.

•

Informal subdivisions of the Paleoproterozoic and Neoproterozoic stratigraphy based on variations in magnetic response (Stevens 2011, The Geological Survey of New South Wales 2009) were

10

removed from the dataset to for display purposes. The exception to this is the informal subdivisions in the Curnamona Group of the Olary Domain in NSW. •

The Kyong Formation that appeared as part of the Thackaringa Group on Willis et al (1989) was not included in the interpretive maps of Stevens (2011) and for display purposes it has also been left off the Broken Hill 1:250 000 Special metallogenic.

•

There were many labelling ambiguities in the unpublished digital dataset of The Geological Survey of New South Wales (2009). Decisions were made on stratigraphic allocation by the authors of the map to remove these ambiguities. This included units assigned with ? in areas undercover.

•

Post-Delamerian to recent units including Cambrian, Devonian and Cenozoic units have been shown as semi-transparent overlays over older (basement) units.

Metamorphic framework The Broken Hill Domain preserves two major metamorphic events. This are: •

a high-T/P prograde deformation of a Paleoproterozoic epicontinental rift basin — the

Curnamona Rift Basin, during the Olarian Orogeny (~1620–1580 Ma; peak metamorphic facies and isograd map shown on map Inset 1); and, •

a second metamorphic event during the Delamerian Orogeny (~ 514–500 Ma; retrograde

mineral zone and isograd map shown on map Inset 2) that resulted in retrograde metamorphism of the high grade terrain and prograde metamorphism of younger sequences.

Although the general distribution of metamorphic grade has been defined by the previous studies, most studies do not propose metamorphic isograds for the entire Broken Hill Domain, none have addressed areas under cover, most gloss-over the metamorphic/structural and compositional complexity of the terrane, and many are markedly contradictory or inconsistent with other studies. As part of the development of the Broken Hill Metallogenic map a reconnaissance study was undertaken to develop a new and complete metamorphic facies and isograd maps for the Broken Hill and Olary domains in New South Wales. The methodology undertaken to develop the metamorphic layer included in this map is summarised in Fitzherbert (in prep) with the additional findings relating to the application of metamorphic facies/isograd maps and mineralisation being summarised in Fitzherbert and Downes (in prep).

Time–space plot The time–space plot for the Broken Hill map sheet area has been updated and modified from that published by Willis (1989). The majority of the changes in the Paleoproterozoic reflect the U–Pb SHRIMP dating studies of Page et al (2005) and Stevens et al (2008). The Lithostratigraphic/time

11

diagram of Connor and Preiss (2008) depicts the Willyama Supergroup of the Olary and Broken Hill Domains against an absolute time-scale in millions of years and was useful for the construction of the time-space plot. Age ranges for the construction of the Mesoproterozoic parts of the time-space plot were interpreted from Stevens et al (1986), Burton (2001), Page et al (2005) and Stevens (2006, 2011). The monazite age dates of Forbes et al (2008) and McFarlane and Frost (2009) have also been included. The Neoproterozoic part of the time-space plot is based on the work of Cooper et al (1978). The absolute age ranges have been assigned based on statigraphic correlation with dated Neoprterozoic sequences in South Australia (e.g. Scheibner & Basden 1998). Significant changes to the absolute timing of Cryogenian successions in South Australia were proposed by Preiss (2000, 2010) and summarised in Bushfield and Heron (2014). The absolute age ranges of Cryogenian succession for New South Wales have been modified to reflect these changes. The retrograde metamorphic field gradient and extensive retrograde schist zone development have been assigned to the Cambrian Delamerian Orogeny based on the monazite age dates presented in Dutch et al (2005), Rutherford et al (2007) and Raimondo et al (2007).

Shown as part of the time–space plot are the major deposit types and mineralising events with the dominant commodity(s) for the area. These types/events are indicated by a coloured symbol relating to the deposit classification schema and commodity type. In addition, the size of the deposit gives a visual indication as to the relative importance of that deposit type/event. The deposit names shown beneath the symbol relates to a representative and/or type deposit associated with that event. Due to space considerations in general only one “type” deposit was named.

REVERSE SIDE TO THE MAP The reverse side of the map has been used to present information relevant to a wider audience. This area includes a brief summary of the mining history and geological history of the area and is illustrated by images of photographs of historical interest and examples of some of the minerals of Broken Hill. Due to space considerations, the references for the articles on the mining history (McQueen) and geological history (Fitzherbert & Downes) were not included. The full text for these articles including references are provided as separate Geological Survey of New South Wales reports (McQueen 2014— GS2013/0951, Fitzherbert & Downes 2014 — GS2014/1830).

DISCUSSION The project to creation the Broken Hill Metallogenic map has required a review of existing mineral deposit data held by the Geological Survey of New South Wales. This has highlighted those deposits and mineral systems are well documented and those deposits and districts where future work should be focussed to better understand the mineral potential of the area. In addition, the project has provided

12

reality check about the relative importance of many deposit-types and mineral districts within the map sheet area.

The project has shown that the NSW mineral system classification schema (Downes et al 2009, 2011) is robust and useful in understanding the metallogenesis of individual project areas. It has highlighted that some deposit-types, especially those related to reduced gold-bearing metamorphic fluids and tinbearing pegmatites are generally absent or of low importance in the study area. This combined with the metamorphic facies/isograd data suggests that these deposit types are relatively unimportant within the Broken Hill Domain and that the area has low potential for future economic discoveries of significant size.

A major outcome of the project is the revision of the time–space plot for the Broken Hill map sheet area. This revision collates many of the incremental changes to the understanding of the geology and timing of events for the area and the wider Curnamona province.

ACKNOWLEDGMENTS Many people have contributed to the mineral occurrence dataset for the Broken Hill metallogenic map. These include Rob Barnes, Michael Bartholomaeus, Bob Brown, Gary Burton, Peter Downes, Steve Lishmund, Greg MacRae, Shelly Mills, Cameron Perks, Neil Raphael, Barney Stevens, Jim Stroud and John Whitehouse. Data collection for Broken Hill area has been an ongoing Geological Survey of New South Wales project since at least the beginning of the 20th Century with major studies being undertaken by numerous workers including Andrews (1912).

REFERENCES BARNES R.G. 1988. Metallogenic studies of the Broken Hill and Euriowie Blocks, New South Wales, 1. Styles of mineralisation in the Broken Hill Block. New South Wales Geological Survey — Bulletin 32(1), 1–116.

BARNES R.G. 1989. Broken Hill Block Southwest 1:50 000 metallogenic map. Geological Survey of New South Wales, Sydney.

BARTHOLOMAEUS M.A., BARNES R.G. & BURTON G.R. 1995. Broken Hill Block Southeast 1:50 000 metallogenic map. Geological Survey of New South Wales, Sydney.

BOWMAN H.N. & STEVENS B.P.L. 1976. The New South Wales Geological Survey metallogenic mapping program. Geological Survey of New South Wales, Report GS1975/059.

13

BURTON G.R. 1999. Euriowie Block 1:50 000 metallogenic map. Geological Survey of New South Wales, Sydney.

BURTON G.R. 2001. Corona 1:250 000 geological map explanatory notes. Geological Survey of New South Wales, Report GS 2001/277 (unpublished).

BUSHFIELD M.E. & HERON D.P. 2014. Sequencing the Sturtian icehouse: dynamic ice behaviour in South Australia. Journal of the Geological Society, London 171, 443– 456.

CONOR C.H.H. & PREISS W.V. 2008. Understanding the 1720-1640 Palaeoproterozoic Willyama Supergroup, Curnamona Province, Southeastern Australia: Implications for tectonics, basin evolution and ore genesis. Precambrian Research 166, 297–317.

COOPER P.F., TUCKWELL K.D., GILLIGAN L.B. & MEARES R.M.D. 1978. Geology of the Tarrowangee and Fowlers Gap 1:100 000 sheets 7135, 7235. Geological Survey of New South Wales, Sydney.

DICKINSON K.L. 1972. Mining history of the silver, lead, zinc and copper mines of the Broken Hill district to 1939, excluding the Main Line of Lode. Geological Survey of New South Wales—Bulletin 21, 96 pp.

DOWNES P.M., BLEVIN P.L., FORSTER D.B., WHITEHOUSE J., LEWIS P. & BARNES R.G. 2011 (poster). Mineral systems of New South Wales version 4 — 2011. Geological Survey of New South Wales, Report GS2010/0917.

DOWNES P.M., LEWIS P., BLEVIN P., FORSTER D.B., WHITEHOUSE J. & BARNES R. 2008. Mineral systems in New South Wales – Version 1. 2008 (poster). Geological Survey of New South Wales, Report GS2010/0909.

DUTCH R.A., HAND M. & CLARK C. 2005. Cambrian reworking of the southern Australian Proterozoic Curnamona Province constraints from regional shear zone systems. Journal of the Geological Society of London 162, 763-775.

FORBES, C.J., BETTS, P.G., GILES, D. & WEINBERG, R. 2008. Reinterpretation of the tectonic significance of high-temperature metamorphism in the Broken Hill Block, NSW, and implications on the Palaeo- to Meso-Proterozoic evolution. Precambrian Research 166, 338–349.

14

FITZHERBERT J. (in press). Redefined peak and retrograde metamorphic isograds for the Broken Hill and Euriowie blocks, NSW. Quarterly Notes of the Geological Survey of New South Wales.

FITZHERBERT J.A. & DOWNES P.M. 2014. A concise geological history of the Broken Hill region. Geological Survey of New South Wales Report GS2014/1830.

FITZHERBERT J. & DOWNES P.M. (in prep.). Application of metamorphic facies/isograd maps to the understanding of a regionally stratified anatectic-igneous complex and its associated mineralisation, Broken Hill, NSW.

FITZHERBERT J.A., DOWNES P.M., COLQUHOUN G.P., BLEVIN P.L. & FORSTER D.B. 2014. Broken Hill 1:250 000 Special Metallogenic Map. Geological Survey of New South Wales, Maitland, Australia.

GEOLOGICAL SURVEY OF NEW SOUTH WALES 2009. New South Wales 1:100 000 scale interpretive Proterozoic geology – Broken Hill. Poster presented at Broken Hill Exploration Initiative (BHEI) conference 2009. Geological Survey of New South Wales, NSW Industry & Investment, Maitland (unpubl.).

LEWIS P. & DOWNES P.M. 2008. Mineral systems and processes in New South Wales: a project to enhance understanding and assist exploration. Quarterly Notes of the Geological Survey of New South Wales 128, 1–15. Geological Survey of New South Wales, Maitland.

LISHMUND S.R. 1982. Non-metallic and tin deposits of the Broken Hill district. Geological Survey of New South Wales— Bulletin 28, 176 pp.

MCFARLANE C.R.M. & FROST B.R. 2009. Constraints on the early metamorphic evolution of Broken Hill, Australia, from in situ U-Pb dating and REE geochemistry of monazite. Journal of Metamorphic Geology 27, 3–17.

MCQUEEN K.G. 2014. Mining history of the Broken Hill region, NSW. Geological Survey of New South Wales report GS2014/1817.

PAGE R. W., STEVENS B. P. J. & GIBSON G. M. 2005. Geochronology of the sequence hosting the Broken Hill Pb – Zn –Ag orebody, Australia. Economic Geology 100, 633–661.

PREISS W.V. 2000. The Adelaide Geosyncline of South Australia and its significance in Neoproterozoic continental reconstruction. Precambrian Research 100, 21–63. 15

PREISS W.V. 2010. Geology of the Neoproterozoic to Cambrian Adelaide Geosyncline and Cambrian Delamerian Orogen. In: Korsch R. J. & Kositcin, N. eds. South Australian Seismic and MT Workshop 2010, pp. 34 – 41. Geoscience Australia Record 2010/10.

RAIMONDO T., CLARK C., HAND M., CLIFF J. & ANCZKIEWICZ R. 2013. A simple mechanism for midcrustal shear zones to record surface-derived fluid signatures Geology 41 (6), 711-714.

RAPHAEL N.M. & BARNES R.G. 1999. Broken Hill Block North 1:50 000 metallogenic map. Geological Survey of New South Wales, Sydney.

RUTHERFORD L., HAND M. & BAROVICH K. 2007. Timing of Proterozoic metamorphism in the southern Curnamona Province: implications for tectonic models and continental reconstructions. Australian Journal of Earth Sciences 54(1), 65-81.

SCHEIBNER E. & BASDEN H. ed. 1998. Geology of New South Wales — Synthsis. Volume 2 Geological Evolution. Geological Survey of New South Wales, Memoir Geology 12(2).

STEVENS B.P.J. 1986. Post-depositional history of the Willyama Supergroup in the Broken Hill Block, NSW. Australian Journal of Earth Sciences 33, 73-98.

STEVENS B.P.J. & CORBETT G.J. 1993. The Redan geophysical zone: part of the Willyama Supergroup? Broken Hill, Australia. Australian Journal of Earth Sciences, 40, 319-338.

STEVENS B.P.J. 1998. The origins of Broken Hill rock types and their relevance to mineralisation. In: Gibson, G.M., compiler, Broken Hill Exploration Initiative Conference, Abstracts. Australian Geological Survey Organisation, Record, 1998/25, 109-114.

STEVENS B. P. J. 2006. Advances in understanding Broken Hill geology. In: Korsch R. J. & Barnes R. G. eds. Broken Hill Exploration Initiative Conference September 2006, pp. 166 – 175. Geoscience Australia Record 2006/21.

STEVENS B.P.J., PAGE R.W. & CROOKS A. 2008. Geochronology of the Willyama Supergroup metavolcanics, metasediments and contemporaneous intrusions, Broken Hill, Australia. Australian Journal of Earth Sciences 55, 301–330.

16

STEVENS B.P.J. 2011. Interpretation of Broken Hill 1:25,000 map series. Geological Survey Report GS2015/0123. Geological Survey of New South Wales.

STEVENS B.P.J., WILLIS I.L., BROWN R.E & STROUD W.J., 1983. The Early Proterozoic Willyama Supergroup: definitions of stratigraphic units from the Broken Hill Block, New South Wales. Geological Survey of New South Wales, Records, 21(2), 407-442.

WILLIS I.L. 1989. Broken Hill Stratigraphic Map, 1:100 000. Geological Survey of New South Wales, Sydney.

WILLIS I.L., BROWN R.E., STROUD W.J. & STEVENS B.P.J., 1983. The Early Proterozoic Willyama Supergroup: stratigraphic subdivisions and interpretations of high- to low-grade metamorphic rocks in the Broken Hill Block, New South Wales. Journal of the Geological Society of Australia, 30, 195-224.

17