The Curnamona Province is a remnant of a once continuous Late Palaeoproterozoic sedimentary basin and orogenic belt extending from Queensland to South Australia. It experienced several periods of sedimentation, volcanism, deformation and metamorphism between 1.72-1.59 Ga during the Olarian Orogeny, including the deposition of the Willyama Supergroup, intrusion of the Ameroo Subsuite, and formation of the Broken Hill Pb-Zn deposit at 1.685 Ga. The province was further deformed by the Delamerian Orogeny between 0.51-0.49 Ga.

1. Regional tectonic context of the
Curnamona Province
Anthony Reid and Wolfgang Preiss
Geological Survey of South Australia

2. Pb-­‐Ag-­‐Zn
deposit
Cu
deposit
/
occurrence

3. Pb-­‐Ag-­‐Zn
deposit
Cu
deposit
/
occurrence
Olympic
Cu-­‐Au
Province

4. Age
(Ma)
Central/Western
Gawler
Craton
Curnamona
Province
Eastern
Gawler
Craton

5. Central/Western
Gawler
Craton
Curnamona
Province
Eastern
Gawler
Craton
Basement
Cover
Large
igneous
province
&
metallogenic
event
Cover
Age
(Ma)

6. Central/Western
Gawler
Craton
Curnamona
Province
Eastern
Gawler
Craton
Basement
Cover
Cover
Age
(Ma)
Large
igneous
province
&
metallogenic
event

7. Gawler
Craton
Curnamona
Province
Adelaide
Broken
Hill
Marla

8. ~1730
–
1690
Ma
High-­‐T;
Transpression
Kimban
Orogeny
Broken
Hill
MineralisaMon:
Broadly
coeval
with
deposiMon
~1685
Ma
~1720
–
1640
Ma
sedimentaMon;
extension
Low
–grade
or
no
metamorphism

9. Gawler – Curnamona setting ca. 1710–1690 Ma
Gawler
–
transpression
–
transtension:
• Metamorphism
and
deformaMon
–
Kimban
Orogeny
• Subdued
topography
• Local
sedimentaMon
(e.g.
Labyrith
Fmn)
Curnamona
–
extension:
• SedimentaMon
~
Lower
Willyama
Supergroup
• MagmaMsm
–
e.g.
Ameroo
Subsuite
‘Gawler’
crust
‘Curnamona’
–
thinned
crust
Kalinjala
Shear
Zone
Broken
Hill
Zn-­‐Pb-­‐Ag

10. ca. 1600 Ma
Previously
unmetamorphosed
Metamorhpic
belt

11. 1630 – 1590 Ma
Olarian Orogeny:
Early HT-LP
metamorphism &
subsequent
compression

12. 1630 – 1590 Ma
Olarian Orogeny:
Early HT-LP
metamorphism &
subsequent
compression
Similar aged
deformation and
metamorphism in
northern Gawler Craton
granulite
Decreasing
metamorphic
grade
UPPER
CRUST

13. ca. 1590 Ma
Hiltaba Event:
magmatism,
hydrothermal fluid
flow, synchronous
with late Olarian
structures
BVS
Hiltaba
Hiltaba

14. Hillside
PorMa;
Kalkaroo
Moonta
-­‐
Wallaroo
Carrapateena
Olympic
Dam
Prominent
Hill
ca. 1590 Ma
Mineralisation
IOCG
mineralisaHon:
High
fluid
volume;
relaHvely
oxidised
Gold-­‐dominated
mineralisaHon:
more
reduced

15. The Curnamona Province is a small
remnant of an originally continuous
system of Late Palaeoproterozoic
(1.75-1.64 Ga) sedimentary basins
and
an ~1.6 Ga orogenic belt
extending at least from
north Queensland to
Fleurieu Peninsula

16. Evidence from seismic surveys:
• Curnamona E-W line
• Curnamona N-S line
• Gawler Craton E-W line
East-dipping thrusts cutting Corunna
Conglomerate, pre-1590 Ma Gawler
Range Volcanics
Northern margin of deformed Willyama
Supergroup thrust against 1.59-1.58 Ga
Radium Creek Gp of Mt Painter Inlier:
clastic sediments deposited in syn-
Olarian foreland basin
CURNAMONA
PROVINCE
Olary Domain
Broken Hill
Domain
Southeast-dipping
thrusts across
Curnamona Province

17. Domains and Inliers of the
Curnamona Province
Olary Domain crops out in Kalabity, Plumbago,
Outalpa and Weekeroo Inliers
Broken Hill Domain crops out in Broken Hill,
Euriowie and Poolamacca Inliers
Redan Domain crops out in Broken Hill Inlier
Moolawatana Domain crops out partly in Mount
Painter and Mount Babbage Inliers
Mulyungarie, Mudguard, Moorowie and
Quinyambie Domains are entirely subsurface

18. Part of the original
‘Seamless Geology’
map (solid geology)
of Curnamona Province
in SA and NSW
showing stratigraphic
subdivision as envis-
aged in the 1990s
Paragon Group
Sundown Group
Broken Hill Group
Thackaringa Group
Redan Gneiss

19. Total magnetic intensity of part of Olary Domain showing high and low TMI of
Neoproterozoic rift corridors & complex magnetic pattern of Willyama Supergroup

20. Olarian thrusts 1640-1620 Ma pelitic blanket 1580 Ma bimodal volcanics, sediments
1590 Ma
foreland basin
Northern Olarian thrust front
CURNAMONA N-S SEISMIC

21. SUNDOWN GROUP
BROKEN HILL GROUP
Larry Macs Subgroup: Plumbago, Bimba Ettlewood Calc-silicate Member
THACKARINGA GROUP
RANTYGA GROUP
15 m.y. hiatus
Purnamoota Subgp: Hores Gneiss
PARAGON GROUP
?15 m.y. hiatus
Allendale Metasediments
OLARY DOMAIN BROKEN HILL DOMAIN Ma
Walparuta Formation
Raven Hill Subgroup
STRATHEARN GROUP
Mount Howden Subgroup
~1655-1640
~1705
~1710
~1715-1720
~1720
~1695-1700
CURNAMONA GROUP
Ethiudna Subgroup
Peryhumuck Formation v v v v v v v
Cathedral Rock Formation
Tommie Wattie Formation v v v v v v
Wiperaminga Subgroup v v v v v v v
~1685

22. + + +
+
+
+
- - -
-
-
+
-
+ Upright nappe limbs - Inverted nappe limbs

23. Solid geology of
part of Bimbowrie
Conservation Park
• Major rock units and
structures
• Syndepositional faults
in Ethiudna Subgroup
• A-type Ameroo
Subsuite intruded
during hiatus between
Ethiudna and Larry
Macs Subgroups
• Refolded overturned
nappe limb
• Sturtian glacial valley
fill
• Delamerian shear zone
younging
younging

24. • Early high-temperature metamorphism and migmatisation, perhaps under
a thick insulating pelitic blanket
• Early continuous and progressive ductile deformation in mid-crust by
isoclinal, recumbent folding and thrusting, resulting in gradual crustal
thickening
• Early folds with sheath morphology to explain diverse fold axis
orientations and apparent vergences; overall tectonic transport to NW
• Later folds tend to be more upright and thick-skinned, but formed within
the same overall stress regime
• Granites result from mid-crustal melting of sediments, perhaps induced by
a regional deep crustal or mantle event (‘Hiltaba Event’) at 1590 Ma
• Granites may be incidental to Olarian Orogeny
TECTONIC
EVOLUTION
OF
OLARIAN
OROGENY
~?1620–1590
MA
OLARIAN OROGENY ?1.63 – 1.59 Ga

25. Major events in the Curnamona Province
• 1.72-1.715 Ga: Rifting of a continental basement; deposition of Curnamona
Group evaporitic siliciclastic sediments (known only in Olary and
Mulyungarie Domains); A-type felsic volcanism
• 1.71-1.70 Ga: Extensional faulting; intrusion of Ameroo Subsuite A-type
granite and hiatus in deposition in Olary Domain; deposition of siliciclastic
sediments of Rantyga and Thackaringa Groups in Broken Hill Domain
• 1.70-1.695 Ga: Larry Macs Subgroup transgressive onto eroded surface of
Curnamona Group; base-metal anomalous Bimba Formation (Olary
Domain) and Ettlewood Calc-silicate Member (Broken Hill Domain); thin
volcaniclastic Plumbago Formation deposited on maximum flooding
surface; ?conformable transition from Thackaringa to Broken Hill Group
• 1.695-1.685 Ga: Broken Hill Group (Broken Hill Domain) and Raven Hill
Subgroup (Olary Domain) mainly fine-grained siliciclastic deposition

26. Major events in the Curnamona Province
• 1.685 Ga: Mafic intrusives; submarine volcaniclastic Hores Gneiss and
formation of inhalative Broken Hill Pb-Zn-Ag orebody (Broken Hill Domain)
• 1.685-1.67 Ga: Dominantly fine siliciclastic deposition of Sundown Group
in Broken Hill Domain; possible equivalents in Olary Domain
• 1.67-1.655 Ga: Possible hiatus in deposition in both domains
• 1.665-1.64 Ga: Dominantly fine siliciclastic deposition of Paragon Group
(Broken Hill Domain), Strathearn Group (Olary & Mulyungarie Domains)
• 1.64-1.63 Ga: Speculative deposition of thick insulating pelitic blanket
• 1.63-1.62 Ga: Earliest onset of Olarian metamorphism and migmatisation;
uncertain onset of Olarian deformation
• 1.62-1.60 Ga: Olarian Orogeny possibly diachronous and propagating from
southeast to northwest; northwest-verging nappes, thrusts and sheath
folds; low-angle foliations; possibly peak metamorphism from granulite in
the southeast to greenschist in the north

27. Major events in the Curnamona Province
• 1.60-1.59 Ga: Continued northwest-directed tectonic transport refolds nappes
into upright folds defining the arcuate ‘grain’ of Curnamona Province; steep
axial plane foliations; ; northern thrust front intersected on N-S seismic transect
near Moolawatana; deposition of upward-coarsening Radium Creek Group in a
syn-Olarian foreland basin
• 1.59 Ga: Intrusion of late tectonic Ninnerie Supersuite granites, including S-
type Bimbowrie and Mundi Mundi Suites; I-type intrusions in western Olary
Domain indicate mantle involvement; part of the regional ‘Hiltaba Event’
• 1.59-1.58 Ga: Extrusion of Benagerie Volcanics in central Curnamona
• 1.59-1.57 Ga: Network of steep anastomosing greenschist-facies shear zones
cuts the whole Curnamona Province with E-W, ENE-WSW and WNW-ESE
orientations; bending of upright fold trends and fold interference on E-W axes
to produce dome and basin structures; differential uplift, exhuming the deepest
nappes in the southeast (granulite facies) and shallowest in central
Curnamona where Benagerie Volcanics are still preserved
• 1.57-0.83 Ga: Peneplanation with no recorded events; speculative Musgravian
overprint at 1.2 Ga?

28. Major events in the Curnamona Province
• 0.83-0.8 Ga: Willouran-age NE-SW rifting and intrusion of mafic dykes
(Gairdner Dolerite and equivalents
• 0.8-0.7 Ga: Initiation of half grabens along SW margin of Curnamona
Province; deposition of Burra Group siliciclastics and carbonates
• 0.7-0.65 Ga: Sturtian-age rifts encircle the Curnamona Province and define
its margins; thick glacio-marine sedimentation
• 0.65-0.51 Ga: Remainder of thick Neoproterozoic and early Cambrian
sedimentation; thin platform cover over central Curnamona
• 0.51-0.49 Ga: Delamerian Orogeny; interfering NNW-SSE and ENE-WSW
fold trends; partial inversion of rift half grabens to form corridors between
inliers; mostly greenschist facies metamorphism of basement and cover
• 0.49-0.12 Ga: Peneplanation and deep weathering
• 0.12-0 Ga: Onlap of marine (Cretaceous) and non-marine (Cenozoic)
sediments; uplift of Flinders, Olary and Barrier Ranges as ancient reverse
faults are reactivated under E-W compression