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Advances in understanding the Advances in understanding the geology of the Eastern Fold Belt, geology of the Eastern Fold Belt,
Mount Isa regionMount Isa region
Ian WithnallIan Withnallwith contributions from Allan Parsons (GSQ),with contributions from Allan Parsons (GSQ),
Chris Carson & Narelle Neumann (GA) Chris Carson & Narelle Neumann (GA) Mt Isa Civic Centre, 24 June 2008Mt Isa Civic Centre, 24 June 2008
Australian Government
Geoscience Australia
Western
Fold Belt
Murphy Ridge
South Nicholson BasinLawn Hill Platform
Leichhardt R. Fault Trough & Myally ShelfKalkadoon-Leichhardt Block
Wonga Belt (Mary Kathleen Zone) Eastern
Fold Belt
Geological Regions
Outcrop limit of Proterozoic rocks
Seismic lines
Quamby-Malbon & Cloncurry-Selwyn Zones
Corella Fm
Simplified Time-space Diagram for Eastern Fold Belt (after Blake, 1987)
Plum Mtn Gneiss Double Crossing MetsBASEMENT >1900Ma
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
COVER SEQUENCE 11875-1850Ma
Leichhardt Volcanics
Kalkadoon Batholith
COVER SEQUENCE 21800-1740Ma
Argylla Formation
Magna Lynn Metabasalt
Argylla Fm
Soldiers Cap Group
Ballara Qtzt
Marraba Volcs
Mitakoodi Qtzt
Overhang Jspt
Corella Formation
Doherty Fm
Stavely Fm
Answer Slate
Marimo Slate
Kuridala Fm
COVER SEQUENCE 31700-1670Ma
Wonga Batholith (incl Burstall Granite & related plutons
Deighton Qtzt
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Williams, Naraku, Wimberu Batholiths & related plutons
Roxmere Qtzt
WIDESPREAD EROSION
REGION-WIDE DEFORMATION & METAMORPHISM 1620-1550MA (ISAN OROGENY)
EROSION
EROSION
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
MARY KATHLEEN GROUP
MALBON GROUP
MT ALBERT GROUP
TEWINGA GROUP
~1740Ma
~1550-1500Ma
Some comments on the Blake model for the Eastern Succession
• Based on joint BMR-GSQ mapping from 1968-1978 – no detailed structural studies seriously attempted
• Most boundaries assumed to be stratigraphic (resulting in some confused and conflicting relationships)
• Geochronology largely Rb-Sr and traditional U-Pb dating. SHRIMP dating in infancy and focussed on granites and so-called extrusives (metarhyolite and “tuff”)
• The interpretation of the Corella-Stavely-Doherty rocks appears to be a compromise – Blake believed that there were at least two different ages of these rocks - an idea hotly disputed by Wilson & Derrick
Subsequent research on the Eastern Succession• Detailed structural studies by BMR and university groups 1988-
1992 (Blake & Stewart)• Numerous PhDs, Honours theses and staff research from JCU
through the 1990s• AGSO deep crustal seismic transect - 1994• Structural studies by Monash staff & students in the late 1990s• Continued SHRIMP dating through the 1990s by Page
(BMR/AGSO/GA) and others (e.g. Nuttman & Giles)• Sequence stratigraphic analysis & SHRIMP dating in the
Western Succession by Southgate & others as part of NABRE, AMIRA P552 in late 1990s-2000 provided a temporal framework for correlations with the Eastern Succession
• New work by GA including structural studies by Gibson & SHRIMP dating (including detrital zircons) by Neumann in conjunction with pmd*CRC since 2001
• Revised mapping by GSQ since 2005 (Withnall and Parsons) and SHRIMP dating by Neumann and Carson (GA)
Event chart for the Leichhardt, Calvert & Isa Superbasins
Kalkadoon-Leichhardt Block & Wonga Belt
• Basement of Kalkadoon-Leichhardt Block dated at ca 1865Ma –Kalkadoon Granite & Leichhardt Volcanics essentially coeval
• Leichhardt Volcanics mostly overlain by Magna Lynn Metabasalt – not dated, but generally regarded as part of younger sequence and equivalent in age to the Eastern Creek Volcanics in the Western Succession. However, some evidence for it being basement
• Argylla Formation – felsic volcanics and some sediments; in the Kalkadoon-Leichhardt Block and Wonga Belt dated at 1778Ma
• Overlain unconformably by the Ballara Quartzite, and in turn by the Corella Formation.
• Zircon dating of a tuff in the Ballara Quartzite and crystallisation ages from the Burstall Granite/Revenue Granite indicate that the BallaraQuartzite and Corella Formation were deposited between 1760 & 1740Ma
• Consistent with correlation of the Corella Formation with the QuilalarFormation in Western Succession (max dep age of 1748±3Ma)
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Wonga ~1760-1740Ma
Kalkadoon-Leichhardt Block & Wonga Belt
• The Wonga Batholith contains granites ranging from 1760Ma to ~1740Ma
• In the Wonga Belt, mylonitised Argylla Formation cut by undeformed granite constrains a deformation in this area to between 1780 and 1740Ma
• This Wonga Event has been interpreted as an extensional event and may be related to the commencement of deposition of the BallaraQuartzite (and the Quilaler Fm in the west)
• The Burstall Granite and a series of other plutons were emplaced at ~1740Ma
• Constrain the age of the Corella Formation and considered to correspond with the break between the Leichhardt & Calvert Superbasins in the Western Succession. Probably a similar break in the Eastern Succession
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Kalkadoon-Leichhardt Block & Wonga Belt
• The Corella Formation is overlain by the Deighton Quartzite, possibly unconformably. Age of the lower part is not well-constrained (max depage of ~1750Ma) – mafic lavas may correlate with the Fiery Creek Volcanics at ~1710Ma (Big Supersequence in the west)
• Upper part has a imprecise max dep age of ~1690Ma (Prize or Gun Supersequence).
• In the northern part of the Wonga Belt, the Knapdale Quartzite may be a correlative of the Deighton Quartzite
• A sequence of locally carbonaceous scapolitic metasiltstones (formerly mapped as part of the Corella Formation) include the host of the Dugald River deposit - now mapped as Mt Roseby Schist - has a max dep age of ~1685Ma
• Appears to be overlain by the Coocerina Formation and Lady ClayreDolomite
• Succession may be equivalent to the Gun Supersequence in the Western Succession (which includes the Mt Isa Group)
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Dugald RiverDugaldDugald RiverRiver
Cover
Quamby Conglomerate
Naraku Batholith
Metadolerite
Burstall-age granites
Wonga-age granites
Corella Formation
Chumvale Breccia
Overhang Jaspilite
Ballara Qtzt, Mitakoodi Qtzt
Argylla Fm/Bulonga Volcs
Boomara Metamorphics
Tommy Creek Microgranite
Lady Clayre Dolomite
Mt Roseby Schist
Knapdale Quartzite
Coocerina Formation
Tommy Creek area
Porphyritic felsic volcanics
Quartzite conglomerate & sandstone
Marble, calc granofels, minor siltstone & sandstone
Muscovite-garnet schist
Mafic to intermediate lavas & clastics
Undivided (graphitic schist, marble & calc granofels)
Dugald River – Mt Roseby area
Northern Marraba-Quamby area(revised by Withnall 2006-07)
Quamby-Malbon Belt• Oldest rocks are the Double Crossing Metamorphics to
the west of Selwyn and the Boomarra Metamorphics in the Boomarra Horst
• Double Crossing Metamorphics intruded by the Gin Creek Granite, but all other contacts probably tectonic (detachments?)
• Gneiss and migmatite grade westwards and northwards away from the Gin Creek Granite into chloriticmetasiltstone – abundant mafics including possible lavas
• Gin Creek Granite and migmatite leucosomes in the gneiss are both ~1740Ma (Burstall age) indicating a localised metamorphic event at this time
• Detrital spectra hard to interpret – main peak at 1870Ma (Kalkadoon-Leichhardt source) but some grains as young as 1790Ma
• Could be equivalents of Guide or Myally Supersequences• The Boomarra Metamorphics are ~1775Ma (equivalent to
the Argylla Formation) although volcanics are rare -predominantly quartzite and biotite schist intruded by abundant amphibolite (originally mapped as Soldiers Cap Group)
Cloncurry
Cloncurry
Leichhardt Leichhardt River Fault River Fault TroughTrough
Kal
kado
onK
alka
doon
--Le
ichh
ardt
Leic
hhar
dt
QuambyQuamby--MalbonMalbon
WongaWonga
Gin Creek GraniteGin Creek Granite
BoomarraBoomarra MetsMetsDouble Crossing MetsDouble Crossing Mets
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSION
Wonga ~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
• Fault-bounded – Pilgrim Fault to west, Overhang Fault on east and possibly thrust under Tommy Creek Block to the north
• Sequence of rocks not easily correlated with those in the Kalkadoon-Leichhardt Block or Wonga Belt –allocthonous?
• Essentially similar volcanics and sediments to the Argylla Formation but 1760Ma (20ma younger) – now referred to as Bulonga Volcanics
• Overlain by thick pile of mafic lavas and some sediments - Marraba Volcanics – no equivalents to west
• Thick sequence of feldspathic sandstone, with some mafic lavas and rare rhyolite (~1755Ma) – correlative with the Ballara Quartzite, but thicker and more feldspathic
• Marraba Volcs & Mitakoodi Qtzt deposited in ~5ma• Overhang Jaspilite – iron and manganese-rich siltstone
and limestone (commonly stromatolitic) – enigmatic siliceous breccias (Chumvale Breccia) - may correlate with the lower part of the Corella Formation, but appears to be overlain by the Corella Formation north of the Mitakoodi Block
Quamby-Malbon Belt -Mitakoodi Block
Cloncurry
Cloncurry
Kal
kado
onK
alka
doon
--Le
ichh
ardt
Leic
hhar
dt
QuambyQuamby--MalbonMalbon
WongaWonga
WongaWonga
Over
hang
Fault
Pilg
rim
Fault
?
Overhang JaspiliteOverhang Jaspilite
MarrabaMarraba VolcanicsVolcanicsMitakoodi QuartziteMitakoodi Quartzite
BulongaBulonga VolcanicsVolcanics
Argylla FormationArgylla Formation
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Mitakoodi Block
Quamby-Malbon Belt – Corella-type rocks
• Most extensively exposed ‘unit’ in the Mount Isa Inlier• Originally mapped as a single unit, the Corella
Formation by Carter et al (1961) and Derrick et al (1977); except for a small area in south mapped as Stavely Formation by Carter et al
• Mainly thin-bedded calcareous metasediments passing into calc-silicate rocks
• Scapolitic in places and may have been deposited in an evaporitic carbonate shelf environment
• Regionally extensive breccias• Coherent stratigraphy in the Kalkadoon-Leichhardt and
Wonga Belts with well defined relationships & readily divisible into 3 members
• Difficult to place stratigraphically in the Quamby-MalbonBelt
– forms a complex of lithologic subdivisions rather than stratigraphic members
– generally more deformed and metamorphosed
Quamby-Malbon Belt – Corella-type rocks
• Blake suggested that the Corella Formation probably contained multiple sequences:
– ‘old Corella’ deformed & metamorphosed pre-1740Ma in the Wonga Belt and Kalkadoon-Leichhardt Block
– ‘young Corella’ ca 1600Ma in the Tommy Creek area
– possibly rocks of intermediate age– assigned the rocks in the SE to Doherty
Formation (based on a 1720Ma ‘metarhyolite’ age) and possibly equivalent Stavely Formation
• Blake’s ideas were strongly disputed by Wilson & Derrick
• Subsequently, the Corella Formation was retained for most of the outcrop area, except for the Doherty/Stavely Formations in the SE, with an arbitrary sheet boundary ‘fault’
Cloncurry
Cloncurry
WongaWongaLeichhardt Leichhardt River Fault River Fault TroughTrough
Kal
kado
onK
alka
doon
--Le
ichh
ardt
Leic
hhar
dt
Lawn Lawn HillHill
QuambyQuamby--MalbonMalbon
Quamby-Malbon Belt – Corella-type rocks
• The recent work has shown that Blake was largely correct
• Pre-1740Ma Corella Formation is probably restricted to the Kalkadoon-Leichhardt Block, Wonga Belt and northern part of the Quamby-Malbon Belt including the BoomarraHorst
• Corella-type rocks south and east of Cloncurry are probably continuations of Stavely & Doherty Formations
Cloncurry
Cloncurry
WongaWongaLeichhardt Leichhardt River Fault River Fault TroughTrough
Kal
kado
onK
alka
doon
--Le
ichh
ardt
Leic
hhar
dt
Lawn Lawn HillHill
QuambyQuamby--MalbonMalbon
Quamby-Malbon Belt – Corella-type rocks in the Tommy Creek area
• In addition to the Mt Roseby Schist of the Wonga Belt, another younger package has been identified in the Tommy Creek area – the Milo beds
• A heterogeneous succession of calcareous and carbonaceous metasediments and mafic to felsic metavolcanics intruded by high-level microgranite plutons (Tommy Creek Microgranite).
• Dating of the microgranite and detrital zircons from the metasediments bracket the age of the Milo beds to 1665-1660Ma.
• Younger SHRIMP ages on metarhyolite at about 1620Ma are yet to be explained
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Milo beds <1660Ma
Tommy Ck ~1653Ma
Mitakoodi BlockTommy Creek
Geology of the Tommy Creek – Corella Park area (mapping by Hill et al 1992 & Withnall, 2006)
Tommy Creek area – ‘Milo beds’
Mitakoodi Quartzite
Cover
Granitoids
Metadolerite
Porphyritic rhyolite
Corella Formation
Chumvale Breccia
Overhang Jaspilite
Quartzite conglomerate & sandstone
Marble, calc granofels, minor siltstone & sandstone
Muscovite-garnet schist
Graphitic schist
Mafic to intermediate lavas & clastics
Tommy Creek Microgranite
Argylla Formation
Undivided (graphitic schist, marble & calc granofels)
RoxmereRoxmere QuartziteQuartzite
Stavely FormationStavely FormationDoherty FormationDoherty Formation
Corella FormationCorella FormationMitakoodi BlockMitakoodi Block
Tommy Creek MicrograniteTommy Creek Microgranite
Soldiers Cap GroupSoldiers Cap Group
Milo bedsMilo beds
KuridalaKuridala FormationFormationAnswer/Answer/MarimoMarimo SlateSlate
Mt Mt RosebyRoseby Schist etcSchist etc
Quamby-Malbon Belt – Corella-type rocks in the Selwyn-Marimo area
• Stavely Formation – sandstone and siltstone, locally calcareous, and impure limestones (superficially like Corella Formation)
• Appears to become more calcareous and more metamorphosed eastwards and may grade into the Doherty Formation, although sharp jumps in grade associated with faults
• Both contain extensive areas of breccia (mechanism uncertain, but probably related to extension and/or fluid overpressuring) – locally intrusive relationships (e.g with Soldiers Cap Group)
• Stavely Formation locally has a gradational relationship with the Roxmere Quartzite (thickening and probably shallowing upwards sequence)
• All other contacts are tectonic• Detrital zircons suggest a max dep age of 1740Ma
(i.e. post-Burstall/Gin Creek igneous/metamorphic event)
• Possible ‘metarhyolite’ in the Doherty Formation is 1725Ma
• Detrital zircons in the Roxmere Quartzite give a 1710Ma max dep age
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Milo beds <1660Ma
Tommy Ck ~1653Ma
Mitakoodi BlockTommy Creek
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
Doherty Fm~1725Ma
LOCALISED METAMORPHISM & DEFORMATION (EXTENSIONAL?) FOLLOWED BY EROSION
Marimo-Stavely
RoxmereRoxmere QuartziteQuartzite
Stavely FormationStavely FormationDoherty FormationDoherty Formation
Corella FormationCorella FormationMitakoodi BlockMitakoodi Block
Tommy Creek MicrograniteTommy Creek Microgranite
Soldiers Cap GroupSoldiers Cap Group
Milo bedsMilo beds
KuridalaKuridala FormationFormationAnswer/Answer/MarimoMarimo SlateSlate
Mt Mt RosebyRoseby Schist etcSchist etc
Quamby-Malbon Belt – Answer Slate-Marimo Slate-Kuridala
Formation• Contacts previously inferred to be stratigraphic -
suggesting the Stavely Formation was underlain by the Answer Slate and Kuridala Formation and overlain by the Marimo Slate
Quamby-Malbon Belt – Answer Slate-Marimo Slate-Kuridala
Formation• Contacts previously inferred to be stratigraphic -
suggesting the Stavely Formation was underlain by the Answer Slate and Kuridala Formation and overlain by the Marimo Slate
• However, most contacts are marked by faults –probably folded thrusts - ferruginised and silicified zones
RoxmereRoxmere QuartziteQuartzite
Stavely FormationStavely FormationDoherty FormationDoherty Formation
Corella FormationCorella Formation
Mitakoodi BlockMitakoodi Block
Soldiers Cap GroupSoldiers Cap GroupAnswer/Answer/MarimoMarimo SlateSlate
Revised geology of the Marimo area(Parsons & Withnall, 2006-07)
Marimo
Marimo
Marimo
Stavely
Stavely
Stavely
Roxmere
Quartz Mylonite
RoxmereRoxmere QuartziteQuartzite
Stavely FormationStavely FormationDoherty FormationDoherty Formation
Corella FormationCorella FormationMitakoodi BlockMitakoodi Block
Tommy Creek MicrograniteTommy Creek Microgranite
Soldiers Cap GroupSoldiers Cap Group
Milo bedsMilo beds
KuridalaKuridala FormationFormationAnswer/Answer/MarimoMarimo SlateSlate
Mt Mt RosebyRoseby Schist etcSchist etc
Quamby-Malbon Belt – Answer Slate-Marimo Slate-Kuridala
Formation• Contacts previously inferred to be stratigraphic -
suggesting the Stavely Formation was underlain by the Answer Slate and Kuridala Formation and overlain by the Marimo Slate
• However, most contacts are marked by faults –probably folded thrusts (ferruginised and silicified zones)
• Answer Slate now considered to be equivalent to upper part of the Kuridala Formation and probably the Marimo Slate
• Max dep detrital zircon dates are– Answer Slate ~1660Ma– Marimo Slate ~1655Ma– Kuridala Formation (New Hope Sandstone)
~1675Ma• We intend to raise the Kuridala Formation to
Group status to include an as yet unnamed lower psammite, the New Hope Sandstone and the upper part, now mapped as Answer Slate.
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSION
Wonga ~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Milo beds <1660Ma
Tommy Ck ~1653Ma
Mitakoodi BlockTommy Creek
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
Doherty Fm~1725Ma
LOCALISED METAMORPHISM & DEFORMATION (EXTENSIONAL?) FOLLOWED BY EROSION
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
New Hope Sdst<1675Ma
Answer Slate <1660Ma
Unnamed psammite
Marimo-Stavely
KURIDALAGROUP
Cloncurry Belt – Soldiers Cap Group
• Consist of three units, Llewellyn Creek Formation, Mt NornaQuartzite and the mafic Toole Creek Volcanics
• Originally considered to be basement to Corella/Doherty Formation
• Detrital zircon max dep ages indicate that the Soldiers Cap Group is one of the youngest units in the Eastern Succession
• Max dep ages are ~1660-1680Ma, but a tonalite within a mafic sill that intrudes the Llewellyn Ck Fm is ~1678Ma
• Toole Creek Volcanics have a max dep age of 1658Ma• The data suggests that the Soldiers Cap and Kuridala Groups
are equivalent in age – correlations can be made between:– New Hope Sandstone and Mt Norma Quartzite– Answer Slate (which contains abundant mafic sills and
possibly some basalts) and the Toole Creek Volcanics
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSION
Wonga ~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Milo beds <1660Ma
Tommy Ck ~1653Ma
Mitakoodi BlockTommy Creek
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
Doherty Fm~1725Ma
LOCALISED METAMORPHISM & DEFORMATION (EXTENSIONAL?) FOLLOWED BY EROSION
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
New Hope Sdst<1675Ma
Answer Slate <1660Ma
Unnamed psammite
Marimo-Stavely
Mt Norna Qtzt
Llewellyn ~1680Ma
Toole Ck <1660Ma
KURIDALAGROUP
SOLDIERS CAPGROUP
Isan Orogeny
• Deformation and metamorphism intermittently over almost 100ma – at least four recognised events
• Earliest high-grade metamorphic event in the Isan Orogeny in the Eastern Succession constrained by dates on metamorphic monazite, titanite and zircon rims to between ~1600 and 1585Ma – some monazite suggest it may have started even earlier (~1620Ma)
• Monazite ages and zircon overgrowths give a variety of younger ages, including 1570 and 1520Ma
• Voluminous I and A-type magmatism over ca 55my from about 1550 to 1495Ma associated with the Williams Batholith and related plutons. Many of these plutons, including some of the youngest are deformed
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Milo beds <1660Ma
Tommy Ck ~1653Ma
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
Doherty Fm~1725Ma
LOCALISED METAMORPHISM & DEFORMATION (EXTENSIONAL?) FOLLOWED BY EROSION
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
New Hope Sdst<1675Ma
Answer Slate <1660Ma
Unnamed psammite
Mt Norna Qtzt
Llewellyn ~1680Ma
Toole Ck _1660Ma
Williams, Naraku, Wimberu Batholiths & related plutons 1550-1495MaREGION-WIDE DEFORMATION & METAMORPHISM 1620-1550MA (ISAN OROGENY)
Event chart for the Leichhardt, Calvert & Isa Superbasins
Correlations with the Western Succession
• Pre-1740 Ma rocks in the Kalkadoon-Leichhardt Block and Wonga Belt correlate reasonably well with the Western Succession– Argylla Formation and Magna Lynn Metabasalt are equivalent to
the Myally Supersequence– The Ballara Quartzite and Corella Formation are equivalent to the
Quilaler Supersequence• Deighton and Knapdale Quartzite are difficult to place, and possibly
correlate with the Big or Prize Supersequences or both –unconformities are suggested by conglomerates in the DeightonQuartzite
• The Mt Roseby Schist, Coocerina Fm & Lady Clayre Dolomite can be equated to the Gun Supersequence and may be deeper water equivalents of the Paradise Creek Formation
Correlations with the Western Succession• In the Quamby-Malbon Belt, correlations are less certain• The Boomara Metamorphics and Double Crossing Metamorphics are
probably correlatives of the Myally Supersequence• The Bulonga Volcanics and Marraba Volcanics have no equivalents
elsewhere – correlate with a break in the west – the felsic volcanics may be extrusive equivalents of the older Wonga granites
• The Mitakoodi Quartzite and Overhang jaspilite can be equated with the Quilaler Supersequence
• The Stavely & Doherty Formations and Roxmere Quartzite are difficult to place because of lack of data – max dep ages are inconclusive (although post-1740Ma) and rocks could partly correlate with depositional breaks in the west when the shoreline could have been east of the Wonga Belt– Stavely-Doherty show an apparent eastward increase in carbonate,
possibly related to a siliciclastic facies passing into a carbonate platform
Correlations with the Western Succession
• The lower part of the Soldiers Cap and Kuridala Groups may have been deposited during the break between the Prize and Gun Supersequences (during emplacement of the Sybella Batholith)
• However, the upper part of the Soldiers Cap and Kuridala Groups can be correlated with the Gun Supersequence and can be interpreted as the basinal facies equivalent to the platform facies of the Western Succession
• The voluminous tholeiitic basalts and dolerite sills in these groups may be related to a transition from rift to drift when the Georgetown Province may have separated from Mount Isa
Revised Time-space DiagramPlum Mtn Gneiss??
KALKADOON-LEICHHARDTBLOCK
WONGA
EASTERN FOLD BELT
QUAMBY-MALBON CLONCURRY
Leichhardt Volcanics
Kalkadoon Batholith
Argylla Formation ~1780Ma
Magna Lynn Metabasalt
Ballara Qtzt ~1755Ma
Corella Formation
REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)
~1845-1875Ma
Burstall~1740Ma
Deighton Qtzt<1690Ma?
White Blow Fm
Knapdale Qtzt
Coocerina Fm
Lady Clayre Dolm
Mt Roseby Schist <1685Ma
WONGA
EXTENSIONWonga
~1740-1760Ma
Double Crossing <1790Ma?
Boomarra ~1775Ma
Gin Ck~1740Ma
Corella Fm
Bulonga Volcs ~1760Ma
Marraba Volcs
Mitakoodi Qtzt ~1755Ma
Overhang Jspt
Milo beds <1660Ma
Tommy Ck ~1653Ma
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
Doherty Fm~1725Ma
LOCALISED METAMORPHISM & DEFORMATION (EXTENSIONAL?) FOLLOWED BY EROSION
Stavely Fm<1740Ma
Roxmere Qtzt<1710Ma
New Hope Sdst<1675Ma
Answer Slate <1660Ma
Unnamed psammite
Mt Norna Qtzt
Llewellyn ~1680Ma
Toole Ck _1660Ma
Williams, Naraku, Wimberu Batholiths & related plutons 1550-1495MaREGION-WIDE DEFORMATION & METAMORPHISM 1620-1550MA (ISAN OROGENY)
Myally
Quilalar
Gun
Big &/or Prize?
LEIC
HH
AR
DT
SUPE
RB
ASI
NIS
A
SBC
ALV
ERT
SB