Academic literature on the topic 'Geology Queensland Georgetown Inlier'

AbstractThe earliest of four distinct phases of deformation recognized in the central part of the Proterozoic Mount Isa inlier involved brittle extensional faulting at shallow crustal levels. Extensional faulting produced stacks of imbricate fault slices, listric normal faults and characteristic tourmalinerich breccias. Structures belonging to this phase occur over a large part of the inlier and indicate an important phase of basin-forming crustal or lithospheric extension at 1750–1730 Ma. Late intense ductile deformation and tight folding of the imbricate systems destroyed part of these older structures, and obscures their existence in many parts of the inlier.

The only method of sampling the present day lower continental crust is through volcanic eruptions that transport samples of country rock to the surface. The composition, mineralogy, and age of three lower crustal xenoliths were examined from a preserved volcanic edifice, Hill 32, which erupted in North Queensland. It was found that all three samples represented former feldspathic orthogneisses. Through zircon U-Pb geochronology, the samples were found to have been subject to intense metamorphism and anatectic melting approximately 260Ma. Through rutile U-Pb geochronology, the eruption of Hill 32 in North Queensland was quantitatively dated to have erupted 1.5Ma.

Landsat Thematic Mapper, NSOOl Aircraft Thematic Mapper, Geoscan Mk. II. Multispectral Scanner and Airborne Gamma Radiometric data have been used to address a variety of geological problems in the Mary Kathleen area, 60 km east of Mt. Isa, NW Queensland. This area forms part of the Cloncurry Complex, a structurally complicated mass of diverse igneous and metamorphic rocks in the Precambrian Mt. Isa Inlier for which many stratigraphic problems remain to be solved. The Landsat Thematic Mapper data have been the most extensively used in this study. They are the least problematic data type and provide new geological information at scales up to 1:50 000. The NSOOl Aircraft Thematic Mapper data have similar spectral but superior spatial resolution in comparison with the satellite data. They suffer from increased geometric and noise-related problems, but the increase in spatial resolution has allowed the solution of problems, at scales up to 1:10 000, which could not be comprehensively addressed with the satellite data. The higher spectral resolution Geoscan Mk. II Multispectral Scanner aircraft data used in the latter part of the study can be used to remotely identify surface mineralogy. The logarithmic residual technique has proved the most successful approach to enhancing the radiance data sets. When applied to the lower spectral resolution data the technique achieves good discrimination of most lithologies, produces an albedo image useful for structural mapping and yields more information than can be extracted using conventional techniques. When applied to the higher spectral resolution data the technique allows remote mineral identification. Many of the geological problems in the area have been wholly or partially solved using suitably processed radiance data. The Airborne Gamma Radiometric data have the lowest spatial resolution. Only discrimination has been possible with this data set. These data contain no terrain information and are therefore difficult to use in the field. Integration of the gamma radiometric data with satellite data has been successful in overcoming this problem. The gamma radiometric data have allowed the separation of some lithologies which cannot be separated using the radiance data sets but have contrasting radiometric counts.

Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1997?
National Grid reference SF53-14 (Alice Springs), SF54-1 (Mount Isa) (1:250 000). Includes bibliographical references (leaves [32-36]).

The geological history of the Early Palaeozoic in eastern Australia is not known precisely. The eastern margin of the outcropping Precambrian Craton 'Tasman Line' is poorly understood. The Thomson Orogen, which underlies much of eastern Queensland, lies to the east of the Tasman Line. Basement to the Tasman Orogenic Zone is poorly understood, but knowledge of this basement is critical to our understanding to the processes that formed the eastern margin of the Precambrian craton. The Lolworth-Ravenswood Province lies to the east of the Tasman Line in northeast Queensland. A study of basement terranes in the Lolworth-Ravenswood Province will therefore provide some insights as to the nature of crust beneath this area, and therefore to the basement to the Thomson Orogen. The Fat Hen Creek Complex comprises para-authchthonous bodies of granitoid within middle to upper amphibolite facies metamorphic rocks. Data contained herein demonstrate that the composition and geochemistry of the granitoid are compatible with the generation of the granitoid by partial anatexis of the metamorphic rocks that are part of the Cape River Metamorphics. Temperature and pressure of anatexis is determined to be between 800-850OC and 5-9kb. Under these conditions, experimental data indicate that meta-pelite and meta-greywacke will produce between 5-10% melt coexisting with biotite, cordierite, garnet and plagioclase. The mineralogy of the granitoid bodies in the Fat Hen Creek Complex is consistent with partial anatexis of meta-greywacke at these temperatures and pressures. 5-10% melt is generally insufficient to allow efficient separation of melt and restite. The granitoids of the Fat Hen Creek Complex are interpreted as being a closed system with melt generated during high-grade metamorphism not separating from the residium. U/Pb dating of zircon from the Fat Hen Creek Complex indicate two distinct periods of zircon growth. The older episode occurred during the Late Cambrian to Early Ordovician. A second episode is dated as Middle Ordovician. This younger age coincides with the onset of regional compression, and may be related to exhumation of a mid-crustal layer during thrusting. The Lolworth Batholith is one of three granite batholiths in the Lolworth-Ravenswood Province. It comprises mainly muscovite-biotite granite, with smaller areas of hornblende-biotite granite to granodiorite. Sills and dykes of muscovite and garnet-muscovite leucogranite extensively intrude both of these types. The hornblende-biotite granite to granodiorite is metaluminous, with petrographic and geochemical characteristics similar to the adjacent Ravenswood Batholith. U-Pb SHRIMP ages also overlap with those from the Ravenswood Batholith. ENd(tc) values of ~-3 suggest a significant crustal contribution in the magma. Zircon populations determined using the SHRIMP suggest some inheritance from a Neoproterozoic source. The two-mica granites make up over 80% of the batholith and show little variation throughout. Aluminium Saturation indices range dominantly from 1-1.1, in keeping with the muscovite-bearing nature of the granites. U-Pb ages are significantly younger than the hornblende-biotite granitoids. ENd(tc) is ~-10, suggesting a greater role for crustal material in these granites than in the hornblende-bearing varieties. Previously, these granites were interpreted as S-types, mainly on the basis of the presence of muscovite. Low Na/Ca and Na greater than K are both considered as indicators of source compositions and both are characteristic of a mafic igneous rather than a meta-sedimentary source. Anatexis of mafic igneous rocks at temperatures less than~1000OC are found experimentally to produce peraluminous melts similar to those which produced the two-mica granites. The third major rock-type in the Lolworth Batholith is muscovite leucogranite, which occurs as sills and dykes intruding older granites and basement. The age of the leucogranite was not determined, but it has sharp contacts with the two-mica granite suggesting that the latter had cooled prior to intrusion of the former. The leucogranite is strongly peraluminous and is deemed to have been derived from anatexis of a supra-crustal (meta-sedimentary) source. The batholith is therefore deemed to comprise three different elements. The hornblende-biotite granitoids are the western extension of the adjacent Ravenswood Batholith. The two-mica granite and muscovite leucogranite are derived from different sources, but may be part of the same crustal anatexis event. During the Early Palaeozoic, the Lolworth-Ravenswood Province saw the intrusion of three granite batholiths into a basement of Late Neoproterozoic to Cambrian meta-sedimentary rocks. Also, Late Cambrian to Early Ordovician and Middle Ordovician high-grade metamorphism accompanied by partial anatexis is recorded at several sites across northeast Queensland. Although this metamorphism is restricted to these sites, they are widespread across the area suggestive of a widespread metamorphic event at these times. Similar metamorphism is recorded in the Arunta Inlier in Central Australia increasing the possible extent of this event. The geochemistry, isotopic characteristics and zircon populations of granites in the Lolworth-Ravenswood Province are used to characterise their source rocks; and thus the basement to the Province. Precambrian basement is indicated to underlie the entire province. However, the source rocks for the eastern part of the Province (Ravenswood and into the Lolworth Batholiths) are different to source rocks for the western part of the Province. Georgetown-type crust extends eastwards from the outcropping area, extending under the western Lolworth-Ravenswood Province. Late Mesoproterozoic rocks are recorded from the Cape River area adjacent to the Lolworth Batholith. They are also indicated as source-rocks for granites in the Ravenswood Batholith. Rocks of this age are characteristic of Grenvillian-age mobile belts in the United States. Their presence in north Qeensland has implications for the breakup of Rodinia, the Mesoproterozoic-age super continent that broke up during the Neoproterozoic.

The geological history of the Early Palaeozoic in eastern Australia is not known precisely. The eastern margin of the outcropping Precambrian Craton 'Tasman Line' is poorly understood. The Thomson Orogen, which underlies much of eastern Queensland, lies to the east of the Tasman Line. Basement to the Tasman Orogenic Zone is poorly understood, but knowledge of this basement is critical to our understanding to the processes that formed the eastern margin of the Precambrian craton. The Lolworth-Ravenswood Province lies to the east of the Tasman Line in northeast Queensland. A study of basement terranes in the Lolworth-Ravenswood Province will therefore provide some insights as to the nature of crust beneath this area, and therefore to the basement to the Thomson Orogen. The Fat Hen Creek Complex comprises para-authchthonous bodies of granitoid within middle to upper amphibolite facies metamorphic rocks. Data contained herein demonstrate that the composition and geochemistry of the granitoid are compatible with the generation of the granitoid by partial anatexis of the metamorphic rocks that are part of the Cape River Metamorphics. Temperature and pressure of anatexis is determined to be between 800-850OC and 5-9kb. Under these conditions, experimental data indicate that meta-pelite and meta-greywacke will produce between 5-10% melt coexisting with biotite, cordierite, garnet and plagioclase. The mineralogy of the granitoid bodies in the Fat Hen Creek Complex is consistent with partial anatexis of meta-greywacke at these temperatures and pressures. 5-10% melt is generally insufficient to allow efficient separation of melt and restite. The granitoids of the Fat Hen Creek Complex are interpreted as being a closed system with melt generated during high-grade metamorphism not separating from the residium. U/Pb dating of zircon from the Fat Hen Creek Complex indicate two distinct periods of zircon growth. The older episode occurred during the Late Cambrian to Early Ordovician. A second episode is dated as Middle Ordovician. This younger age coincides with the onset of regional compression, and may be related to exhumation of a mid-crustal layer during thrusting. The Lolworth Batholith is one of three granite batholiths in the Lolworth-Ravenswood Province. It comprises mainly muscovite-biotite granite, with smaller areas of hornblende-biotite granite to granodiorite. Sills and dykes of muscovite and garnet-muscovite leucogranite extensively intrude both of these types. The hornblende-biotite granite to granodiorite is metaluminous, with petrographic and geochemical characteristics similar to the adjacent Ravenswood Batholith. U-Pb SHRIMP ages also overlap with those from the Ravenswood Batholith. ENd(tc) values of ~-3 suggest a significant crustal contribution in the magma. Zircon populations determined using the SHRIMP suggest some inheritance from a Neoproterozoic source. The two-mica granites make up over 80% of the batholith and show little variation throughout. Aluminium Saturation indices range dominantly from 1-1.1, in keeping with the muscovite-bearing nature of the granites. U-Pb ages are significantly younger than the hornblende-biotite granitoids. ENd(tc) is ~-10, suggesting a greater role for crustal material in these granites than in the hornblende-bearing varieties. Previously, these granites were interpreted as S-types, mainly on the basis of the presence of muscovite. Low Na/Ca and Na greater than K are both considered as indicators of source compositions and both are characteristic of a mafic igneous rather than a meta-sedimentary source. Anatexis of mafic igneous rocks at temperatures less than~1000OC are found experimentally to produce peraluminous melts similar to those which produced the two-mica granites. The third major rock-type in the Lolworth Batholith is muscovite leucogranite, which occurs as sills and dykes intruding older granites and basement. The age of the leucogranite was not determined, but it has sharp contacts with the two-mica granite suggesting that the latter had cooled prior to intrusion of the former. The leucogranite is strongly peraluminous and is deemed to have been derived from anatexis of a supra-crustal (meta-sedimentary) source. The batholith is therefore deemed to comprise three different elements. The hornblende-biotite granitoids are the western extension of the adjacent Ravenswood Batholith. The two-mica granite and muscovite leucogranite are derived from different sources, but may be part of the same crustal anatexis event. During the Early Palaeozoic, the Lolworth-Ravenswood Province saw the intrusion of three granite batholiths into a basement of Late Neoproterozoic to Cambrian meta-sedimentary rocks. Also, Late Cambrian to Early Ordovician and Middle Ordovician high-grade metamorphism accompanied by partial anatexis is recorded at several sites across northeast Queensland. Although this metamorphism is restricted to these sites, they are widespread across the area suggestive of a widespread metamorphic event at these times. Similar metamorphism is recorded in the Arunta Inlier in Central Australia increasing the possible extent of this event. The geochemistry, isotopic characteristics and zircon populations of granites in the Lolworth-Ravenswood Province are used to characterise their source rocks; and thus the basement to the Province. Precambrian basement is indicated to underlie the entire province. However, the source rocks for the eastern part of the Province (Ravenswood and into the Lolworth Batholiths) are different to source rocks for the western part of the Province. Georgetown-type crust extends eastwards from the outcropping area, extending under the western Lolworth-Ravenswood Province. Late Mesoproterozoic rocks are recorded from the Cape River area adjacent to the Lolworth Batholith. They are also indicated as source-rocks for granites in the Ravenswood Batholith. Rocks of this age are characteristic of Grenvillian-age mobile belts in the United States. Their presence in north Qeensland has implications for the breakup of Rodinia, the Mesoproterozoic-age super continent that broke up during the Neoproterozoic.

This item is only available electronically.
The Mount Cuthbert mine is situated ~100km NE of Mt Isa near the eastern edge of the Kalkadoon Leichhardt Belt (KLB); a Proterozioc block of the Mt Isa Inlier that divides the world class mineral regions of the IOCG-style Eastern Fold Belt (EFB) and the Mount Isa style copper deposits of the Western Fold Belt (WFB). KLB hosted deposits display characteristics related to both the EFB and WFB style of mineralisation; however mineralisation at Mount Cuthbert is indicative of a genesis for KLB hosted deposits related to metasomatic and tectonic events responsible for mineralisation in the EFB. The Mount Cuthbert mine is a low tonnage-high grade, shear controlled, retrograde chalcopyrite-pyrite-pyrrhotite deposit hosted within silica-dolomite and biotite-chlorite altered schists and felsic volcanic units of the Leichhardt Volcanics. The paragenetic alteration sequence is composed of 5 alteration stages: Stage 1) sodic alteration (albite + quartz); Stage 2) K-Fe-Ca alteration (siderite + calcite + dolomite+ quartz + biotite ± magnetite ± ilmenite ± apatite ± pyrite); Stage 3) mineralisation (chalcopyrite + quartz ± pyrite ± pyrrhotite ± calcite ± chlorite); Stage 4) major chloritisation; Stage 5) oxidation and localised enrichment to chalcocite. The alteration halo within the deposit is characterised by a proximal alteration envelope (<50m) consisting of chalcopyrite, pyrite, quartz, dolomite and chlorite, an intermediate alteration envelope (50-500m) described by quartz-carbonate veining with minor chalcopyrite, pyrite and pyrrhotite, in addition to extensive biotite and chlorite alteration and minor magnetite alteration. A distal alteration envelope (>500m) is identified tentatively as albite dominant. The trace geochemistry of the main chalcopyrite ± pyrite ore phase reveals elevated Ni, Zn, Cd and Hg in pyrite and elevated Sn, Pb, Se, V, Cr, Te, Ga, As, Cd, Mo, Ga, Bi and Sb in chalcopyrite. Differing elemental trends within the ore minerals supports paragenetic evidence suggesting several phases of sulphide growth. The characteristics and features of the Mount Cuthbert deposit outlined in this study show the greatest number of similarities to other low tonnage-high grade, shear hosted deposits present in the KLB (i.e. Mighty Atom, Orphan). This suggests that despite having a genesis related to that of the EFB, KLB deposits are uniquely their own style of mineralisation. This supports a shear-zone associated exploration model that is specific to the KLB.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015

Includes copies of articles co-authored by author during the preparation of this thesis in back pocket.
Includes bibliographical references (leaves 113-124).
viii, 172 leaves : ill. (some col.), maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Focuses on the impact of change in the distribution of heat producing elements on lithospheric thermal regimes and on temperature dependent processes such as metamorphism, magmatism and deformation, with application to Proteozoic Australia (Mount Isa and Mount Painter inliers).
Thesis (Ph.D.)--Adelaide University, Dept. of Geology and Geophysics, 2001

Includes copies of articles co-authored by author during the preparation of this thesis in back pocket.
Includes bibliographical references (leaves 113-124).
viii, 172 leaves : ill. (some col.), maps ; 30 cm.
Focuses on the impact of change in the distribution of heat producing elements on lithospheric thermal regimes and on temperature dependent processes such as metamorphism, magmatism and deformation, with application to Proteozoic Australia (Mount Isa and Mount Painter inliers).
Thesis (Ph.D.)--Adelaide University, Dept. of Geology and Geophysics, 2001

This item is only available electronically.
The Ernest Henry Iron-oxide Copper Gold (IOCG) deposit is by far the largest in the Eastern Succession of the Mount Isa Inlier. In the current genetic model, the release of CO2 from fluids sourced from enriched mantle was critical to brecciation and mineralisation. However, a weakly mineralised and brecciated shear zone within the orebody named the ‘Inter-lens’ separates the orebody into two distinct lenses. The Inter-lens was not well reported early in the life of the mine and has not been taken into account in the current ore deposit models. Establishing the relative timing of the Inter-lens structure provides strong geological constraints for the formation of the orebody. In this study, optical petrographic investigations, Scanning Electron Microscopy (SEM) and Mineral Liberation Analysis (MLA) were used to investigate the protolith. Key mineral relationships and textures were assessed to reveal the paragenesis of the Inter-lens. Structural observations in oriented drill core complemented underground mapping of exposures of the Inter-lens to reveal the deformational history of the Inter-lens with respect to the Ernest Henry orebody. The protolith was revealed to be Mount Fort Constantine Metavolcanics that have undergone intense deformation with a metasomatic evolution broadly consistent with the main orebody. Mineralisation stages overprinted tectonic fabrics via veining, replacement and infill, providing direct evidence that the Inter-lens is a pre-mineralisation structure. Preservation of the Inter-lens during brecciation and mineralisation of the Ernest Henry deposit requires that the currently accepted ‘explosive’ breccia model must be revised.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016