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1
Macintosh, J. N. "Age and basin evolution of the Cuddapah Supergroup, India." Thesis, 2010. http://hdl.handle.net/2440/103376.
Full textAbstract:
This item is only available electronically.U-Pb zircon geochronology indicates deposition of the Cuddapah Supergroup, Cuddapah Basin, India occurred for at least 986 million years. Deposition started after 2502±17 Ma with the deposition of the Gulcheru Formation and ended after 913±11 Ma with the deposition of the Cumbum Formation. Maximum depositional ages have been found for individual formations within the Cuddapah Supergroup; the Pulivendla Formation has a maximum deposition of 1899±19 Ma and the Bairenkonda Formation has a maximum depositional age of 1660±22 Ma. Thermal events during the Palaeoproterozoic present a possible cause of basin formation. At this early stage of the Cuddapah Basin’s evolution the provenance of sediments was the Dharwar Craton, which currently underlies the basin and borders it on the north, south and west sides. The uplift of the Eastern Ghats on the eastern margin affected the evolution of the Cuddapah Basin, changing the shape and the sediments of the basin. Uplift and deformation events in the Eastern Ghats folded the eastern side of the Cuddapah Basin and are responsible for its present crescent shape. The formation of the Eastern Ghats caused increased subsidence to the east, creating an asymmetry in the depth of the basin. The provenance of the sediments of the Cuddapah Supergroup changed to the Eastern Ghats for the deposition of the youngest stratigraphic group, the Nallamalai Group.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
2
Pluckhahn, D. "The Palmer Granite: geochronology, geochemistry and genesis." Thesis, 1993. http://hdl.handle.net/2440/87543.
Full textAbstract:
This item is only available electronically.Various igneous bodies have intruded the Palmer area throughout the Delamerian Orogeny. The earliest, the Rathjen Gneiss, intruded either before or during D1 which gave it the prominent foliation. D1 was also responsible for crenulations in migmatite veins throughout the area. These crenelated migmatite veins are in areas folded by D2 mesoscale folds. Some pegmatite veins are also folded by D2 folds. The Palmer Granite intruded during D2 as is seen by shearing in a semi-crystalline state and a tectonic foliation that has been folded. The ballooning of the granite during emplacement deforms the surrounding sediments and the pre-granite folds hence their axes lie parallel to the contact of the granite. The effect of the granite intruding during the deformation has lead to the axis of the D2 folds forming after the granite to have a degree of randomness about their axis. Migmatite grade was reached again after the intrusion of the granite causing melt veins to develop to disrupt the foliation. D3 formed a regional syncline of the area combined with some small scale folding within the granite, however a foliation did not form. The emplacement of the granite and some other igneous bodies throughout the area has been controlled by using the bedding plane of the Kanmantoo. The geochemical trends throughout the Palmer Granite is formed by two different groups fractionally crystallising zircon, amphibole and biotite. This results in a decrease of normally incompatible elements. The two groups form by one group from a homogeneous source and the other a heterogeneous source. The xenoliths crystallised from a mafic magma. The amphibolites form two groups according to their differentiation and genetic relationship. They both form by fractional crystallisation however U and Pb are decreasing cannot be explained by this. Another possible mechanism is liquid un-mixing. To tie all of the groups together a model of a mafic pluton that crystallises the xenoliths as a chilled margin. The mafic magma evolves some of the Palmer Granite whilst turbulently convecting hence homogenising the magma. A magma recharge forms the more evolved mafic and this forms more Palmer Granite which convects in a laminar fashion forming heterogeneities. Part of the mafics evolve enough to be caught up in the Palmer Granite and as it does not crystallise zircons all the fractional crystallisation of the Palmer Granite must have occurred in the mafic plution.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 1993
3
Jagodzinski, E. "The geology of the Gawler Range Volcanics in the Toondulya Bluff area and U-Pb dating of the Yardea Dacite at Lake Acraman." Thesis, 1985. http://hdl.handle.net/2440/86564.
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This item is only available electronically.At Toondulya Bluff a sequence of 'older' Gawler Range Volcanics dip in an easterly direction beneath the overlying Yardea Dacite, and are intruded by the comagmatic Hiltaba Granite. The volcanics occur as a series of tuffs and lava flows. Geochemical evidence suggests these volcanics are related to each other by fractional crystallisation, with plagioclase, clinopyroxene, K-feldspar and titan-magnetite, and accessory zircon and apatite controlling differentiation trends. The Si-rich Hiltaba Granite and Yardea Dacite formed from the final, highly fractionated melts. Geothermometry suggests the volcanic and granite crystallised at temperatures within the range 680deg-850degC. The initial magma from which the lithologies were derived, was formed by partial melting of a lower crustal source probably of granulitic composition. Lake Acraman is believed to have been a site of meteoritic impact in the late Proterozoic (~600 Ma ago). Fragments of dacitic ejecta have been identified within the Bunyeroo Formation, Flinders Ranges and dating of these fragments gives an age of c.1575 Ma using single zircon ion probe dating techniques (Gostin et al in prep.). U/Pb dating of the Yardea Dacite at Lake Acraman reveals it to be of comparable age to these fragments (1603-1631 Ma). The lower intercept of the discordia line reveals there has been no resetting of the U/Pb system in response to the postulated meteoritic impact.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 1985
4
Teale, W. J. G. "Structure, geochronology and geochemistry of the Kadavur Dome, southern India." Thesis, 2010. http://hdl.handle.net/2440/106272.
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This item is only available electronically.An Investigation of the structure of the Kadavur Dome in India’s Southern Granulite Terrain has revealed an absence of domal features, and instead evidence for poly-deformational folding and thrusting. Zircon U/Pb analysis by Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICPMS) reveals that the quartzites of the Kadavur Valley in the north of the Madurai Block were deposited between the late Palaeo- and early Neoproterozoic. The depositional age and the detrital zircon populations found in the Kadavur quartzites are analogous to the depositional age and detrital zircon populations found in the Itremo Group of central Madagascar, which has been identified as a part of the former continent Azania. Metamorphic zircon rim analyses of Kadavur quartzites yield dates of ~840ma and ~882 Ma. These rims are interpreted as a result of contact metamorphism induced by the intrusion of nearby anorthositic gabbros, dated in this study at 825 ± 17 Ma. Thermal Ionisation Mass Spectrometry (TIMS) on whole rock samples of the igneous suite present in the Kadavur area reveal negative εNd values, while evidence of crustal contamination has been found by both Sensitive High Resolution Ion Microprobe (SHRIMP) analysis of oxygen isotopes and LA-Multicollector-ICPMS analysis of Lu/Hf isotopes. Thin section analysis reveals that the igneous suite is divided mineralogically into two broad groups. Major, trace and rare earth element (REE) geochemical analysis of these groups shows that they are also divided chemically. Geochemical discrimination plots of these samples suggest an Island Arc Basalt/Tholeiite petrogenesis. Of particular interest is a felsic gneiss sampled in the Kadavur Valley that has been interpreted as either a tuffaceous/volcanoclastic meta-sediment or felsic intrusive. The implication of this sample being a tuffaceous meta-sediment is that its age would date the Kadavur sequence and hence date the Itremo Group.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Haggar, W. P. "Structure and geochronology of the Alpine Schist, New Zealand." Thesis, 2013. http://hdl.handle.net/2440/100132.
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This item is only available electronically.The Alpine Schist is located on the eastern margin of the Alpine Fault, which accommodates oblique collision between the Pacific and Australian plates in New Zealand. Collision has been active since the Cenozoic and exhumation models predict that surface rocks were buried ~20km in the Pliocene. Despite this, fabrics of Mesozoic age are inferred to be preserved at the surface. In order to test the age of fabric formation, transects were conducted across the Alpine Schist to measure the foliation. Rock samples were collected to date the age of zircon and 40Ar/39Ar age of muscovite in order to constrain the age of metamorphism and fabric formation within the Alpine Schist. The structural data displayed two populations of foliations: a dominant foliation tracking towards the orientation of the Alpine Fault and a minor shallower orientation. The geochronological data highlighted ages for the formation and deposition of the Alpine Schist protolith and metamorphism associated with the Rangitata Orogeny. Muscovite 40Ar/39Ar data analysis yielded Pleistocene closure temperatures of the argon system. The heterogeneous foliation orientation and muscovite age suggested differential strain and fabric formation with the Alpine Schist during Plesitocene uplift along the Alpine Fault. The study of the active Southern Alps orogen and constraining the structural and geochronological features will enable more accurate interpretation of fossil orogens and their relationship with plate tectonics.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2013
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Schneider, A. N. "Protolith age and role in tectonic significance of the Eastern Ghats Domain, east India." Thesis, 2010. http://hdl.handle.net/2440/106235.
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This item is only available electronically.U/Pb age analyses were conducted on detrital zircons from Khondalites in the Eastern Ghats Belt (EGB) in eastern peninsular India. This study was aimed at determining detrital ages to help understand the nature of the protolith to the metasedimentary rocks. These khondalite terrains make up the most extensive terrains in the EGB yet they are poorly understood. They are important because they help constrain timing of tectonism in the Mesoproterozoic and the formation of Rodinia and Eastern Gondwana. There were very few detrital zircons in the samples collected from the EGB and age analyses could not be made from them. Metamorphic ages were recorded from metamorphic/metamorphically recrystallised zircons. The age of metamorphism recorded in these zircons is approximately 900 Ma. This age agrees with metamorphic ages predicted from previous studies. This metamorphism is a result of the collisional orogeny that amalgamated eastern India with eastern Antarctica in the Mesoproterozoic. A Pan-African overprint has been recorded in the zircon ages which range from 660-560 Ma. These are predicted to be from lead loss due to metamorphism and can be seen on the concordia plots for U/Pb age data.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Howlett, D. P. "Geochronological constraints on Yambah and Chewings-aged deformation at Mt Boothby in the south eastern Reynolds Range, Central Australia." Thesis, 2012. http://hdl.handle.net/2440/92257.
Full textAbstract:
This item is only available electronically.Zircon and monazite U–Pb isotope geochronology combined with structural mapping in the Mt Boothby region in the central Aileron Province in Central Australia has constrained the timing of two tectonically distinct phases of high-grade deformation and metamorphism. The first event (D1/M1) occurred at around 1790 Ma and was associated with the emplacement of a bimodal magmatic suite that underwent high-grade deformation prior to the emplacement of voluminous granite also at around 1790 Ma. The timing of D1/M1 coincides with the early stages of the Yambah Event, which is widely recognised in the southern Aileron Province, but has not previously been unequivocally shown to be associated with deformation . Subsequent pervasive reworking occurred over the interval 1600-1570 Ma, and was associated with long-lived granulite-grade metamorphism. The timing of this event coincides with the Chewings Orogeny which largely shaped the tectonic geology further west in the Reynolds and Anmatjira Ranges. During the Chewings Orogeny the c.1790 Ma D1 structures were transposed into a composite S1/S2 fabric. Map scale F2 folding is interpreted to have a shallow plunge suggesting that the S1 fabric may have originally been shallow dipping, raising the possibility that deformation was extensional in nature, and coeval with deposition of the nearby Reynolds Range Group which is constrained to the interval 1806-1785 Ma. Although inferred here to be Yambah aged, the timing constraints for D1 /M1 also overlap with the c. 1800 Ma Stafford Event which was associated with voluminous felsic magmatism, mafic magmatism and extreme geothermal gradient magmatism. This suggests that an extended period of extension, sedimentation, magmatism and deformation may have occurred at around 1800 Ma in the central Aileron Province.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
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Robertson, B. D. "The geology, petrology and geochemistry of the volcanics in the Kokatha Region, Gawler Ranges, South Australia." Thesis, 1989. http://hdl.handle.net/2440/128628.
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This item is only available electronically.Volcanics in the Kokatha region present a wider range of rock types than in other areas of the Gawler Ranges. High temperature Mg rich basalt flows through to rhyolite ignimbrites and air fall tuffs outcrop. Two magmatic cycles are observed with a cycle consisting of initial basalts, followed by voluminous dacites and rhyodacites. The final phase of the cycle following the rhydacites represents a period of more explosive activity resulting in the deposition of rhyolitic ignimbrites, air fall tuffs rhyolitic flows and pyroclastics. Geochemical data indicate both fractionation and mixing of fractionated components were active igneous processes resulting in the formation of layered magma chambers. The layering of the magma chambers being well illustrated in the stratigraphy of the volcanic pile. Further evidence for cyclic fractionation trends exists, with a relative depletion of incompatible elements in the second cycle when compared to the first cycle. Discrimination diagrams plot the rocks from Kokatha in the calc-alkaline field. Calc-alkaline series usually indicate subduction processes however volcanism at Kokatha is intracratonic. Rb-Sr data give an isochron age of 1588.4 ± 14 Ma suggesting the rocks from Kokatha are a part of the lower sequence of the Gawler Range Volcanics. Samples from both cycles produce the isochron indicating a melt from a homogeneous source. Neodymium data suggest a basaltic input from the mantle assimilating with lower crust is a likely source. A possible tectonic model for volcanism is presented. Initially a flux of mantle-derived basalt enters the lower crust. This provides heat for large scale melting. Assimilation of lower crustal melts and mantle-derived basalts may or may not occur however a homogeneous source is formed. Diapirism resulting in upper crustal magma chambers allows the formation of a layered magma chamber. Eruption of the magma results in the stratigraphic sequence of volcanic rock units.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1989
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Travers, D. C. "Geochronology, geochemistry and petrogenesis of mafic magmatism in the Coompana Province." Thesis, 2015. http://hdl.handle.net/2440/118238.
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This item is only available electronically.The Coompana Province between the Gawler Craton in South Australia and the Yilgarn Craton in Western Australia is one of the least understood geological regions in Australia. Recent work by Spaggiari and Smithies (2015) suggests that the known crustal precursors in the Coompana Province originated in a new crustal generation event at ca. 1900 Ma. This new juvenile crustal element then evolved through three distinct reworking and magmatic events at ca. 1610 Ma, ca. 1500 Ma, and between ca. 1192 – 1150 Ma (Wade et al., 2007; Spaggiari and Smithies, 2015). Dating of mafic volcanics underlying the Bight Basin in the south-eastern Coompana Province using the Sm-Nd mineral isochron method has revealed a fourth distinctive episode of mafic magmatism at ca. 860 Ma. The geochemical and Nd-isotopic signatures of ca. 860 ma mafic magmatism, including Nb and Ti anomalies, LREE enrichment, K-anomalies, and highly evolved εNd(860Ma) values between -9.9 and -12.7 provide evidence for assimilation and reworking of subduction/arc related Coompana Province crust. Magmatism at ca. 860 Ma in the Coompana Province was most likely coeval with widespread magmatism that occurred over Central and Southern Australia between ca. 800 – 830 Ma. Magmatism during this period was associated with the NE-SW directed intracratonic extension that resulted in the Centralian Superbasin and produced various suites of mafic volcanics and intrusives referred to collectively as the Willouran Basic Province. We suggest that the Willouran Basic Province now be extended to include the ca. 860 Ma mafic volcanics and intrusives in the south-eastern Coompana Province.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
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Reid, B. A. "Structural, geochronological and tectonic evolution of the central Eastern Ghats Province, India: Araku-Anantagiri-Visakhapatnam." Thesis, 2010. http://hdl.handle.net/2440/102762.
Full textAbstract:
This item is only available electronically.The central Eastern Ghats Province is part of a series of terranes that collectively form the Eastern Ghats in India. The Eastern Ghats is a Mesoproterozoic to early Neoproterozoic orogen associated with the formation of the supercontinent Rodinia, c. 1.1 to 0.95 Ga. The central Eastern Ghats Province consists of metaquartzites and metapelites (khondalites) that are intruded by granitoids. The location of proto-India within Rodinia is disputed because of recently presented palaeomagnetic data. This has generated confusion about whether the protoliths to the Eastern Ghats Province metasedimentary rocks were deposited adjacent to proto-India or as an exotic terrane later accreted to India. U-Pb geochronology, in conjunction with Hf isotopes of zircons, constrain the maximum depositional age, determine provenance and identify the location of deposition. A maximum depositional age of 1.14 Ga on the protoliths to the khondalites has been determined from U-Pb zircon geochronology. The short period of time between deposition and the orogenesis related thermal event indicates that the sediments were deposited adjacent to the Bastar Craton. Provenance work identifies a number of sources within India and east Antarctica lending support to the theory that these continents were contiguous prior to the Eastern Ghats Orogeny. Structural transects and mapping reveals that shortening associated with the collision of east Antarctica and proto-India occurred along a NE-SW trending axis.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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McDonald, G. D. "The petrology and timing of the Anabama Granite and associated igneous activity, Olary Region, SA." Thesis, 1992. http://hdl.handle.net/2440/122489.
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This item is only available electronically.Two ideologies of thought exist when models of granite genesis are considered. Do they represent the products of direct fractionation of a basaltic mantle melt, or, do they form in accordance with the restite model of White and Chappell (1977)? Assimilation and fractional crystallization (AFC) modelling of Nd - and Sr - isotopic data from the Anabama Granite, of this study, and data from the granites of the southern Adelaide Fold Belt, Antarctica and the Lachlan Fold Belt of New South Wales, all of approximately the same age, appears to reflect mixed sources with components derived both from an average Delamerian basalt composition and an average Archean crust composition. Results indicate that the Anabama Granite mostly represents primitive Delamerian basalt, contaminated by 12- 14 % Archean crustal material. Field relationships of the Anabama Granite indicate that it was the site of multiple magmatic intrusions, between approximately 490- 425 Ma. These intrusions are represented by several episodes of hydrothermal alteration and crosscutting dykes. A long-lived thermal source, not represented in the southern Adelaide Fold Belt, may be responsible for this ongoing magmatic activity. Examples of these dykes are the lamprophyre dyke, dated at 457 ± 18 Ma, which is similar in composition and appearance to the lamprophyres near Truro (South Australia) and the dacite porphyry dyke which crosscuts all other lithologies and was dated at 425 ± 13Ma. This age corresponds to the onset of thermal activity in the Lachlan Fold Belt, and therefore, leads to the suggestion that the region where the Anabama Granite outcrops may represent the western margin of the thermal perturbation responsible for the production of granitic melts in the Lachlan Fold Belt at around 400 Ma. Differences in source regions for the Anabama Granite, the granites of Antarctica and those of the Lachlan Fold Belt are recognized by the different Nd- and Sr - isotopic ratios, although all granites may represent the same process of formation, that being AFC. The dacite porphyry's isotopic signature indicates a more primitive source than that suggested for the Anabama Granite, and therefore its genesis does not represent a remelting of the Anabama Granite or of its source region. Geochemically, the Anabama Granite is similar to the Reedy Creek Granodiorite of the southern Adelaide Fold Belt and the Wanda Granodiorite of western Victoria. It can also be classified as an I-type granite using the criteria established by Chappell and White (1974). Geophysical gravity modelling of the Anabama Granite was carried out and it was found that the granite extends to a depth of approximately 15 km and dips uniformly to the north west. Thus giving an indication that fracture propagation, rather than plutonism, is the mechanism of granitic melt transport through the upper crust for the Anabama Granite and granites of the southern Adelaide Fold Belt.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1992
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Blades, Morgan. "The age and origin of the western Ethiopian Shield." Thesis, 2013. http://hdl.handle.net/2440/83744.
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This item is only available electronically.Western Ethiopia is made up of a range of supra-crustal and plutonic rocks. The Precambrian exposures of the Western Ethiopian Shield are positioned within the juvenile Neoproterozoic crust of the Arabian Nubian Shield and the older, predominately gneissic Mozambique Belt (Woldemichael et al. 2010). The age and origin of the Western Ethiopian Shield are still largely unidentified. The aim of this paper is to constrain the age and origin of the sedimentary and igneous rocks within the Western Ethiopian Shield. This will be done using isotopic techniques. The detrital zircons have been analysed for U-Pb age (yielding maximum depositional ages and age provenance information) and Hf isotopes (to investigate the nature of zircons). Geochemical analysis on the Thermal Ionisation Mass Spectrometer (TIMS), Inductively Coupled Plasma Mass Spectromentry (ICP-MS) and microprobe has also been undertaken. One of the focuses is the examination of the volcanic and volcaniclastic successions, as well as, the geochemical nature of the ultra-mafic bodies in the Shield. The geochemistry of metavolcanic and meta-volcaniclastic data suggest that the origin of the volcanics formed in an arc-like setting. Relatively low niobium; however, suggest that the mantle source may have been more enriched than that seen in modern volcanic arcs. Detrital zircons, obtained from a meta-sandstone, yielded provenance age peaks at ~2499 Ma, ~1855 Ma and between 1100-800 Ma and a maximum depositional age of 838 ± 13 Ma. Hf Isotopes from the same zircons demonstrated that both the oldest and youngest populations have broadly juvenile Hf isotopic values however; ~1820 Ma age shows significantly evolved Hf isotopic values. A minimum age constraint on the deformation was provided by the U-Pb age of 572 .6 ± 7.6 Ma and yielded whole epsilon Nd values of 3.74 and epsilon Hf values of 6.79-7.98, demonstrating a juvenile origin. A significant aspect of the Arabian-Nubian Shield is the interpretation of the N-S oriented regional shear zones. Concentrically zoned mafic/ultramafic bodies, previously identified as remnants of the oceanic crust, are suggested to be Alaskan-type intrusions. Though chemically different to typical Alaskan-type intrusions these display a subduction affinity and have close associations to shear-zone hosted intrusions elsewhere in the Arabian Nubian Shield. Thus, they have been interpreted as being formed in similar supra subduction intrusive settings.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2013
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Simpson, C. A. "Constraints on Proterozoic crustal evolution from an isotopic and geochemical study of clastic sediments of the Gawler Craton, South Australia." Thesis, 1994. http://hdl.handle.net/2440/88297.
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This item is only available electronically.The Gawler Craton comprises tocks varying in age from Archaean to more recent Phanerozoic sediments. The rocks of greatest interest in defining processes of early crustal formation and evolution in the Australian continent, are the basement material older than approximately 1400 Ma (pre-cratonisation), comprising deformed and metamorphosed rocks suites of Archaean and Proterozoic metasediments and gneisses. These suites span an immense period of intense geological history, and as such are a topic of much past and present study. Detailed mapping in the Tumby Bay region of eastern Eyre Peninsula outlines stratigraphic and structural evolution of a sequence of Proterozoic rock suites, these are proposed to be related to other recognised deformation episodes elsewhere within the Gawler Craton, thus regional correlation is inferred. A new theory for development of two lineations within the map region is postulated by two movement directions along the Kalinjala Mylonite Zone. Geochemically the Proterozoic sediments of the Gawler Craton are similar to upper crustal average values of Taylor & McClennan (1985). However, characteristic depletions in Nb and Sr are recognised. Consistency in trace element compositions for Archaean and Proterozoic samples would suggest recycling of older Archaean crust into Proterozoic sediments and granitoids. Analysis of representative trace element ratios and indices of alteration and weathering suggest some change in geochemistry throughout the Proterozoic period. Selected Proterozoic elastic sedimentary suites were geochemicaly and isotopically (Sm-Nd) analysed, with the data being presented within this thesis. The most interesting of these being the Pandurra Formation, red-bed sediments deposited within the north-eastern Stuart Shelf region of the Gawler Craton. These sediments exhibit a change in measured isotopic values, with younger epsilon neodymium (ENd), and higher Sm/Nd ratios observed (ENd(O) = -14.67, Sm/Nd = 0.2441), than typical older Gawler Craton rocks (average Proterozoic sediments ENd(O) = -21.85, Sm/Nd = 0.1847). This isotopic shift is also recognised within the Adelaide Fold Belt to the east of the Gawler Craton (average shales ENd(O) = -16.20, Sm/Nd = 0.1942). A source for these younger signatures is not recognised within the Gawler Craton, and therefore more distal province sources, OR isotopic alteration in the originally considered 'robust' Sm-Nd isotopic system, are proposed.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 1994
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Cave, B. W. "U-Pb geochronology and trace element analysis of apatite and calcite from Ernest Henry." Thesis, 2017. http://hdl.handle.net/2440/126656.
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This item is only available electronically.Ernest Henry is the largest known IOCG deposit in the Eastern Succession of the Mount Isa inlier, NW Queensland. To improve our understanding of the timing of alteration and mineralisation in the Ernest Henry deposit, we attempt to date apatite from the Interlens (a pre-mineralization structure) and the ore-stage breccia, and calcite from the Interlens, ore-stage breccia and post-mineralization alteration using the in-situ U-Pb LA-ICP-MS method. This also approach provides the opportunity to examine the trace element composition of the minerals, which can be used to identify their sources and constrain metasomatic processes. Coarse-grained apatite from Interlens was dated at 1581 ± 16 Ma, coeval with regional peak metamorphic conditions and D2 deformation of the Isan Orogeny. Finer-grained apatite from the Interlens produced an age of 1557 ± 23 Ma, possibly representing regional D2, D2.5 or D3 deformation, coeval with retrograde metamorphic conditions. Ore-stage apatite produced an age of 1529 ± 39 Ma, coeval with the accepted age for sulphide mineralisation, D3 deformation and the formation of the nearby Mount Margaret Granite. Calcite samples were unable to be dated by this method, as the samples were dominated by common lead. Trace element analysis indicate that apatite from the Interlens and ore-stage assemblage were sourced from magmatic/hydrothermal fluids. Furthermore, metasomatism and coupled dissolution re-precipitation reactions of apatite were induced by a Na and/or Ca rich fluid, possessing varying amounts of Cl and S. Calcite from this study displays similarities with altered granites, and greisen type deposits, likely the result of fluid diffusing through the heavily altered Mount Fort Constantine host rocks. This study also geochemically links calcite from the Ernest Henry and the nearby E1 deposit, suggesting the REE composition of calcite may be used to link hydrothermal systems from various deposits.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
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Neumann, N. L. "Isotopic and geochemical characteristics of the British Empire Granite as indicators of magma provenance and processes of melt generation in the Mount Painter Inlier, South Australia." Thesis, 1996. http://hdl.handle.net/2440/114328.
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This item is only available electronically.The production of granitic magmas at shallow to midcrustal depths by anatexis of crustal material requires a significant thermal perturbation of the normal crustal geothermal regime. Thermal perturbations leading to anatexis may be initiated by crustal thickening associated with deformation, intrusion and/or upwelling of heat sources from lower crust or mantle regions or by anomalous concentrations of heat-producing elements, U, Th and K. This thesis explores the origin of shallow to mid-crustal peraluminous granites within the Mount Painter Inlier, together with their relationship to older granite suites, as indicators of magmatic processes during crustal deformation of the Delamerian Orogeny. The geochemical and isotopic characteristics of granites and gneisses of the Mount Painter Inlier indicate two distinct periods of granitic evolution involving different source regions and magmatic processes. Proterozoic granites and gneisses reflect magmatic sources and processes similar to those involved in the evolution of other Australian anorogenic Proterozoic terrains, although extreme concentrations of U, Th and K suggest an important role for element concentration within accessory minerals during granite genesis. Field relationships, together with geochemical and isotopic characteristics of the Palaeozoic(?) British Empire Granite indicate evolution from a complex mixture of surrounding metasediments and granites in a number of possible scenarios. The additional thermal energy required to produce the British Empire Granite from partial melting of this package at depths of approximately 12 to 15 km is consistent with perturbed thermal regimes resulting from anomalous internal heat production due to the extreme concentration of U, Th and K within the Proterozoic units.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1996
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Telenko, B. "High pressure metamorphism during intracratonic orogenesis: physical conditions and rates from the Amata region, Musgrave Province." Thesis, 2010. http://hdl.handle.net/2440/106276.
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This item is only available electronically.The intracratonic orogenesis of the Petermann Orogeny caused the formation of high-pressure, low-geothermal gradient, eclogite facies rocks. These geologically rare rocks are found in the exposed orogenic core, observable near the Traditional community of Amata, in the Musgrave Province. Their formation remains a mystery and as a result two contrasting models have been proposed to explain their formation; namely whether orogenesis occurred in “hot” crust and was long lived, or occurred in “cold” crust and was short-lived. In situ LA-ICP-MS analysis of monazite show that metamorphism occurred at c. 598 Ma. Using conventional thermobarometric techniques, peak conditions are estimated to have reached ~640 °C and ~11.5 kbar. Integrating this data with petrological observations and calculated P-T pseudosections, a clock-wise P-T path was defined, which is typical of an orogenic setting. Diffusion modelling using garnet compositional profiles from grains of both relict composition and those interpreted to be reset, estimated the minimum duration for prograde metamorphism to be ~27 Myr. The same garnet grains show little to no evidence of cooling/exhumation, which has been attributed to the low metamorphic peak temperature. Results of this study make a direct contribution to two contrasting models for orogenesis. Combining new evidence from this study with tectonothermal evidence from the western Musgrave Province and sedimentological data from the Officer Basin to the south, it is concluded that shear heating (or short-lived deformation) is not a plausible model for Petermann-aged deformation. Despite the lack of spatially continuous data across the Musgrave Province, long-lived orogenesis is the more supported model in light of new evidence emerging from this study.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Verco, R. T. "A metamorphic, geochronological and structural framework for the evolution of the Leeuwin Complex, south west Western Australia." Thesis, 2008. https://hdl.handle.net/2440/136898.
Full textAbstract:
This item is only available electronically.The Leeuwin Complex of southwestern Western Australia forms the best exposed component of the Pinjarra Orogen, where early Cambrian deformation and metamorphism represents one of the final events in Gondwana amalgamation. Three structurally different domains within the Leeuwin Complex are identified and a structural model for pure shear (coaxial strain) is preferred for the subhorizontal structures of the central structural domain. This is based on the identification of four phases of progressive deformation within the central structural domain that are interpreted to have occurred during or after peak metamorphism. Subvertical compression accounts for D1 and D2 deformation and D3 represents a transition from subvertical compression to pure shear east-west shortening. D4 structures are interpreted as post peak metamorphism east-west extension. U-Pb SHRIMP and LA-ICPMS analysis of zircon and monazite constrain peak metamorphism to c522 Ma. Thermobarometric calculations for peak metamorphic mineral assemblages yield average P-T estimations of 7.24 ± 0.61 kbar and 687 ± 28°C for the Leeuwin Complex. P-T calculations based on mineral rim compositions reflect retrograde conditions ~0.5 - 1 kbar less and ~50 - 100°C cooler than peak metamorphic conditions, implying that the Leeuwin Complex remained at mid-crustal levels after peak metamorphism. Analysis of chemical zoning in garnet suggests that after a prolonged period at mid-crustal depths, the Leeuwin Complex was exhumed rapidly. Sm - Nd isotopic data are presented for selected samples that reflect the two apparent protoliths of the felsic orthogneisses. Epsilon-Nd values are comparable to Sm - Nd isotope data from eastern Antarctica. Evolved Epsilon Nd is interpreted to indicate that the petrogenesis of the Leeuwin Complex protoliths involved partial melting of an enriched crustal source, is interpreted to be the Mesoproterozoic Naturaliste Plateau, which is considered to be a western continuation of the Albany-Fraser crust.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2008
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Cox, G. M. "Jebel Tays ophiolitic thrust sheet, Saudi Arabia: tectonic setting, petrogenesis and geochronological framework." Thesis, 2009. http://hdl.handle.net/2440/128700.
Full textAbstract:
This item is only available electronically.The Arabian Nubian Shield (ANS) records multiple episodes of terrane amalgamation associated with the closure of the Mozambique Ocean and the amalgamation of Gondwana. Evidence for such amalgamation events are recorded by repeated ophiolite decorated sutures across the ANS. The Jebel Tays ophiolite is situated in the eastern portion of the ANS, within the Ad Dawadimi Basin and surrounded by the Abt Schist. This basin separates the Afif and Ar Rayn arc terranes and represents one of the last terrane amalgamation events affecting the exposed ANS. I identify mafic magmatism associated with Jebel Tays as a low titanium island arc tholeiite with forearc affinity (boninitic) in contrast to the island arc tholeiite magmatism of the nearby Halaban ophiolite. Furthermore, I place robust zircon ages on mafic magmatism of 678 ± 5.1 Ma for the gabbros of Jebel Tays and 674.4 ± 5.7 Ma for the Halaban ophiolite. Based on the stratigraphy and structure of Jebel Tays and the sub-greenschist nature of the thrust contacts I propose that Jebel Tays represents a forearc ophiolitic thrust sheet. Its obduction was associated with extensive serpentinite mud volcanism within a forearc environment associated with a west dipping subducting slab. From detrital zircons obtained from the Abt Formation I constrain deposition of the Ad Dawadimi basin sediments to ca 600 Ma, making them Ediacaran in age, a date that coincides with a new LA-ICP-MS monazite metamorphic age of 599.8 ± 5.8 Ma obtained from a trondhjemite that cross cuts the Jebel Tays body. This is in agreement with previously published 40Ar/39Ar ages which I interpret as metamorphism associated with final basin closure and the amalgamation of the Afif and Ar Rayn Terranes.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2009
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Wenk, H. L. "The tectonic evolution of the North Qinling Terrane, Qinling Orogen, Central China." Thesis, 2016. http://hdl.handle.net/2440/121357.
Full textAbstract:
This item is only available electronically.The Qinling Orogenic Belt represents a collisional orogen, involving a complex architectural and geological history from the Proterozoic to late Palaeozoic. The timing of plate collision and orogenesis is under debate, due to the presence of highly deformed and metamorphosed exotic terranes within the orogeny. One such terrane is the North Qinling Terrane, which comprises a metasedimentary sequence of gneisses, schists, marbles and amphibolites known as the Qinling Group. Its origin and evolution are not well known, but it forms a well-defined tectonic unit separated from the North China Craton by Neoproterozoic and Palaeozoic suture zones and volcanic terranes. Here I present zircon and apatite U-Pb data, coupled with Perple_X metamorphic constraints. Four metamorphic samples were chosen to examine the tectonic affinity of this terrane, timing of major metamorphic events and the age of the potential basement. Two granitoid samples are dated to constrain the age of magmatic activity. Detrital zircon U-Pb data puts the formation of the Qinling group schist younger than the late Mesoproterozoic (1067 Ma), showing limited similarities in the zircon age spectra to the Cathasyia Terrane. Felsic gneiss samples are interpreted to be metagranitoids, with their protoliths intruding at ca. 850-900 Ma. Granitoids yielded two ages of magmatism, one in the Neoproterozoic (889.9 ± 6.9 Ma), suggesting similarities with the metagranitoid protoliths. The other intruded in the Palaeozoic (414 ± 18 Ma), with an apatite U-Pb age constrained to 421 ± 16 Ma, suggesting the suite did not reach the apatite closure temperature of 450 ºC in subsequent tectonic events. Timing of metamorphisim is constrained by the zircon record, with an age range between ca. 494-463 Ma through the use of low Th/U ratios of the youngest zircon in three of the four metamorphic samples. This study furthers understanding of Neoproterozoic and Palaeozoic tectonic evolution North Qinling Terrane.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016
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Maughan, J. K. "Geochemistry of the mafic sequences in the Cloncurry District, Queensland: implications for crustal accretion and prospectivity." Thesis, 2016. http://hdl.handle.net/2440/121123.
Full textAbstract:
This item is only available electronically.The Cloncurry District, Queensland, is a classic Iron Oxide Copper Gold (IOCG) terrain. However, the geochemical characteristics of the numerous mafic intrusives (dominantly dolerite dykes), which are often spatially and temporally associated with mineralisation, have never been studied in detail. Specifically, the newly described dolerite-associated Great Australia-Taipan-Mongoose-Magpie (GATPMM) deposits are thought to represent a distinct Cu-Co-carbonate-rich, Au-poor style of IOCG mineralisation that has not been documented elsewhere in the district. Trace element geochemistry provides evidence that these dykes formed from lower crust fractionation and magmatic ascent throughout intracontinental extension. There are significant REE links to previously studied granites of the Naraku and Williams Batholith within the district, indicating a similar melt source for both igneous lithologies. Geochronological studies of hydrothermal titanite (1515± Ma) and apatite (1177±37 Ma and 1179±41 Ma) from the Mongoose prospect provide constraints on the age of initial intrusion and alteration and provide evidence for thermal-tectonic activity within the Eastern Succession ca. 1100-1200 Ma, possibly related to the Albany-Fraser and/or Musgravian Orogenies. Geochemical relationships between mineralised dolerite samples from the CuDECO Rocklands deposit and local barren dolerite samples are also analysed and display geochemical similarity. This is consistent with the interpretation that dolerite geochemistry alone is not an indicator of prospectivity and is not linked to the distribution of mineralisation.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016
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Collins, L. J. "Low-temperature mica schists of Anglesey, UK: cold subduction on the margin of Avalonia." Thesis, 2017. http://hdl.handle.net/2440/126658.
Full textAbstract:
This item is only available electronically.Anglesey in North Wales is considered to contain the oldest exposures of lawsonite-glaucophane blueschist in the world, marking the first appearance of lawsonite in the geological record, and heralding the emergence of truly modern subduction thermal regimes. The blueschists formed in the late Neoproterozoic during subduction beneath Avalonia. Interlayered within the blueschist unit are rare lenses of garnet-bearing metapelite that form part of a lithological association with more voluminous garnet-free metapelites. Detrital U-Pb zircon geochronology of the metapelites indicates that deposition of the protolith occurred ~630-590 Ma ago. The dominant detrital zircon ages correspond to the age of arc magmatism along the inferred margin of Avalonia, suggesting that the bulk of the detritus was derived from erosion of the arc. The presence of less abundant older zircons that range in age up to 2Ga, suggest that the arc was built on an ancient continental margin. This suggestion is supported by Nd isotopic compositions of the metapelites, which indicate derivation from an evolved source. The rare garnet metapelites contain the metamorphic assemblage garnet-muscovite-chlorite-albite-quartz-titanite-rutile-pyrite in which coronas of rutile surround titanite. Phase equilibria forward modelling of the metapelites indicates a prograde burial path that culminated with conditions around 400-450°C, at pressures of 10-12kbar. These conditions give an average thermal gradient of around 40°C/kbar, which is comparatively warm for lawsonite-bearing rocks. This suggests the Anglesey lawsonite-bearing blueschists record the onset of global subduction thermal regimes in the late Neoproterozoic that can stabilise lawsonite, rather than simply being a fortuitous preservation of widely developed refrigerated metamorphic rock systems.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
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Lewis, C. J. "A structural, geochronological & geochemical investigation of the Abt Schist; Ad Dawadimi Terrane; central Saudi Arabia." Thesis, 2009. http://hdl.handle.net/2440/129334.
Full textAbstract:
This item is only available electronically.The Ad Dawadimi Terrane lies on the eastern margin of the Arabian-Nubian Shield between the ~800-600 Ma Ar Rayn Terrane to the east and the Palaeo-Neoproterozoic (1800-630 Ma) Afif Terrane to the west. The Ad Dawadimi Terrane is considered to be one of the most homogeneous terranes of the Arabian Shield and is dominated by the Abt Schist, a greenschist facies metamorphic unit of fine-grained sandstones and siltstones. Structural data shows variations in the foliations between the Ad Dawadimi Terrane’s eastern and western margins. The east is dominated by westsouth-west verging sub-horizontal, moderately inclined, open, asymmetrical folds with a subhorizontal to gentle south-south-east plunge. The western margin, although less well constrained, is dominated by folds with a west-north-west vergence, sub-horizontal, moderately – gently inclined, open, asymmetrical geometry; with a north-east south-west extensional component. 206Pb/238U data for Abt Schist samples within the Ad Dawadimi Terrane give a maximum depositional age of 594 ±14 Ma (2σ error at 95-105% concordance). Two 40Ar/39Ar metamorphic muscovite step-heating analyses yield peak metamorphic of ages ~616 ± 3 Ma and ~613 ± 6 Ma thus being within error of the youngest 206Pb/238U detrital zircon age. A number of zircon grains yield 206Pb/238U ages >1 Ga suggest a Mesoproterozoic, or older, influence on the source for the Abt sediments. This is supported by TIMS TDM model ages ~1154 ± 19 Ma suggesting Abt Schist protolith sediments were influenced by late Mesoproterozoic sources. Sedimentary geochemical analyses of immobile elements suggest sediments derived from the Afif Terrane were deposited into a fore-arc setting above a west dipping subducting slab. The very short time period between deposition and basin closure also suggests a fore-arc setting. Post deformation mafic dykes cross-cut the dominant foliation of the Ad Dawadimi Terrane, suggesting a period of extension after basin closure.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2009
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Capogreco, N. "Provenance and thermal history of the Beetaloo Basin using illite crystallinity and zircon geochronology and trace element data." Thesis, 2017. http://hdl.handle.net/2440/126541.
Full textAbstract:
This item is only available electronically.The Beetaloo Basin of the ‘greater McArthur Basin’, is a 15,000km2 Palaeoproterozoic depocenter which hosts shallow water, dominantly marine, clastic sedimentary rocks and is a large hydrocarbon reserve. Here I present LA-ICP-MS detrital zircon U-Pb age data, Rare Earth Elemental zircon and illite crystallinity XRD results and compare with existing studies to explore the variation in provenance throughout the basin and to better understand its temperature history as much of the basins’ history is still unknown. Nine sandstone and seventeen shale core samples were analysed. New constraints were placed on the depositional age for the Corcoran Formation to between 1390 ± 27 Ma and 1324 ± 4 Ma. The Velkerri Formation, Moroak Sandstone and Kyalla Formation of the Maiwok Sub-group all largely supported the results of previous studies yielding comparable maximum depositional ages. Zircon phosphorous concentrations revealed a largely I-type granitic source rock indicating the granites were formed in arc related settings. Detrital zircon age data revealed possible origins of sediments showing that the Corcoran Formation has a major source of ca. 1600 Ma zircons which are not unlike rocks from Eastern Queensland orogens. The Velkerri Formations’ main age peak falls at ca. 1765 Ma which shows a change to older detrital source rocks with more similarities to the Arunta and Kathleen and Western Orogenies. Moving up-section to the Moroak Sandstone and Kyalla Formations, samples shift to younger ca. 1560 Ma peak ages at the base of the Moroak followed by a gradual increase in age with younger sequences where a maximum peak age of ca. 1795 Ma is found in the mid Kyalla Formation. This gradual increase shows a gradual shift in sediment source from E/SE sources to southern source regions. Illite crystallinity data show that the shales within the Beetaloo Basin have experienced much greater temperatures than at present. Altree 2 has an XRD calculated bottom-hole temperature of 155°C at1647m depth, the Jamison records 156°C at 1695m with the Elliot being the hottest at 194°C at 1697 deep. These values were then used to calculate the amount of cover removed from present day. Altree 2 returned an estimate of 2050m of cover removed, Jamison 1769m and Elliot with the most cover removed at 2680m showing that the southern region of the Beetaloo Basin has experienced the greatest uplift since maximum subsidence followed by the northern Altree 2.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
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Dupavillon, P. R. "Metamorphic evolution of the western Gawler Craton." Thesis, 2015. http://hdl.handle.net/2440/118006.
Full textAbstract:
This item is only available electronically.The tectonothermal evolution of the western Gawler Craton, including the Fowler Domain, during Proterozoic Australia is currently poorly understood. In-situ U-Pb ages obtained in this study from the Fowler Domain yielded ages of metamorphism at c. 1732–1701 Ma attributed to the Kimban Orogeny, and at c. 1599 Ma attributed to Kararan/Hiltiba events. Quantitative phase equilibria modelling, i.e. pressure-temperature pseudosections, provide the first modern metamorphic constraints on pressure–temperature conditions for two areas within the Fowler Domain and are ~2.6–7.4 kbar and 550– 700°C for the Barton Block, and 8.2–8.7 kbar and 450– 475°C for the Nundroo Block which equate to apparent thermal gradients of approximately ~116–135°C /kbar and ~50–60 °C/kbar respectively. These thermal gradients occur within the hotter part of the ‘high T/P or Barrovian’ (Barton Block) and ‘colder than normal’ (or eclogite–high-pressure granulite, Nundroo Block) subdivisions of P–T space. This is suggestive of extension in the Barton Block and later convergence in the Nundroo Block. Kimban-aged tectonism in other parts of the Gawler Craton records thermal gradients ranging between ~150–133 °C/kbar. These differences in thermal gradients are appreciable, and in some cases different from previous studies on the Fowler Domain. The Curnamona Province (north-north eastern South Australian Craton) possesses sedimentation and thermal gradients consistent with divergence within this time period. This has prompted many scientific debates surrounding tectonic regime of the Proterozoic time line, which are yet to include any metamorphic quantitative pressure-temperature considerations. Apparent thermal gradients presented in this study are consistent with both divergence within the Kimban Orogenesis time line 1730–1690 Ma, and convergence within Kararn-/Hiltiba time line 1600–1550Ma. These processes are interpreted to record Tasmanide type tectonic regimes.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
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Benton, R. Y. "A petrological, geochemical and isotopic investigation of granitoids from the Olary Province of South Australia – implications for Proterozoic crustal growth." Thesis, 1994. http://hdl.handle.net/2440/120547.
Full textAbstract:
This item is only available electronically.Analysis of granitoids from the Olary Block of South Australia, gave rise to the identification of three genetically different granitoids. The Bimbowrie Granite, characterised by high Al203, CaO, K2O, P205, Rb, Sr, Pb, Zn and low Na20, Nb, Zr, Ga and Y is an S-type granite, considered to be largely a product of partial anatexis and melt segregation from adjacent and underlying migmatitic metasediments during a high grade metamorphic event. The Basso Granodiorite with high Si02, Zr, Nb, Y and LREE and low CaO, Al203, MgO, V, Ba and Sr is a typical A-type granite, that is it formed from remelting of crust from which earlier granites had been extracted, or alternatively from fractionation of basaltic magma. It intrudes the host metasediments and is subsequently intruded by the Bimbowrie Granite. Thirdly, the Antro Tonalite exhibits I-type characteristics with high Fe203, Na20, CaO and Ti02 levels and low LREE and K2O. Rb-Sr dating produced an isochron age of 1642 ± 5 Ma for the Basso Granodiorite and metasedimentary units. The Rb-Sr isotope system is easily reset, and generally registers significantly younger ages. Hence, 1642 ± 5 Ma may reflect the timing of a metamorphic/deformational event. Sm-Nd isotope investigations into the Olary Block revealed a clustering of model ages. The Bimbowrie Granite has DM model ages of 2.6 - 2.67 Ga, recording the age of extraction from the mantle. One sample did however produce an age of 3.28 Ga, reflecting the granite’s source. That is, it may be sampling metasediment derived from older crust, present either as a basal sequence upon which the current stratigraphy is deposited or alternatively it may be sourcing a metasedimentary pile with a greater crustal residence time than the exposed metasediments. DM model age for the metasediment of 2.55 Ga further supports the notion that the Bimbowrie Granite formed as a result of in situ melting of the metasedimentary sequence. 2.12 - 2.13 Ga DM model ages were determined for the Basso Granodiorite. One sample did however have a TDM similar to the S-type granites of 2.61 Ga; this clearly indicates crustal contamination of this sample during emplacement, whereas the other samples reflect true mantle separation ages. Regardless of the exact rates of crustal growth, it is clear that large volumes of continental crust were formed during the Palaeo- Mesoproterozoic. Identification of crustal production peaks for the Australian continent at -3600 Ma, -2600 Ma, -2200 Ma and -1800 Ma by McCulloch (1987), are reinforced by the data obtained herein. Two peaks were established, one at -2600 Ma for the Bimbowrie Granite and the other at -2200 for the Basso Granodiorite. Controversy still remains over whether these periods are discrete growth episodes or simply reflect a variation in the rate of recycling of continental crust into the mantle.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1994
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Trestrail, J. L. "U-Pb detrital zircon, geochemical and Nd isotope constraints on sedimentary provenance of the Chewings Range Quartzite, Warumpi Province, Arunta Region, NT." Thesis, 2010. http://hdl.handle.net/2440/106279.
Full textAbstract:
This item is only available electronically.The Chewings Range Quartzite is a meta-sedimentary cover sequence located in the Warumpi Province of the Arunta Region. U-Pb detrital Zircon analysis of the Chewings Range Quartzite indicates a minimum depositional age of ~ 1640Ma, with the main population of zircons residing within a range of 1700 – 1800Ma. Evidence from Sm-Nd isotopic data suggests that a series of Staurolite Garnet Schists, often grouped with the Chewings Range Quartzite, has a significantly more juvenile character. This suggests that it may represent a new unit with a significantly differing provenance to that of the Chewings Range Quartzite. Combined REE, geochemistry and detrital zircon dating suggests that the Chewings Range Quartzite was derived primarily off the Arunta Region and North Australian Craton, while the Stauralite Garnet Schists holds more affinity with juvenile Musgrave Province to the south.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Morphett, W. J. "Geochronological and structural insights into the evolution of the Lower Burra and Callana Groups near Arkaroola: structural mapping and U-Pb metamorphic monazite dating." Thesis, 2013. http://hdl.handle.net/2440/106291.
Full textAbstract:
This item is only available electronically.The lowermost sediments of the Adelaide Supergroup near Arkaroola display pronounced structural complexity and anomalously high metamorphic grade. The timing of the structures, fabrics and metamorphism in the region remain unconstrained, although all are currently interpreted to have occurred during the Delamerian Orogeny. Monazite U/Pb geochronology provides a useful technique for dating amphibolites facies rocks and, combined with map scale and micro structural observations, suggests the peak metamorphism and at least one deformation event occurred significantly earlier than the Delamerian Orogeny. Monazite derived 206Pb/238U age estimates place the timing of peak metamorphism at 705.2±7.4 Ma with observations from thin section revealing a bedding parallel fabric pre-dating peak metamorphism. U/Pb analysis also reveals a second monazite growth event at 644.2±8 Ma the cause of which is hypothesised to be fluid related. Regional folding and axial planar fabric generation post-dates this metamorphism and can be seen to overprint the earlier fabric and wrap the cordierite porphyroblasts. This final deformation event remains largely unconstrained as in situ dating of monazite was not possible in this study. The inferred parasitic relationship between the folds within the studied region and the Arkaroola Syncline which folds the youngest sediments in the Adelaidian Sequence allows for the deposition to be constrained subsequent to the conclusion of the Adelaide Rift Complex.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2013
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Smith, T. M. "‘McArthur’s Zircons, a Tale of Two Arenites’ – provenance and evolution of the Maiwok Sub-Group, McArthur Basin, Northern Territory." Thesis, 2016. http://hdl.handle.net/2440/121233.
Full textAbstract:
This item is only available electronically.The Beetaloo Basin is a sub-basin of the ‘greater McArthur Basin’, a >180,000 km2 ca. 1800-900 Ma basin system that covers much of northern Australia and, in its Mesoproterozoic section, hosts extensive hydrocarbon reserves. The nature of the basin and provenance of the rocks within the basin are largely unknown. Here I present detrital zircon U-Pb data from twelve sandstone core samples from the Maiwok Sub-group, and compare them with existing outcrop samples from the Urapunga Region within the McArthur Basin to examine the maximum depositional ages of the formations, to address intra-basin correlation, and examine both temporal and spatial provenance variations. Detritus analysed yielded early Palaeoarchean to early Neoproterozoic ages from sandstone formations of the Maiwok Sub-group, in the Beetaloo Basin (Fig. 1). In the Beetaloo Basin; the Bessie Creek Sandstone formation was deposited between 1386 ± 13 Ma and 1324 ± 8 Ma, and the Moroak Sandstone formation was deposited after1375 ± 15 Ma. The formation logged as the Moroak Sandstone (320.0-391.72m) in Altree 2 drillcore was logged incorrectly. Detrital zircon data has shown this sandstone is too young to be the Moroak Sandstone. I have reinterpreted this interval in Altree 2 as Bukalorkmi Sandstone from 359.5-391.72m and Jamison Sandstone from 320.0-359.5m (Fig. 7). In Altree 2, the Bukalorkmi Sandstone was deposited after 1194 ± 25 Ma and the Jamison Sandstone was deposited between 959 ± 18 Ma and 513 ± 12 Ma. Temporal provenance variations are minimal between the Bessie Creek Sandstone and the Moroak Sandstone, but much greater between the Moroak Sandstone and the Jamison/Bukalorkmi Sandstone formations. The Walton High defines a spatial provenance boundary from the north and the south (Fig. 12). This boundary affects Maiwok Sub-group sandstones, including exposed formations, and has been under appreciated in previous studies.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016
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Van, Leeuwin A. T. dV. "New constraints on the tectonometamorphic evolution of the Fisher Terrane, central Prince Charles Mountains, eastern Antarctica." Thesis, 2017. http://hdl.handle.net/2440/128283.
Full textAbstract:
This item is only available electronically.The Fisher Terrane, located in the central region of the Prince Charles Mountains, east Antarctica, evolved during the Mesoproterozoic as a magmatic arc system. Metapelitic schists from the Fisher Massif were deposited after 1206 ± 49 Ma and yield metamorphic monazite ages of c. 538–505 Ma relating to the regionally recognized Neoproterozoic to early Cambrian Prydz Event. Calculated phase equilibria modelling constrains the metamorphic conditions during this event to 2.6–4.0 kbar and 553–576°C, relating to apparent thermal gradients of 144 °C/kbar to 212 °C/kbar. Conditions such as these are plausibly related to metamorphism taking place in an extensional back-arc setting which was then subsequently inverted and thickened via continental collision. A migmatitic felsic gneiss from Nilsson Rocks yields metamorphic monazite 206Pb/238U ages between 1115–1050 Ma with a weighted average age of 1085.0 ± 7.1 Ma. This metamorphic event may relate to a similarly aged episode of subduction related magmatism identified elsewhere in the central Prince Charles Mountains. This study therefore presents evidence of previously unidentified Prydz-aged high-thermal gradient metamorphism in the Fisher Terrane as well as identifying an older c. 1085 Ma metamorphic event not documented elsewhere in the Prince Charles Mountains.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
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Brett, D. "Structural, geochemical and isotopic investigation of granitoids within the central area of the eastern Weekeroo Inlier, Olary Domain, South Australia." Thesis, 1998. http://hdl.handle.net/2440/119992.
Full textAbstract:
This item is only available electronically.In the central part of the eastern Weekeroo Inlier, Olary Domain, two types of granite have been identified. This thesis explores both granite types in order to explain possible tectonic environments and geological evolution during the Proterozoic. The A-type Walter Outalpa granite is characterised by high Si02, Zr, Nb, Y, rare earth elements (REE) and low MgO, CaO, Ti02, P205 and light field strength elements (LFSE). High zircon saturation temperatures differentiate this fractionated A-type granite from potential fractionated I-type granites. The peraluminous granite is characterised by high Si0, Al203, Rb, U, Th, and low MgO, CaO, Ti02, Sr and light REE. It displays strong geochemical similarities to the Bimbowrie S-type granite. Consistent geochemical and isotopic characteristics for the Walter Outalpa granite and other similar A-type granites across the Olary Domain indicate a single regional crustal plus mantle source. Partial melting of lower Archaean crust due to lithospheric thinning is proposed. Geochemistry and isotopic analysis of the peraluminous granites suggest varying infracrustal sources for loosely grouped S-type granites in the Olary Domain. Previous interpretations for the depositional environment of the Willyama Supergroup metasediments in a continental rift setting are supported by comagmatic A-type volcanics and granites within the central part of the eastern Weekeroo Inlier. An extensional environment during emplacement is consistent with evidence for shallow level emplacement such as graphic texture, and the absence of a contact aureole for the Walter Outalpa granite. There is foliation development and evidence of folding for three deformation events during the Proterozoic Olarian Orogeny. Timing relationships between granitoids and metasediments in this area have constrained relative timing of emplacement. Low temperature solid state deformation affected the A-type Walter Outalpa granite after emplacement into Willyama Supergroup metasediments. Crosscutting relationships between the peraluminous granite and adjacent deformed metasediments imply a late to post D2 emplacement for this granite.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1998
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Then, M. "Constraints on the origin of early high-heat producing (U-Th enriched) granitic magmatism in central Australia." Thesis, 2016. http://hdl.handle.net/2440/121352.
Full textAbstract:
This item is only available electronically.The southern margin of central Australia is characterised by anomalous heat production, 3–5 times higher than global averages. Paleoproterozoic voluminous granitoid complexes in the region are important in the study of this anomalous heat flow. Ca.1800 Ma high-heat producing granites in Mt Boothby have A/NCK (molecular Al2O3/(CaO+Na2O+K2O)) ratios > 1, indicating a predominant origin from partial melting of metasedimentary rocks. The Boothby Orthogneiss is characterised by moderately negative Eu anomalies (Eu/Eu*: 0.03–0.43) and strong depletion in Ba, Rb, Nb and Sr. The enrichment of Ba and Rb relative to Sr and high K2O contents also support a metasedimentary source. The heat production values calculated for the Boothby Orthogneiss and the surrounding Lander formation show that the region is enriched in heat producing elements. The U-Pb zircon age data of inherited zircons in these granites are similar to the detrital zircons of the widespread outcropping; Lander formation. Nd values of -3.5 to 1.3 of the granites infer an evolved crustal source coupled with mixing of a newly mantle-derived component through lower crust assimilation. Zircon saturation temperatures calculated suggest that the Boothby intrusive complex was emplaced at 688–845oC, with a maximum temperature of 776oC, implying an arc environment with associated fluid-flux melting in the mantle wedge, ultimately controlled by subduction dynamics.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016
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Kolesik, P. "U–Pb geochronology of volcano–sedimentary moraine sediments of the Bunger Hills: implications for Mesoproterozoic evolution of East Antarctica." Thesis, 2016. http://hdl.handle.net/2440/120941.
Full textAbstract:
This item is only available electronically.The Bunger Hills and adjacent areas of Wilkes Land and Queen Mary Land occupy the very western periphery of the Musgrave–Albany–Fraser Orogen, and represent one of the few exposures within east Antarctica with direct correlations to Australian constituent terrains of this continental-scale system. U–Pb analyses of detrital zircons from volcano–sedimentary moraine sediments of the Bunger Hills yield concordant 206Pb/238U ages ranging from ca. 1364 Ma to ca. 1040 Ma (n = 842), with a main late Mesoproterozoic magmatic zircon population clustered at ca. 1179–1161 Ma. Strong parallels with the time profile of in-situ rocks from the Stage 2 Albany–Fraser Orogen (AFO), the Bunger Hills and Windmill Islands, suggest these were the likely provenances for the associated moraine detritus. The Bunger Hills lie downstream from outcrops of the geographically inaccessible Sandow Group, which comprises clastic and mafic volcanoclastic rocks. It is interpreted that the sedimentary moraine materials of the Bunger Hills were derived from the glacial erosion of the Sandow Group supracrustal successions. The lithological character, sedimentary fill pattern and advanced diagenesis suggest that the Sandow Group formed within an active intra-continental rift-basin and represents the upper-crustal expression of extensional tectonism. Reconnaissance U–Pb geochronology of authigenic titanite suggests basin development occurred close to or within the time frame of the high-grade metamorphism recorded in the Bunger Hills. Therefore basin development was probably directly associated with the second major thermo–tectonic phase of the AFO (Stage 2; ca. 1215–1140 Ma). Due to the essentially non-metamorphosed volcano–sedimentary nature of the detritus in the sedimentary rocks, it seems likely that the evolving Mesoproterozoic orogenic system was not deeply exhumed during basin development.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016
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Williams, M. A. "Unravelling polymetamorphism in east Antarctica using evidence from the Cape Denison moraines, Terre Adélie Craton, and Gawler Craton, South Australia." Thesis, 2015. http://hdl.handle.net/2440/118241.
Full textAbstract:
This item is only available electronically.Polymetamorphic signatures in rocks can be difficult to deconvolve, especially where events have similar metamorphic grade. In situ and erratic samples from the Terre Adélie Craton, Antarctica, and in situ samples from the formerly contiguous Gawler Craton, South Australia, are examined to deconvolve microstructural, pressure–temperature and geochronological evidence of terrane-scale polymetamorphism. In situ monazite U–Pb geochronology shows that coastal and erratic samples record c. 1700 Ma and c. 2420 Ma ages, consistent with known ages of the Kimban and Sleafordian events, respectively. In situ samples from the Antarctic coast record exclusively c. 2420 Ma ages whereas most erratic samples from the glacial moraines at Cape Denison record only c. 1700 Ma ages. Phase equilibria forward modelling for the c. 2000 Ma Redbanks Charnockite uniquely constrains peak metamorphic conditions of the c. 1700 Ma Kimban Orogeny to 5.0–7.2 kbar and 700–860 ºC. Peak metamorphic conditions of the c. 2420 Ma event are ~5–8.7 kbar and 690–1000 ºC, as constrained by in situ samples from the Terre Adélie coast. As the peak pressure–temperature conditions for the two events are similar and the record of polymetamorphism is cryptic and spatially variable in the rock record, Antarctic samples that only record Kimban ages are interpreted as reflecting either a record of complete overprinting of the older (c. 2420 Ma) event, or that the rocks are younger than the c. 2420 Ma event. In such a situation polymetamorphism at a terrane scale may only be detected by differences in geochronological data. This study serves to highlight the careful approach required when investigating polymetamorphic terranes and argues that a spatially variable record of overprinting metamorphism is possibly related to locations of retrogression occurring either in the waning/exhumation stages of the earlier event or between events.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
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Anderson, J. R. "High-P-T early Palaeoproterozoic metamorphism in southern India." Thesis, 2010. http://hdl.handle.net/2440/98283.
Full textAbstract:
This item is only available electronically.Southern India is comprised of granulite facies metamorphosed crustal blocks, separated by crust penetrating shear zones that have experienced a diverse tectonothermal history from the Archaean to Cambrian. The early Palaeoproterozoic metamorphosed Salem Block in southern India preserves felsic and mafic gneisses ideal for investigating the aerial extent of the preserved Archaean-Palaeoproterozoic southern Indian crust and the metamorphic rock record in the Archaean-Palaeoproterozoic transition. U-Pb zircon, in situ monazite geochronology and zircon REE analysis obtained using Laser-Ablation Inductively-Coupled-Plasma Mass-Spectrometry (LA-ICP-MS), and P-T phase equilibria and average P-T conventional thermobarometry calculated using THERMOCALC from the Kanja Malai Hills, demonstrate that the Salem Block extends south to at least the northern Palghat-Cauvery Shear System. Peak P-T estimates of ~800-850 ºC and 14-16 kbar at ca. 2490 Ma were attained in the southern Salem Block and suggest decompression followed peak metamorphism. The P-T-t constraints in the southern Salem Block are anomalously high pressure compared to other Archaean-Palaeoproterozoic metamorphic events and require thermal regimes that are typically generated in convergent plate margin settings.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2010
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Thomas, M. C. "Erskine Sandstone Formation: a provenance and geochronological study within the Fitzroy Trough, Western Australia." Thesis, 2012. http://hdl.handle.net/2440/95492.
Full textAbstract:
This item is only available electronically.The Erskine Sandstone Formation is located in the Fitzroy Trough, within the northern Canning Basin, Western Australia. The provenance evolution of the onshore Triassic sandstone of the Erskine Sandstone Formation has not previously been researched. Field work was conducted predominantly at two areas, the Erskine Range, the type section of the Sandstone, and the May River outcrops which include the Pinnacle Rock outcrop. Field work in the area showed a transitional boundary between the underlying Blina Shale and the Erskine Sandstone Formation making identification of the boundary zones difficult. Through the use of U-Pb zircon analysis on samples taken from the Erskine Range and the May River, this study suggests the two outcrops have differing sources. Samples taken from the Erskine Range contain Permian aged sediments which are not present in the May River samples. The significant presence of Mesoproterozoic sediments in the May River samples which are not reflected in the Erskine Range samples further suggests different sources. The large presence of Palaeoproterozoic sediments in both the Erskine Range and the May River outcrops suggests the uranium rich King Leopold Ranges is a possible source. These sediments, combined with the presence of reductants in the Erskine Sandstone Formation suggest the possibility of sandstone-hosted uranium mineralisation within the Fitzroy Trough. Other possible sediment sources include the Musgrave Block and Arunta Inlier, located to the south, and suggest a complex detrital history of the Fitzroy Trough.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
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Lawson-Wyatt, M. A. "Regional Inkamulla-aged (ca. 1740–1755 Ma) tectonism along strike of the Mt Hay-Redbank Hill region, southern Aileron Province, central Australia." Thesis, 2012. http://hdl.handle.net/2440/92908.
Full textAbstract:
This item is only available electronically.LA-ICP-MS U-Pb monazite and zircon geochronology from granulite facies metapelites and granites indicate Inkamulla-aged metamorphism has occurred in the southern Aileron province, immediately east of the Mt Hay and Mt Chapple massifs. Gneissic metasediments and a granitic gneiss from an EW-striking structural belt in the southern Aileron Province yield ages reflective of the Inkamulla Igneous Event (1754-1741 Ma) and the Chewings Event (1593-1545 Ma), along with magmatic ages of 1627 and 1641 Ma. The Chewings age is interpreted to represent structural reworking associated with discrete shear zones along the northern margin of the EW belt. Magmatic ages of ca. 1640 Ma typically associated with Warumpi Province magmatism and deformation are found within the study area, which weakens the argument that the Warumpi terrane is exotic from the Aileron Province. The metamorphic conditions of 780-920°C and 5-10 kbars indicate an elevated geothermal gradient.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
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Fields, C. E. "Liebig-aged (c. 1640 Ma) magmatism and metamorphism in c. 1760 Ma crust in the Warumpi and southern Aileron Province, central Australia: a case for revising the tectonic framework of Proterozoic Australia." Thesis, 2012. http://hdl.handle.net/2440/92217.
Full textAbstract:
This item is only available electronically.The southern margin of the North Australian Craton (NAC) has been suggested to represent a long-lived (c. 1860 to 1600 Ma) active margin that preserves a cryptic record of the growth and assembly of the Australian continent. The Warumpi Province is juxtaposed against the southern Aileron Province, and has been interpreted as exotic to the NAC, though the timing of collision between the Warumpi Province and the southern Aileron Province is contentious. U-Pb zircon and monazite LA-ICP-MS geochronology from granulite facies metapelites and granitic gneisses along the southern margin of the Aileron Province and northern margin of the Warumpi Province, has shown it is characterised by c. 1780-1740 Ma magmatic rocks and c. 1640-1615 Ma magmatic and metamorphic rocks. The evidence for these events is preserved in kilometre-scale migmatitic boudins and low-strain zones enveloped by pervasive E-W trending higher strain belts. The overprinting high strain fabrics are Grenvillian age and constrained to c. 1175-1070 Ma. Phase equilibria modelling on a garnet-sillimanite-cordierite metapelite dated at c.1616 Ma, from a low-strain domain within the southern Aileron Province, indicates that peak metamorphic conditions were ~7-8 kbar and between 740-900 °C, and were associated with a down-pressure or decompressional P-T history. A metamorphic monazite age of c.1620 Ma was also preserved in a granitic gneiss located in an older, low-strain domain. The presence of the c. 1760 Ma and c. 1640 Ma timelines in both the Warumpi and Aileron Provinces calls into question the proposed exotic nature of the Warumpi Province. A speculative interpretation is that the Liebig-aged metamorphism and magmatism, seemingly associated with relatively shallow orientated, low strain fabrics, represents a period of extension rather than collision.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
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Falster, G. M. "Geochronological and sedimentological constraints on the evolution of the lower Cuddapah Basin, India." Thesis, 2011. http://hdl.handle.net/2440/96124.
Full textAbstract:
This item is only available electronically.The Palaeo- to Mesoproterozoic Cuddapah Supergroup was deposited in the Cuddapah Basin, which is one of a number of Proterozoic volcano-sedimentary basins that overlie the Indian Shield. On the south-western margin of the basin, the stratigraphic succession in the basal Papaghni and Chitravati groups is initially composed of gravelly fluvial deposits with dominant sediment input coming from the western foreland. These are succeeded by shallow-water stromatolitic dolomite and shale with a significantly reduced siliciclastic component, and finally by sub-tidal laminated silt and sand. A detailed facies analysis of these rocks suggests that deposition occurred initially in an active extensional setting which subsequently developed into a passive extensional setting. Stable isotope geochemistry of dolomites in the Vempalle Formation of the Papaghni Group indicates that deposition of the formation may initially have occurred in a restricted setting where δ13C varied according to fractionation via environmental processes. Whether the Vempalle Formation was deposited in a shallow marine or lacustrine milieu is equivocal; δ13C values may correlate with the conclusion of the global oceanic “Lomagundi” positive δ13C excursion around 2100 Ma, however, this inference requires the carbonates to have been precipitated in oceanic water, and have retained their primary isotopic signature during pervasive dolomitisation. U-Pb dating of detrital zircon grains from the Gandikota Formation – previously thought to be the uppermost formation of the Chitravati Group – yields a maximum depositional age of 1207 ± 22 Ma. This is significantly younger than intrusive igneous rocks within the Cuddapah Supergroup and it is therefore likely that the Gandikota Formation is part of the overlying Meso- to Neoproterozoic Kurnool Group. The detrital zircon age spectrum of the Gandikota Formation indicates significant sediment input from the east, which is likely to be a result of the thrusting of the Eastern Ghats Belt onto the Eastern Dharwar Craton and a reversal of the prevailing extensional regime in the Cuddapah Basin. A number of authors have proposed a genetic link between the Cuddapah Basin and several other Proterozoic basins of the Indian Shield. This study provides no reason to directly correlate the temporally and spatially distinct basins.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011
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Kimpton, B. J. "The geological relationship between Kanmantoo Cu-Au deposit mineralisation, hydrothermal metasomatism and igneous intrusives." Thesis, 2018. http://hdl.handle.net/2440/130628.
Full textAbstract:
This item is only available electronically.The Kanmantoo Cu-Au deposit has been in episodic operation since 1846, one decade after the capital city of Adelaide was established some 40 kilometres to the NW. Regionally and within the host stratigraphy there exists archetypal evidence of the Cambrian Delamerian Orogeny through a complex structural, metamorphic and intrusive history. Consequently, numerous theories exist within the literature regarding a syngenetic or epigenetic style of mineralisation and the debated contribution, if any, of magmatic hydrothermal fluids. This study has documented numerous felsic intrusive vein sets within the Kanmantoo Cu-Au deposit which have been utilised to constrain the role of igneous activity on mineralisation within a wider Delamerian context. Monazite U–Pb ages of felsic veins show that intrusion first occurred at syn-peak metamorphic, syn-orogenic conditions (495.11 ± 2.79 Ma), continuing periodically until post-peak metamorphic, extensional conditions (483.43 ± 2.52 Ma). Intrusions are coeval with mineralisation and are temporally and geochemically analogous to magmatic activity in the adjacent Monarto and Murray Bridge provinces. Analysis of trace elements in monazites identifies the Kanmantoo Cu-Au deposit as a syn- to post-peak metamorphic hydrothermal anomaly which, combined with the presence of felsic veins, indicates that mineralisation resulted partly from fluids generated by a pluton at depth. These findings broadly confirm the prospectivity of Delamerian-affected terranes throughout large parts of South Eastern Australia where pervasive intrusive geology exists.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018
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Al-Kiyumi, M. "Constraining the age and provenance of the basal quartzites of the Centralian Superbasin." Thesis, 2018. http://hdl.handle.net/2440/130321.
Full textAbstract:
This item is only available electronically.The Heavitree Formation of the Amadeus Basin, central Australia, is thought to correlate with a number of similar formations in the Officer, Ngalia, Georgina and Murraba Basins that formed the Centralian Superbasin. The Jasper Gorge Formation of the Victoria Basin and Jamison Sandstone of the Beetaloo Sub-basin are also thought to be corollaries. These formations are all constrained to being younger than ca. 1.0 Ga by U-Pb detrital zircon studies. However, in all cases, this is suspected to considerably pre-date the timing of deposition. Here, we present new U-Pb and Hf data from seven samples of the Amadeus Basin Heavitree Formation to a) better constrain the age of the Heavitree Formation, b) investigate the spatial variation in provenance of the Heavitree Formation, and, c) compare it with other ‘Supersequence 1’ quartzites from the wider Centralian Superbasin.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018
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Simpson, A. D. W. "The Meso-Cenozoic deformation history of Thailand and Myanmar; insights from calcite U-Pb and apatite fission track thermochronology." Thesis, 2018. https://hdl.handle.net/2440/133682.
Full textAbstract:
This item is only available electronically.Given the absence of suitable dating methods, the timing of low-temperature crustal deformation is usually established by indirect methods (such as apatite fission track (AFT) thermochronology). Few studies have previously ventured into directly constraining the absolute timing of brittle deformation (such as authigenic illite dating). U-Pb dating of calcite in tectonic veins represents a new method to potentially directly date brittle deformation events (Roberts and Walker, 2016). By utilising this method in combination with apatite U-Pb and fission track thermochronology, this study sheds new light on the upper crustal deformation history of Thailand and Myanmar. U-Pb calcite ages demonstrate tectonic activity at ~216-209Ma in the Khao Kwang Fold and Thrust Belt associated with the Indosinian stage 2 collision between the Sibumasu Block and the Indochina Block. Brittle deformation along the Three Pagodas Fault Zone (TPFZ) was dated at ~45Ma and ~24Ma (and possibly as recently as ~1.3Ma). AFT thermochronology suggests exhumation in the Tin province of southern Myanmar at ~26Ma-18Ma. These dates are in agreement with previous regional AFT studies in Thailand and with calcite U-Pb dates for the TPFZ, suggesting fault reactivation in response to the India-Eurasia collision and rifting in the Andaman Sea. Calcite U-Pb ages were obtained with uncertainties as low as ~1%, which is an unprecedented precision for the timing of brittle deformation. This work further demonstrates that calcite elemental mapping, in combination with U-Pb dating, can be used to distinguish different calcite growth events. Particularly enrichments in Mn or depletions in LREE concentrations in calcite seem useful to distinguish different fluids and associated calcite (re)crystallisation events. Although further work is required to enhance our understanding of both Pb diffusion in calcite as well as geochemical tracers for calcite recrystallization, the combination of calcite U-Pb with apatite fission track thermochronology is a promising novel tool to enhance our understanding of the timing of brittle deformation.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018
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Greenslade, M. M. "Ultrahigh temperature metamorphism: testing models for collision vs extension." Thesis, 2015. http://hdl.handle.net/2440/118029.
Full textAbstract:
This item is only available electronically.The Warumpi Province has been interpreted to be exotic and accreted to the Northern Australian Craton (NAC) during the Liebig Orogeny at c.1640Ma. However, phase equilibria modelling of melt-deficient, Mg-Al rich granulite facies rocks at Hill 830, in the Mount Liebig area show contradictory evidence of a decompressional pressure-temperature path and a high metamorphic gradient of 90°Ckbar. This interpretation in conjunction with abundant c.1780- 1740Ma and c.1640Ma magmatism in the southern Aileron and Warumpi Provinces, indicate that the tectonic regime at c.1640Ma may instead be a south-migrating, extensional scenario, compared to the previously accepted collisonal regime; speculating that the Warumpi Province is not ‘exotic’ to the NAC.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
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Chalk, H. C. "Mesoproterozoic bimodal magmatism of southern Australia: assessing relative mantle input and implications for IOCG mineralisation prospectivity." Thesis, 2014. http://hdl.handle.net/2440/109703.
Full textAbstract:
This item is only available electronically.Mesoproterozoic magmatism of the Gawler Craton and the Curnamona Province demonstrates regions of variable mantle input characteristics. Zircons from Hiltaba Suite granitoids and Gawler Range Volcanics, Gawler Craton, return εHf(T) values ranging from +7.1 to -0.4, +2.0 to -7.4, and +0.2 to -5.3 from the western, central, and eastern Gawler Craton respectively. Ninnerie Supersuite granitoids and Benagerie Volcanic Suite, Curnamona Province, return εHf(T) values ranging from +2.5 to -3.8. Mantle input modelling of the central/eastern Gawler Craton and the Curnamona Province returns similar mantle input fraction values ranging from 0.1 to 0.6, averaging 0.3, and 0.1 to 0.6, averaging 0.3, respectively. Hiltaba Suite magmatism of the western Gawler Craton is compositionally more juvenile than the central and eastern regions. The western Gawler Craton mantle input fractions range from 0.2 to 0.9 averaging 0.5, more elevated than the central/eastern regions of the Gawler Craton and the Curnamona province. The Benagerie Ridge region of the Curnamona Province displays similar bimodal ca. 1590 Ma magmatism, εHf(T) values, mantle input characteristics, crustal preservation (exhumation) and regional iron oxide copper-gold alteration as the highly prospective Olympic IOCG Province, Gawler Craton.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2014