The Aegean region contains numerous metamorphic core complexes that reflect post-collision extensional tectonics. The largest of these is the Menderes Massif of western Turkey, which covers an area of ~40,000 km². The Selimiye Shear Zone bounds its southern border and is a key location for studying the metamorphic history of the massif. Models of the tectonic evolution of the region requires an understanding of the peak pressure-temperature (P-T) conditions recorded by rocks in the massif, and the time (t) at which they achieved those conditions. However, limited P-T-t data exists in the Southern Menderes Massif. Here, P-T-t data was obtained from garnet-bearing rocks collected perpendicular to strike along seven transects spaced about 35 km across the Selimiye Shear Zone. Garnets in nine samples from four transects were analyzed using high-resolution back-scattered electron (BSE) imagery, X-ray element (Fe, Mg, Mn, Ca and Y) maps, and quantitative compositional analyses. Both zircon and monazite grains were dated in rock thin section using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS) to ascertain the timing of events recorded by the rocks. Some garnet X-ray element maps show zoning consistent with multiple stages of growth, diffusion, and retrogression. Distinct zones in each sample are visible on high contrast BSE images and can be related to Y, Fe, and Mn contents. The conventional garnet + biotite geothermometer and garnet + plagioclase + muscovite + biotite geobarometer were used to estimate peak metamorphic P-T conditions. These range from 556±10°C to 671±27°C, and 15.3±0.2 kbar to 22.4±0.5 kbar. The temperatures are similar to previous estimates, but the pressures appear about ~10 kbar higher the previous estimates. U-Pb zircon ages range from 2022±30 Ma (13.4% disc.) to 254±5 Ma (13.4% disc.). Based on Th/U contents, the oldest ages are likely related to inherited grains from magmatic sources. The youngest zircon age is the first reported Triassic grain from the Southern Menderes Massif and may relate to the closure event of the Paleo-Tethyan Ocean. A younger history is recorded by U-Pb and Th-Pb monazite ages, which range Cretaceous to Miocene. Monazite geochronology is hindered by the contamination of high amounts of common Pb, but U-Pb and Th-Pb age calculations show Miocene to Jurassic ages. The textures of monazite (i.e. drusy, filling cracks of garnet and in reaction with allanite) imply that ages could record crystallization and/or fluid dissolution/reprecipitation mediated events in the Oligocene. Data reported here support the observation that polymetamorphic events are recorded in the Southern Menderes Massif rocks in close proximity to the Selimiye Shear Zone. Two options are possible environments of continental exhumation of rocks along the zone: (1) a polymetamorphic history that records relict high-pressures from previous metamorphic events or (2) a single-stage exhumation of high-pressure rocks. / text

Spatial correlation functions, which quantify spatial relationships among porphyroblasts over a range of length scales, can be used in combination with other techniques of quantitative textural analysis to constrain crystallization mechanisms in metamorphic rocks. The utility, reliability, and robustness of these functions, however, depend critically upon correct methods of calculation and application to geological samples. Application of the L' -function, Pair Correlation Function, and Mark Correlation Function (Stoyan and Stoyan, 1994) to artificial arrangements of crystals yields results consistent with their predetermined ordering and clustering qualities. These results serve as a foundation for the interpretation of more complex simulated and natural crystal arrays. Analysis of artificial and simulated crystal arrays in which ordering signals are obscured in various ways (displacing crystals in an ordered array by increasing amounts, reducing the number of crystals, and increasing the sample's aspect ratio) demonstrates that these scale-dependent functions are robust indicators of effects diagnostic of certain crystallization mechanisms, even in complex circumstances. The effects of clustering of nucleation sites, however, can strongly obscure any underlying signal that might reveal crystallization mechanisms. The L' -function and the Pair Correlation Function are sensitive to short-range ordering of crystals, which may reflect suppression of nucleation in the vicinity of growing porphyroblasts. The Mark Correlation Function is sensitive to size-isolation correlations, which may reflect retardation of growth among crystals competing for nutrients. Interpretation of these functions, however, requires careful attention to proper calculation of Monte Carlo simulations, which are used to identify values of the functions that constitute a null-hypothesis region for comparison to samples with unknown ordering and clustering characteristics. To yield functional values commensurate with those calculated for a particular natural rock specimen, each simulation must match as closely as possible several critical features of the natural rock, including the set of crystal radii, limitations on the observability of crystals, and the shape and size of the bounding surface of the sample. Crystallization mechanisms in seven previously studied garnetiferous rocks from three localities (Carlson et al., 1995; Denison and Carlson, 1997) have been re-assessed using both scale-dependent correlation functions and single-valued spatial statistics, both evaluated by comparison to rigorously computed null-hypothesis regions. The results confirm previous inferences that the nucleation and growth rates of the garnet porphyroblasts in these specimens were governed by rates of diffusion through the intergranular medium. / text

The rocks studied in this thesis have been the subject of considerable discussion as to their original nature. J. D. Bateman of the Geological Survey of Canada considers that they are of igneous origin whereas others believe that they are metamorphosed sediments. It was thought that a petrographical study might provide some information that would help to decide the problem and it was with this object in view that this study was undertaken. Cree Lake, in the vicinity of which the rocks occur, is situated 2 miles North of the Sherritt-Gordon Mine, Manitoba, which lies about 20 miles east of the Manitoba-Saskatchewan border and 120 miles northwest of the north end of L. Winnipeg. The Sherritt-Gordon copper-zinc ore deposit is a very remarkable deposit in that it is a tabular body with a total outcrop length of 16,000 feet and an average width of 15 feet, thus being one of the longest exposed ore bodies in the world. The rocks in question outcrop around Found Lake which lies very close to and just to the southeast of Cree Lake (see Map 44-4) and fall into two groups; firstly, thos that outcrop south of Found Lake in an area which was mapped by J. D. Bateman as an oval body of oligoclase granite (Map 44-4, No. 12) about one mile long and 1/4 mile wide and secondly, those that outcrop as three smaller masses north of Found Lake but enclosed by the arms of Cree Lake and mapped as anorthositic gabbro (Map 44-4, No. 11). [...]

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The Gawler Craton in South Australia consists of an Archaean to Palaeoproterozoic core surrounded and intruded by a series of Palaeo- to Mesoproterozoic metasediments and igneous suites. The region has experienced a protracted c. 1700 Myr tectonic history from the Archaean through to the Mesoproterozoic, experiencing numerous cycles of deformation, magmatism and basin development. Despite hosting a number of mineral deposits, including the immense Olympic Dam iron oxide-copper-gold deposit, the tectonothermal evolution of the Gawler Craton remains poorly constrained. A significant ambiguity in our current understanding of the geological framework of the Gawler Craton revolves around the timing and spatial distribution of the tectonic events within the craton and their metamorphic evolution. This study addresses some of this ambiguity by unravelling the timing and tectonothermal evolution of the reworked southern Gawler Craton, using a combination of structural and metamorphic analysis, coupled with targeted geochronology. These methods have been applied to three locations representing different lithologies across the southern Gawler Craton. Putting absolute time into structural and metamorphic analysis is a vital tool for unravelling the development of ancient and modern orogenic systems. Electron Probe Micro-Analysis (EPMA) chemical dating of monazite provides a useful method of obtaining good precision age data from monazite bearing assemblages. This technique was developed at the University of Adelaide in order to constrain the timing of reworked assemblages from the southern Gawler Craton. EPMA measurements carried out on samples of known age, from Palaeoproterozoic to Ordovician, produce ages which are within error of the isotopically determined ages, indicating the validity of the developed setup. This technique, together with SHRIMP monazite and titanite and garnet Sm-Nd geochronology, was used on selected samples from the southern Gawler Craton to determine the timing of high-grade metamorphism and deformation. The results show that the Sleaford Complex records evidence of an early D₁event during the c. 2450 Ma Sleaford Orogeny recorded within structural boudins. The majority of the data indicates that the region underwent subsequent reworking and thorough overprinting during the 1725–1690 Ma Kimban Orogeny. In the Coffin Bay region, Palaeoproterozoic peraluminous granites of the Dutton Suite are reworked by a series of migmatitic and mylonitic shear zones during the Kimban Orogeny. Peak metamorphic conditions recorded in mafic assemblages indicate conditions of 10 kbar at 730°C. The post-peak evolution is constrained by partial to complete replacement of garnet – clinopyroxene bearing mafic assemblages by hornblende – plagioclase symplectites, which record conditions of c. 6 kbar at 700°C, implying a steeply decompressional exhumation path. The Shoal Point region consists of a series of reworked granulite-facies metapelitic and metaigneous units which belong to the late Archaean Sleaford Complex. Structural evidence indicates three phases of fabric development with D₁retained within boudins, D₂consisting of a series upright open to isoclinal folds producing an axial planar fabric and D₃, a highly planar vertical high-strain fabric which overprints the D₂ fabric. Geochronology constrains the D₁ event to the c. 2450 Ma Sleafordian Orogeny while the D₂the D₃events are constrained to the 1730–1690 Ma Kimban Orogeny. P-T pseudosections constrain the metamorphic conditions for the Sleafordian Orogeny to between 4.5–6 kbar and 750–780 °C. Subsequent Kimban-aged reworking reached peak metamorphic conditions of 8–9 kbar at 820–850 °C during the D₂ event. Followed by near isothermal decompression to metamorphic conditions <6 kbar and 790–850 °C associated with the development of the D₃high-strain fabric. The Pt Neill and Mine Creek regions are located in the core and on the flank of the crustal scale Kalinjala Shear Zone, which forms the main structural element of the poorly exposed Kimban Orogen. Samples record a similar structural development with a dextrally transpressive system resulting in a layer parallel migmatitic gneissic to mylonitic KS₁ fabric which was subsequently deformed and reworked by upright folds and discrete KD₂ east-side-down sub-solidus mylonitic shear zones during east-west compression. Geochronology constrains the timing of deformation and metamorphism to the Kimban Orogeny between 1720 and 1700 Ma. Metamorphic P-T analysis and pseudosections constrain the peak M₁ conditions in the core of the shear zone to 10–11 kbar at c. 800 °C reflecting lower crustal conditions at depths of up to 30 km. On the flank of the shear zone the M₁ conditions reached 6–7 kbar at 750 °C followed by sub-solidus reworking during KD₂ at conditions of 3–4 kbar at 600–660 °C, suggesting a maximum burial of <24 km. Cooling rates suggest that the core of the shear zone cooled at rates in excess of 40–80 °CMa⁻¹ while the flank underwent much slower cooling at < 10°CMa⁻¹. The rapid cooling and inferred decompression in the core of the shear zone reflects rapid burial and exhumation of lower-crustal material into the mid-crust along the Kalinjala Shear Zone. The absence of evidence for extension indicates that differential exhumation and the extrusion of lower-crustal material into the mid-crust was driven by transpression along the shear zone and highlights the role of transpression in creating large variations in vertical exhumation over relatively short lateral extents. Garnet is a vital mineral for determining constrained P-T-t paths as it can give both the P-T and t information directly. However, estimates of the closure temperature of the Sm-Nd system in garnet vary considerably leading to significant uncertainties in the timing of peak conditions. Five igneous garnets of varying size from an undeformed 2414 ± 6 Ma garnet – cordierite bearing s-type granite from the Coffin Bay region, that were subjected to high-T reworking during the Kimban Orogeny, have been dated to examine their diffusional behaviour in the Sm-Nd system. Garnets were compositionally profiled and then dated. A direct correlation exists between grain size and amount of resetting highlighting the effect of grain size on closure temperature. Major element and REE traverses reveal homogonous major element profiles and relict igneous REE profiles. The retention of REE zoning and homogenisation of major element zoning suggests that diffusion rates of REE’s are considerably slower than that of the major cations, in disagreement with recent experimental determinations of the diffusion rates of REE in garnet. The retention of REE zoning and the lack of resetting in the largest grains suggests that Sm-Nd closure temperature in garnet is a function of grain-size, thermal history and REE zoning in garnet. The findings of this study provide the first temporally constrained tectonothermal model of the evolution of the southern Gawler Craton. The P-T conditions obtained from the earliest D₁ fabric provide the first quantitative constraints on the P-T conditions of the southern Sleafordian Orogeny. The P-T-t evolution determined for the 1725–1690 Ma Kimban Orogeny indicate it developed along a clockwise P-T path, and dominates the structural and metamorphic character of the southern Gawler Craton. The large variations in exhumation over short lateral extents reflect the exhumation of lower crustal rocks during the Kimban Orogeny driven by transpression during the development of a regional transpressional ‘flower structure’. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372052 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

The Gawler Craton in South Australia consists of an Archaean to Palaeoproterozoic core surrounded and intruded by a series of Palaeo- to Mesoproterozoic metasediments and igneous suites. The region has experienced a protracted c. 1700 Myr tectonic history from the Archaean through to the Mesoproterozoic, experiencing numerous cycles of deformation, magmatism and basin development. Despite hosting a number of mineral deposits, including the immense Olympic Dam iron oxide-copper-gold deposit, the tectonothermal evolution of the Gawler Craton remains poorly constrained. A significant ambiguity in our current understanding of the geological framework of the Gawler Craton revolves around the timing and spatial distribution of the tectonic events within the craton and their metamorphic evolution. This study addresses some of this ambiguity by unravelling the timing and tectonothermal evolution of the reworked southern Gawler Craton, using a combination of structural and metamorphic analysis, coupled with targeted geochronology. These methods have been applied to three locations representing different lithologies across the southern Gawler Craton. Putting absolute time into structural and metamorphic analysis is a vital tool for unravelling the development of ancient and modern orogenic systems. Electron Probe Micro-Analysis (EPMA) chemical dating of monazite provides a useful method of obtaining good precision age data from monazite bearing assemblages. This technique was developed at the University of Adelaide in order to constrain the timing of reworked assemblages from the southern Gawler Craton. EPMA measurements carried out on samples of known age, from Palaeoproterozoic to Ordovician, produce ages which are within error of the isotopically determined ages, indicating the validity of the developed setup. This technique, together with SHRIMP monazite and titanite and garnet Sm-Nd geochronology, was used on selected samples from the southern Gawler Craton to determine the timing of high-grade metamorphism and deformation. The results show that the Sleaford Complex records evidence of an early D₁event during the c. 2450 Ma Sleaford Orogeny recorded within structural boudins. The majority of the data indicates that the region underwent subsequent reworking and thorough overprinting during the 1725–1690 Ma Kimban Orogeny. In the Coffin Bay region, Palaeoproterozoic peraluminous granites of the Dutton Suite are reworked by a series of migmatitic and mylonitic shear zones during the Kimban Orogeny. Peak metamorphic conditions recorded in mafic assemblages indicate conditions of 10 kbar at 730°C. The post-peak evolution is constrained by partial to complete replacement of garnet – clinopyroxene bearing mafic assemblages by hornblende – plagioclase symplectites, which record conditions of c. 6 kbar at 700°C, implying a steeply decompressional exhumation path. The Shoal Point region consists of a series of reworked granulite-facies metapelitic and metaigneous units which belong to the late Archaean Sleaford Complex. Structural evidence indicates three phases of fabric development with D₁retained within boudins, D₂consisting of a series upright open to isoclinal folds producing an axial planar fabric and D₃, a highly planar vertical high-strain fabric which overprints the D₂ fabric. Geochronology constrains the D₁ event to the c. 2450 Ma Sleafordian Orogeny while the D₂the D₃events are constrained to the 1730–1690 Ma Kimban Orogeny. P-T pseudosections constrain the metamorphic conditions for the Sleafordian Orogeny to between 4.5–6 kbar and 750–780 °C. Subsequent Kimban-aged reworking reached peak metamorphic conditions of 8–9 kbar at 820–850 °C during the D₂ event. Followed by near isothermal decompression to metamorphic conditions <6 kbar and 790–850 °C associated with the development of the D₃high-strain fabric. The Pt Neill and Mine Creek regions are located in the core and on the flank of the crustal scale Kalinjala Shear Zone, which forms the main structural element of the poorly exposed Kimban Orogen. Samples record a similar structural development with a dextrally transpressive system resulting in a layer parallel migmatitic gneissic to mylonitic KS₁ fabric which was subsequently deformed and reworked by upright folds and discrete KD₂ east-side-down sub-solidus mylonitic shear zones during east-west compression. Geochronology constrains the timing of deformation and metamorphism to the Kimban Orogeny between 1720 and 1700 Ma. Metamorphic P-T analysis and pseudosections constrain the peak M₁ conditions in the core of the shear zone to 10–11 kbar at c. 800 °C reflecting lower crustal conditions at depths of up to 30 km. On the flank of the shear zone the M₁ conditions reached 6–7 kbar at 750 °C followed by sub-solidus reworking during KD₂ at conditions of 3–4 kbar at 600–660 °C, suggesting a maximum burial of <24 km. Cooling rates suggest that the core of the shear zone cooled at rates in excess of 40–80 °CMa⁻¹ while the flank underwent much slower cooling at < 10°CMa⁻¹. The rapid cooling and inferred decompression in the core of the shear zone reflects rapid burial and exhumation of lower-crustal material into the mid-crust along the Kalinjala Shear Zone. The absence of evidence for extension indicates that differential exhumation and the extrusion of lower-crustal material into the mid-crust was driven by transpression along the shear zone and highlights the role of transpression in creating large variations in vertical exhumation over relatively short lateral extents. Garnet is a vital mineral for determining constrained P-T-t paths as it can give both the P-T and t information directly. However, estimates of the closure temperature of the Sm-Nd system in garnet vary considerably leading to significant uncertainties in the timing of peak conditions. Five igneous garnets of varying size from an undeformed 2414 ± 6 Ma garnet – cordierite bearing s-type granite from the Coffin Bay region, that were subjected to high-T reworking during the Kimban Orogeny, have been dated to examine their diffusional behaviour in the Sm-Nd system. Garnets were compositionally profiled and then dated. A direct correlation exists between grain size and amount of resetting highlighting the effect of grain size on closure temperature. Major element and REE traverses reveal homogonous major element profiles and relict igneous REE profiles. The retention of REE zoning and homogenisation of major element zoning suggests that diffusion rates of REE’s are considerably slower than that of the major cations, in disagreement with recent experimental determinations of the diffusion rates of REE in garnet. The retention of REE zoning and the lack of resetting in the largest grains suggests that Sm-Nd closure temperature in garnet is a function of grain-size, thermal history and REE zoning in garnet. The findings of this study provide the first temporally constrained tectonothermal model of the evolution of the southern Gawler Craton. The P-T conditions obtained from the earliest D₁ fabric provide the first quantitative constraints on the P-T conditions of the southern Sleafordian Orogeny. The P-T-t evolution determined for the 1725–1690 Ma Kimban Orogeny indicate it developed along a clockwise P-T path, and dominates the structural and metamorphic character of the southern Gawler Craton. The large variations in exhumation over short lateral extents reflect the exhumation of lower crustal rocks during the Kimban Orogeny driven by transpression during the development of a regional transpressional ‘flower structure’. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372052 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

Cretaceous continental extension was accommodated by the development of the Paparoa Metamorphic Core Complex, resulting in the separation of New Zealand from Gondwana. High grade (Lower Plate) and low grade (Upper Plate) rocks are separated by the Ohika and Pike Detachment Faults. The two detachment faults have distinctly different histories, with greater exhumation along the Pike Detachment Fault. The onset of crustal extension is proposed to have commenced along the Pike Detachment Fault at 116.2 ± 5.9 Ma (Rb/Sr dating). Both geochemical and geochronological approaches are adopted for this thesis, through the in situ analysis of oxygen and hafnium isotope ratios, trace metals and U-Pb content. Chemical changes are tracked during the petrogenesis of the Buckland Granite, with mafic replenishment observed in the later stages of crystallisation. Crystallisation temperatures of the Buckland Granite are calculated using zircon saturation thermometry, with an average Ti-in-zircon temperature of 697℃ (upper-amphibolite facies). Inherited zircons in Lower Plate rocks show distinct age peaks at c. 1000, 600 and 300 Ma, illustrating the incorporation of heterogeneous local crust (Greenland Group and Karamea Batholith). Model ages (TDM) are calculated for inherited zircons of the Lower Plate rocks, which record the time at which magma bodies (zircon host rocks) were extracted from the mantle. Maximum and minimum model ages for the Buckland Granite average at 3410 Ma and 2969 Ma, with the maximum TDM value of 3410 Ma coinciding with the proposed major crustal formation event of the Gondwana supercontinent at c. 3.4-3.5 Ga. Two distinct U-Pb zircon age peaks are observed in the Buckland Granite at 102.4 ± 0.7 and 110.3 ± 0.9 Ma. The 110.3 ± 0.9 Ma age is interpreted as the crystallisation age of the pluton, while the 102.4 ± 0.7 is proposed to represent a younger thermal (magmatic?) event associated with the 101-102 Ma Stitts Tuff.

Thesis (Ph. D.)--University of Adelaide, Dept. of Geology and Geophysics, 1987. / Typescript. Maps in back pocket of v. 1. Microfiches in back pocket of v. 2. Microfiches contain petrographic descriptions, total rock XRF analyses and microprobe analyses. Includes bibliographical references (leaves 160-183 (v. 2)).

Thesis (Ph.D.) -- University of Adelaide, Dept. of Geology & Geophysics, 2000? / Appendix 4 and 5 in pocket on back cover. Bibliography: p. 123-130.

Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references. Also available in electronic format on the Internet.