This thesis represents a general study of the geology of an area of approximately 140 square miles, situated in Ungava, New Quebec, which covers part of the eastern “contact” of the so called “Labrador Trough“ with the granite-gnei ss-migmatite complex. The study is based on field work carried out during the summers of 1954 and 1955 for the Quebec Department of Mines, and laboratory investigation at McGill University during 1955 and 1956. The abject of this paper is to prove that the rocks in that part of the "Labrador Trough” show progressive regional metamorphism towards the East and North.

The origin of anorthosite has been for a long time a subject of controversy in geological literature. While most geologists agree that anorthosites are igneous rocks produced from a basic magma by some process of magmatic differentiation, others maintain that they are of metamorphic origin. One possible approach to the origin of anorthosites leads through the study of their trace elements. It is well known that some trace elements are typically concentrated in minerals formed in early stage differentiation, while others are preferentially incorporated in the late differentiates.

Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1999. / National Grid Reference (SI 54-2, SH-14) 1:250 000. Includes bibliographical references (leaf 47).

In the Mesozoic, dinosaur abundance and diversity steadily increased from the Carnian to the Triassic booming soon after the end Triassic Mass-Extinction event (ETE), marking a key period in archosaur history. In southern Africa, the Triassic–Jurassic Boundary (TJB) is contained in the richly fossiliferous, fluvio-lacustrine-aeolian Upper Triassic to Lower Jurassic strata of the Stormberg Group. More specifically, the middle Norian – Pliensbachian Elliot and Clarens formations (upper Stormberg Group) of main Karoo Basin, host a diverse tetrapod osteological and ichnite record. Due to an absence of high resolution radioisotopic age determinations, the exact stratigraphic placement of the TJB remains unknown. Although diverse ichnofossils attributed to Saurischians and Ornithischians are preserved in the Stormberg Group, the record is dominated by isolated tridactyl tracks that can be assigned to common ichnogenera like Grallator, Eubrontes and Kayentapus. Ideally, these track morphologies would reflect the trackmaker's autopod morphology, but complex interactions between the trackmaker and tracking substrate may affect the final footprint shape. Tracks with a high morphological preservation grade may be used to infer information (e.g., body length, hip height, weight) about the trackmaker, which is especially useful when skeletal remains are scarce, as is the case with theropod body fossils in the Elliot and Clarens formations. Herein, we present the findings of an extensive southern African field-based study to quantify the morphological variation of Grallator, Eubrontes and Kayentapus tracks across the TJB in the upper Stormberg Group. Furthermore, this study produced the first detrital zircon Uranium–Lead (U-Pb) LA-ICPMS ages of the major ichnosites from this region, and confirmed that the TJB is within the Elliot Formation, near the boundary of the lower and upper Elliot Formation (i.e., near the contact of the informal lEF and uEF). Across this contact, the considered tridactyl tracks become more abundant, larger and have a less pronounced medial digit projection. These morphological changes are gradational, with tracks from the Clarens Formation being distinct to tracks from the lEF, while the uEF tracks being intermediate between the lEF and Clarens Formation. A decrease in the mesaxony (Dp/TS ratio) and a decrease in medial digit projection relative to track length can be detected in both small and large tridactyl tracks. These apparent trends in the upper Stormberg Group are consistent with global tridactyl trends, which suggest an overall increase in theropod abundance and body size across the Jurassic. Moreover, the reason for the less prominent medial pedal digit is linked to a better weight distribution across the autopod in the increasingly larger theropods. Last but not least, Grallator, Eubrontes and Kayentapus ichnogenera which may be attributed to at least three different groups of theropod-like trackmakers, suggest a higher palaeo-diversity and abundance of tridactyl dinosaurs in southern Africa than is known from the osteological record.

Crustal deformation models have a first-order rheological division, with pressure-dependent brittle deformation predominating at shallow depths, and temperature-dependent viscous deformation occurring in the deeper levels of the crust. The brittle-ductile transition zone separates these two regimes, it occurs at approximately 350°C for quartz and it is characterised by mixed-mode brittle and viscous deformation. Complex fault zones exhumed to the surface may preserve evidence that can explain the mechanics and the complex slip behaviour of faults. Fault rocks response to applied shear stress is affected by environmental conditions during deformation (such as temperature and pressure), composition of fault zone, fluid presence and strain rate. Thus, the interplay of these factors determines the slip style of a specific fault and may lead to multiple slip styles that overprint each other. The Nuy Valley area in Worcester, Western Cape, South Africa, exposes a section through the deeper parts of the Cape Fold Belt, where the Malmesbury Group schists experienced thrust faulting in response to crustal shortening. Individual thrust faults are manifested in different ways, with quartz-cemented breccias, limestone mylonites, abundant quartz veining and cataclasites attesting to faulting occurring by a diversity of slip style, which allows investigating how the interplay of the controlling factors lead to the observed diversity of fault rock. Through mineral equilibria modelling, the pressure-temperature conditions under which faulting occurred was determined to lie between 5 - 8 KPa and 250 - 420C, with fluid content lines indicating low amounts of dehydration during peak metamorphism. The exhumed fault being analysed in this study was active at 10 - 15 km deep at 25C.km-1 geothermal gradient. The temperature over this transition is relatively constant and short ranged throughout geological evolution of Worcester and the cyclic superposition of ductile and brittle deformation and change in slip styles along fault zones as found in Nuy Valley cannot be justified by ambient temperature and pressure oscillations. Lithotype and competency of wallrocks play an essential role in deformation partitioning by being crucial determinants of rheological properties, and accounts for the coexistence of brittle and ductile fabrics but not for cyclic overprint of slip styles. Fluid presence is evidenced by an intense network of quartz veins and hydraulic breccias and contributes to the weakening and strengthening of wallrock during deformation. Slip style diversity in the study area is considered to the result of the interplay of compositional variabilities, fluid flow and strain rate variations associated with the seismic cycle.

The Broken Hill deposit, Aggeneys, is a metamorphosed stratiform Cu-Pb-Zn-Ag sulphide deposit situated in the mid-Proterozoic supracrustal sequence of the Bushmanland Subprovince in the Namaqualand Metamorphic Complex. The deposit comprises two superposed orebodies, each consisting mainly of massive sulphide lenses and iron formation which are hosted within a metapelitic schist close to major quartzite horizons. This study is concerned with the tectonically lower orebody (LOB). The iron formation is magnetite-rich and contains varying proportions of (Fe,Mn)-rich silicates (garnet, amphibole, olivine, orthopyroxene, pyroxenoid), quartz and Cu-Pb-Zn-sulphides. These minerals occur in mm- to 5 cm-thick bands and are often traceable over tens of metres. The well preserved banding is considered to represent bedding. Five different varieties of silicate-rich mesobands in the iron formation can be distinguished based on the predominant mineral assemblage: (a) amphibole-olivine-quartz +/- garnet, (b) amphibole-quartz, (c) garnet-apatite-quartz +/- amphibole, (d) garnet-apatite-quartzorthopyroxene, (e) pyroxferroite-quartz +/- amphibole and (f) quartz. These rocks all contain magnetite, and Ba-rich biotite is common but is not always present.

Bibliography: leaves 69-76. / Knowledge of nutrient dynamics within aquatic ecosystems are of fundamental importance for water quality management, especially in cultivated areas where irrigation farming pose a salinization and eutrophication risk to water bodies. A range of water quality problems is associated with eutrophication, which is generally controlled by the nutrients nitrogen and phosphorus. The lower Olifants River is situated in an arid region with intensive irrigation agriculture. This study set out to investigate the loading and fate of nitrogen and phosphorus in the lower Olifants River.

Bibliography: pages 78-81. / The Cape Fold Belt is a 250Ma orogenic belt comprised of rocks of the Cape Supergroup, an Ordovician to Devonian sedimentary sequence. The mountainous areas, which reach over 2000m, are composed of the faulted and highly jointed quartzites and sandstones of the Table Mountain Group, which acts as the main deep aquifer. It is from the secondary porosity of this aquifer that over ten thermal springs issue forth, ranging in temperature from ~27°C to 64°C. Samples of the integrated total monthly rainfall were taken for several months at each of four stations around the Cape Fold Belt. Values ranged from δ¹⁸O=- 8.3⁰/₀₀ and 6δ=-37⁰/₀₀ to 1.2⁰/₀₀ and 7⁰/₀₀, respectively. Integrated recharge values based on a full year of observation at UCT, Cape Town, are δ¹⁸O =- 3. 7o/oo and 6δ = -10⁰/₀₀. Eleven thermal springs were sampled in 1995, four of which were sampled once a month for several months, over the same period that the rain was being sampled. The average discharge values for the four springs sampled monthly are, for δ¹⁸O and δD respectively, at Malmesbury - 3.9⁰/₀₀, -18⁰/₀₀; at Citrusdal -4.9⁰/₀₀, - 20⁰/₀₀; at Brandvlei - 5.6⁰/₀₀, - 30⁰/₀₀ and at Calitzdorp -7.3⁰/₀₀,-40⁰/₀₀. A meteoric water line for the Cape Mediterranean climate area was calculated by the general form of a structural regression, using the monthly data weighted by rainfall amount. It has the equation δD = 7.38δ¹⁸O + 18.6. Using the same calculation technique, but not weighting the data, the data for the thermal springs yield a water line with the equation δD = 8.32δ¹⁸O + 16.5. The difference in gradient suggests that the springs are recharged from a colder and isotopically more fractionated weather system, such as during a previous colder climate regime, or at high altitude. There is no evidence for isotope exchange between the groundwater and host rocks; rather, the shift of the spring water line to less negative δ¹⁸O values suggests evaporation prior to recharge. Oxygen and hydrogen isotope ratios from the discharged spring water are clearly more negative than those expected for rain falling at the spring, which can be explained by recharge at much higher altitudes. The springs are therefore believed to be recharged high on mountains in the near vicinity. A continental effect was observed in the spring data, with respect to the distance from the west coast, which is the direction from which weather systems approach. Most of the thermal springs of the Cape Fold Belt seem to be recharged at high altitude in nearby mountains, whereafter the water is heated by geothermal gradient upon reaching depths of two to three kilometres via the secondary porosity of the Peninsula Formation, finally reaching the surface by means of various faults, which allow passage through the impermeable Cedarberg Formation. Isotopically light carbon is released at some springs in the form of CO₂ and CH₄ (total carbon δ¹³C≈- 21⁰/₀₀). These gases could come from near surface bog environments, however, at Malmesbury, where H₂S is also released, a possible geological source is indicated for the CO₂ and the CH₄.

Includes bibliographical references. / Eighty-five peridotitic and pyroxenitic xenoliths from the Arnie, Pigeon and Misery kimberlites in the Lac de Gras region, Northwest Territories, Canada were selected for inclusion in this study. The three kimberlites are situated within a 40 km radius of one another on the BHP property, and all are diamond-bearing. The Misery kimberlite is presently being mined, and the Pigeon kimberlite is part of · the future BHP-DiaMdt Ekati mining plan. A petrographic study of the xenoliths using both transmitted light microscopy and binocular microscopy was followed by major anti trace element analysis. Major element compositions of individual minerals were determined using a wavelength dispersive electron microprobe, and trace element abundances were determined using laser ablation ICP-MS. Pressures and temperatures of equilibration were then determined using 'garnet-olivine, garnet-orthopyroxene and trace element geothermobarometers (TNi, Per).

Summary in English. / Includes bibliographical references. / In 1993, dredge-sampling from 40.6°S to 525.5°S, during cruise 9309 of the R/V Maurice Ewing, greatly increased the number of basalts recovered from this section of the southern Mid-Atlantic Ridge (SMAR), and significantly expanded the global suite of samples from slow-spreading ridges.