Metadiabase sills constitute up to 27 percent of a steeply-dipping assemblage of ancient volcanic rocks in Roy and McKenzie townships, Chibougamau region, northwest Quebec. Three rock types are represented. They are, from lower to upper parts of the sills, metapyroxenite, metadiabase, and diabase-pegmatite. Comparison is made with “metadiorite” and “metagabbro” sills in an adjoining area. Chemical and planimetric analyses show that layering of the sills is the result of magmatic differentiation which is characterized by iron-enrichment. The metadiabase sills are similar to the intrusive phase of plateau-type basaltic magma in chemical composition and in trend of differentiation.

This thesis presents a structural, mineralogical and alteration study of the Henderson copper orebodies, located in the Chibougamau region of Quebec. The orebodies were discovered early in 1956 as the result of drilling two holes on an electromagnetic anomaly. Approximately 90,000 feet of drilling in 1957 outlined some 4,750,000 tons of ore with an average grade of 2.01% copper, 0.057 ounces of gold per ton and with small amounts of nickel and cobalt. A road and causeway have been constructed to the site and shaft sinking is now in progress.

Note: Missing page 28. / In spite of the many studies of the various Paleozoic systems in the Rocky Mountains, no one has dealt satisfactorily with the beds immediately below the known Upper Devonian strata. Several factors are involved. The beds are not so resistant as those above and they are usually found at the base of fault blocks. Thus the sections are talus covered and incomplete due to faulting. Fossils are rare and there is no adequate means of correlation between widely spaced sections.

The term “semi-microfossils”, here proposed for the first time in palaeontology, refers to those fossils which, though easily recognized by the naked eye, depend upon microscopic examination for at least their specific identification. Included in this group are (i) Bryozoans, (ii) Scolecodonts, (iii) Conodonts, and (iv) Ostraoods. Of these, the bryozoans and scolecodonts have been selected for detailed study owing to their abundance in the Black River and Trenton formations in the Province of Quebec.

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.

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.

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).