Search

John Tuzo Wilson (1908-1993) was one of the greatest Canadian scientists of the 20th century. His contributions to Earth Sciences, leading the formulation of the theory of plate tectonics, have revolutionized our understanding of how the planet Earth works and evolved over the past 4 billion years. This 50th anniversary special issue of the Canadian Journal of Earth Sciences is dedicated in honour of John Tuzo Wilson, who inspired tens of thousands of students all around the world to study the Earth. This special issue contains 12 papers dealing with various aspects of the 'Wilson Cycle' in the geologic record, plate tectonics, mantle plumes, and how John Tuzo Wilson accepted 'continental drift' and formulated the theory of plate tectonics. The contributions have mostly been made by geoscientists who directly or indirectly associated with John Tuzo Wilson and have contributed significantly to the plate tectonics paradigm. [ABSTRACT FROM AUTHOR]

Mountain building in the western part of the Archean Superior Province culminated with the formation of regional strike-slip faults. This paper reports on the kinematics and timing of several major faults at the juncture between the Uchi, English River, Winnipeg River, and western Wabigoon subprovinces. Sinistral-oblique mylonitization along the northeast-striking Miniss River fault occurred at 2681 [ABSTRACT FROM AUTHOR]

Canadian society faces a significant decline in the number of active mines and in the discovery rate of base and precious metal deposits. Exploring in the shadows of active and former mines with improved metallogenic models and new technologies is one way to address this problem. Another way is to diversify mineral exploration outside known mining camps and target prospective but underexplored settings and nonconventional mineral deposits. In Canadian terms, diversifying exploration commonly translates into targeting gneissic and granitic terrains where modern geoscience knowledge may be rare or only at reconnaissance scale and where key regional and local indicators and vectors to ore may be missing in the geological record. Though underexplored settings abound in Canada, only one orogen has an aura that discourages exploration: the Grenville Province. Consequently, even though the Grenville Province provides the best model of a deep continental-collision zone so far studied anywhere on Earth and constitutes a microcosm of continental accretion, it remains underexplored, underprospected, undermapped and underestimated. It is thus essential to revisit the mineral potential of the most accessible orogen of the Canadian Shield, search for its missing volcanic belts, reexamine its ore deposits and mineral occurrences, and explore new research avenues using the best remote-sensing device on Earth: human eyes. This special issue captures advances associated with regional field investigations by government that played a special role in opening up frontier areas for mineral exploration. Papers stemming from academia and government–university–industry consortiums investigate further some of the topics covered by these and earlier surveys and others contribute structural and metamorphic insights that will be valuable in future mapping projects. The advances reported here for the Grenville Province may provide impetus to revisit other Grenville-age terrains worldwide, just as metallogenic models developed in other countries have provided the means to look in a different manner at the Grenville orogen for mineral deposits. Collectively all the various approaches presented in this volume help us to revamp our way of looking at the mineral potential of the Grenville orogen. [ABSTRACT FROM AUTHOR]

There are two unreconciled interpretations for the age and character of the boundary separating the Cambrian–Ordovician Potsdam and Beekmantown groups that underlie the Ottawa Embayment in eastern Ontario. These stratal groups consist of interior facies of the central Laurentian Platform. As exposed in the type section of the Nepean Formation (upper Potsdam Group), located in the City of Ottawa, the boundary was previously interpreted to be conformable and of Early Ordovician age. This intepretation was of enormous impact on subsequent regional geology compilations that showed a diachronous boundary across the platform interior. From recent subsurface analysis across eastern Ontario, the contact was interpreted to be disconformable, a sequence boundary separating Late Cambrian and Early Ordovician strata. This paper reexamines the type section. Lithologically, the group boundary should be repositioned downsection by ~1.5 m. The contact now lies coincident with a disconformity that has a paleorelief of < 10 cm. The proposed revision is geologically significant. Previous collections of Early Ordovician conodonts from the type section, used to define the age of what had been interpreted to be upper Potsdam strata, now fall entirely within the lower Beekmantown Group. Nepean (Potsdam) strata exposed in the type section remain undated. Regional correlation of the disconformity across the Laurentian platform suggests that Nepean strata at the type section are likely of Late Cambrian age. There now exists a regionally coherent separation of Cambrian and Ordovician sedimentation patterns in the Ottawa Embayment. [ABSTRACT FROM AUTHOR]

This Special volume published by the Canadian Journal of Earth Sciences consists of a collection of six papers on the petrology, geochemistry, and metallogeny of igneous rocks emplaced in large igneous provinces (LIPs). The papers provide a snapshot of results presented at a Special Session of the 2017 Geological Association of Canada – Mineral Association of Canada Joint Annual Meeting held in Kingston, Ontario, by members of the vibrant geoscience community dedicated to the study of LIPs. Participants applauded the idea of a joint session on these topics and as a result, the session fostered animated discussions and new collaborations. The scope of magmatic and metallogenic studies of LIPs often precludes the type of brainstorming that took place during the meeting. This Special volume demonstrates that a robust understanding of magmatic processes represents the essential first step towards the search for mineral deposits in LIPs worldwide. [ABSTRACT FROM AUTHOR]

Introduces a series of articles featured in the special issue of the "Canadian Journal of Earth Sciences." Discussion of articles on the final compendium of papers on the Alberta Basement Transect of Lithoprobe.