Increased use of renewable energy, coupled with electrification of the economy, is considered important in efforts to limit future climate change. This energy transition is predicted to increase demands for some commodities, many of which are now labelled as critical mineral. The quest for such commodities is now a persistent theme for the resource industry and emerging government policies. This review for non-specialists explains several key concepts but also explores some challenges and apparent contradictions in the context of Canada. Canada now has a list of 31 critical minerals, but this includes some major commodities for which domestic production is significant and supply risk is low. The differences between our list and those of other jurisdictions reflect our more specific definitions. Most other commodities on Canada’s list are also identified by other countries and some are specifically linked to the energy transition. These include cobalt, lithium, manganese, nickel, graphite and vanadium (used in electric vehicle batteries and static energy storage), rare earth elements (REE; used for magnets in EV motors and wind turbines) and some rarer elements (e.g. germanium, gallium, indium and tellurium) used in photovoltaic (solar) energy systems. Some of these are potential primary products (e.g. lithium, graphite and REE) but many others (e.g. cobalt, platinum group elements and the photovoltaic elements) are byproducts from the production of major commodities, notably nickel, copper and zinc. The REE represent coproducts that are closely associated in nature and very hard to separate from each other; they are produced as a group. There are some specific challenges in exploring for and developing critical mineral resources. The end-use technology driving demand evolves on a timescale of years, but mineral exploration and development now typically take multiple decades. Material substitutions and unpredictable developments in technology complicate the exact prediction of future demands. The forecasts of overall relative demand growth are impressive, but for some key commodities global production will remain small in absolute terms, which may limit the potential for new discoveries. Simple measures of grade and tonnage are not always guarantees of viability, because deposits of some commodities (e.g. the REE) are mineralogically complex. Byproduct commodities cannot be produced in isolation, and many of these are only extracted in smelting and refining. Domestic production of these commodities is effectively lost if concentrates are exported for processing. The emissions and environmental impacts associated with production of critical mineral resources will also become important if such activity is to be linked to wider climate goals. This may present challenges in northern Canada, where renewable or low-carbon energy options are limited. Most draft Land Use Plans in the north presently emphasize large-scale land conservation, which could limit future exploration access before resource potential is fully assessed. Given the strong divisions of opinion about resource development, especially in the north, controversy and polarized debate will not easily be avoided. There are no simple answers to challenges that are political or jurisdictional rather than technical, but there is definitely a need for more public geoscientific information. This will help to identify areas of greatest potential, evaluate known deposits and contribute to future sustainable development. For many of the commodities on our critical mineral resources list, data for Canada remains incomplete, especially in more remote regions that are generally considered to have the highest potential.

Over the years, it has become a tradition that the first issue of Geoscience Canada contains some sort of editorial piece. When the deadline looms in March, I regret that this precedent was ever established. What can I possibly write that has relevance and interest to readers? We are still here, obviously, and we plan to continue as best we can and serve our Geoscience Community in Canada. Surviving as a small scientific journal in a large pond has more than its fair share of challenges, but our long-term goal is to grow and prosper, not just to persist. Our ongoing efforts would not be possible without the support of volunteers and GAC members, and of course the invaluable work of managing editor Cindy Murphy. So let my first statement this year be one of sincere thanks to Cindy and to all who assist us every year in smaller ways to produce the journal. In previous editorials, I have outlined some of the challenges that we face, and especially the need for the submission of good papers on diverse topics. This is the only viable route towards raising our profile and impact in a world dominated by corporate publishing. I have discussed the open-access concept, and its possible benefits to journals like us, even with the additional fiscal challenges that it implies. In 2020, I even ventured into the impact of the Covid-19 pandemic on the lives and work of Earth Scientists, mostly in an effort to find silver linings in a large bank of clouds. I doubt that many readers really want to hear more on that subject after two more years, as it is all too familiar. All of these topics are important to Geoscience Canada, and some are clearly vital, and many will come back in future years. Hopefully, Covid will not be in that latter group. So, the search for topics suited to a 2022 editorial seemed fruitless for quite some time. In the end, I decided to avoid all the obvious but well-worn subjects and will spend a few pages to instead contemplate the past. Not the recent past, or even some historical past, but the distant and mysterious geological past that lies at the very heart of our chosen calling. Those who read to the end of this might well feel that this is no more than an escapist flight into imagination, and perhaps just a diversion from the many serious issues confronting our world in the spring of 2022. There may be indeed some truth in this perspective. The two technical papers featured in this first issue for 2022 have much in common, although this is certainly not by our design. Both articles focus on the use of detrital zircon U– Pb geochronology to solve geological problems, but they also share a deeper theme. Superficially, they include statistics, probability density charts and tables of data, but they are in the end delving into something more fundamental. Both papers seek to recreate vanished worlds places that existed tens to hundreds of millions of years ago on an Earth that was simultaneously familiar and alien. Earth Scientists are uniquely privileged to be aware of a multitude of vanished worlds, to the extent that we may take them for granted. It is just part of geoscience thinking in the broad sense, and we do not often pause to contemplate the enormity of such concepts. But I believe it serves us well to indulge our fascination for this far greater picture. Like many of us, I started out intending to study something else in my teens, but then ended up in some first-year geology classes. I was lucky enough to encounter young and passionate instructors, and the heady combination of the new global tectonics and visions of long-vanished worlds that they gave me led to a different academic path. It was like being exposed to the speculative breadth of science fiction buried within the scope of a vast historical adventure, and fifty years later, I still feel exactly that way. Earth Science truly gives us multiple worlds to explore, although at times we wish for even more. The paper by James Sears and Luke Beranek is built from measurements on thousands of nearly invisible zircon grains, but it transports us well beyond such details. It returns us to a pre-glacial North America that had a very different geography and climate, and a great river that rivalled our modern Amazon. Robert Bell of the Geological Survey of Canada speculated in 1895 that most of North America once drained into Arctic waters, before huge ice sheets remodelled our geography. The story of the “Bell River”, as it later came to be called, is now stored in the sands and silts of a vast delta beneath the frigid Labrador Sea, and by scattered residual outcrops on the Great Plains. This concept is astonishing enough, but it seems that this vanished northern Amazon once had headwaters in the desert southwest of our continent, although it was likely not arid in those times. James and Luke suggest that the development of the Colorado Plateau, including the early Grand Canyon, might be part of the Bell River’s long story. After 50 years, I still marvel at how Earth processes link such distant Volume 49 2022 1

Labradorite is an unusual gemstone in many respects, despite being a variety of plagioclase feldspar, probably the most common mineral in the Earth’s crust. Calcic plagioclase is common in mafic igneous rocks, especially gabbros, norites, troctolites and anorthosites, but it is generally unremarkable in appearance. However, gem labradorite exhibits striking colours on cleavage surfaces when viewed from exactly the right direction. Intense blues and greens are most common, but shades of brown, yellow and red also occur. This phenomenon results from optical interference effects caused by microscopic exsolution lamellae that have very specific and consistent thicknesses. This special type of iridescence is termed ‘labradorescence’ because it is very specific to this mineral. Labradorite was one of the earliest gemstones to be recognized in Canada, first collected by a Moravian missionary around 1773, and named by the famous mineralogist Abraham Werner in 1780. However, it was noted long before this, as there is an Inuit legend about the Northern Lights becoming imprisoned on the rocky coast of Labrador. The typical blue and green colours of the stone are indeed reminiscent of the auroral displays for which the region is famous.In its type area around the town of Nain, labradorite is hosted by massive anorthositic rocks that are regionally extensive. The anorthosites generally contain > 90% plagioclase, with lesser pyroxene, olivine and Fe-Ti oxides. Labradorescence is variably present in the feldspars, and small pockets of bright colour occur sporadically within otherwise unremarkable rocks at many locations. More extensive gem-quality labradorite is associated with very coarse-grained (pegmatitic) zones, and several attempts at exploiting such material were made at a location now known as Tabor Island. Another well-known location in an inland area is appropriately known as “the Pearly Gates”, but this remains unexploited. Coarse- grained, equigranular anorthosite containing 5-20% iridescent feldspar was quarried for dimension stone near Nain intermittently for about 20 years, and was marketed under the trade name ‘Blue Eyes’. Much potential remains for future production of stone of this general type in the Nain area, although the remote location and climate present logistical challenges.Labradorite also occurs in many other places, and sources of significance include Norway, Finland, Australia and the island of Madagascar. Scandinavia is famous for the dimension stone known as Larvikite or “Blue Pearl”. This is a feldspar-rich monzonite that contains much iridescent plagioclase, but is darker in colour than typical Labrador anorthosites. Madagascar provides much of the material now used for craft purposes, even in the northern region where the mineral was first recognized. However, labradorite-rich stones are now being used by Inuit carvers, in addition to more traditional materials such as soapstone and serpentinite.

The spectacular angular unconformity at Siccar Point is the most famous site associated with James Hutton (1726–1797), but it was not his only place of insight. In 1785, three years before he discovered Siccar Point, Hutton examined outcrops in the still-remote valley of Glen Tilt, in the Scottish Highlands. He documented contact relationships between Precambrian metasedimentary rocks and Paleozoic granite bodies, although he had no knowledge of their true ages. Near to the hunting lodge where he and his colleague John Clerk of Eldin stayed, veins of granite clearly cut through relict bedding in the stratified rocks and disrupt their layering, breaking apart individual strata and leaving fragments (xenoliths) surrounded by granite. Hutton correctly deduced that the granite must originally have been in a ‘state of fusion’ and was forcefully injected into much older ‘schistus’. Such conclusions contravened prevailing ideas that granite bodies formed from aqueous solutions, and also refuted a wider philosophical view that granite and other crystalline rocks were the oldest and first-created parts of the Earth. Hutton’s key outcrops in Glen Tilt are easy to visit, although they do require a long (but easy) roundtrip hike of some 25 km. These are certainly not the most spectacular intrusion breccias that I have ever seen, but they are very instructive, and were very influential, because they sparked a long, and at times acrimonious, debate about the origins of igneous rocks and especially granite. This controversy had many strange twists and turns. These include the disappearance of Hutton’s original manuscript after his death, and its serendipitous rediscovery a century later, and the similar loss and rediscovery of exquisite drawings by John Clerk, almost two centuries after they were first penned. Among the lost drawings is an early example of detailed outcrop-scale mapping, which would become a key field-work technique. Hutton’s vision of granite as the product of hot, liquid material that moved upward in the Earth’s crust (plutonism) eventually prevailed over the idea that crystalline rocks formed from a primordial ocean that once enveloped the Earth (neptunism), but this victory did not come easily or quickly. In another strange twist of history, new evidence from the Cape of Good Hope in South Africa eventually acted to further the plutonist cause. Glen Tilt has changed very little since the time of Hutton, but the observations that were made here, and the long debate that followed, brought fundamental changes in our understanding of the Earth. Although Siccar Point should remain the first entry on the bucket list of any prospective geopilgrim to Scotland, the long and beautiful valley of the River Tilt should also be a priority. RÉSUMÉLa spectaculaire discordance angulaire de Siccar Point est le site le plus célèbre associé à James Hutton (1726–1797), mais ce n'était pas le seul lieu qui l’ait inspiré. En 1785, trois ans avant de découvrir Siccar Point, Hutton a examiné des affleurements dans la vallée encore enclavée de Glen Tilt, dans les Highlands écossais. Il a documenté les contacts entre les roches métasédimentaires précambriennes et les corps granitiques du Paléozoïque, bien qu'il ne connût pas leur véritable âge. Près du pavillon de chasse où lui et son collègue John Clerk of Eldin ont séjourné, des veines de granit ont clairement percé le litage relique dans les roches stratifiées et perturbé leur superposition, brisant les strates individuelles et laissant des fragments (xénolithes) entourés de granit. Hutton a correctement déduit que le granit devait à l'origine être dans un « état de fusion » et qu'il avait été injecté de force dans des « schistes » beaucoup plus anciens. De telles conclusions contrevenaient aux idées dominantes selon lesquelles des corps granitiques se formaient à partir de solutions aqueuses et réfutaient également une vision philosophique plus large selon laquelle le granit et d'autres roches cristallines étaient les parties de la Terre les plus anciennes et les premières créées. Les principaux affleurements de Hutton à Glen Tilt sont faciles à visiter, bien qu'ils nécessitent une longue randonnée (mais facile) d'environ 25 km aller et retour. Ce ne sont certainement pas les brèches d'intrusion les plus spectaculaires que je n’ai jamais vues, mais elles sont très instructives et ont eu un rôle très influent, car elles ont déclenché un long débat, parfois acrimonieux, sur les origines des roches ignées et en particulier du granit. Cette controverse a eu de nombreux rebondissements étranges. Ceux-ci incluent la disparition du manuscrit original de Hutton après sa mort, et sa redécouverte fortuite un siècle plus tard, et la perte et la redécouverte similaires de dessins remarquables de John Clerk, près de deux siècles après qu’ils aient été esquissés. Parmi les dessins perdus, se trouve un premier exemple de cartographie détaillée à l'échelle des affleurements, qui deviendra une technique clé de travail sur le terrain.La vision de Hutton du granit en tant que produit d'un matériau chaud et liquide qui s'est déplacé vers le haut dans la croûte terrestre (plutonisme) a finalement prévalu sur l'idée que des roches cristallines se sont formées à partir d'un océan primordial qui enveloppait autrefois la Terre (neptunisme), mais cette victoire n'est pas venue facilement ou rapidement. Dans une autre tournure étrange de l'histoire, de nouvelles preuves provenant du Cap de Bonne-Espérance en Afrique du Sud ont fini par faire avancer la cause plutoniste. Glen Tilt a très peu changé depuis l'époque de Hutton, mais les observations qui ont été faites ici, et le long débat qui a suivi, ont apporté des changements fondamentaux dans notre compréhension de la Terre. Bien que Siccar Point devrait rester en haut de la liste des lieux à visiter de tout visiteur potentiel lors d’un pèlerinage géologique en Écosse, la longue et belle vallée de la rivière Tilt devrait également être une priorité.

If one thing is beyond discussion in June of 2020, it is that we are living in unique times, even if pandemics are far from unique in longer Human history.A short article in this issue on the topical concept of the Anthropocene closes with a quote that (in part) reads that "....some humility is in order about our, thus far, infinitesimal part in the history of the planet".Our high-technology society has certainly received a stark reminder of the power of the natural world, as it struggles to prevail over one of the most primitive of life forms.Few previous analyses of the pandemic threat that I have read fully captured the economic impacts and ethical dilemmas that confront us in this time of Covid.Many in the Canadian Geoscience Community suffered these impacts and some are now directly touched by illness or bereavement.On behalf of those involved in Geoscience Canada, I extend sympathies and condolences, and the hope that the time of Covid will be brief.The American Geological Institute (AGI) recently initiated a study on the impacts of Covid-19 on the Geosciences and invited contributions from member organizations (see www.americangeosciences.org/workforce/covid19).No great insight is needed to see how the prohibition of large gatherings and the need for physical distancing could have far-reaching implications for many of the things that we typically do.We will need to think about how to conduct important field work, especially in remote and isolated areas, how to mount our vital professional conferences, and how to educate the next generation of Geoscientists.We should expect that the global pandemic will wreak changes to many other things that we have not yet considered.AGI's initiative is a good step, and one that will hopefully provide some direction and context as we move into next year.There are of course much wider questions to consider, such as whether this global crisis might force society to better confront the threat of climate change or even to rethink the relationship between the Human and Natural worlds.These

Ophiolites are complex assemblages of ultramafic and mafic igneous rocks that are now widely considered to be pieces of ancient oceanic crust that were emplaced on to the continents courtesy of global plate tectonics. However, most examples were originally considered parts of enormous layered mafic intrusions and so were interpreted in that light. The new understanding of ophiolites in the late 1960s and early 1970s was a crucial part of the global Earth Science revolution, and they are now central to all plate tectonic models developed for ancient orogenic belts. Although their equivalence to oceanic crust is now well established, many ophiolites may not be ‘typical’ examples of such, and not all examples are identical. Most ophiolites likely formed in subduction-influenced environments rather than at mid-ocean ridges. Ophiolites remain important foci for research in the 21st century, and many questions remain about their environments of formation and especially their mechanisms of emplacement onto the continents. Although it was not the first to be seen as a relic of a vanished ocean, the Bay of Islands Igneous Complex in western Newfoundland is one of the best preserved and most easily accessible ophiolites in the world. In the late 20th century, research work in this area proved highly influential in understanding the oceanic crust, and in unravelling the diachronous events involved in the progressive destruction of an ancient stable continental margin as arcs and microcontinental blocks were accreted along it. Parts of the Tablelands Ophiolite lie within Gros Morne National Park, which is a UNESCO world heritage site because of its importance to our understanding of global tectonics. The wider region around the park also includes the Cabox Aspiring Geopark Project, now also in the process of seeking recognition through UNESCO. This article provides background information on ophiolites and the development of our ideas about them, and links this material to four self-guided field excursions that allow examination of many classic features. These excursions range from a collection of roadside outcrops, to some relatively easy hiking excursions on official National Park trails, and eventually to a more challenging off-trail hike that ascends to the summit plateau of the Tablelands to visit rare exposures of the Moho (the Mohorovičić Discontinuity, i.e. the lower boundary of the Earth’s crust) and the underlying upper mantle rocks. Collectively, the field stops should allow geologically-minded visitors to experience some amazing geology in a spectacular and sometimes surreal landscape. RÉSUMÉLes ophiolites sont des assemblages complexes de roches ignées ultramafiques et mafiques qui sont maintenant généralement considérées comme des fragments de croûte océanique ancienne qui ont été charriés sur les continents grâce à la tectoniqueglobale des plaques. Cependant, la plupart des exemples étaient à l'origine considérés comme faisant partie de vastes intrusions mafiques stratifiées et ont donc été interprétés dans ce contexte. La nouvelle compréhension des ophiolites à la fin des années 60 et au début des années 70 a été un élément crucial de la révolution des sciences de la Terre. Les ophiolites sont désormais au coeur de tous les modèles tectoniques des plaques développés pour les anciennes ceintures orogéniques. Bien que leur équivalence avec la croute océanique soit maintenant bien établie, de nombreuses ophiolites peuvent ne pas en être des exemples « typiques », et tous les exemples ne sont pas identiques. La plupart des ophiolites se sont probablement formées dans des environnements influences par la subduction plutôt qu’au niveau des dorsalis océaniques. Les ophiolites restent un thème de recherché important au XXIe siècle et de nombreuses questions subsistent quant à leurs environnements de formation et notamment à leurs mécanismes de mise en place sur les continents. Bien qu'il n’ait pas été le premier à être identifié comme un vestige d'un océan disparu, le complexe igné de la baie des Îles, dans l'ouest de Terre-Neuve, fait partie des ophiolites les mieux conservées et les plus facilement accessibles au monde. À la fin du XXe siècle, les travaux de recherche dans ce domaine ont joué un rôle déterminant dans la comprehension de la croûte océanique et dans la compréhension des événements diachrones impliqués dans la destruction progressive d'une ancienne marge continentale stable au fur et à mesure de l'accrétion d'arcs et de blocs microcontinentaux. Une partie des Tablelands Ophiolite se trouve dans le parc national du Gros-Morne, site classé au patrimoine mondial de l'UNESCO en raison de son importance pour notre compréhension de la tectonique globale. La région plus large autour du parc comprend également le projet Cabox Aspiring Geopark, qui est également à la recherche d’une reconnaissance dans le cadre de l’UNESCO. Cet article fournit des informations de base sur les ophiolites et le développement de nos idées à leur sujet, et relie ce matériel à quatre excursions autoguidées qui permettent d'examiner de nombreuses caractéristiques classiques. Ces excursions vont d’une collection de visites d’affleurements au bord de la route, à des randonnées relativement faciles sur les sentiers officiels du parc national, et finalement à une randonnée plus difficile hors-piste menant au plateau sommital des Tablelands pour visiter de rares affleurement du Moho (la discontinuité de Mohorovičić, c’est-à-dire la limite inférieure de la croûte terrestre) et des roches du manteau supérieur sousjacentes. Collectivement, les visites sur le terrain devraient permettre aux visiteurs amateurs de géologie de faire l'expérience d'une géologie remarquable dans un paysage spectaculaire et parfois surréaliste.

The angular unconformity at Siccar Point in Scotland is one of the most famous localities in the history of geology. At this spot, steeply dipping, folded turbiditic sandstone of early Silurian age is clearly overlain by subhorizontal red conglomerate, breccia and sandstone of late Devonian age. Siccar Point was not the first unconformity ever to be described or illustrated, but it is unquestionably one of the most spectacular and informative that geologists are likely to see. In June of 1788, a famous excursion by James Hutton, John Playfair and Sir James Hall first discovered this striking evidence for the cyclic nature of geological processes and the probable antiquity of the Earth. Contrary to myth, it was likely not the inspiration for Hutton’s famous phrase no vestige of a beginning, no prospect of an end, but Playfair’s metaphor of looking so far into the abyss of time is forever associated with this place. Siccar Point influenced many other geologists, including the young Charles Lyell, who would eventually bring the ideas of James Hutton together with those of William Smith, to build the uniformitarian paradigm that founded modern geology. Lyell’s writings would in turn influence the young Charles Darwin in his search for the reality and causes of evolution. Siccar Point is easy to visit from the historic and vibrant city of Edinburgh, and such a pilgrimage is easily combined with other sights of geological or cultural interest. Visiting the shrine involves a short coastal hike in one of the most beautiful parts of Scotland. This article combines practical advice for would-be pilgrims to Siccar Point with some historical context about its pivotal role in the development of geological ideas in the enlightenment of the late 18th and early 19th centuries.RÉSUMÉLa discordance angulaire de Siccar Point en Écosse est l'une des localités les plus célèbres de l'histoire de la géologie. À cet endroit, un grès turbiditique plissé à fort pendage du début du Silurien est recouvert de conglomérats rouges subhorizontaux, de brèches et d’un grès de la fin du Dévonien. Siccar Point n'est pas la première discordance qui ait été décrite ou illustrée, mais c'est sans conteste l'une des plus spectaculaires et révélatrices que les géologues puissent voir. En juin 1788, avec leur célèbre excursion, James Hutton, John Playfair et Sir James Hall ont découvert cette preuve frappante de la nature cyclique des processus géologiques et de l`ancienneté probable de la Terre. Contrairement à ce qu'on croit, ce n'est probablement pas la fameuse phrase de Hutton « aucun vestige d'un début, aucune perspective de fin », mais la métaphore de Playfair « voir si loin dans l'abîme du temps » qui est à jamais associée à ce lieu. Siccar Point a influencé de nombreux autres géologues, y compris le jeune Charles Lyell, qui a fini par réunir les idées de James Hutton et celles de William Smith qui ont défini le paradigme uniformitariste, devenu le fondement de la géologie moderne. Les écrits de Lyell influenceront à leur tour le jeune Charles Darwin dans sa recherche de la réalité et des causes de l'évolution. Il est facile de se rendre à Siccar Point depuis cette ville chargée d'histoire et dynamique qu’est Édimbourg, et un tel pèlerinage se combine facilement avec d'autres sites d'intérêt géologique ou culturel. La visite de ce « sanctuaire » implique une courte randonnée côtière dans l'une des plus belles régions d'Écosse. Le présent article combine des conseils pratiques pour les visiteurs potentiels à Siccar Point et présente un historique de son rôle central dans le développement des idées géologiques à la fin du XVIIIe siècle et au début du XIXe siècle.

Like most who opted for geoscience as a vocation rather than a mere job, I am often asked exactly why I chose this particular career path, and continue to be involved in my retirement. There are also times when I ask myself the very same question, but it usually boils down to this – being a geologist provides opportunities to visit inspiring, unique and often remote locations through field work and other field trips. In Scotland a couple of years ago, on a conference trip that led to the following article, I read Stephen Baxter’s excellent book Revolutions in the Earth. I thoroughly recommend it – as a biography of James Hutton it gives some insight into his personality – and it illustrates the love-hate relationship that geologists have with field work. In a letter written to a friend, Hutton complained “Lord pity the arse that’s clagged to a head that will hunt stones”. I could amplify this with a detailed footnote explaining the meaning of the archaic dialect verb to clag, but I don’t need to because all geologists will understand Hutton’s sentiment. We don’t really have a choice in this – our interest in exploring the natural world is just part of who we are. Such a conclusion may not be fully scientific, but there’s no denying its truth. Even in a technological age where some geoscience careers are built around black boxes and vast computer models, geology remains at its core an observational science, and the theories that we build are ultimately subject to the ground truth of field observations. It was the lure of field work, the outdoors and travel that brought me into geology, and I know that the same is true for many of my colleagues. Modern geoscience may be sophisticated, multidisclipinary and quantitative, but it always links back to careful field observations and their thoughtful interpretation. Even if technology gives us details and constraints, the essential plotline of the story of Earth comes from reading the rocks. Geoscientists are generally keen and adaptable travellers, who like to get off the beaten tourist paths, sometimes at their own peril. One of the great things about being a student of the Earth is that it surrounds us, and there will always be something interesting to find out, wherever we roam. We enjoy a special relationship with the Earth because we understand its dynamic nature and can visualize it in four dimensions. Travelling geologists are always glancing surreptitiously at roadside outcrops as they flash by, or asking exactly why that range of hills is where it is and shaped just so. This can at times be a source of great frustration to our families or our travelling companions, but it is a natural expression of our curiosity about all things that connect to earthly processes. The one thing that I fear most in aging is to lose such curiosity, as happened to my father. Our idea for a new series in Geoscience Canada that can provide helpful travel information and thoughtful geological context for influential or exceptional field areas is an attempt to both exploit and celebrate our innate curiosity. We envisage a series of articles that will provide readers not only with historical and scientific context for areas of remarkable geology, but also the essential practical information for self-directed excursions. In many cases, there is more than enough technical geoscientific data available for these places, but it is scattered within specialist publications, most of which require other knowledge to fully comprehend. To bring such sources together and communicate them more widely is by itself a service to our science. Areas of great scientific interest are commonly also featured in field trip guides, often from conferences, but these documents can be difficult to locate and access. Even if such sources can be tracked down, they will often emphasize the specialized technical aspects of sites over their wider context, and may lack the practical considerations of where they are and exactly how one might get there. Our vision for articles in Classic Rock Tours is to bring this information together in one place, such that geological context, site descriptions and practical advice are integrated with good maps, clear graphics, and interesting photographs. We do not see this series primarily as a venue for original research, but rather for synthesis and presentation of material from varied sources. It is true that a determined and time-consuming search of literature can eventually provide much of the information that a keen travelling geologist needs, but we seek here to place it all conveniently in one easily accessible source. We envisage papers in this series to sit at an intermediate technical level, so that they will inform and interest a wide cross-section of the Geoscience Canada readership. We also envisage a diverse target audience, not restricted to professional geoscientists engaged in conference or vacation travel. Many areas around the world provide type examples and/or influential sites that have influenced wider geological thought, so these articles can have considerable educational value, even if Volume 45 2018 25

The publishing industry has altered beyond all recognition in the first two decades of the 21 century, and scientific journals cannot evade the ever-shifting winds of change. There has been a fundamental leap from the expensive hardcopy printing of glossy scientific journals to online digital delivery of most content. Even for those journals that maintain print format, production is less, and many scientists now elect to do their reading and research from a laptop or a tablet. Geoscience Canada went ‘digital only’ about four years ago, and the advantages in terms of costs and flexibility are clear. I will admit that I personally miss the feeling of relaxing in a comfortable chair with my coffee and flipping through the printed pages, but there is no going back on this trend. Online publishing transforms access to scientific material on a global basis; readers on the other side of the world, where libraries would likely not archive printed copies of Geoscience Canada, can now easily read our scientific papers. Providing, that is, that they buy a personal subscription, or that their employer or institution (if they have one) holds an institutional subscription. Our annual subscription fee is amazing value (at less than $100 per year), but costs for some geoscience journals are hundreds or even thousands of dollars annually, and institutional subscriptions are even more expensive. Online publishing still requires subscriptions, because it depends on users paying for access, but such access does not come cheap. This seems a strange paradox, given the cost of digital publishing is so much less than printed media. Many universities now face severe challenges in maintaining these expenditures, and subscriptions to specialized journals are being discontinued, leading to protests from individual researchers. However, those in the ivory towers remain the most favoured in terms of their access to online journals. Ironically, the online digital revolution has actually made access to this vital information more difficult for others within the research community. Those who work outside universities or select government institutions have more limited access, and it is becoming increasingly difficult to seek out such material at your local university library, if indeed one is available to you. Procuring a copy of some hard-to-find article can be a real challenge, and the cost of downloading a single paper is as much as buying a hardcopy book – in some cases the only recourse is to beg the assistance of academic colleagues or even students. Gone are the days when I would walk down Elizabeth Avenue on a nice day to browse some recent issues of journals in the periodicals reading room at Memorial University. Most of the journals that I used to look for are no longer even on the shelves, and hardcopy back issues are increasingly relocated to distant, dusty and inconvenient offsite storage. Papers that are published by scientists who are supported by government funding, in government institutions and at universities, now often appear in journals that the general public or unaffiliated researchers cannot freely or easily access. The online digital revolution makes the sharing of information easier for all of us, and the internet now connects us across the globe, but this new tree of knowledge has yet to fully blossom for scientific publishing. This again seems paradoxical, for commercial scientific publishing remains highly profitable even in times when most other parts of the sector confront serious fiscal challenges in maintaining their business models. Even before low-cost online publishing arrived, scientific publishers enjoyed lower costs, because the authors of papers are unpaid, as are the reviewers and most scientific editors. Given this backdrop, it is not surprising that discontent with access restrictions and increasing subscription costs has grown, and some in the research community have called for deliberate boycotts of prominent corporate publishers. It is also not surprising that research funding agencies, which mostly disperse public resources, are increasingly concerned that their investments are not rewarded by wide visibility and availability of their research. The Open Access concept emerged as a possible solution to this growing dilemma, and it is now a persistent topic wherever scientists gather and talk, although opinions and viewpoints are understandably diverse. Three research funding agencies in Canada, including NSERC, which is the principal source for geoscience research funding, now require that peer-reviewed

Visible/Infrared Reflectance Spectroscopy (VIRS) measures absorption in the 350 nm to 2500 nm region of the electromagnetic spectrum, where many minerals have distinct responses that allow their identification, even within mixed parageneses. The VIRS method characterizes a range of hydrothermal and supergene alteration minerals, and also some primary igneous and metamorphic minerals. Data acquisition is simple and rapid, but interpretation is more complex, requiring a large database of reference spectra. Automated computer programs can simplify and expedite this process, but human analysis and reasoning are also required, and VIRS data are most useful where combined with other data, notably petrography and geochemistry. Several pilot studies, summarized here, illustrate the versatility of the VIRS method. Studies of alteration, associated with epithermal gold mineralization, easily recognized key indicator minerals such as pyrophyllite, alunite, dickite and topaz; such information may be useful in mapping zoned alteration systems, and vectoring toward the most favourable areas. A study of footwall alteration in a VMS deposit did not support previous visual identifications of pyrophyllite, but gave ambiguous results with respect to kaolinite. Modelling showed that subordinate kaolinite could be masked by interference from more abundant white mica (sericite). The VIRS data from a mesothermal vein-type gold deposit indicate subtle alteration signatures, on a scale of several metres, around auriferous veins, even though visual evidence for such effects is muted. The mineralogical causes for this effect are as yet unresolved, but this does not prevent its use as a proximity indicator in exploration. Studies of porphyry-style Mo–Cu deposits, associated with sheeted veins, document the progressive overprinting of regional chloritedominated propylitic alteration by focused potassic to phyllic alteration associated with the mineralization. A later stage of advanced argillic alteration, typified by kaolinite, was also documented in one deposit. A reconnaissance investigation of rareearth element (REE) mineralization in Labrador suggests potential for the VIRS method in studies of host rocks and mineralization. The VIRS data can distinguish Na–Fe-rich chain silicates characteristic of peralkaline igneous rocks from common pyroxenes and amphiboles, facilitating identification of potential host suites. The REE also generate unusual absorption features in the visible and near infrared, which directly indicate specific REE ions. Although there are few reference spectra for complex REE-bearing minerals, the VIRS data recognize mineralized samples, and may help to identify samples collected on the basis of other criteria, for geochemical assays. Finally, VIRS analysis of samples from central Labrador now provides the first reference spectra for the REE-enriched mineral eudialyte.