The Allure of Vanished Worlds

Abstract

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