Life and Times
For the past couple of years I have been a member of the group working to organize the 2013 GAC-MAC Conference (Geological Association of Canada – Mineralogical Association of Canada). The meeting is now just a month away and there has been a steady stream of tasks: editing guidebooks, organizing field trips, sending out advertisements, attending meetings … which helps to explain why posts on this page have been rather thin lately. It will be a really good meeting, and it will be really good to have it over with!
One of the most exciting parts of the conference, from my point of view, will be a symposium in honour of my M.Sc. supervisor, Rolf Ludvigsen, titled Life and Times of Phanerozoic Seas. The session description states:
This symposium is to celebrate the work of Rolf Ludvigsen. Rolf has been a major force in invertebrate paleontology in Canada for nearly four decades, mainly specializing in trilobites. After leaving academia, his focus shifted toward the popularization of paleontology. This Special Session encourages a wide variety of presentations about organisms and their activities in ancient seas.
This description says a lot, but it also leaves out a lot. As my supervisor at the University of Toronto, Rolf was mercurial, confrontational, charming, demanding, maddening, entertaining, and tremendously intimidating. He challenged his students by expecting nothing but the best from us, and his approach got results. Several of his former students and postdocs have gone on to successful professional careers in paleontology, and his influence has been immense. The full-day session is organized by Rolf’s former students and colleagues; we are sorry that he cannot be physically present, but his presence will be felt.
Rolf Ludvigsen with students current and past at the 1986 Albany Canadian Paleontology and Biostratigraphy Seminar. L-R: me, Steve Westrop, Brian Pratt, and Rolf. Our cups undoubtedly hold coffee.
World Water Life
Whale Cove, Grand Manan Island, New Brunswick: a still morning, with a herring weir on the horizon
This morning I awoke from a dream. I was standing on a darkened shore, looking out toward the unbroken line of pale horizon. The sea was still and deep, immense and incomprehensible.
I got up and put water into the coffee pot. After breakfast, we drove downtown. The talk on the radio was of the risk of flooding in the Red River Valley, the result of deep snow that accumulated here through the winter. This land is flat, a surface of horizontal clay deposited at the bottom of what was, at the time, the world’s largest lake.
Over the bridge, we crossed the still ice-covered waters of the Assiniboine River, which constantly transports phosphorus and nitrogen that have washed from the fields and feedlots of Saskatchewan and western Manitoba. A little farther along we could see the Red River on our right, carrying those nutrients to Lake Winnipeg, where they will contribute to the ongoing problems of anoxia and cyanobacterial blooms. We passed numerous buildings faced with mottled limestone, every slab of it holding the skeletons of creatures that lived in the waters of a warm, tropical sea.
Water in all its physical forms at Airport Cove, Churchill, Manitoba
Arriving at the office, I turned on the computer, then scrolled through the e-mail listings of new results in marine biology and paleontology. In the lab, I poured the water to prepare a pot of lab-grade coffee and began unpacking and washing some of last summer’s collections, laying them out to dry by the sink. These fossils are the remains of animals and plants that lived and died in ancient lagoons and tidal ponds, strange things such as jellyfish, horseshoe crabs, and eurypterids.
Back at the computer I sorted through data, trying to better understand the ecology of ancient tidal flats during an interval of declining sea level. Looking at e-mail again, I discovered something I didn’t know: today was World Water Day. How appropriate it seemed that my day so far had involved virtually nothing in which water was not a major, central factor. World Water Day is focused most specifically on water as a resource, on the push for universal access to clean, fresh water, but it also considers the hydrological cycle, pollution, and climate change.
View from The Whistle, Grand Manan Island
Those of us who study anything to do with water are, of course, attuned to water-related phenomena as we pass through the world. But what of the rest of the populace? Water is essential to every aspect of our lives, yet day-to-day it seems that we hear far more about the diets and sartorial choices of the infinitely fascinating Kardashian family than we do about water issues.
Unless we are in flood season, or our well runs dry, or our favourite beach is threatened by green scum, water is seen as “worthy but dull.” It is taken for granted until something happens that affects us directly. This basic fact is used to advantage by some governments, and by others whose interests may benefit from wilful misdirection of public attention.
Near Whitehead Island, New Brunswick
Water is of critical importance, and freshwater and seawater can both be threatened by certain industrial activities. Yet in Canada we are apparently satisfied with a government that, by its actions, has decided that water is entirely dispensable, that aquatic ecosystems are a nuisance and get in the way of efficient industrial development. How else can we understand decisions to close down one of the world’s most important water research institutions, to support the foolhardy development of a bitumen pipeline across the Cordillera to a tanker terminal on a complex and sensitive coastline, and to essentially remove federal protection from the great majority of our inland waterways?
Those of us who study ancient seas can examine only little pieces of huge subjects, which are sporadically preserved and can therefore only be partly comprehended. Modern water is infinitely better studied and understood, but what help are all the studies in the world if we cannot save the things that all of us should hold dear?
© Graham Young, 2013
Marble Table
Wandering through the Earth galleries at the Natural History Museum a few years ago, I came upon this splendid marble table. The intricate inlay work highlights a range of mid-Paleozoic fossils: cephalopods, corals, algae, and stromatoporoid sponges, enclosed in variously coloured veined and brecciated limestones.
Although I took many photos of the table (far more than shown here), I foolishly did not look to see if there was any signage explaining it, and I have not been able to find any proper explanation online. The most I can glean is that the table may have been made relatively recently, and that the limestones may all be from the Devonian of south Devon.
If you know more about the source, please share this information with a comment!
The orthoconic cephalopods all have their apertures pointing toward the table’s axis.
Umbilicus
With the work I have been doing on the Manitoba Legislative Building, I thought I would spend some time in the New Brunswick Legislative Assembly Building during a recent visit to Fredericton. It is a very different structure, an intimate, almost house-like Second Empire building, in contrast with Manitoba’s imposingly cavernous neoclassical parliament. I had planned to mostly look at geological features of this building, but I was distracted …
An umbilicus is an origin, the place at the middle or beginning of something larger. For humans it is another word for our navel. The navel is the point of expansion for your body, where it gained sustenance as you grew in the womb. For coiled molluscs such as snails and Nautilus, the umbilicus is the hole at the centre of its shell whorls, the axis of its coils, effectively the place where the coiling growth began.
My origins are in an old place. In the middle of that old place, most appropriately, is this uniquely beautiful open spiral. The umbilicus of the town and the province.
The building was designed by J.C.P. Dumaresq, an architect who created many other important buildings in the nineteenth century Maritimes. Since he was a Nova Scotian born in Sydney, I am tempted to speculate that this staircase was inspired by the spiral that can be seen in an abraded snail shell on the beach, or maybe by a whelk’s egg case. I also suspect that some of the form of this coil may have come from the minds and hands of the highly-skilled carpenters, of whom there were many in New Brunswick at that time.
Perhaps the spiral was suggested by New Brunswick’s fiddleheads, which turn up in many other places as symbols of the province. On the front of the building, a series of fiddlehead-form brackets support the little balconies. Looking in detail, I realized that each of these has different decoration and depicts a different organism; I am particularly fond of the dragon bracket!
These fiddleheads are close to being logarithmic spirals, like Nautilus shells. The staircase (being a staircase) is not, but its complicated form is far beyond my extremely limited mathematical understanding. I can only contemplate and wonder. Umbilicus.
Overall, the exterior of the building is an elegant and coherent piece of Second Empire style, executed in fine sandstone. I will try to discuss its geology in a future post!
If you wish to learn about the man who designed this building, please read my sister’s fine article in the Dictionary of Canadian Biography.
© Graham Young, 2013
Death Horizon
Cephalopods belonging to the genus Kinaschukoceras, spread across a bedding plane surface
When people discuss the extinction of dinosaurs and its possible cause by catastrophic events, one question that often comes up is, “if the last dinosaurs all died out at once, then where are the bodies”? Shouldn’t we find the carcasses, the Tyrannosaurus and Triceratops stretched out as if asleep, under the soft blanket of iridium-enriched dust that emanated from the Chicxulub impact site?
Let’s think about this for a minute or two. Any bedrock exposure that happens by chance to intersect the Cretaceous-Paleogene boundary is just that: a chance happening. And we can thus apply the laws of statistics to the issue of dinosaur bodies. I am not going to challenge either of us to do the math, but think about how rarely you see vertebrates larger than, say, a house cat, as you walk, drive, or fly across the surface of this planet.
Sure, you can find large ponderous vertebrates everywhere if you are surrounded by an anomalous anthropogenic assemblage, such as on Manhattan Island or in the middle of a dairy herd. There are also plenty of large wild mammals in localized hotspots . . . the centre of a caribou herd on the barrengrounds, or floating above the feeding belugas at the mouth of the Churchill River. But I can recall many days travelling across Canada where I might have been lucky to see one bear, or one coyote, or one moose in a drive of more than 1000 kilometres. If we take this distribution and average it out, you will appreciate that, on a randomly-selected two-dimensional outcrop that is much less than a kilometre across, your chances of finding a single dead dinosaur are infinitesimally minute. And that is even if dinosaurs were very abundant, right up to the time that the last of them were snuffed out by the Chicxulub event (which is also debatable).
A large specimen of Kinaschukoceras
Nevertheless, even if the bodies cannot be found at the end-Cretaceous horizon, there are places where we do see fossils concentrated into particular strata. These are generally the result of local conditions. A bone bed may record the mass death of a herd in a catastrophe such as a flood. A bed packed with the skeletons of filter-feeding invertebrates such as oysters or brachiopods may simply be the result of their huge abundance on an ancient seafloor where the environment was favourable, or it may be because they were concentrated by the winnowing of waves and currents.
Those sorts of death horizons are not difficult to understand, even if the detailed analysis of the ancient environment can be painstaking and laborious. But what if we find a place where upper trophic carnivores are all concentrated, with little evidence of their presumed prey or food? What does that mean?
This was brought to mind by the place in these photos. In the Ordovician Stony Mountain Formation of the Grand Rapids Uplands, central Manitoba, we find a variety of fossils. In some beds, the ancient seafloor was inhabited by corals, which can even be resting in the places where they grew. Elsewhere there are abundant burrows and gastropods. But in this particular bed of clotted dolostone, the only obvious fossils are these nautiloid cephalopods that glory in the genus name Kinaschukoceras (they may belong to the species Kinaschukoceras shamattawaense; talk about a mouthful!).
How can it be that these large predators are spread across the bed, with no evidence of what they might have been predating upon? Cephalopods are rare elsewhere in these rocks, so this really is an anomalous occurrence.
Small patches of in-place outcrop occur across a large area of weathered dolostone
I suspect that, in this case, there were a few factors at play. First of all, these were probably free-swimming creatures that lived somewhere up in the water column, possibly some distance above these seafloor sediments. Nautiloid cephalopods are readily transported after death by waves and currents, and it is entirely likely that these animals did not live right here, and that they may have been transported to this place of deposition. Also, perhaps the nautiloids preyed on creatures that lacked mineralized hard parts, in which case the prey would be unlikely to be preserved as fossils.
The clotting and mottling of the sediment indicates that there was life on the seafloor, but the conditions might not have been particularly favourable for many forms, which may explain why we have not found seafloor body fossils here. Finally, a sedimentary stratum is not generally a snapshot of what was living in a place on a single day or year, and it could represent centuries or millennia. Beds commonly contain time-averaged assemblages, and we sometimes talk about Konzentrat-Lagerstätten, which represent intervals in which little sediment was deposited (in which case the fossils may appear much more abundant than the organisms were in life).
These factors and others could all be at play when we observe this sort of death horizon, but it is only after detailed, thorough detective work that the paleontologist may be able to determine the true story.
© Graham Young, 2013
Saint’s Rest
Saint’s Rest Beach
What could possibly be more pleasant than a February afternoon by the Bay of Fundy? There may be some February days that possess a pleasantness exceeded by the average tonsillectomy or root canal, but Tuesday was not one of those. Under a warm and gentle sun the temperature was an unseasonal +6, the sea was a bright transparent blue, and the air was as clear and sweet as I have ever experienced.
Rocky shore at Sheldon Point
The Irving Nature Park is a tremendously diverse sample of shoreline within the City of Saint John. Rocky shore, cliff, shingle beach, sand beach, salt marsh, coastal mixed forest: all of these can be found between Taylors Island, Saint’s Rest Beach, and Sheldon Point. The geology is also of interest: Neoproterozoic or Cambrian bedrock (which looked like metavolcanics to me) is overlain by glacial sediment, and the beach contains a wonderful variety of boulders and cobbles. With such varied geology, it is little wonder that the Saint John area has become North America’s first Global Geopark.
The salt marsh boardwalk
Manawagonish Creek in the salt marsh (note to my prairie friends: those shiny surfaces are mud, not ice!)
The nature park is a fantastic resource to have within easy reach of a city; it is privately owned and maintained by the Irvings. On this beautiful day it was obviously popular as we passed a steady stream of runners, hikers, and dog-walkers. In the marsh the grasses look dead and the birds were rather sparse on the ground, but with days such as this, can spring really be far away?
A tidal channel in the salt marsh
An islet in the salt marsh channel
As is the case on Grand Manan, dead trees at the edge of the salt marsh suggest relative sea level change. Either the sea has risen enough that high tides have killed the trees, or the land has been sinking.
Vegetated bar between the beach and the salt marsh
Manawagonish Island, just offshore, is also a nature reserve.
Saint’s Rest Beach
A spectacular mudflow emanates from the bluff
The clasts in this breccia boulder are illustrative of Saint John’s varied geology (Canadian quarter for scale)
Yellow birch in the woods on Taylors Island
© Graham Young, 2013
Late Ordovician Konservat-Lagerstätten in Manitoba
Fossils from the Airport Cove site, part 1: spectacular examples of dasycladalean green algae on bedding plane surfaces (The Manitoba Museum, MM B-339, B-340).
Canada is remarkably rich in Konservat-Lagerstätten, sites at which unusual fossils are preserved. For the past while, Dave Rudkin and I have been co-editing a series for Geoscience Canada called Great Canadian Lagerstätten, which compiles reviews of these sites, covering many intervals from the geological record. The third paper in the series is based on our own research, describing the fossils from three unusual localities in central and northern Manitoba. Together with our co-authors, we have had a lot of fun putting this together: it was interesting to have the chance to assess the state of our “art”, to see where we really are with our research. We have learned a lot about these fossils, but still miles to go before we put this project to bed.
Fossils from the Airport Cove site, part 2: (c) Articulated scolecodont apparatus (jaws of a polychaete worm)(MM I-4062). (d) Large phosphatic or chitinophosphatic tubes of uncertain affinity (MM I-4061). (e) Finely preserved organic eurypterid cuticle (MM I-4063).
The abstract of the paper follows below. If you are interested in downloading a pdf of the entire paper, it can be found here.
Konservat-Lagerstätten, deposits in which soft-bodied or lightly sclerotized fossils are preserved, are very rare in Ordovician strata. Three significant sites are known from Upper Ordovician rocks in Manitoba: at Cat Head – McBeth Point, William Lake, and Airport Cove. These sites are in two distinct sedimentary basins: the former two are in the Williston Basin, while the latter is in the Hudson Bay Basin. All three sites contain marine fossils, but each has a different assemblage that contributes a distinct piece of the diversity picture. Important groups represented at one or more of the sites include seaweeds (algae), sponges, cnidarian medusae (jellyfish), conulariids, trilobites, eurypterids, xiphosurids (horseshoe crabs), and pycnogonids (‘sea spiders’). The different biotas reflect depositional conditions at each site. Many of the fossils are unknown elsewhere in the Ordovician at the family level or higher. The province of Manitoba therefore makes a significant contribution to knowledge of Late Ordovician biodiversity.
Fossils from the Airport Cove site, part 3: (f) Partial eurypterid abdomen (MM I-4586). g. ‘Head’ region of eurypterid-like arthropod (MM I-4064A). (h) The holotype specimen of the xiphosurid (horseshoe crab) Lunataspis aurora; note the preserved eye and dark-stained areas (MM I-4000). (i) This degraded example of L. aurora is surrounded by a halo of dark staining, possibly the result of postmortem decomposition of soft tissue and leakage of body fluids (MM I-4585).
