Thursday, December 09, 2021

Roadside geology in three billion years on the back roads

(7 photos)

This week Back Roads Bill asks us to look at roadside rock cuts to learn about what makes up Northern Ontario and there is a guidebook to help

Bill Steer

SOO TODAY

Rock cuts are found throughout Northern Ontario remember to pull well off the road for safety's sake.

Bill Steer for Village Media

When driving along the main or the back roads, a multitude of colours, interesting wavy patterns and lines are visible within the rock cuts in some locations. There are three billion years of history to discover and understand at these stops.

In Northern Ontario, road builders don't always take the path of least resistance they go straight through the Canadian Shield creating accidental geologic classroom lessons. We know the exposed rock faces as rock or road cuts. It is a great way to see the rocks that are normally hidden.

Most of us are neophytes when it comes to rocks but they can reveal different layers of rock, faults, igneous intrusions, and many other geologic structures that are normally difficult to see.

In basic terms, geology is the study of the earth, the materials of which it is made, the structure of those materials, and the processes acting upon them over time. It also includes the study of organisms that have inhabited our planet like fossils, Manitoulin is famous for that.

Where to start

Mark Hall, lives within the City of Greater Sudbury and he is a 'professional landman,' an industry term not so familiar.

He is a mining landman specializing in hard rock mineral prospects and project development with more than 20 years of experience in acquiring and managing mineral lands, for both the government and private companies in Canada and the USA.

He said the rocks of Northern Ontario tell many stories and hold even more secrets. Most of that secret information is covered by dirt and plants and will never be revealed to humans, but we do get a glimpse of the Canadian Shield geology whenever we travel the highways.

Every rock cut along the road is a tiny window into the hidden bedrock that we drive by.

One must be able to see the rocks to understand them, and our road cuts can provide wonderful exposures of what lies beneath. A great example is the road cut on Hwy. 69 at the Bowes Street exit at Parry Sound.

This road cut is like a first-year structural geology course in one picture.

Next time you pass by (not for the driver) look to see the way the rocks are layered, then notice that they are not flat but bent and folded like children’s play dough. That folding is the result of enormous tectonic forces twisting the rock layers into what you see today.

When the rock can bend no more, it snaps.

See where the layers are interrupted along straight lines? These are faults where one side has slid past the other. You would not want to be there when that happened because that movement is what causes earthquakes.

Don’t worry, that earthquake because it likely happened billions of years ago.

This sounds rock solid but I think I need a tutorial.

One of the geological features in 'Road Rocks' is the dynamic Ouimet Canyon near Dorion.

Bill Steer for Village Media

Road Rocks Ontario

The best way is to stop and look at all those rock cuts up close and personal. It was like a gold discovery I found the definitive guidebook written by a geologist who has spent a lifetime looking at the roadside rocks.

Dr. Nick Eyles has been teaching geology at the University of Toronto for almost forty years.

He is an award-winning author of the best-selling geology books Road Rocks Ontario and Ontario Rocks.

After completing a five-part series with CBC on the geology of Canada that aired in 2008, Nick was on the road with the Canadian Broadcasting Corporation for seven months in 2009-10 as host of Geologic Journey – World a five-part Nature of Things series with David Suzuki. Rock on with Nick.

The ripple rocks just west of Desbarats is one of the most interesting roadside geology locations.

Bill Steer for Village Medi

The province of Ontario contains many sites of outstanding geological importance. Many are internationally well known and attract visitors from around the globe. Others no less important remain hidden in plain sight. This is what I have been searching for.

"During the last three billion years Ontario has been witness to giant tectonic collisions as North America collided in turn with South America and Africa creating huge mountains now long gone," Nick said. "Many of Ontario's northern rocks originated as magma on ancient ocean floors long before life flourished. The province has been dented by fiery meteorites, drifted across the equator, been flooded by tropical seas rich in marine life and scraped bare by ice sheets."

As an addendum to another recent Back Roads Bill story, he said, “ Many rocks are sacred to First Nations peoples who believe that rocks are inhabited by may maymaygwayshiwuk who appear every now and again to torment humans.”

Click this link to learn more about that.

There is a lot of rock in Ontario and this book offers only a glimpse of what can be found in the thousands of outcrops by side of the road. Armed with what you learn from this guide you’ll pretty soon figure what that other stuff might be.

And besides that, he said, “Most of the stops are close to coffee stops.”

There is hope for me now.

As drive the northern route of Highway 11, west of Beardmore and east of Nipigon you will see these magnificent palisades; and there is hiking trail to the top.

Bill Steer for Village Media

See the map for some of the book’s locations and page numbers with Back Roads Bill photos.

Nick recommends stopping by the Rock Walk in Haileybury to get a primer on the rocks you will see; that’s on page 440.

In the easy-to-read Road Rocks Ontario book, there are more than 250 geological wonders to discover. It has GPS coordinates for each site and a location map. This guidebook has been on the back roads since its publication in 2013.

And while you are at it here are a few free government publications on roadside rocks in a printable .pdf format that will help you with your schooling and a field guide to the Sudbury area and an entire series of Northern Ontario geo tours.

Always remember to pull off the road as the apron allows.

Now, if I can just figure out how to drive the back roads and read the guide at the same time?

Santa knows I won’t do that because I don’t want that lump of coal again, we have peat but not coal in Northern Ontario. I do not have rocks in my head others may say differently.

Dinosaur faces and feet may have popped with color

by University of Texas at Austin

Most birds aren't as colorful as parrots or peacocks. But if you look beyond the feathers, bright colors on birds aren't hard to find: Think pink pigeon feet, red rooster combs and yellow pelican pouches.

There's a good chance that extinct dinosaurs rocked pops of color on similar body parts and may have flashed their colors to entice mates, just as birds do today, according to a study led by researchers at The University of Texas at Austin.

"Living birds use an array of pigments and can be very colorful on their beaks, legs, and around their eyes," said Sarah Davis, a doctoral candidate at the UT Jackson School of Geosciences who led the study. "We could expect that extinct dinosaurs expressed the same colors."

The research was published in the journal Evolution on Dec. 6.

The takeaway on potential dinosaur color schemes comes from broader findings about skin and tissue color in the common ancestor of living birds and extinct dinosaurs, an ancient archosaur that lived near the beginning of the Triassic period. By analyzing whether bright body color was present in living dinosaur relatives—including turtles, crocodiles and over 4,000 bird species—the researchers determined that the common ancestor had a 50% chance of having bright colors in the soft tissues of its body.

The bright colors examined in the study typically come from carotenoids—a class of colorful red, orange and yellow pigments that birds extract from their food. Carotenoids do not fossilize as well as brown and black pigments, which means scientists must study color in living animals to look for clues about color expression in their extinct ancestors.

The researchers used the data collected from birds and other animals to make phylogenic reconstructions, a scientific method used to investigate the evolutionary histories of species. The 50% estimate for bright color applies equally to skin, beaks and scales of the ancient archosaur. In contrast, the research found that there was a 0% chance that claws and feathers were brightly colored, which is consistent with other research, Davis said.

The study also examined the connection between color and a diet high in carotenoids, with Davis finding that birds with higher carotenoid diets (plant- and invertebrate-rich) were more likely to be colorful than meat eaters. What's more, she found that plant-eating birds expressed bright colors in more places on their bodies than meat eaters or omnivores.

"The earliest dinosaurs were pony-sized and ate large, vertebrate prey," said study co-author Julia Clarke, a professor at the Jackson School. "Different groups shifted to plant-dominated or mixed diets. This shift likely led to changes in coloration of skin and non-feather tissues."

In addition to coloring the past, the research puts living birds in a new perspective. Davis said that the bird groups examined in the study have a reputation for being drab—especially in comparison to songbirds, which were excluded from the study because they are the most distantly related to their nonavian dinosaur ancestors.

But aside from their feathers, the birds turned out to be quite colorful. The study found that about 54% of the 4,022 bird species studied had bright colors. Of this group, 86% of species expressed bright color in only non-feathered tissues.

Mary Caswell Stoddard, an associate professor at Princeton University, said that the study provides important insights on bird color that often go overlooked.

"There is so much more to birds' color than their plumage—just think of the vibrant orange-yellow bill of a toco toucan—but feathers tend to get the most attention," she said. "This study unravels the evolutionary history of carotenoid-based coloration not just in plumage but also in the beaks and skin of birds and their relatives."Why some of Darwin's finch nestlings have yellow beaks

More information: Sarah N. Davis et al, Estimating the distribution of carotenoid coloration in skin and integumentary structures of birds and extinct dinosaurs, Evolution (2021). DOI: 10.1111/evo.14393

Journal information: Evolution

Provided by University of Texas at Austin

Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain

Article
Open Access
Published: 09 December 2021

Pablo Navarro-Lorbés,

Javier Ruiz,

Ignacio Díaz-Martínez,

Erik Isasmendi,

Patxi Sáez-Benito,

Luis Viera,

Xabier Pereda-Suberbiola &

Angélica Torices

Scientific Reports volume 11, Article number: 23095 (2021) Cite this article

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Abstract

Theropod behaviour and biodynamics are intriguing questions that paleontology has been trying to resolve for a long time. The lack of extant groups with similar bipedalism has made it hard to answer some of the questions on the matter, yet theoretical biomechanical models have shed some light on the question of how fast theropods could run and what kind of movement they showed. The study of dinosaur tracks can help answer some of these questions due to the very nature of tracks as a product of the interaction of these animals with the environment. Two trackways belonging to fast-running theropods from the Lower Cretaceous Enciso Group of Igea (La Rioja) are presented here and compared with other fast-running theropod trackways published to date. The Lower Cretaceous Iberian fossil record and some features present in these footprints and trackways suggest a basal tetanuran, probably a carcharodontosaurid or spinosaurid, as a plausible trackmaker. Speed analysis shows that these trackways, with speed ranges of 6.5–10.3 and 8.8–12.4 ms−1, testify to some of the top speeds ever calculated for theropod tracks, shedding light on the question of dinosaur biodynamics and how these animals moved.

Introduction

One of the perennial questions in the paleobiology of non-avian theropod dinosaurs is their capacity for locomotion, e.g.1,2. How did they move? How fast did they go? Over the years, these questions have been approached from various points of view based on osteological information, with anatomical (e.g., morphology, muscular attachments, size) and anatomically-derived biomechanical models (e.g., mass, force, and momentum) being used to estimate the maximum speed of locomotion3,4,5,6,7. Another way of better understanding how extinct theropods moved is to examine their tracks and trackways, e.g.8. To this end, Alexander9 proposed an equation using dynamic similarity to calculate the absolute speed of dinosaurs from ichnological data on the basis of footprint length (to obtain the height at the hip) and stride length. This and other methods e.g.10,11 have been used in the last few decades by many ichnologists to analyse the locomotion dynamics shown by hundreds of trackways, e.g.11,12,13,14.

Walking is the most common behaviour inferred from dinosaur fossil trackways9,10,11,15, although some minor cases of running or trotting have also been identified13,16,17,18,19,20,21,22,23. Indeed, 96% of the 1802 Kayentapus dinosaur strides studied by Weems 13 were made by animals with a walking behaviour, whereas just 4% of them were made by dinosaurs with a more energetic way of movement. Of this 4%, the great majority is consistent with trotting displacement, whereas just one of the trackways could correspond to a running behaviour13. In the Early Cretaceous of Spain, a theropod trackway of six consecutive footprints with pace lengths of more than two metres preserved in a trampled surface was found at La Torre 6B (Igea, La Rioja)24 (Fig. 1), for which has been inferred high speeds of more than 10 ms−1 (Refs.25,26,27). The trackway from La Torre 6A was initially mentioned by Aguirrezabala et al.24 with the presence of two non-consecutive footprints and the probable presence of a third between them, lost by erosion. During new field campaigns in this area, two significant findings have recently been made: a new footprint was discovered to add to the La Torre 6B trackway, and the discovery of three new footprints in La Torre 6A that confirm the presence of a second high-speed trackway in La Torre tracksites. Both trackways shed light on locomotion, speeds and even behaviour of non-avian theropods.

Results and discussion

Tracks and trackways

The La Torre 6A-14 trackway (Fig. 2) preserves only five of the six footprints because the third footprint in the trackway was at a point of the tracksite where the top layers of rock have been lost. The footprints are tridactyl, functionally mesaxonic, and longer than wide (mean length and width, respectively, of 32.8 cm and 30.2 cm). The footprints show well-preserved digit impressions (Fig. 3A). The divarication angle between the digit II and IV impressions is about 67° and varies from 57° to 75°. The metatarsophalangeal area is very shallow in the first footprint and elongated in footprints 2, 4 and 6. The impression of digit II is always deeper than digit IV, and in footprints 2 and 4 a sharp longitudinal groove is preserved, probably related to the claw imprint. The digit III impression also shows a deep area in its distal zone, but the claw imprint is at a higher level than the rest of the digit. In footprint 6, the posterior area of digit III is preserved as a narrow and shallow groove. Pad imprints are identified in footprints 2, 4, and 5. The impression of digit IV is elongated, has a sharp distal end, and is the shallowest of all digits. The mean values for the pace angulation, stride length and pace length are 169°, 523 cm and 265 cm, respectively.

CONTINUE READING HERE

Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain | Scientific Reports (nature.com)

How Did Crocodiles Survive the Asteroid That Wiped Out the Dinosaurs?

By MIKE LEE, FLINDERS UNIVERSITY DECEMBER 8, 2021

Asteroid Planet Atmosphere

There are two main reasons crocodiles survived the asteroid that killed the dinosaurs. First, crocodiles can live for a very long time without food. Second, they lived in places that were the least affected when the asteroid hit Earth.

When the asteroid hit earth

About 66 million years ago, dinosaurs ruled Earth. But then a massive asteroid, more than 9 kilometers wide, slammed into the shallow sea near what is now Mexico.

The explosion from this was so huge, it led to global earthquakes, tidal waves, bushfires, and even poisonous rain.

Also, the asteroid hit at one of the worst possible places, where the rocks could easily be “exploded” (or vapourised). This threw up massive amounts of dust into the sky, blocking out the Sun for many months and sending Earth into a long, dark, and freezing winter.

Without sunlight, the green plants died, followed by the plant-eating animals that ate them to survive, and the meat-eaters that ate the plant-eaters.

Credit: Michael Lee

Scientists think three-quarters of all the different kinds (species) of animals on Earth were wiped out – including most dinosaurs.

But some managed to survive for a range of reasons.

One important group of dinosaurs sailed through, helped by their ability to fly and find food in faraway places. Their feathers protected them from the cold, and their beaks let them eat buried seeds found near dead plants.

Amazingly, these dinosaur survivors are still with us today. We call them birds!

A battle-scarred saltwater crocodile resting near the Daintree River in North Queensland. Credit: Michael Lee

Crocodiles had some keys to survival

Crocodiles were another group that famously survived the asteroid. Obviously, they can’t fly, don’t have feathers, and don’t eat seeds! But they had other secrets to success.

Firstly, crocodile bodies use very little energy. They lie around a lot, breathe slowly and even have a very slow heartbeat. This is how they can hold their breath underwater for more than an hour.

It also means they can go without food for months, and sometimes more than a year. This would have been very helpful when food (such as other animals) became hard to find once the asteroid hit.

Dinosaurs, on the other hand, were generally more active, which means they needed more energy – especially meat-eaters like Velociraptor. Without food, they would have died quickly.

Dinosaurs such as Velociraptor would have struggled to survive without much food after the asteroid hit. That is, if they survived in the first place.

Crocodiles also lived in places where losing green plants didn’t make a big difference. Think of a forest or a grassland (where many dinosaurs lived): if the plants there die, then all the animals that need them die too, including the meat-eaters which are left with no food.

But the crocodile survivors mostly lived in places like rivers, lakes, and coasts. The animals living in these places don’t need green plants as much. Dead plants and animal material washes in from surrounding land, which is eaten by tiny creatures, which are then eaten by larger creatures including crocodiles.

So unlike dinosaurs living on the land, crocodiles in a river would not have starved as soon as the green plants died.

Our mammalian ancestors also survived

A similar reason helps explain why human beings’ ancestors also survived the asteroid impact. These were the small mammals that lived near the end of the age of dinosaurs, which eventually gave rise to all the different kinds of mammals around today (including humans).

They were mainly small, rat-like things that scurried about in the dead leaf litter on the ground, eating insects and worms. These tiny creatures relied not on living green plants, but on dead leaves and bark falling from the trees, or being blown and washed in from elsewhere.

So just like the crocodiles, our tiny ancestors survived the asteroid partly because they didn’t depend heavily on living plants. A good thing too: these lucky survival skills are the reason you and I are here today!

Written by Mike Lee, Professor in Evolutionary Biology (jointly appointed with South Australian Museum), Flinders University.

This article was first published in The Conversation.

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