Scotland’s Isle of Skye reveals landmark dinosaur footprints dated to the Middle Jurassic era

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Footprints belonging to two different kinds of dinosaurs, discovered on Scotland’s Isle of Skye, have revealed new details of how the now-extinct creatures evolved and moved during a period of the Jurassic era. Traces of the dinosaurs were found both as part of trackways and as isolated marks, scientists said.

The fossils were spotted in April 2016 by researchers Davide Foffa and Hong-Yu Yi. The following year, paleontologist Dr Stephen Brusatte from the University of Edinburgh and his student Paige dePolo came back to the site to take a closer look at the prints and find out more. They are not so easy to access, located in the wave-pounded tidal zone of a headland called Brother’s Point. A collaborative study of the footprints by the University of Edinburgh, Staffin Museum, and the Chinese Academy of Sciences, led by dePolo, was presented on April 2, 2018, in the Scottish Journal of Geology, along with a full catalog of images of the 50 footprints.

The team has dated the tracks at about 170 million years of age, and conclude that they were made by the gargantuan animals as they waded through a shallow lagoon. In the distant past, when these tracks were made, Earth was a very different place. It was shortly after the time when Pangaea started to break apart, and our planet was transforming into the continents we know today.

In those days, experts believe that the area of Skye was positioned somewhere in the subtropic belt, with a much warmer climate. According to Brusatte, “This was a subtropical kind of paradise world, probably kind of like Florida or Spain today.”

The latest find of dinosaur prints in Scotland is a source of great excitement in the worlds of paleontology and geology because they are from the Middle Jurassic epoch. As Brusatte explained to National Geographic, this was an important time in dinosaur evolution. It is probably the era when the first birds appeared and the largest species of sauropod were thriving, but dinosaur fossils from this period are scarce compared to other periods. The recent find follows hot on the heels of the discovery in 2015 of hundreds of Middle Jurassic sauropod tracks at another location on the Isle of Skye, Duntulm beach. The Brother’s Point prints were found in older rocks than those of the 2015 discovery.

The study has increased knowledge of dinosaurs from this era significantly and offered some valuable insights: for instance, sauropods were roaming this corner of the globe for a greater period of time than previously thought.

Sauropods were the largest land-dwelling animals at that time, and despite their size, they were plant-eating creatures. The field team not only mapped tracks from sauropods; scattered among them are distinctive three-toed prints belonging to theropods, a distant and more primitive relative of the Tyrannosaurus Rex. These meat-eating dinosaurs were able to grow to about 6.5 feet in height.

The largest sample of theropod footprint left on the Isle of Skye was about 19.6 inches across, which is still nowhere close to the largest belonging to a sauropod–one example of these was reportedly some 27.5 inches across.

The endeavors of the researchers were not without challenges. As the area is continuously hammered with cold winds and rain, the team could not easily proceed with mapping the area. Another challenge was the high tides that regularly reclaimed the footprints, hence the team were constantly clock-watching while they measured and inspected the tracks on the rocky ledges. They also had to improvise with cameras and equipment, but in the end, it paid off, as 3-D images of the terrain were produced.

Part of the dinosaur traces found were actually hand prints, Brusatte explained, a clue that it was a huge creature in question, like the sauropod. This enormous animal, which could grow up to 50 feet long, needed all four limbs to support itself while lumbering around. The theropod tracks indicate that these dinosaurs walked only on their hind legs.

Sauropods were previously thought to have been purely amphibious creatures, the Smithsonian notes. Paleontologists of the early 20th century believed that sauropods could not walk on the land because of their weight. Evidence that was acquired later on proved the contrary. And the recent finds coming from Scotland suggest that, while some representatives of the species were able to move comfortably on land, others opted to wade through waters near the coast.

In fact, Brusatte remarked to National Geographic, sauropods “were so dynamic and so energetic,” meaning it is likely that they were abundant in various environments as their species spread around the world.

Brusatte also acknowledged that more Middle Jurassic era dinosaur fossils could lurk hidden on the Isle of Skye, hence this might be only the beginning of what this Scottish island has to offer to knowledge of dinosaurs in the world.

 Stefan Andrews

Asteroid impact plunged dinosaurs into catastrophic ‘winter’

Artwork impactImage copyright   BARCROFT PRODUCTIONS/BBC
Image captionArtwork: The impact hit with the energy equivalent to 10 billion Hiroshima bombs

Scientists say they now have a much clearer picture of the climate catastrophe that followed the asteroid impact on Earth 66 million years ago.

The event is blamed for the demise of three-quarters of plant and animal species, including the dinosaurs.

The researchers’ investigations suggest the impact threw more than 300 billion tonnes of sulphur into the atmosphere.

This would have dropped temperatures globally below freezing for several years.

Ocean temperatures could have been affected for centuries. The abrupt change explains why so many species struggled to survive.

“We always thought there was this global winter but with these new, tighter constraints, we can be much more sure about what happened,” Prof Joanna Morgan, from Imperial College London, told BBC News.

The new assessment is reported in the journal Geophysical Research Letters.

Lift boat MyrtleImage copyright    MAX ALEXANDER/B612/ASTEROID DAY
Image caption The drill project is revealing new insights on one of the most astonishing events in Earth history

The UK geophysicist was the co-lead investigator on the 2016 project to drill into what remains of the impactor’s crater under the Gulf of Mexico.

She and colleagues spent several weeks retrieving the rock samples that would allow them to reconstruct precisely how the Earth reacted to being punched by a high-velocity space object.

Their investigations suggest the asteroid approached the surface from the north-east, striking what was then a shallow sea at an oblique angle of 60 degrees.

Roughly 12km wide and moving at about 18km/s, the stony impactor instantly excavated and vaporised thousands of billions of tonnes of rock.

This material included a lot of sulphur-containing minerals such as gypsum and anhydrite, but also carbonates which yielded carbon dioxide.

The team’s calculations estimate the quantities ejected upwards at high speed into upper atmosphere included 325 gigatonnes of sulphur (give or take 130Gt) and perhaps 425Gt of carbon dioxide (plus or minus 160Gt).

The CO2 would eventually have a longer-term warming effect, but the release of so much sulphur, combined with soot and dust, would have had an immediate and very severe cooling effect.

Jo MorganImage copyright  MAX ALEXANDER/B612/ASTEROID DAY
Image caption   Prof Morgan pictured with some of the rock samples drilled from beneath the Gulf of Mexico

An independent group earlier this year used a global climate model to simulate what would happen if 100Gt of sulphur and 1,400Gt of carbon dioxide were ejected as a result of the impact.

This study, led by Dr Julia Brugger from the University of Potsdam, Germany, found global annual mean surface air temperatures would decrease by at least 26C, with three to 16 years spent at subzero conditions.

“Julia’s imputs in the earlier study were conservative on the sulphur. But we now have improved numbers,” explained Prof Morgan.

“We now know, for example, the direction and angle of impact, so we know which rocks were hit. And that allows us to calibrate the generation of gases much better. If Julia got that level of cooling on 100Gt of sulphur, it must have been much more severe given what we understand now.”

The generation of what has become known as the Chicxulub Crater was an astonishing event.

The initial hole punched in the Earth would have been about 30km deep and 80-100km across. Unstable, and under the pull of gravity, the sides of this depression would then have collapsed inwards.

At the same time, the centre of the bowl likely rebounded, briefly lifting rock higher than the Himalayas, before also falling down to cover the inward-rushing sides of the initial hole. And although this violent reconfiguration of the Earth’s crust took just minutes to complete, its consequences led to the fifth great mass extinction on our planet.

Chicxulub Crater – The impact that changed life on Earth

Drill siteImage copyrightNASA
Image captionThe outer rim (white arc) of the crater lies under the Yucatan Peninsula itself, but the inner peak ring is best accessed offshore
  • A 12km-wide object dug a hole in Earth’s crust 100km across and 30km deep
  • This bowl then collapsed, leaving a crater 200km across and a few km deep
  • The crater’s centre rebounded and collapsed again, producing an inner ring
  • Today, much of the crater is buried offshore, under 600m of sediments
  • On land, it is covered by limestone, but its rim is traced by an arc of sinkholes
CenoteImage copyright  MAX ALEXANDER/B612/ASTEROID DAY
Image caption    Mexico’s famous sinkholes (cenotes) have formed in weakened limestone overlying the crater

The project to drill into Chicxulub Crater was conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). The expedition was also supported by the International Continental Scientific Drilling Program (ICDP).