'Dinosaur graveyard' found behind New Jersey mall
|The fossil bed is located in an old, disused quarry in New Jersey |
[Credit: Rowan University]
Now hopes are high that a quarry behind a shopping centre in New Jersey may hold the remains of giant reptiles killed in the die-off - the first fossil evidence of the event to ever be found.
Palaeontologists uncovered what has been described as a 'mass death assemblage' at a quarry pit in the Mantua Township in central New Jersey.
At the time of the creatures' death, the region is believed to have been a shallow sea.
Fossils found so far include those of mosasaurs - fearsome creatures as large as a bus, considered by many to be dinosaurs, but are technically described as ancient marine reptiles.
Marine snails, shell-like brachiopods with hard valves, shark teeth, boney fish, sea turtles, moss-like bryozoan colonies, and marine crocodile remains have also been discovered.
The shallow sea would have been teeming with life, more so than on the land, so if a single event hit the region, a large number of prehistoric marine animals would have been affected.
Following initial excavations, the experts believe the site and remains closely date to the mass extinction event.
To prove their hypothesis, the experts are looking for a thin layer of iridium-rich sediment - evidence of an asteroid hitting Earth.
According to a popular theory, when the asteroid hit the Yucatán Peninsula in Mexico, it created a crater six miles (10km) wide, throwing up enough debris into the atmosphere to block out sunlight.
It is likely that dinosaurs and marine reptiles living closer to the site of the impact felt its effects sooner than others living in what is now China, for example.
In particular, unless the creature was hit directly by a huge lump of space rock, they wouldn't have died straight away.
That doesn't mean they wouldn't have felt the effects of the event, however, at a later time or over a longer period.
And this is where the problem lies when trying to directly tie fossils to the mass extinction event.
|Researchers excavating part of the bone bed that contains thousands |
of fossils from close to the mass dinosaur extinction
[Credit: Rowan University]
For example, the dust cloud created by the impact prevented plants from growing around the world. This didn't happen overnight.
Once this food source died out, it would have disrupted the food chain and ultimately caused most dinosaurs and marine reptiles to starve to death.
For example, T-Rex became extinct likely because it couldn't eat lumbering herbivores as they had died out when plants were unable to grow.
After the debris from the impact settled back on Earth, however, it settled in a layer known as the 'K-T boundary' between the Cretaceous and Tertiary periods, which contains the iridium-enriched dust.
If found at the quarry, this dust could mark the mass extinction because it is a common element found in asteroids believed to have sparked the devastating event.
Leader of the excavations Dr Kenneth Lacovara, said that if the hypothesis is found to be correct, the 65-acre fossil quarry could provide an 'unparalleled window into a pivotal moment in Earth history'.
In the Cretaceous period, when T-rex roamed the Earth, the site was a shallow sea some 10 miles (16km) from an ancient mountain range.
It was home to sea turtles, crocodiles and fearsome mosasaurs as long as a bus, which lived in the warm waters.
The quarry was, until recently, owned by the Invers and Company and was mined for mudstone used in fertiliser for more than a century.
However, it was also known for containing at treasure trove fossils and has since been purchased by Rowan University for $2 million (£1.4 million).
The company was aware of the important bones inside the pit and even when it was losing money, pumped out groundwater - a move that maintained the site and preserved the fossils.
The university plans to continue excavating the site and even open a museum showcasing fossils found at the site.
While fossils are being discovered throughout sediment in the pit, it is a single concentrated layer that experts are really interested in.
This layer was the ancient sea's bottom, 40ft (12 metres) below the surface and potentially holds the bones of dinosaurs that died in the mass extinction.
Palaeontologists think this may be the case because the skeletons of larger animals remain mostly intact, indicating they died at the same time and their bodies settled on the bottom of the sea bed, The New York Times reported.
The layer has been dated close to the time that a meteor is thought to have struck, triggering the mass extinction event.
It's not known over what times span the creatures died.
Experts believe the mass extinction took some 33,000 years to play out across the globe after the asteroid impact, but since the fossils were found close together, it suggests a much shorter time span for the deadly plume of dust to claim its victims.
Leader of the excavations Dr Kenneth Lacovara, said: 'We've uncovered thousands of fossils including the remains of ancient sea turtles, crocodiles, and portions of fearsome marine lizards called mosasaurs.'
Asked whether the death scene relates to the extinction that wiped out the dinosaurs, he said: 'We don't know yet, but we are testing this hypothesis by examining the fossils, the sediments and the chemistry,' Dr Lacovara said.
'Certainly we have rocks that are near that time. I know we're damned close.
'We are in the trying-to-poke-holes-in-it phase. There's going to be so many arrows aimed at that.'
Rowan President Ali A. Houshmand said: 'Our vision for the fossil quarry goes beyond educating schoolchildren. We will transform it into an internationally prominent centre of research for people of all ages.'
Since 2012 the town has hosted local 'dig days' at the site to give local people the opportunity to search for fossils alongside Dr Lacovara and his team. More than 8,000 visitors have carefully dug for fossils.
Author: Sarah Griffiths | Source: Daily Mail [January 13, 2016]