Scientists Discover "Log Jam" of Dinosaur Bones in the Morrison Formation

Scientists Discover New Fossil Site

An expedition hoping to find specimens for a Chicago museum have hit the jackpot with the discovery of a vast number of jumbled up dinosaur bones in an ancient river system outside of Hanksville, Utah in the western United States of America.

The researchers, representing the Burpee Museum of Natural History, had been hoping to find specimens for the museum's new display centre which is currently under construction. This new discovery will give them plenty of options, as so far, six types of dinosaur have been identified along with a number of other important finds that provide a detailed picture of the western North American landscape in the late Jurassic.

A "Log Jam" of Fossilised Bones

It seems the team have uncovered a "log jam", a series of fossils that represent the aftermath of a single flood event (or perhaps numerous floods), with drowned animals being washed down stream and ending up in part of a river system with more flood debris including trees and other plant material. The site is then gradually covered over with sediments and preserved as fossils, providing a remarkable insight into the fauna and flora of this part of the world approximately 148 million years ago.

Providing Palaeontologists with Plenty of Data

These "log jams" can provide palaeontologists with a tremendous amount of information about a particular ecosystem, as a vast amount of fossil material is uncovered. This new site includes numerous dinosaur remains, some of the bones are articulated but the majority are scattered and jumbled up. Amongst the fossil bones are the fossilised remains of conifers, so well-preserved that the texture of the bark can still be made out along with growth rings on the broken branches and trunks. These pieces probably created a natural dam which enabled the collection of all the carcases of animals caught in the floods to be washed up together in the same area. Dendrochronologists (scientists who study the growth rings of timber), should be able to obtain climate data from the fossilised wood. Wide growth rings followed by narrow growth rings would indicate distinct seasons, such as a wet season with rapid growth followed by a dry season with limited tree growth. This site could help provide further information on life in the late Jurassic (Tithonian faunal stage).

A Glimpse into an Ancient American Landscape

These log jam sites are very important to palaeontologists, because of the wealth of data they contain, although such finds are rare, when they do occur they permit scientists a unique access to ancient worlds.

Similar discoveries have been made recently elsewhere in the world, most notably Argentina where a number of new Cretaceous dinosaur fossils have recently been excavated.

Within a National Monument

This new quarry is within the Dinosaur National Monument Park, an area protected by the U.S. National Parks Service, an area that is one of the most important sites in the world for dinosaur fossils. The National Monument site was established in 1915 by Presidential decree, and much of what we know about dinosaurs such as Apatosaurus, Diplodocus, Allosaurus, Camptosaurus and Dryosaurus is due to fossil discoveries made in this area.

This part of Utah was first recognised as being scientifically important in 1909, when an almost complete Apatosaurus skeleton was discovered by an expedition from the Carnegie Museum of Natural History (Pittsburgh, Pennsylvania). Between 1909 and 1923 the site was continually excavated and approximately 350 tonnes of fossil bones were removed, providing the backbone (no pun intended), of most of the world's Jurassic dinosaur fossil collections.

Commenting on the discovery, palaeontologists have stated that they are very excited at the prospect of exploring the site further and perhaps being able to discover some dinosaur fossils that are new to science and indicate a new species.

A Chance to Study Sauropods (Long-necked Dinosaurs)

For the research team, this discovery will give then an opportunity to study more Sauropod fossils including Apatosaurus, Diplodocus (Diplodocids) and the more heavily built Macronaria, a clade of Sauropods that includes the Brachiosaurids and Camarasaurids. The name Macronaria, literally means "big nostrils", a reference to the distinctive box-like skulls of these huge dinosaurs, where the naris (hole in the skull for the nostrils) is bigger than the orbits (the hole in the skull for the eyeballs). It is thought that these large nostrils were filled with moist membranes that would have cooled the brain as these animals wandered around the hot Jurassic landscape.

The area of land around the town of Hanksville has been known as a source of fossils to locals and land managers for years, but it was only in the last few weeks that its potential impact to science became apparent. Amateur fossil hunters had picked over the site but no extensive excavations had taken place thus leaving those fossils below ground in pristine condition. The Bureau of Land Management intends to close the site to the public to permit a proper scientific excavation to take place.

Stegosaurus and Allosaurus

It is hoped that the Burpee group will provide more information on some already well-known dinosaurs such as the meat-eater Allosaurus, plus the herbivores Stegosaurus and Camptosaurus. Elements of a Brachiosaurid type fossil have already been recovered by the scientists assisted by local volunteers. Despite being a very well-known dinosaur, remains of these animals in the Morrison Formation are very rare. The only virtually complete skeleton of a Brachiosaurus was found in Tanzania, it is on display at the Humboldt Museum of Berlin. This animal has been reclassified as a different type of Brachiosaur by some scientists and re-named Giraffatitan, although this re-working of the evidence has yet to gain universal approval and most palaeontologists refer to the Humboldt specimen as a Brachiosaurus. Perhaps the Brachiosaur remains at the Hanksville site will give scientists a rare opportunity to compare the African and North America types of Brachiosaur.

The Most Important Morrison Formation

The fossil area is approximately half a mile in diameter and probably represents a sandbar deposit upon which all these organic remains came to rest. Whether this marks a single flood event or a gradual build up of debris in one area over a number of years has yet to be determined. One thing is for sure, this new site will help cement the Morrison Formation as one of the most important Mesozoic sites of all and provide fresh insight into well-known dinosaurs, but relatively poorly researched animals such as the North American Brachiosaurids.

It is sometimes difficult for the public to appreciate how little is still known about famous dinosaurs such as Diplodocus and Brachiosaurus for example. Although scientific techniques have improved and new fossils found, there is still so much more to learn about these amazing creatures. A point that is all too often overlooked when the likes of "Walking with Dinosaurs" a ground breaking BBC TV documentary series featured the animals of the Morrison Formation in episode two of the series -"Time of the Titans".

Everything Dinosaur is a company run by parents, teachers and real dinosaur experts. It specialises in developing educational dinosaur toys, models, clothing and games and strives to help young people learn more about science through their fascination with prehistoric animals. Many of the items featured on the Everything Dinosaur website have been designed and tested by the teachers and real dinosaur experts in the company.

To learn more about the products and services we offer at Everything Dinosaur click on our website links.

Our aim is to help young people learn more about Earth sciences through their fascination with dinosaurs and other prehistoric animals. Team members are happy to provide advice and support supplying free quizzes, drawing materials, puzzles, games even recipes for dinosaur themed biscuits and birthday cakes. With something like 600 products on line including dinosaur party supplies, Everything Dinosaur has built up a strong reputation assisting parents, guardians and fellow teachers, helping young people to learn more about science through creative play.

Japanese Scientists Identify Dinosaur Skin Impression

Hadrosaur Skin with Fine Scales or Is it a Dinosaur Fossil at All?
The country of Japan is not well-known for its dinosaur fossils. Situated on the notorious "ring of fire" in the Pacific, the islands that make up Japan are subjected to considerable seismic forces. However, a number of important dinosaur discoveries have been made by geologists and palaeontologists as they study sedimentary rocks laid down in the Mesozoic Era. Isolated teeth representing a yet unknown genus of large Theropod (meat-eating) dinosaur have been found in Hakusan, Ishikawa Prefecture on the northern coast of Japan's main island. The teeth have been dated to the Early Cretaceous and they suggest that if there were apex predators living in the area that was to form the islands of Japan then there would have been a substantial and thriving dinosaur-based eco-system with many more types of plant-eating dinosaur for the large carnivores to prey upon. Fossils of giant plant-eating dinosaurs known as Sauropods have also been found, most notably a fragmentary fossil of a leg bone from a huge, long-necked dinosaur. Representatives from the Palaeontological Society of Japan reported on the finding of a huge Sauropod femur (the thigh bone of a Sauropod). This single fossil represents the largest type of dinosaur found in the country to date.
Fossilised Skin Impression Discovered
Japanese scientists have just published the description of a remarkably well-preserved fossil which shows the imprint of a dinosaur's skin. The fossil measures a little under twenty centimetres in length and eleven centimetres wide at its widest part. Although the discovery of a dinosaur skin impression has yet to be confirmed, if the find is validated then this is only the second time that an impression of a dinosaur's skin has been found in the country.
The fossil was found in 2001 by an amateur fossil hunter, exploring a series of ninety-eight million year old, fine sandstone deposits in Amakusa, Kumamato Prefecture. It actually consists of two pieces, as the fossil had been broken up as a result of weathering at the site. The first section the forms the top, right portion of the fossil was found and then a few months later the second part of the fossil, representing the larger, lower portion of the fossil material was found.
Ancient Geology of Japan
For much of the Mesozoic Era the series of islands that make up the country we now know as Japan lay underwater, however, what land that remained above sea level was part of the eastern coast of Laurasia, a huge, super-continental land mass that covered much of the northern hemisphere since its formation in the Ordovician geological period. It was only during the Tertiary period that the string of volcanoes that make up the Japanese islands was pushed away from the Asian mainland; eastward by tectonic plate movements. Since their formation, the Japanese islands have been moved back and forth from the Asian mainland as the landmass is pushed and pulled by the plate movements.
Showing Fine Detail of a Reptile's Skin
The skin impression shows fine detail. The impression of individual, polygonal shaped scales can be clearly seen. The scales are approximately two millimetres in diameter. Palaeontologists have speculated that since the fine strata in which the fossil was found represents a tidal flat deposit, a dinosaur may have rested on the tidal flats and left a skin impression which was eventually fossilised.
Could this Be the Skin of a Hadrosaur?
It is not known what sort of dinosaur may have left this skin impression. Experts at the Fukui Prefectural Dinosaur Museum have examined the fossil skin imprint and they have suggested that this impression may have been made by a Hadrosaur (duck-billed dinosaur) or the skin impression may not represent dinosaur fossil material at all. A number of duck-billed dinosaur fossils have been found in Japan and palaeontologist know from fossils found elsewhere in Asia from rocks of the same age that Hadrosaurs were abundant. It is possible the fossil could represent evidence of a duck-billed dinosaur resting on a sandbank, however, it is perhaps more likely that this is the skin impression left behind by another reptile, not a dinosaur at all.
Crocodile Theory
Crocodiles are often seen today basking on sand banks. During the Cretaceous there were many crocodile-like creatures that probably had similar habits. Palaeontologists have proposed that it is more likely that the skin impression was made by a member of the Choristodera such as a Champsosaur.
Whether the fossil represents dinosaur material or not, it is the best preserved skin impression yet found in Japanese Cretaceous strata. The Chief Researcher at the Fukui Dinosaur Museum has heralded the find as significant stating that this is the first fossil in Japan that shows reptilian scales clearly.
It is likely that once the examination has been completed the specimen will be put on display in a museum close to where the two fossil pieces were actually discovered.
Everything Dinosaur is a company run by parents and teachers. It specialises in developing educational dinosaur toys, models, clothing and games and strives to help young people learn more about science through their fascination with prehistoric animals. Many of the items featured on the Everything Dinosaur website have been designed and tested by teachers and real dinosaur experts.
To learn more about the products and services we offer at Everything Dinosaur click on our website links.
Our aim is to help young people learn more about Earth sciences through their fascination with dinosaurs. With something like 900 products on line including dinosaur party supplies, Everything Dinosaur has built up a strong reputation assisting parents, guardians and fellow teachers.