A group of researchers from Trinity College Dublin, University College Dublin, National University of Ireland, Galway, the University of Birmingham, and the Gemological Institute of America used a combination of computed tomography, to produce X-Ray images of the fossil, and laser ablation, to evaluate the chemistry of the bones to examine the causes of this alteration.
CT-image of K. galvani listed below showing the alteration in the bones. Credit: Dr. Aodhan OGogain, Trinity College Dublin
Dr. Aodhán Ó Gogáin, from Trinitys School of Natural Sciences, is the lead author of the research study. He said: “Normally in fossil bone, we see that the internal initial structure is protected. But when we looked at the X-Ray pictures of fossils from Jarrow we see that no internal bone morphology has been preserved which bones have actually been partially changed by the surrounding coal.”
The team also discovered apatite protected in the bones.
Dr. Gary OSullivan, a co-author in the research study stated: “The chemistry of the apatite crystals can tell us a lot about how it formed, whether it grew naturally in the animal, formed when the animal was being buried or whether some other factors affected its development. Apatite is a major constituent of living bone so it is no surprise we discover some maintained in these bones. Nevertheless, when we take a look at the chemistry of apatite in the bones from Jarrow we discover that this apatite was formed by heated fluids within the Earth
Dr. Aodhán Ó Gogáin included: “We have likewise had the ability to radiometrically date the apatite which shows it formed during a time when all the continents on Earth were coming together and colliding to form the supercontinent Pangaea. As these continents clashed, they formed mountain belts with super-heated below ground fluids streaming through them. It is these super-heated fluids, which streamed throughout Ireland that prepared and melted the bones of these fossils triggering the change we see today.”
Trinitys Dr. Patrick Wyse Jackson, another co-author said: “The Jarrow assemblage is of major scientific significance and is a substantial aspect of Irelands geoheritage. It is fantastic that finally the concern of what changed the fossil bones of these animals has been resolved.”
Referral: “Metamorphism as the reason for bone change in the Jarrow assemblage (Langsettian, Pennsylvanian) of Ireland” by Aodhán Ó Gogáin, Gary OSullivan, Thomas Clements, Brendan C. Hoare, John Murray and Patrick N. Wyse Jackson, 7 December 2022, Palaeontology.DOI: 10.1111/ pala.12628.
Fossils from this website have one distinct feature: their initial internal bone morphology has been altered so that now it is difficult to make out detail from the fossils. When we looked at the X-Ray images of fossils from Jarrow we see that no internal bone morphology has actually been maintained and that bones have actually been partly replaced by the surrounding coal.”
Apatite is a significant constituent of living bone so it is no surprise we discover some maintained in these bones. It is these super-heated fluids, which flowed throughout Ireland that cooked and melted the bones of these fossils triggering the modification we see today.”
A picture of the Jarrow amphibian Keraterpeton galvani. Credit: Dr. Aodhan OGogain, Trinity College Dublin
A mystery that has puzzled scientists for decades has been fixed relating to ancient tetrapods, which were amphibian-like animals that lived more than 300 million years back.
The Jarrow Assemblage, an essential fossil site in Ireland, includes fossils of these ancient tetrapods that appear to have had their bones prepared after death. These fossils were discovered in a coal seam in Co.
Fossils from this site have one distinct function: their original internal bone morphology has actually been changed so that now it is challenging to make out information from the fossils. The cause of this modification has actually baffled scientists, with explanations for this modification typically believed to be due to acid liquifying the bones when the animals were very first buried.