Abandoned fossil burrows dating back 330 million years, 100 million years before the appearance of the first dinosaurs, have been found in limestone rock on the coast of Doolin in County Clare.
Dr. Eamon Doyle, geologist for the Burren and Cliffs of Moher UNESCO Global Geopark and Clare County Council, who made the discovery, says the burrows were excavated by marine creatures in a very shallow sea and are the oldest known occurrence of this type of fossil burrow anywhere in the world.
At that time Clare was located near the Equator and looked and felt a lot like the tropical Bahamas today.
Dr. Doyle explained, “The abandoned burrows are filled with coarse sand made of fossil debris and were most likely filled in during a storm event that moved large amounts of coastal sand around. This storm may have forced the creatures to abandon their burrows.”
“This is the oldest known occurrence of this particular type of fossil burrow known as Psilonichnus,” added Dr. Doyle. “They are considered to be trace fossils, that is the remains of the activity of a creature rather than the remains of the creature itself.”
He continued, “The burrows are most similar to the burrows of modern shrimp and crabs, however while early relatives of shrimp had evolved at that time and are the most likely makers, crabs didn’t evolve until millions of years later.”
“As no burrowing creatures were found in the burrows it must remain an open question as to who actually made the burrows, for now. The investigation continues,” concluded Dr. Doyle.
Pat Dowling, Chief Executive of Clare County Council, commented, “This and previous discoveries highlight the uniqueness of our ancient landscape in the Burren. Clare County Council is pleased to support the work of the Burren and Cliffs of Moher UNESCO Global Geopark.”
A research paper entitled “The earliest occurrence of the ichnogenus Psilonichnus: a new record from the Mississippian of the West of Ireland” is published in the international scientific journal, Ichnos. The paper is co-authored by Dr. Eamon Doyle (Burren and Cliffs of Moher UNESCO Global Geopark, Clare County Council), Dr. Patrick Orr (UCD School of Earth Sciences) and Dr. John Murray (School of Natural Sciences, NUI Galway; Irish Centre for Research in Applied Geosciences).