Between a four billion year-old rock and a hard place

Pull open the drawer of a desk in an office of a corner building in the limestone quadrangle of NUI Galway, and you might find a piece of rock that is over four billion years old. “Might”, because by the time you read this, Prof Martin Feely should have found a new home for his sample of the oldest piece of the Earth’s crust discovered by man. And if he hasn’t, his research assistant Dr Allessandra Costanzo will have made sure he does, in her own gently persuasive southern Italian way.

For Prof Feely's rare sample of planet, found a decade or so ago by geologists in Acasta some 300km north of Yellowknife in the Canadian Northwest Territories, is set to go on display in Galway's "hidden museum" next month. "Ice Road Truckers country" is how Prof Feely describes the remoteness of the area where his piece of Acasta gneiss hails from. For just as the truck drivers of History Channel's series traverse the frozen lakes and rivers of remote Arctic regions, so intrepid geologists need few magnetic forces to draw them to strange, desolate and, hopefully, untouched crops of rock.

Our island’s equivalent of Acasta is on Annagh Head near Belmullet in north Mayo, which has yielded material all of two billion years old. The “Annagh gneisses”, as they are called, are the earliest known samples of Irish crust. They are among some 15,000 rock, mineral and fossil specimens from many continents, housed in Victorian varnished oak display cabinets in the James Mitchell Museum in NUI Galway (NUIG). Dr Costanzo has become intimate with the collection, since she rose to a challenge to refurbish the gallery some 18 months ago.

So, as her team of decorators on deadline scale tall ladders and joke about scraping away pre-Cambrian paint, Dr Costanzo takes me on the most magical mystery mini-tour of the crystals, minerals, rocks and gemstones now displayed behind newly polished glass. Thanks to some small funding and some large voluntary effort by members of the Galway Geological Association, the cases were cleaned, painted, fitted with locks and with new information panels, charting a timeline of the Earth’s formation, long before and during a time when Ireland was much closer to the Equator than now. Though much of the material is from the original collection by the university’s first geology professor, William King, some of it has been recently donated. Adrian Ryder, a student on the university’s gemmology diploma course has given his collection of more than 400 gemstones, including a square-cut 1,590 carat ruby weighing 318 grams, a 4,300 carat emerald, and 21 faceted and rough diamonds weighing just over four grams in all.

The latter complements the museum’s existing samples of diamond in kimberlite, as in the very deep igneous rock named after South Africa’s town of Kimberley. It was there that a farmer tripped over a rock in a field in 1866 and set off a fever that led to the creation of the “Big Hole”. Prof Feely and Dr Costanzo and their earth and ocean science colleagues recognise the attraction of their “geological time capsule”. Some space has been earmarked for temporary exhibitions – such as one on evidence of microbes in “deep time”, as explored in a recent collaboration between geologists and microbiologists on campus.King’s many fossils, including his internationally-renowned Permian monograph from north-eastern England and his skeleton of a plesiosaurus from Lyme Regis in Dorset, are still big draws. King was something of a scientific celebrity of his time, for he influenced future animal and plant classifications, and he also established the antiquity of neanderthal man.

Dr Costanzo and team have dusted and polished up microscopes which had been stashed away in stores. She was delighted to find a walking stick which King may have used on his original field trips, and a timber hand-painted sign, which she has hung up next to the visitors’ book. It reminds the public that “sticks and umbrellas are to be left in the stand” and that “no dogs are allowed”. The locks on cases are an unfortunate 21st century addition, she says, but necessary for all that. As this newspaper reported over a decade ago, one indigenous specimen was removed from the collection by a student who “had not advanced sufficiently in his studies to realise he would need a lot more gold than that small nugget to make his fortune”.

Galway’s James Mitchell Museum in the NUIG quadrangle re-opens to the public from December 6th.