Cari The Geologist And Certified U2 Freak is sure to love this post.

Volcanoclast hosts this month’s Accretionary Wedge on countertop geology.

Have you seen a great countertop out there?  Sure, everyone says it’s “granite”, but you know better.  Take a picture, post it on your own blog or send it to me and I’ll post it for you.  Do you think you know what it is or how it was formed?

I was all set to write about the rapakivi granite (that’s “Baltic brown” to you realtors out there, who refer to everything as granite or marble) in my kitchen when, hark, from the sky down came a reminder of a really cool countertop of yesteryear. Black marble with deformed fossils. Or more precisely, a lightly-toasted, black, fossiliferous, Irish limestone in the shape of a large octagon that belongs to U2.

Black "marble" of Kilkenny

Some science channel or the other provides constant background noise in my house (with signal being occasional exclamations such as “That in NO WAY could have caused the K-T extinction,” “When will these TV earthquake scientists balls up and start talking about strain instead of stress?”, “That 3D dinosaur has more feathers than our last Thanksgiving turkey” and “Really, did that American geologist just say MOGMA?!” There’s also the gratuitous repetition of “bass-solt” after a Britisher says the word “basalt.” Nope, never really left fifth grade.) For the last few days, a Science channel commercial on heavy rotation has been the trailer for U2′s new documentary From The Sky Down. The U2 fans are going to be on me like a pack of rabid … U2 fans for this, but one can only take so much Bono cooing about the transition from playing notes to finding The Great Pumpkin or something while creating Achtung Baby. It’s like those who say they found god in geology or New Orleans; a lot of times life simply boils down to being really good at something and enjoying doing it. For the good times and cash money.

The roof over the bar (photo by bobsrocket on Flickr CC-BY-NC-SA)

Anyway, Accretionary Wedge. Countertops. U2 commercial. Of course! The Kilkenny marble countertop of Dublin’s Octagon Bar in the Clarence Hotel owned by Bono and The Edge. I’ve been in there twice, but it wasn’t until the second time, when the place was a lot less crowded, that I nodded off looked down, noticed the fossils, especially the sheared brachiopod (see above – bottom right), and realized that I was looking at the beginning stages of a marble with preserved fossil fragments. The bartender is usually asked when Bono’s coming in or if she’s waited on The Edge so was really surprised when she caught me scrutinizing the bar and asking her if she knew its source. That it’s Irish is all she knew which sealed it – Lower Carboniferous “marble” from County Kilkenny in the southeast of Ireland. Not to be confused with a Kilkenny stout, which I am pretty sure can be had at the Octagon Bar while listening to The Joshua Tree, which in my opinion was the best U2 album ever.

Is there anything you cannot do, Ireland?

Further reading: Kilkenny Geology