The Ophiolite Controversy is like the Granite Controversy, just heavier, and more mafic. Even more than continental crust, oceanic crust suffers a continuing process of creation and destruction, born in spreading centers and dying in subduction zones. (Thus ljk's and alcaray's posts are bookends, the alpha and omega of oceanic crust.)

Ophiolites are mafic and ultra mafic rocks (representing oceanic crustal rocks) that have been smeared, faulted, folded, and metamorphosed within continental crust rocks. For most of geology's history, these were the only oceanic crustal rocks we could get our hands on. While a complete sequence of these rocks on a continent are rare (as dtb points out) there are lots of pieces laying around. Gabbros are just one of the deeper phases of oceanic rocks, representing magma chambers under a mid ocean ridge. Argueing how to put those pieces together to understand the puzzle of the genesis of oceanic crust is part of the history of geology. Thousands of papers have been written and careers consumed in formulating our current understanding of the oceanic crust. Now we have a single core, a mere pinprick through fresh, unaltered, un-screwed up oceanic crust. The results will be argued for years.

Next stop would be layered gabbros (if they get that far), then cumulate peridotites, then Harzburgite/lherzolite rocks.