The rock known as gabbro features in many trendy kitchen countertops, where its durability, heat resistance, and bold black-and-white veining make it an attractive addition. Its chemistry also made it ideal for creating the early building blocks of the continents, according to a new study published in Nature Communications.
Early Earth was covered in a hardened shell of dark basaltic crust that crystalized as the planet’s primordial ocean cooled. How the lighter and chemically distinct continental crust formed later is still under debate.
The new study proposes that gabbros melted within early Earth to form rocks known as TTGs—a mix of tonalite, trondhjemite, and granodiorite—which made up most early continental crust.
“Many people are preparing their dinner on the type of rock that was responsible for making our modern continents,” said the study’s first author Matthijs Smit, a geochemist at the University of British Colombia in Canada. Smit was struck by the revelation while casually cutting an onion for a meal at a friend’s house.
Tom Metcalfe 