Composition of basalts from the Romanche Fracture Zone

Igneous rocks from the active part of the fracture zone that have undergone transtension are referred to alkaline rocks. According to some indications, they are younger that oceanic tholeiites of the southern fault-line ridge, which were affected by elevated pressure in the past.

These data indicate with a high probability that the Romanche Fracture Zone belongs to a rare group of magmatically active demarcation transform lines that separate large oceanic domains different in structural and geochemical features.