Composition of basalts from the Romanche Fracture Zone

New magnetometric, petrological, and geochemical data on basalts from the central Romanche Fracture Zone allow to classify these rocks into two groups. 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.针对罗曼什断裂带（Romanche Fracture Zone）中部玄武岩的磁测、岩石学与地球化学新数据，可将该区域的玄武岩划分为两组。发育于断裂带活动区段、经历走滑拉张作用的火成岩，被归类为碱性岩。现有证据表明，该类碱性岩的形成年代晚于南部断层脊的大洋拉斑玄武岩（oceanic tholeiites）——这类玄武岩在地质历史中曾受高压环境影响。上述数据以极高置信度证实：罗曼什断裂带属于一类罕见的、具有岩浆活动性的分界转换断裂带，该类断裂带可分隔结构与地球化学特征存在显著差异的大型大洋域。