Are flood basalts associated with subduction zones? Geologists have long been intrigued by the existence of huge areas of lava flows on the Earth’s surface. Known as flood basalts or large igneous provinces (LIPs), they are associated with significant environmental impacts and mass extinctions. These formations occur both on land (for example the Deccan Traps in India) and underwater (the Java-Ontong Plateau).
The mechanism for the creation of these massive lava flows has largely been ascribed to large-scale magmatism caused either by crustal rifting or by an upwelling of hot rock from deep within the Earth (a mantle plume). Now a team of scientists at the Scripps Institution of Oceanography has identified a third potential explanation for their formation.
The Columbia River Flood Basalts
The most recent province on the earth’s surface is the Columbia River LIP, a newcomer whose beginnings are dated to a mere 17 million years or so ago. Although its origin has been hotly debated, to date, the broad consensus has been that it was in fact initiated by a mantle plume.
The Scripps Institution scientists aren’t the first to suggest a non-plume origin – but their study is remarkable in that it proposes a third possible mechanism. According to Dr Lijun Liu, co-author of the study, the research suggests that ‘flood basalt can in fact be generated by subduction, a process of plate tectonics.’
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