A review of marine large igneous province (LIP) volcanism: Beyond the textbook model

Dr. Jörg Geldmacher, GEOMAR

Abstract

Oceanic plateaus, the marine expressions of Large Igneous Provinces (LIPs), are vast submarine high plains and ridges formed by large outpourings of mainly mafic (magnesium- and iron-rich) lava during short geological time (i.e., few million years). Marine LIPs are crucial for understanding deep-Earth processes, past ocean–climate interactions, and major biotic crises (including mass extinctions). In particular, they record episodes of abnormal mantle melting not explained by standard seafloor spreading or subduction, making them critical tests for mantle plume models and whole-mantle convection. The geochemistry of their lavas provides snapshots of distinct mantle reservoirs and helps to constrain long-term chemical heterogeneity and recycling processes in the Earth’s mantle.

According to classical mantle plume model, LIPs form by the upwelling of a hot, mushroom-shaped plume of mantle material rising from great depths. Upon arrival at the base of the lithosphere, the plume flattens, spreads out and generates widespread volcanism by adiabatic melting. Some years ago, it was suggested that oceanic plateaus form entirely by shallow mantle processes related to plate tectonics (“great plume debate”). More recently, there is mounting evidence that interaction between mantle plumes and mid-ocean ridges gives rise to oceanic plateaus. A conclusive explanation of this relationship, however, is still lacking.

Dr. Jörg Geldmacher is a senior scientist at GEOMAR in Kiel and Privatdozent at Kiel University whose long-standing research focuses on the igneous geochemistry, geochronology, and mantle dynamics of oceanic LIPs and other intraplate volcanic systems. Over more than two decades he has led and contributed to major expeditions and drilling projects (e.g., IODP Expedition 324 on Shatsky Rise, and recent SONNE cruises to Hess Rise and Madagascar Ridge). In his talk he will provide a review of current models and open question and challenges in marine LIP research and links to global climate/extinction events.