Forrest Horton
Associate Scientist
Department of Geology & Geophysics
Woods Hole Oceanographic Institution
Nutrients from Large Igneous Provinces
Earth's past has been punctuated by large volcanic eruptions that covered much of the continental surfaces with lava and ash. These volcanic eruptions, known as large igneous provinces (LIPs), changed the geochemical composition of continental surfaces and disrupted climate and biologic cycles. In addition to their detrimental effects for many forms of life, my research suggests that massive flood basalts might also provide a long-term source of nutrients. Phosphorus in particular limits primary productivity in the oceans over geologic time scales because so little phosphorus is available in the continents. The erosion of LIPs—often rich in phosphorus—may enhance phosphorus delivery to the oceans.
My work suggests that the rapid succession of LIP eruptions that occurred as the supercontinent Rodinia broke up from ~800 to 600 million years ago may have increased phosphorus delivery to the oceans at a critical time. In addition to potentially triggering Snowball Earth glaciation events in which the climate switched to ice house conditions, these LIPs may have supplied enough phosphorus to accelerate primary productivity in the oceans and trigger the oxygenation of Earth's atmosphere. For more information, see my paper:
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Horton, F., 2015, Did phosphorus derived from weathering of large igneous provinces fertilize the Neoproterozoic ocean? Geochemistry, Geophysics, Geosystems, v. 16, 1723–1738.
