Under the Volcano* (continued)

Globally, a majority (85%) of volcanic activity is associated with the formation of new seafloor, called oceanic crust, along the mid-ocean ridge system. Each year enough magma is produced along mid-ocean ridges to pave over an area the size of Ohio in a half-foot of lava. The remaining 15% of the Earth’s annual budget of magma rises up to form ocean islands and plateaus like Hawaii and Iceland, or to feed volcanoes like Mount Saint Helens on land. Surprisingly, while magmatism is perhaps the single most important process in terms of the geologic evolution of Earth, we know remarkably little about the physical structure that lies beneath active volcanoes.

Once magma is produced and accumulates in the near-surface plumbing system of a deep-sea volcano, we enter into a realm where the intensity of chemical, physical and biologic processes are staggering. Temperatures can vary by more than 1000°C across short distances. These temperature changes power hydrothermal processes that chemically alter the environment and efficiently transport energy and nutrients to animal and microbial communities living on and beneath the seafloor. It is at these small scales, that tectonic, hydrothermal and magmatic processes interact vigorously in ways that are unfamiliar and fascinating.

A central theme of my research is to reveal the structure beneath active volcanoes in order to understand the geologic processes that occur along mid-ocean ridges and oceanic hotspots. With colleagues and students we have investigated a variety of volcanic areas, ranging from sea-floor spreading ridges in the Atlantic and Pacific to the volcanic hotspots of Iceland and the Galapagos. These geologic settings are markedly different from one another, allowing us to address the following question: What are the relations between geologic setting, surface volcanic features, and the subsurface structure of a magmatic system? A new generation of studies – and the next generation of students – is necessary to continue the mission. It is my hope to inspire some of you to join in the fun and adventure of exploratory science.


*"Under the Volcano" is an abstract for a general science lecture I am gave as part of the RIDGE2000 Distinguished Lecture Series. If you are a K-12 teacher interested in these materials, let me know!

Toomey's Site

DEPARTMENT OF Geological Sciences, University of Oregon

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