Posts Tagged ‘geology’

Today’s lecture on the Ocean Anoxic Events (OAE’s) and the geochemistry of extinction begged the question: who controls the Earth?  Are the combined anoxic events and associated C13 events imply that geology – for example, magmatism – is a driver of primary production, or are the events evidence of the evolution of key characteristics in phytoplankton and other organisms?

This is an important question for my work on the Proterozoic, especially the Neoproterozoic.  During the Paleoproterozoic and Neoproterozoic, large d13C isotope excursions are seen in both the organic carbon and carbonate records.  But do these reflect novel characteristics of organisms – for example, increased sinking of organic matter in the form of feces, or the rise of oxygenic phototrophs – or are the organisms being driven by forces outside their control?

Generally, I support the idea that the biology of Earth is at the mercy of Earth’s geology – that major events in the evolution of life and the chemistry of the oceans was driven not by new characteristics in the constituent organims, but by things such as magmatism and climate.  However, this is obviously a heuristic argument – climate, for example, is driven not only by the release of CO2 and methane from hydrothermal vents, but also by the amount of CO2 sequestered by organisms dying, sinking and being buried in the ocean.

So I’m leaving this question open to others: who is the real strongman of Earth?  Biology or geology?

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The first talk I attended was on a subject I am not very familiar with: carbon sequestration. As reducing CO2 emissions to the atmosphere is becoming a priority, much effort is being made on developing ways of sequestrating CO2. What I learned from the talk of prof. S. Gislason, from U. of Iceland, was that storage in basaltic rock, found for exemple in oceanic ridges, is best suited for CO2 sequestrations because it enables the formation of mineral CO2. On the contrary, CO2 sequestration relying solely on structural confinement (i.e. in depleted oil reservoirs, as it is done in US or Canada) or even CO2 dissolution (i.e. in deep saline formations in Norway) is less stable and therefore likely to release CO2 over time. A carbon sequestration project is starting at the Hellisheidi power station in Iceland. This pioneering project involves taking some of the CO2 emitted from the power plant and sequestering it in a nearby basaltic formation. I suggest you visit their website (www.carbfix.com) to follow their progress. Those who have access to the journal Elements can also consult Gislason’s paper in the October 2008 issue that is entirely dedicated to Carbon Dioxide Sequestration.

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