Why Is the Bottom of the World So Blue and the Northern Half So Continental?
In an interview about Thomas North, Shakespeare, and biogeography with Richard Hanania, I mentioned an earlier geophysics paper I wrote in 2007. I am still fond of that article for many reasons—including the fact that it marked the first time that the product of all my years of hard work and research made any news. The report generated articles in various European papers including Germany’s Der Speigel Online and Switzerland’s SonntagsZeitung, and I was thrilled to read geophysicists speaking kindly about the discovery.
The purpose of my article was to explain why the world south of the equator is so oceanic in comparison to the Northern Hemisphere. The direct cause has to do with seafloor spreading—the process by which new ocean floor is emplaced at spreading ridges as ocean basins expand between continents. But there is a tremendous difference in mid-ocean spreading rates in the two hemispheres: Much more oceanic crust is being created every year in the Southern Hemisphere (in the Pacific, Indian, and Atlantic oceans) than in the north, and this has been true for tens of millions of years. But why should this be so?
The title of the paper in which I explored this question was “Geophysical explanation for the disparity in spreading rates between the Northern and Southern hemispheres,” published in The Journal of Geophysics Research (112), 2007. And they also published my video (below) as a companion to the article:
Video accompanying article: “Geophysical explanation for the disparity in spreading rates between the Northern and Southern hemispheres,” Journal of Geophysical Research, 112, B03410, doi:10.1029/2006JB004535)[i]