A GRAND TOUR OF THE OCEAN BASINS

Building on on the remarkable visualization of Earth’s oceanic ages from: http://nachon.free.fr/GE/Welcome.html (Müller et al. 2008), we have assembled a 56-stop “Grand Tour” of the Earth’s ocean basins, which are much richer in diversity than textbook cartoons convey. Our tour is aimed at two target audiences, first to help teachers build self-efficacy and become confident that they can answer student questions about any oceanic region on Earth without delving deep into research literature, and second to demonstrate to students the true diversity of the oceans. Geoscience textbooks present two basic cross sections of ocean basins, a symmetrical double-passive-margin ocean basin like the North Atlantic (north of the Lesser Antilles), and a symmetrical active margin basin, the likes of which has not been seen on Earth since the consumption of the Moluccan Sea. It is rare to see a cross section of oceanic crust such as the Pacific with one side of the spreading ridge four times longer than the other, or eastern Indian Ocean with one active and one passive margin, which serves as a good modern analog for Iapetus—the “Proto-Atlantic Ocean that separated Laurentia from Gondwana before the Palaeozoic collisions that created the Appalachian-Mauritanian-Caledonian Orogeny. A significant minority of ocean basins are underlain by abandoned spreading centers. Many regions are underlain by oceanic crust that developed in a margin basin behind an island arc or in a releasing bend of a transform margin. Most importantly, microplates comprised of only ocean crust grow at spreading ridge triple junctions.

The tour KML and PDF files can be downloaded from www.geode.net. This work is supported by NSF DUE 1323419 “Google Earth for Onsite and Distance Education (GEODE).” Reference: Müller, R. D., Sdrolias, M., Gaina, C., & Roest, W. R, 2008. Age, spreading rates, and spreading asymmetry of the world's ocean crust. Geochemistry, Geophysics, Geosystems, 9(4). doi:10.1029/2007GC001743.