This option requires you, as contest participants, to interpret an excerpt containing a novel idea or mechanism which is taken from
a recent research article or student thesis. Using your imagination, creativity and an animation technology, you will then illustrate
the given description in the form of animation or motion picture.
compare it to the plate tectonics processes of today)
[Excerpt is shown below the animation entries]
"A growing number of researchers feel that the operation of plate tectonics on the early Earth was a vastly different that of today, primarily
due to a higher mantle temperature. Global tectonics evolved from predominantly vertical to predominantly horizontal as the earth cools.
Under early Archean conditions, crustal diaprirism, which is characterised by significant and rapid vertical displacements of mafic volcanic
activities, may have been a dominant form of tectonism. Follow-on effects from this process include a greater degree of partial melting of
upwelling mantle, a thicker, but softer crust, and a softer, weaker lithosphere (continental crust) due to higher geothermal gradient.
Archean tectonic plate spreading rates would have been 2-3 times greater than today's rate, giving rise to a thicker oceanic crust and
thinner lithosphere (continental crust). The lithosphere at the time may have been too buoyant to subduct. In addition, recent modeling
suggests that a hot weak lithosphere, even if dense enough to subduct, would easily break off, removing the slab pull force which is a major
driver of modern plate tectonics. With the secular decrease in radiogenic and thermal inputs, lithospheric strength increases which
eventually impedes crustal turnover and reorganization by diaprirism and allows continents to rise above sea level. The cooling may have
also been aided by the formation of granite in the lithosphere. As diaprirism slows down and becomes inefficient at reorganizing the crust,
further continental formation and development transition towards horizontal tectonism.
This process above is felt to explain the creation of the rocks in the ancient Superior Province of Northern Ontario, which are among the
oldest continental rocks discovered."
Reference: Robin, Catherine M.I. (2010). Diapirism on Venus and the Early Earth and The thermal effect of fluid flows in AECL's Tunnel
Sealing Experiment. Doctoral of Philosophy Thesis submitted to the Department of Physics and Geology.
University of Toronto. Retrieved on May 20th, 2013 via T-space library: http://hdl.handle.net/1807/24863