Our primary topic this week is the Theory of Plate Tectonics, with an emphasis on how the dynamic Earth has affected the evolution of life. We can start with this beautiful world map, showing continents, mountains, ridges, transform faults and trenches in the Pacific and Atlantic Oceans. An excellent, world-class site for ancient maps of the evolving Earth is the Paleomap Project. The US Geological Survey has a thorough site called This Dynamic Earth which covers the basics of plate tectonic theory. The University of Texas hosts The Plates Project which concentrates on producing accurate plate reconstructions of the past. Of course, plate tectonics is an ideal subject for web animations. PBS reviews plate tectonic theory with a simple and clear set of images and animations. Here is a global history of continental movement in the last 750 million years from UC Berkeley. This YouTube video on plate tectonics is narrated with a cool Irish accent.
Here, by the way, is a description of the Ordovician fossiliferous marine limestone at the top of Mount Everest. That fact alone shows the incredible dynamic nature of the Earth’s crust.
As for the primary effect of plate tectonics on us, visit the real-time global earthquake website maintained by the U.S. Geological Survey. You will see how very common earthquakes are around the world, and where you do not want to buy a house. PBS has a nice set of animations of earthquakes from a global perspective, along with volcanoes and the geological phenomenon we now know all too well, tsunamis. Here are summary pages on the devastating 2004 tsunami in the Indian Ocean, the January 2010 Haiti Earthquake and the 2011 earthquake and tsunami in Japan. Note that geologists are still debating the origins of the tsunami.
Remember: Osgood Lecture on March 5, 7:30 pm, Lean Lecture Room (required) — “Invasive species, mass extinctions, and biotic radiations: lessons for today from oceans of the past” (Dr. Alycia Stigall, Ohio University).
Geology in the News –
Your fellow student Grant found this YouTube posting of Walking With Monsters. The first half-hour has many dramatic reconstructions of animals you now know, from the Burgess Shale critters and earliest fish to amphibians. Thanks, Grant.
Climate change is both threatening archaeological (and geological) sites and revealing new artifacts and rocks. I suppose we can conclude that there are some silver linings as the ice relentlessly retreats.
Nice images of dry river beds on Mars, showing direct evidence for its watery past. Where all that water went is a mystery.
Did you know that two-thirds of known meteorites have been collected in Antarctica? You’ll see why after reading this recent account of a British expedition.