Continental drift is created at spreading centers, and this, along with subduction, drives the system of plates in a chaotic manner, resulting in continuous orogeny and areas of isostatic imbalance. The theory of plate tectonics explains all this, including the movement of the continents, better than Wegener's theory. Hans Stille and Leopold Kober opposed the idea of continental drift and worked on a "fixist" geosyncline model with Earth contraction playing a key role in the formation of orogens. Other geologists who opposed continental drift were Bailey Willis, Charles Schuchert, Rollin Chamberlin and Walther Bucher. In 1939 an international geological conference was held
Ice Age: Continental Drift heat. The first details of the sequel were announced on January 10, 2010, when "The New York Times" reported that Blue Sky was working on a fourth film and was in negotiations with the voice cast. Fox later confirmed on May 5, 2010, that "Ice Age: Continental Drift" would be released on July 13, 2012. A soundtrack album of music by John Powell was released on July 10, 2012 by Varèse Sarabande. In addition to Powell's original score, the film also features Beethoven's 9th Symphony. Powell explained his decision: "At the beginning of the film, the creation of the geographical