Continental drift plate tectonics theory. In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the sea, and in 1928 that convection currents within the mantle might be the driving force. Holmes' views were particularly influential: in his bestselling textbook, "Principles of Physical Geology," he included a chapter on continental drift, proposing that Earth's mantle contained convection cells which dissipated radioactive heat and moved the crust at the surface. Holmes' proposal resolved the phase disequilibrium objection (the underlying fluid was kept from solidifying by radioactive heating from the core). However, scientific communication in the '30 and
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