Canada’s history is full of geoscientists who have made important discoveries in the field of geoscience. Geoscientists work to help advance technology, solve problems, preserve the environment, and understand Earth’s processes. One important geologist in Canada’s history is John Tuzo Wilson, known for his contributions to the field of plate tectonics.  John was born in Ottawa, in 1908, to Robert Wilson and Annie Tuzo. His father worked for the Canadian government as an engineer and his mother was an adventurous mountain-climber. Annie had a mountain peak named after her, Mount Tuzo, after she and her guide, Christian Bohren, were the first people to ascend the peak. John’s interest in geology began when he was quite young, and he used to collect rocks and fossils on family trips growing up. John studied physics and geology in his undergrad at the University of Toronto (U of T), graduating in 1930. At the time there was no geophysics program at U of T, however, John found instruction wherever he could and did a joint degree instead. He then moved to England on a Massey Fellowship to study at Cambridge. John moved to Princeton for his Ph.D., completing field work on his own in the Beartooth Mountains in Montana.  After his studies, Tuzo Wilson worked for the Geological Survey of Canada as an Assistant Geologist. In 1938, John married Isabel Dickson in Ottawa. When World War II started, he joined the Royal Canadian Engineers, gaining rank to become a colonel. Isabel followed John to England to be closer to him during the war. They returned to Canada together in 1944 and he started a job as a Professor at the University of Toronto. It was here that John Wilson would spend the bulk of the rest of his career.  John Tuzo Wilson via Smorris123 at English Wikipedia, CC BY-SA 3.0, via Wikimedia Commons John’s research at U of T greatly influenced the field of plate tectonics. At the time, Alfred Wegener’s theory of continental drift was largely disputed. Wegener’s theory, published in the early 1900s, asserted that the continents move in relation to one another over long periods of time. But there were inconsistencies in his theory and a lack of evidence. John initially opposed the theory like most of his colleagues, but reconsidered his position later on. This reconsideration ultimately led to Wilson’s theory of plate tectonics.  One of John’s significant contributions to the theory of plate tectonics was the idea of “hot spots.” He drew inspiration from studying the Hawaiian Islands, theorizing that the islands were created as the Pacific tectonic plate moved northwest, over a magma plume in the mantle. This created the chain of volcanoes decreasing in size and intensity to the southwest. This theory resolved some of the contradictions in Wegener’s continental drift theory. Wegner’s theory asserted that volcanoes form solely as a result of movement at the edges of tectonic plates and so was highly disputed because of the lack of explanation for volcanoes located away from plate boundaries (such as Hawaii). Wilson’s new hot spot theory provided an explanation for why there are volcanoes in other places as well as at plate boundaries.  John’s second major discovery was that of transform faults. A transform fault occurs when two plates move past one another,  sometimes resulting in a build-up of stress (e.g., shear stress). Transform faults may cause landforms to break and move past each other, thereby looking offset from each other in aerial view. This new theory of faults explained the topography of mid-ocean ridges and greatly contributed to the larger theory of plate tectonics.  John continued to teach and research at U of T for many years, but even after he retired from the University, he continued to teach his theories, travelling to over 100 countries. He particularly loved travelling to China, and even wrote a book about his trip to China in 1958 entitled “One Chinese Moon.” He produced the tv series “Planet Earth,” and introduced many episodes, continuing his love for teaching. After Wilson retired, he became the director of the Ontario Science Centre, encouraging exploration and interest in science. He famously posted “please touch” signs on the exhibits. He wanted the centre to be a combination of artefacts and hands-on experiments, and often interacted with visitors and school groups. He also supported the introduction of travelling science exhibits in order to make science accessible to remote Ontario communities. The success of the travelling exhibits contributed to the creation of Science North in Sudbury, which Wilson supported.  John Tuzo Wilson’s many discoveries led to our current theory of plate tectonics. His willingness to test the boundaries of science is what gave him great success. His passion for teaching and love for student exploration has greatly impacted the effectiveness of science centres in Ontario.  Nick Eyles recently published a book about John Tuzo Wilson entitled “Tuzo: the unlikely revolutionary of plate tectonics.” It is an enlightening look at Tuzo’s life and career. APGOEF’s president Dr. Bill Pearson describes the book such: Nick has done a tremendous job pulling together a vast amount of historical information not just on the remarkable life and prodigious achievements of Tuzo Wilson but also documenting in fascinating detail the long and protracted battle between those that believed in a contracting earth versus those that believed in continental drift which eventually evolved into what we now know as plate tectonics…The book wonderfully documents the incredible technical revolution especially following WWII that revolutionized the science of geology and moved it rapidly forward…The account of his WWII service is outstanding, and Nick eloquently outlines how his experiences then gave Tuzo many lifelong skills in communication and leadership that would serve him well in future years…It is a fitting tribute to a remarkable man who is unquestionably Canada’s greatest geoscientist.  Dr. Bill Pearson Check out the book at the University of Toronto Press or Amazon. Sources: Brittanica: J. Tuzo Wilson The Canadian Encyclopedia: John Tuzo Wilson The Canadian Encyclopedia: John Tuzo Wilson’s Theory