The search for how the earth works: a scientific detective story

Back in the 16th century the cartographer Abraham Ortelius noted that the coastlines on either side of the Atlantic Ocean bore a remarkable resemblance to each other, and suggested that “the Americas were torn away from Europe and Africa by earthquakes and floods”. Ortelius’s remarkable observation became lost in the mists of time but it was in fact the very first clue in an amazing scientific detective story.

The mystery to be solved in this story is a formidable one: “How does the earth work?”. Why are the oceans and continents where they are? Have they moved around over time, and if so how? The detectives are scientists and observers from many disciplines and of many nationalities. The clues come from a myriad of sources: fossils, ancient glaciers, the ancient magnetism of rocks, the way volcanoes and earthquakes are distributed around the world, the topography of the ocean floor, and many more. As in most detective stories there are clues that were ignored, misinterpreted, led up wrong tracks or to dead ends, and others stumbled upon by accident. Gradually however they fell into place in a thrilling climax.

By popular demand this is a repeat of the Geo@12 session given in October 2023 which took its audience through this story and introduced some of the “detectives” along the way.

Frances Williams graduated, in times long gone by, with a BSc in Physics from the University of London, and MSc in Geology from the Massachusetts Institute of Technology. In between times she worked for two years at the Woods Hole Oceanographic Institution in Massachusetts, at just the time when new discoveries about the sea floor were pouring in and the ideas leading to the concept of Plate Tectonics were beginning to fall into place. After obtaining her MSc she moved to Ethiopia, where she taught geology for seven years at Addis Ababa University.
For the past 25 years or so Frances has been associated with the University of Adelaide in various roles, and is currently an Honorary Research Associate in the Department of Earth Sciences working in the Tate Museum. She is Past President and currently Secretary of the Field Geology Club of South Australia, and in 2022 was awarded the Burce Webb Medal by the Geological Society of Australia (SA Division) for the promotion of Earth Science in

Image courtesy of Swiss Seismological Service