NEW PARADIGMS FOR TEACHING STRUCTURAL GEOLOGY IN THE 21ST CENTURY

A reader of textbooks on structural geology published during the last quarter of the 20th century might conclude this discipline has matured to a point where there is little argument about the topics, techniques, or underlying methodology. Tables of contents are almost interchangeable, so textbooks are distinguished by including more beautiful photographs, taking on more user-friendly attitudes, or organizing the learning experience in more attractive ways. In keeping with the challenge of the Pardee Symposium organizers I call into question several paradigms that have contributed to this apparent maturity and propose substantive changes in the teaching of structural geology. The focus of my questioning includes well-known geometric constructions, familiar technologies, and fundamental concepts of our discipline. Two prominent geometric constructions are the stereographic projection and Mohr's Circle: the former fails to represent spatial variations in orientation data that are key to understanding the 3D geometry of structures; the latter fails to represent spatial variations in stress/strain fields that are key to understanding the mechanical evolution of structures. Three questionable technologies are the compass/clinometer, the topographic map, and tool specific software. Techniques now taught using these technologies should be supplemented or replaced with those utilizing modern technologies such as the Global Positioning System (GPS), Airborne Laser Swath Mapping (ALSM), and general purpose software such as Matlab. Two fundamental hallmarks of structural geology classes are descriptive geometry and stress/strain analysis. To provide students with analytical skills that bridge the gap between description and physical process, descriptive geometry should be supplemented or replaced with differential geometry. To enable students to formulate the elementary boundary value problems required to understand tectonic processes and their structural products, instruction should begin with the conservation of mass and momentum, and be followed by the incorporation of constitutive laws into these to yield the equations of motion. An exciting and rewarding teaching experience awaits those instructors willing to evaluate and adopt these new paradigms.