The mechanism for continental movement, if any, has not been conclusively established in most K-12 curricula.
Plate tectonics was the scientific consensus by 1968. By 1969 it was being incorporated into university geology programs, but most high school earth science textbooks still hadn't caught up.
What changed?
By 1969, plate tectonics was the working language of professional geology. The theory had been assembled in an extraordinary decade of discovery, seafloor spreading confirmed by magnetic stripes, transform faults geometrically described, subduction zones identified where old oceanic crust plunged back into the mantle. University geology departments were rewriting their curricula. Graduate students who had entered programs skeptical of continental drift were completing dissertations that assumed it. The revolution had been won.
In American high schools, students were graduating without having heard the phrase. The gap between the scientific frontier and the classroom was not unusual, textbook adoption cycles ran seven to ten years, and the texts most students used in 1969 had been written and approved in the early 1960s, when plate tectonics was still being assembled. The Earth Science Curriculum Project, a federally funded effort to modernize high school science, had produced materials incorporating the new geology, but adoption was uneven, dependent on state funding cycles, local school board preferences, and whether a district could afford updated editions.
The result was a generation that could graduate from high school in 1969 knowing that the Moon landings were happening, but having been taught that the continents were essentially fixed. Some students encountered plate tectonics if their school had adopted ESCP materials or if they had an unusually current teacher. Many did not. The theory that had unified all of Earth science, explaining why the Himalayas existed, why earthquakes followed the Pacific Rim, why Africa and South America fitted together, remained absent from the formal curriculum of most American students.
This was not a simple story of education lagging science. The same lag affected popular magazines, encyclopedias, and general-audience science writing. What is notable is the scale of the change that went untaught. Plate tectonics was not a refinement of existing theory. It was a complete replacement of the conceptual framework within which all Earth science questions were asked. Students who graduated without it did not merely lack a piece of knowledge, they lacked the explanatory structure within which that knowledge would have made sense.
