Question - The expanding Earth hypothesis was first formulated in the 1950s by S. Warren Carey, an Australian geologist.

The expanding Earth hypothesis was first formulated in the 1950s by S. Warren Carey, an Australian geologist. Though Professor Carey recognized sea floor spreading and the idea that the continents had once been assembled into the supercontinent of Pangaea, he did not recognize an important element of the modern day plate tectonic paradigm. What was that element and how does it weaken the expanding Earth hypothesis?

Answer:

Subduction – an idea that is central to the notion that newly created lithosphere at midocean ridges is destroyed along converging margins; hence, if over the time frame of millions of years the rate of production of new lithosphere is balanced by its rate of destruction, then the Earth must maintain a constant size.