In 1971 , he and R.A.
Kamaletdinov theorized that the horizontal movements of tectonic plates played a key role in the structure and development of the Earth 's crust .
In 1971 , Kamaletdinov and R.A.
Kamaletdinov theorized that the horizontal movements of tectonic plates played a key role in the structure and development of the Earth 's crust .