Its sound unbelievable that the the inner heat flow of the Earth    (convection) should have enough force to create mountains.

The strong force and  Gravity is unite.

When for a moon is orbiting close to a planet, space between the planet and the Moon become stronger affected (more stretched).

This mean it will be more difficult to contract space.

Because gravity and the strong force is a unity it is in the end the strong force that must do a harder job to keep space contracted as matter.

There are good reasons to suspect this to cause heat.  We have often discovered more heat emission as expected.

For exsample;

• The discover of a liquid  ocean beneath the ice Moon Europe.

• The Hot Volcanic Moon of Jupiter; Io.

• Many planets emit more heat as expected.

• Discovered a lot of heat in connection with strong gravity else where for example inside galaxies and between galaxies etc.

Therefore there are good reasons to suspect that perigee and apogee, as well as aphelion and perihelion have influence of the heat release of the Earth (and our moon).

This could explains the cause of continental subduction. 

When the Earth is approaching the Sun (Perihelion) it could create more inner heat, this could cause the crust to expand and crack and lave would flow up to the cracks and cool down.

By Aphelion less heat would be created, hence the Earth would contract again. Because there is not space for the lave in the cracks by Aphelion, the result would be subduction.

Notice many planets and moons emit more inner heat as expected. 

This would mean that by perihelion inner heat emission is causing the Earth to crack about total 10 cm (diameter), lava moves up to the crack and by aphelion this would cause tension in the crust and hence subduction.

This idea is further supported by the fact that volcano eruption on Earth happens more frequently  in wintertime when the Earth is closer to the Sun  (perihelion 3 January.) ..

 http://www.vulkaneksperten.dk/print.asp?id=3370

Well there can be several other weaker influences but inner heat release from the the inner Earth is the most important one.

The great canyon on Mars must, was caused when Mars was younger and warmer. Lave was also pressing the crust of Mars for a period.

Huge old frozen lava lakes inside the great canyon on Mars.

Image source  here

The ices is cracking each time the Moon Europe moves towards Perihelion..