What processes occur at the boundaries of atmospheric plates a) when they move apart

What processes occur at the boundaries of atmospheric plates a) when they move apart b) when they approach each other

I believe, not atmospheric, but lithospheric) The Earth’s crust has a different structure on the continents and under the oceans. The mainland ZK is composed of three layers – a layer of sedimentary rocks, granite and basalt. Thickness from 30 km under the plains to 80 under the mountains. The oceanic ZC has two layers – a layer of sedimentary rocks and a basalt layer. Thickness – 5-10 km. Consequently, the mainland ZC is stronger than the oceanic one. The substance of the mantle is under the earth’s crust under very high pressure and t is about 3000 g. It constantly “seeks” to break out and “looks for” weak points in the earth’s crust. The oceanic crust is weak, where “breaks” occur more often. Result: “break” – SLABS SPREADING – outpouring of lava – solidification – middle mountain ranges at the bottom of the ocean. When 2 IDEAL PLATES APPROACH, folded mountains are formed, both at the bottom of the ocean and on land (Himalayas). At the APPROACH OF THE MAIN AND OCEAN PLATES – the mainland moves towards the oceanic – mountains along the coast of the mainland and a deep depression in the ocean along the coast (Andes and Peruvian Trench).