Complex sentence: Unlike on Earth, where the rifting of plates produces a corresponding subduction zone, the thick lithosphere of Mars is unable to descend into the mantle, instead it is scrunched up and flayed laterally into mountain ranges in a process called obduction.
Split into simpler sentences: Unlike on Earth, where the rifting of plates produces a corresponding subduction zone, the thick lithosphere of Mars is unable to descend into the mantle. Instead, the compressed zone is scrunched up and flayed laterally into mountain ranges, in a process called obduction.