Cimmerian Orogeny Cimmerian Orogeny The Cimmerian Orogeny was an orogeny that created mountain ranges that now lie in Central Asia. The orogeny is believed to have begun 200–150 million years ago (much of the Jurassic Period), when the Cimmerian plate collided with the southern coast of Kazakhstania and North and South China, closing the ancient Paleo-Tethys Ocean between them. The plate consisted of what are now known as Turkey, Iran, Tibet and western Southeast Asia. Much of the plate's northern boundary formed mountain ranges that were as high as the present-day Himalayas. The orogeny continued well into the Cretaceous and Early Cenozoic.
Svecofennian orogeny broad terms, regardless of details, it has been proposed that the Svecofennian orogeny involved more-less continuous subduction with subduction zones progressively migrating to the southwest. An alternative model postulates subduction included alternating extension and compression cycles, with the orogenic activity ceasing after the collision between the Fennoscandian Craton and the Sarmatian Craton. Prior to the onset of orogeny the Archean-aged craton of what is today northeastern Fennoscandia rifted creating an ocean basin, the "pre-Svecofennian Ocean", that then closed during the Svecofennian orogeny. The closure of this basin was indebted to subduction and resulted thus both in the formation of igneous