The Paleo-Tethys Ocean was an ancient Paleozoic ocean. It sat where the Indian Ocean and Southern Asia are now located. It was located between the paleocontinent Gondwana and the so called Hunic terranes. These are divided into the European Hunic (today the crust under parts of Central Europe (called "Armorica") and Iberia) and Asiatic Hunic (today the crust of China and parts of eastern Central Asia). A large transform fault is supposed to have separated the two terranes.
The Paleo-Tethys Ocean began to form when the two small terranes rifted away from Gondwana in the late Ordovician, to begin moving toward Euramerica in the north, in the process the Rheic Ocean between Old Red Sandstone Continent and the Hunic terranes was to disappear. In the Devonian, the eastern part of Paleo-Tethys opened up, when the North and South China microcontinents, moved northward. This caused Proto-Tethys Ocean, a precursor of Paleo-Tethys, to shrink, until the Late Carboniferous, when North China collided with Siberia. In the late Devonian however, a subduction zone developed south of the Hunic terranes, where Paleo-Tethys oceanic crust was subducted. Gondwana started moving north, in the process the western part of the Paleo-Tethys would close.
In the Carboniferous continental collision took place between the Old Red Sandstone Continent and the European Hunic terrane, in North America this is called the Alleghenian orogeny, in Europe the Variscan orogeny. The Rheic Ocean had completely disappeared, and the western Paleo-Tethys was closing.
By the Late Permian, the small elongated Cimmerian plate (today's crust of Turkey, Iran, Tibet and parts of South-East Asia) broke away from Gondwana (now part of Pangaea). South of the Cimmerian continent a new ocean, the Tethys Ocean, was created. By the Late Triassic, all that was left of the Paleo-Tethys Ocean was a narrow seaway. In the Early Jurassic epoch, as part of the Alpine Orogeny, the oceanic crust of the Paleo-Tethys subducted under the Cimmerian plate, closing the ocean from west to east. A last remnant of Paleo-Tethys Ocean might be an oceanic crust under the Black Sea. (Anatolia, to the sea's south, is a part of the original Cimmerian continent that formed the southern boundary of the Paleo-Tethys.)
- Stampfli, G.M.; Raumer, J.F. von; & Borel, G.D.; Feb 2002 Paleozoic evolution of pre-Variscan terranes: from Gondwana to the Variscan collision in Geological Society of America special paper 364, p 263.