ANALOGOUS TECTONIC EVOLUTION OF THE TETHYAN AND SE ASIAN REGIONS*

The study of tectonic evolution of the Tethyan and SE Asian regions indicates that these two
regions have each passed through southwardly progressing sequences of similar tectonic events. Both regions
have experienced a southward island-arc subduction and back-arc spreading leading to continental
detachment from Gondwanaland, with an earlier southward island arc subduction of Palaeotethys (Tethyan
northern ocean), and continental detachment (Early Devonian) which produced the Neo-Tethys Ocean and the
land masses of the Tethyan region, compared with a later southward island arc subduction of Tethys II, and
continental detachment (Permo-Triassic) which produced Tethys III, and the land masses of the SE Asian
region. The northward subduction of Neo-Tethys (Tethyan southern ocean) and formation of the Alpine
Orogeny (Late Paleocene-Pliocene) in the Tethyan region was accompanied by the opening of the Red Sea to the south of the Arabian Gondwanaland. Similarly, the northward subduction of Tethys III (SE Asian
southern ocean) (Late Oligocene-Present), and arc-continent collision in the SE Asian region was
accompanied by the opening of the Southern Ocean to the south of the Australian Gondwanaland. In both
regions, the younger oceans are formed sequentially southward. The later occurrence of the southward
progressing sequence of tectonic events in the SE Asian region compared with the similar sequence of
tectonic events in the Tethyan region indicates an eastward global migration of tectonic events.