THE ALTAIDS AS SEEN BY EDUARD SUESS, AND PRESENT THINKING ON THE LATE MESOPROTEROZOIC TO PALAEOZOIC EVOLUTION OF CENTRAL ASIA.

Eduard Suess recognized the unusual size and internal tectonic configuration of the mountainous terranes of Central Asia that he termed Altaids and which differ considerably from curvi-linear foldbelts such as the Alps and Urals. However, he did not realize that this orogenic domain or province evolved over a period of some 750 Ma from the late Mesoproterozoic (ca. 1000 Ma) to the late Permian (ca. 260 Ma), contains large volumes of pre-orogenic crust as well as many synorgenic metamorphic complexes, and exhibits many structures similar to modern thrust-and-fold belts. We therefore do not favour the name Altaids for this large orogenic domain because it is associated with the concept of an essentially Palaeozoic evolution and certain features that have since been shown to be incorrect. The non-genetic term Central Asian Orogenic Belt (CAOB) seems to be more appropriate and characterizes one of the largest accretionary terranes on Earth whose evolution has many similarities with the tectonics of the Indonesian Archipelago. In contrast to popular thinking, crustal growth in the CAOB during accretion was not anomalously high but was similar to that in the Palaeozoic Tasmanides of Australia and the Jurassic to Present evolution in southeastern Asia. [ABSTRACT FROM AUTHOR]