Abstract

The northern Gondwanaland margin between Arabia and Australia lacks, on any reconstruction, appropriate and equivalent facies distributions from continental to offshore marine. We consider this due to the separation of “microcontinents” during the Paleozoic and Mesozoic. These “microcontinents” consist of the Lut, Helmand, Nowshera, Karakorum, High Himalaya and Thai-Malaya terranes. Comparison of their Devonian stratigraphies indicate that most of the terranes were part of Gondwanaland in the Devonian. They separated and, in some cases, were rotated into very different orientations during the later Paleozoic. Some terranes, or parts of terranes — such as the Nowshera terrane and the Langkawi part of the Thai-Malaya terrane — may have formed part of the Devonian Asian margin of Tethys. In that case some very complicated tectonic rotations and inserts are needed to explain their present location with respect to other terranes. Reconstruction of any ancient geography must take these exotic terranes into account.

Analysis of each “microcontinent” as a coherent terrane allows us to specify the similarities and differences among the “microcontinents” and the main Gondwanaland margin during the Devonian. This specific analysis is more helpful and rigorous than previous types of analysis. It also points out where further detailed studies are needed.