Palaeomagnetism and Orogenies

Palaeomagnetism has a wide range of application potential and has proved extremely important in palaeogeographic reconstructions and to elucidate aspects of local and regional tectonics. Application of palaeomagnetism to local-regional tectonic studies requires high quality palaeomagnetic reference data but these are often missing or associated with large uncertainties - high quality reference apparent polar wander paths are therefore urgently required for many continents. A complete plate kinematic analysis of for example continent-continent collisions is made difficult since longitude is essentially unconstrained from palaeomagnetic data and modelling old orogens such as the Caledonian Orogeny in Silurian times relies on additional geologic data. Similar modelling problems apply to the somewhat younger Variscan Orogeny and Pangea formation in the Late Carboniferous. In modelling Permian and younger collisions we use 'zero longitudinal average motion of Africa' as the best possible approximation and we show examples of palaeomagnetic modelling of young orogens such as the Himalayas and how these models compare with hotspot and mantle plate motion frames.