or ~800 to ~1200 km) of the 2500 km of crustal shortening was accommodated by thrusting and folding of the sediments of the passive Indian margin together with the deformation of the Tibetan crust. Even though it is more than reasonable to argue that this huge amount of crustal shortening most probably results from a combination of these three mechanisms, it is nevertheless the last mechanism which created the high topographic relief of the Himalaya. The ongoing active collision of the Indian and Eurasian continental plates challenges one hypothesis for plate motion which relies on subduction. Major tectonic subdivisions of the Himalaya One of the most striking aspects of the Himalayan orogen is the lateral continuity of its major tectonic elements. The Himalaya is classically divided into four tectonic units that can be followed for more than 2400 km along the belt (Fig. 5 and Fig. 7). Sub-Himalayan (Churia Hills or Sivaliks) tectonic plate The Sub-Himalayan tectonic plate is sometimes referred to as the Cis-Himalayan tectonic plate in the older literature. It forms the southern foothills of the Himalayan Range and is essentially composed of Miocene to Pleistocene molassic sediments derived from the erosion of the Himalaya. These molasse deposits, known as the "Murree and Sivaliks Formations", are internally folded and imbricated. The Sub-Himalayan Range is thrust along the Main Frontal Thrust over the Quaternary alluvium deposited by the rivers coming from the Himalaya (Ganges, Indus, Brahmaputra and others), which demonstrates that the Himalaya is still a very active orogen. Lesser Himalaya (LH) tectonic plate The Lesser Himalaya (LH) tectonic plate is mainly formed by Upper Proterozoic to lower Cambrian detrital sediments from the passive Indian margin intercalated with some granites and acid volcanics (1840 ±70 Ma). These sediments are thrust over the Sub-himalayan range along the Main Boundary Thrust (MBT). The Lesser Himalaya often appears in tectonic windows (Kishtwar or Larji-Kulu-Rampur windows) within the High Himalaya Crystalline Sequence. Central Himalayan Domain, (CHD) or High Himalaya tectonic plate The Central Himalayan Domain forms the backbone of the Himalayan orogen and encompasses the areas with the highest topographic relief (highest peaks). It is commonly separated into four zones. High Himalayan Crystalline Sequence (HHCS) Approximately 30 different names exist in the literature to describe this unit; the most frequently found equivalents are "Greater Himalayan Sequence", "Tibetan Slab" and "High Himalayan Crystalline". It is a 30-km-thick, medium- to high-grade metamorphic sequence of metasedimentary