The territory of Pakistan occupies, in the northwestern section of the Indian region, a large part of the Indus valley, a depression of tectonic origin similar to the Gangetic one; structurally it represents the weld between the rigid continental block of the Deccan and the mountainous beams that border South Asia. The Neozoic soils of the plains are formed by the detrital deposits of the Indus and its tributaries and reach powers even higher than 1000 m; below are sedimentary layers from the Cenozoic. Open to the S, on the Arabian Sea, in the fertile alluvial region of Sind, the Indus plain is bordered to the E by the modest heights of the Thar, while imposing systems close it on the other sides. AN the Indus depression gives way to the first mountainous folds, the Salt Range, low ridges formed during the Himalayan Cenozoic orogeny, then to the grandiose corrugations of the Himalayas that culminate in the Nanga Parbat massif (8126 m). The upper Indus valley delimits the Himalayan system to the NW and tectonically separates it from the Karakoram and Hindukush chains, of which the highest sections belong to Pakistan: the external slope of Karakoram that culminates in K2 (8616 m), of the Hindukush the south-eastern section dominated by the “seven thousand” of the chain, including the Tirich Mīr (7690 m). Finally, the Indus valley is closed to the W by the bundles of folds that make up the eastern border of the Iranian plateau and the other Afghan lands, essentially represented by the Sulaimān mountains and the Baluchistan chains, which fan out towards Makrān and the coast (Siāhān mountains, Kīrthar etc.). These chains form a bastion interrupted by a few easy steps, including that of Khojak, N of Quetta, between the Sulaimān mountains (culminating at 3374 m in Takht-i Sulaiman) and the mountains of Baluchistan; even more important is the Khyber pass, which corresponds to a deep incision of the Kabul River at the foot of Mount Sikarām (4755 m), on the border with Afghanistan, in the Safed Koh massif.
The territory, with the exception of the rivers of Baluchistan (Dasht, Hingol, etc.), includes a large part of the Indus basin, a fact of capital importance if we consider that the economy of Pakistan, a very arid country, is essentially conditioned the availability of water that this river and its tributaries can provide. After passing the trans-Himalayan sector of its course, where the Indus receives important tributaries (Shyok, Gilgit, etc.), it turns towards the S and in the Peshāwar depression it is reached by Kabul, which collects the waters of the Afghan Hindukush; then, after a long stretch almost parallel to the Sulaimān chain, it receives the contributions of the Punjab rivers. This region, which can be considered as a single large dejection fan at the foot of the Himalayas, is one of the richest and most populous parts of Pakistan. The “five rivers” that cross it (punch precisely means five) drain the outer Himalayan slope, from which they emerge after tortuous courses in deep valleys, often carrying, with devastating fury, large quantities of debris. The major rivers of Punjab are the Chenāb, the Rāvi and the Sutlej, which is the main one. The Indus after the confluence with the Sutlej no longer receives substantial tributes. Its regime depends on monsoon rains and on the melting of snow and ice in its highest stretch (in the Karakoram, which has impressive glaciers, the limit of perennial snow is at 4500 m) and is therefore very irregular. In Sukkur its minimum flow rate (January-March) varies between 500 and 1000 m 3 / s; the maximum (from August to September) between 12,000 and 22,000 m 3 / s. Like those of the Ganges, the floods of the Indus experience incalculable violence, also due to their enormous alluvial masses (the large delta plain, which begins practically in Hyderābād, is due to the considerable debris transport of the river); on the other hand, the beneficial effect of these colossal floods is evident: they allow the irrigation of summer crops and, where possible, the damming of water, including winter ones.
According to findjobdescriptions, the aridity of the climate conditions the vegetal landscape, characterized almost everywhere by the steppe from which, except for the irrigated areas, one passes in the region of the lower Indus to a real desert of dunes; in the northern valley bottoms a riparian vegetation of poplars and elms appears. Above 3000 m the alpine steppe extends, characterized by the Caragana spinosa and by various species of artemisie, and, on the southernmost slopes, limited forest areas. The variety of ecosystems that distinguish the territory see the presence of a differentiated fauna, typical of both the Palearctic regionand the eastern one: snow leopards, deer, bears, ibex, foxes, wild sheep, wild boars, crocodiles, snakes but also donkeys, desert gazelles and camels as well as a large number of bird species. River and marine ecosystems are home to interesting and endangered species including the river dolphin. In 1997, the Ministry of the Environment prepared the creation of an agency that deals with the promotion and protection of the natural heritage; desertification, deforestation to make way for agriculture and pastures, soil erosion as well as soil, water and air pollution are among the major environmental problems. There are numerous protected areas in Pakistan, covering 8.7% of the territory, including 15 national parks.