The rejuvenation of the circumsiberian chains such as the Kunlun Shan, the Tian Shan, the of Iran and Afghanistan, East Turkestan, Tibet, Mongolia itself, a tabular region between distant mountainous alignments. The rejuvenation of the circumsiberian chains such as the Kunlun Shan, the Tian Shan, the of Iran and Afghanistan, East Turkestan, Tibet, Mongolia itself, a tabular region between distant mountainous alignments. The rejuvenation of the circumsiberian chains such as the Kunlun Shan, the Tian Shan, the Alatau, Altaj and the ranges East of Lake Baikal, the latter already partially emerged in the Mesozoic. There were also fractures and sinking, which formed among other things Lake Baikal and the depressions of the Zungaria, between the Tian Shan and the Altaj, of Turfan (-154 m), of the ‘ Issyk-Kul’, of the Balhaš lake etc.. Always concomitant with the great Cenozoic upheavals there was the formation of the vast depressionary surfaces that immediately extend to the edge of the mountainous belt, the alluvial lowlands of Central Asia (or Aralo-Caspian according to Countryaah.com), for a long time constituting a great inland sea, and those of the Indus, the Ganges, Mesopotamia and eastern China. The general settling of the continent did not even leave the Indo-Arab masses immune, which were eventually inclined towards the East: this “rocking” movement was responsible for the birth of the mountainous edges that dominate the Red Sea in the Arabian Peninsula – which rose following the fracture which separated Asia from Africa – and of the Ghats on the Deccan Peninsula. In the Cenozoic the evolution of the eastern and southern belts of the continent also began. In reality, Asia has always been an unstable area: the oldest structures are found in Borneo and Japan, but already at the end of the Paleozoic there were geosynclines whose evolution was responsible for the birth of the current archipelagos of the Far East and of the Indonesia and later the outermost island arches that line up from the Andaman and Nicobar Islands across the Mentawai to Timor. The detachment of the internal arc from the continent with the formation of the interposed shallow seas dates back to the Pliocene. The evolution of this whole marginal belt is still underway and this can be indicated by the very presence of the marine trenches (which reach significant depths, as in the abyss of the Philippines, whose maximum negative altitude is 10,500 m).
Volcanism is very active everywhere, from Indonesia to the Philippines, to Japan, to Kamchatka. The median range of the Asian reliefs is not even completely settled: the last uprights of the Himalayas date back to the Pliocene. Also in the western section, that is, in Anatolia and in the Iranian plateau, some large faults cause frequent earthquakes, indicating an ongoing settlement process. § In relation to this evolution there are very varied geological formations. Continental armor, in particular the Sinic Shield and the Angaric Shield, they are made up of archaeozoic crystalline rocks (granites, gneisses, quartzites) that emerge in the Siberian Plateau, in the Baikal mountains, in eastern China, etc. With crystalline formations that are not so different, the archaic structures also emerge in the Arabian Peninsula and especially in the Deccan, where the mountains Aravalli, which borders it to the North, are among the oldest terrestrial reliefs. The northwestern section of the Deccan is extensively covered by volcanic formations due to expansions of effusive rocks (trapps). Vast sedimentary covers obliterate the oldest rocks; this occurs in a more characteristic way in the Arabian Peninsula where there are sedimentary plateaus from different eras that slope down towards the Persian Gulfhosting rich oil fields. Powerful sedimentary stratifications, which reach thicknesses greater than 5000 m, also cover the Siberian Lowland and in them a large number of horizons are represented, from the Paleozoic to the Neozoic. Sedimentary tables, mostly of continental formation (such as the typical series of the Wealdian, which dates back to the Mesozoic), are also found in Mongolia, where large deposits of fossil dinosaurs have come to light. In the belt of the Cenozoic reliefs the formations are more varied: in the large chains metamorphic formations and granite masses predominate; Sedimentary strata constitute the most extensive marginal bands and sometimes also the inland areas, where the relief has undergone minor corrugations. In addition to the Mesozoic, the Cenozoic is also represented (for example in the outer Himalayan belt). The Neozoic covers cover large sections of the continent and in particular all the great lowlands and valleys. There are both alluvial formations and glacial deposits and this in relation to the different processes of exogenous activity, which was especially intense in correspondence with the higher elevations. Glacial formations are present throughout the mountain range, albeit at different altitudes, and in the northern part of the Siberian region. Extensive are the formations of löss which in the arid phases affected all of Central Asia and the northern Chinese region, that is, the areas immediately close to the innermost desert areas. Volcanic formations predominate in the archipelagos, from which the extremely fertile soils derive which partly explain the high population density of many islands.
