The Study And Investigation On The Assembly And Coupling Petrotectonic Assemblage During Paleozoic–Mesozoic Period At Qimantage Geological Corridor Domain

Qimantage geological corridor domain, which locates at the western part of East Kunlun,borders with the Qaidam Block in the north and Hoh Xil basin in the south,and covers all tectonic units in eastern Kunlun orogenic belt,is the most wide-exposed areas of eastern Kunlun orogenic belts. The magmatic activity of the geological corridor domain mainly occurred during the Caledonian tectonic-magmatic cycle (from Ordovician to Devonian) and Hercynian-Indo-China tectonic-magmatic cycle (from Carboniferous to Jurassic). The Caledonian tectonic-magmatic cycle can be further divided into four stages: Ordovician-Early Silurian tectonic-magmatic stage , Late Silurian-Early Devonian tectonic-magmatic stage,Early Middle Devonian tectonic-magmatic stage,Late Devonian tectonic-magmatic stage. Similarly,the Hercynian-Indo-China tectonic-magmatic cycle can also be classified into 5 categories: Early-Middle Permian tectonic-magmatic stage,Late Permian-Middle Triassic tectonic-magmatic stage (late Anisian-early Latin),Late Triassic tectonic-magmatic stage (Carnian),Late Triassic-Early Jurassic tectonic-magmatic stage (Rhaetian-Hao Tong period).Ordovician-Early Silurian tectonic-magmatic stage:In the north Qimantage tectonic magmatic belt,we have identified four tectonic subduction-related combinations of rocks and structures. We also have identified an ocean-continent subduction-related combinations of rocks and structures at Kunan tectonic-magmatic zone, where the plutonic magma intrusion activities were not well developed, instead, it was characterized by the high development of different type back-arc rift related marine volcanic rocks at the Qimantage region.At the Late Silurian-Early Devonian tectonic magmatic stage,the magmatic rocks were not widely distributed, which mainly belongs to the peraluminous intrusive rock and indicates a continent-continent collision environment. The magmatic activities were very strong during the early and middle Devonian tectonic-magmatic stage, composed mainly by the mafic- and high-K calc-alkaline or alkaline felsic introsive combinations, which indicates a post-collision stage with the characteristics of structural extension.At the stage of Late Devonian-Early Carboniferous tectono-magmatic stage,the magmatic activity was easing gradually with the representative igneous rock assemblage of aluminous or peraluminous alkaline syenogranite"A"-type granite.Early-Middle Permian and Late Permian–Middle Triassic tectono-magmatic stages were at an ocean-continent subduction procedure. During the stage of Early and Middle Permian, there occurred three subduction-related tectonic-magmatic combinations at the Kunlun tectono-magmatic belt. During Late Permian to Middle Triassic stage, it became the aluminous or peraluminous high-silica,high-K alkaline or high-K calc-alkaline combinations,which indicate an Andean continental margin arc formations with very a high maturity. The Middle-Triassic tectono-magmatic stage was at a process of continent-continent collision (at the beginning of such a collision,the subductive lithosphere slab was broken off) when the magmatic activities were concentrated on the north of the Middle-Kunlun tectono-magmatic belt. Such magmatic activities were mainly the combinations of diorite+ quartzdiorite+ tonalite+ granodiorite characterized by extremely rich in MME. Late Triassic tectono-magmatic stage was at a post-collisional process during which the high-K calc-alkaline and alkaline continental intermidate-acid volcanic rock combinations were formed by the strong volcanic activities,while the combinations of aluminous or peraluminous high-K calc-alkaline-alkaline quartz monzobiorite+ granodiorite+ (porphyritic) monzogranite+ syenogranite were formed by the very strong deep-magma intrusion. Late Triassic-Early Jurassic tectono-magmatic stage was the post-orogenic stage during which typical alkaline "A"-type granite combinations ocurred widely.