The Activity And Geological Significance Of The Acidic Intrusion In The Late Caledonian In The Late Caledonian Region Of Altay,xinjiang

The Altai Mountains orogenic belt is located in the western section of the Central Asian Orogenic Belt and records the evolution of subduction of the Paleo-Asian Ocean.It is the largest area of the global Phanerozoic crust.The growth of the crust has both vertical and horizontal growth,however,after the Early Paleozoic,with the assembly of the Siberian plate and Junggar microplate and the disappearance of the ancient Asian Ocean,the main growth of the crust is characterized by vertical growth,with a large number of The medium-acid rock mass spews out,and granite covers almost the entire area,accounting for more than 40% of the total area of this region.Therefore,Therefore,it is of great significance to find out the origin of these granites and their spatial and temporal distributions for the formation and evolution of inversion orogens and to understand the tectonic evolution history of the orogenic belts.Kurman's Prague rock mass is located in the western part of Altai.The rock composition is dominated by fine-grained granite,porphyritic granite,and granodiorite.The rock mass is generally affected by late tectonic action,showing weak deformation,weak metamorphism,and physical development of gneiss.The zircon U-Pb weighted average age of the schistoseite biotite granitoids in the Kurman's Prague rock mass is 410.1±4.3 Ma.It is believed that the rock mass formed in the late Silurian-early devonian and invaded the middle Cambrian-early ordovician Lektas Formation.Kuhlmann Prague rock body belongs to a series of aluminum and calcium alkaline rocks,which has the characteristics of island arc volcanic rocks.The total amount of REE is relatively low,showing the relative enrichment of LREE and the loss of HREE,and Eu negative anomaly is obvious;Among the trace elements,the losses of large ion lithophilic elements(LILE)Ba,Sr,and high field strength elements(HFSE)Zr,Ti,and Nb are significant,suggest that the rock bodies in this area areformed in the syn-collisional diagenetic tectonic setting,it belongs to orogenic crust-derived granite.The comparative analysis of Kuhlmann Prague and Tielik and the Billywiti rock mass in the western part of Altay indicate that the formation characteristics of the Kuhlmann Prague rock body are different from the latter two,which shows the relationship between different sources in the same period and different sources in different periods.In addition,there are two invasive sequences in the Middle Ordovician and the Late Silurian.