{"title":"Polymetamorphism in the Geological Development of the South Altai Metamorphic Belt, Central Asian Foldbelt","authors":"","doi":"10.1134/s0869593824010040","DOIUrl":null,"url":null,"abstract":"<span> <h3>Abstract</h3> <p>The crystalline complexes of the Hercynian South Altai Metamorphic Belt (SAMB), which is a part of the Central Asian Foldbelt more than 1500 km long. They compose different-scale tectonic plates, the level of metamorphism in which at the early stages reached the conditions of high-temperature amphibolite subfacies and, in places, granulite facies. In terms of tectonics, the band of their outcrops is confined to the margin of the North Asian Caledonian continent, stretching from southeast to northwest along the southern slope of the Gobi, Mongolian, and Chinese Altai to Eastern Kazakhstan, where they are represented in the Irtysh shear zone. The SAMB includes poly- and monometamorphic complexes. The age of granitoids formed at the late episode of metamorphism was determined for the Tsel tectonic plate of the Gobi Altai in the southeastern part of the SAMB: from 374 ± 2 to 360 ± 5 Ma. These and previously obtained results show that the early stage of low-pressure metamorphism and the late stage of high-pressure metamorphism occurred in the age intervals of ~390–385 and 375–360 Ma, respectively, almost throughout this belt. A short-term stage of stabilization was between these stages. These processes occurred during the closure of the basin with the Tethys-type oceanic crust of the South Mongolian Ocean (paleo-Tethys I). The spatial position of the SAMB is determined by the asymmetric structure of the basin, in which the active continental margin is represented along its northern part, and the passive one is represented along the southern one (in modern coordinates).</p> </span>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"27 1","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Stratigraphy and Geological Correlation","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1134/s0869593824010040","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The crystalline complexes of the Hercynian South Altai Metamorphic Belt (SAMB), which is a part of the Central Asian Foldbelt more than 1500 km long. They compose different-scale tectonic plates, the level of metamorphism in which at the early stages reached the conditions of high-temperature amphibolite subfacies and, in places, granulite facies. In terms of tectonics, the band of their outcrops is confined to the margin of the North Asian Caledonian continent, stretching from southeast to northwest along the southern slope of the Gobi, Mongolian, and Chinese Altai to Eastern Kazakhstan, where they are represented in the Irtysh shear zone. The SAMB includes poly- and monometamorphic complexes. The age of granitoids formed at the late episode of metamorphism was determined for the Tsel tectonic plate of the Gobi Altai in the southeastern part of the SAMB: from 374 ± 2 to 360 ± 5 Ma. These and previously obtained results show that the early stage of low-pressure metamorphism and the late stage of high-pressure metamorphism occurred in the age intervals of ~390–385 and 375–360 Ma, respectively, almost throughout this belt. A short-term stage of stabilization was between these stages. These processes occurred during the closure of the basin with the Tethys-type oceanic crust of the South Mongolian Ocean (paleo-Tethys I). The spatial position of the SAMB is determined by the asymmetric structure of the basin, in which the active continental margin is represented along its northern part, and the passive one is represented along the southern one (in modern coordinates).
期刊介绍：
Stratigraphy and Geological Correlation is the only journal that provides comprehensive coverage of the fundamental and applied aspects of stratigraphy and the correlation of geologic events and processes in time and space. Articles are based on the results of multidisciplinary studies and are for researchers, university professors, students, and geologists interested in stratigraphy and the chronological features of the world’s geological record.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
