Division of the Early Proterozoic Khargitui Formation of the Sarma Group (Akitkan Orogenic Belt, Siberian Craton) into Different Age Sequences Based on the Results of U–Pb Isotopic Analysis of Zircon
U. S. Efremova, T. V. Donskaya, D. P. Gladkochub, A. M. Mazukabzov, A. V. Ivanov, N. V. Bryansky
{"title":"Division of the Early Proterozoic Khargitui Formation of the Sarma Group (Akitkan Orogenic Belt, Siberian Craton) into Different Age Sequences Based on the Results of U–Pb Isotopic Analysis of Zircon","authors":"U. S. Efremova, T. V. Donskaya, D. P. Gladkochub, A. M. Mazukabzov, A. V. Ivanov, N. V. Bryansky","doi":"10.1134/s1028334x24601913","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>U–Pb (LA-ICP-MS) geochronological studies of detrital zircon from rocks of the Early Proterozoic Khargitui Formation of the Sarma Group, distributed in the central part of the Baikal uplift of the Siberian craton basement and included into the structure of the Sarma zone of the Akitkan orogenic belt, are carried out. It is established that the Khargitui Formation comprises the rocks formed in different time intervals: >2.7, 2.15–1.95, and <1.7 Ga. It is shown that Meso- and Neoarchean age peaks (2.7–3.1 Ga) are characteristic of zircon from leucocratic gneisses, which indicates the formation of gneiss protoliths after 2.7 Ga due to the destruction of Archean granitoids in the Sarma zone of the Akitkan orogenic belt and igneous rocks in the Anabar superterrane basement of the Siberian craton. The time interval of 2.15–1.95 Ga corresponds to the accumulation of protoliths of mica–quartz schists, which is substantiated by the age of the youngest zircon grains of 2150 Ma and the age of metamorphism of these rocks of 1.95 Ga. The presence of an age peak at 1833 Ma and younger zircon grains aged in the range of 1675–1785 Ma in the sample of mica–quartz schist taken from another area of rock outcrops assigned to the Khargitui Formation indicates that the protoliths of these rocks accumulated after the formation of the Akitkan orogenic belt and the South Siberian postcollisional magmatic belt. The results obtained indicate that the rocks assigned to the Khargitui Formation of the Sarma Group of the Western Baikal region cannot be considered as a single stratigraphic unit, since they formed at different stages of the evolution of the Akitkan orogenic belt. It is shown that, based on recent data, the deposits of the Khargitui Formation should be divided into complexes of different ages (stratigraphic units), each of which corresponds to a certain stage of the geological evolution of the territory.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"2014 1","pages":""},"PeriodicalIF":0.7000,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Doklady Earth Sciences","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1134/s1028334x24601913","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
U–Pb (LA-ICP-MS) geochronological studies of detrital zircon from rocks of the Early Proterozoic Khargitui Formation of the Sarma Group, distributed in the central part of the Baikal uplift of the Siberian craton basement and included into the structure of the Sarma zone of the Akitkan orogenic belt, are carried out. It is established that the Khargitui Formation comprises the rocks formed in different time intervals: >2.7, 2.15–1.95, and <1.7 Ga. It is shown that Meso- and Neoarchean age peaks (2.7–3.1 Ga) are characteristic of zircon from leucocratic gneisses, which indicates the formation of gneiss protoliths after 2.7 Ga due to the destruction of Archean granitoids in the Sarma zone of the Akitkan orogenic belt and igneous rocks in the Anabar superterrane basement of the Siberian craton. The time interval of 2.15–1.95 Ga corresponds to the accumulation of protoliths of mica–quartz schists, which is substantiated by the age of the youngest zircon grains of 2150 Ma and the age of metamorphism of these rocks of 1.95 Ga. The presence of an age peak at 1833 Ma and younger zircon grains aged in the range of 1675–1785 Ma in the sample of mica–quartz schist taken from another area of rock outcrops assigned to the Khargitui Formation indicates that the protoliths of these rocks accumulated after the formation of the Akitkan orogenic belt and the South Siberian postcollisional magmatic belt. The results obtained indicate that the rocks assigned to the Khargitui Formation of the Sarma Group of the Western Baikal region cannot be considered as a single stratigraphic unit, since they formed at different stages of the evolution of the Akitkan orogenic belt. It is shown that, based on recent data, the deposits of the Khargitui Formation should be divided into complexes of different ages (stratigraphic units), each of which corresponds to a certain stage of the geological evolution of the territory.
摘要 对分布在西伯利亚克拉通基底贝加尔隆起带中部、被纳入阿基坦造山带萨玛区构造的萨玛组早新生代哈尔吉图地层岩石中的锆英石碎片进行了U-Pb（LA-ICP-MS）地质年代研究。研究确定，哈尔吉图地层由不同时间段形成的岩石组成：2.7、2.15-1.95 和 1.7 Ga。研究表明，白云母片麻岩中的锆石具有中、新元古代年龄峰值（2.7-3.1 Ga）的特征，这表明片麻岩原岩是在 2.7 Ga 之后由于阿基坦造山带萨尔马区的阿基坦花岗岩和西伯利亚克拉通阿纳巴尔超基底的火成岩的破坏而形成的。2.15-1.95Ga的时间间隔与云母石英片岩原岩的堆积相对应，最年轻的锆石颗粒的年龄为2150Ma，这些岩石的变质年龄为1.95Ga，这些都证实了这一点。在另一个属于哈尔吉图地层的岩石露头地区采集的云母石英片岩样本中，出现了一个 1833 Ma 的年龄峰值和年龄在 1675-1785 Ma 之间的较年轻的锆石颗粒，这表明这些岩石的原岩是在阿基坦造山带和南西伯利亚碰撞后岩浆带形成之后堆积的。研究结果表明，西贝加尔湖地区萨玛组哈尔吉图地层的岩石不能被视为单一地层单元，因为它们形成于阿基坦造山带演化的不同阶段。研究表明，根据最新数据，哈尔吉图地层的沉积物应划分为不同时代的复合体（地层单元），每个复合体对应于该地区地质演变的某一阶段。
期刊介绍：
Doklady Earth Sciences is a journal that publishes new research in Earth science of great significance. Initially the journal was a forum of the Russian Academy of Science and published only best contributions from Russia. Now the journal welcomes submissions from any country in the English or Russian language. Every manuscript must be recommended by Russian or foreign members of the Russian Academy of Sciences.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
