Abstract <p>Geochemical and geochronological (U–Pb method on zircon, ID-TIMS) studies of igneous rocks of the Olekma–Stanovoy dike complex in the eastern segment of the Stanovoy volcano-plutonic belt of the Central Asian orogenic belt have been carried out. The age of intrusion of rhyolite dikes of this complex has been established as 110 ± 1 Ma. This age corresponds to the completion of the Stanovoy volcano-plutonic belt’s formation in its eastern segment within the Dzhugdzhuro–Stanovoy superterrain. This terminal magmatic impulse in the Stanovoy belt (110 Ma) is represented exclusively by felsic rocks, including rhyolite dikes of the Olekma–Stanovoy complex, rhyolites of the Ugan volcanic field, and granites of the Irakan complex. All of them are classified as high-silica and high-alumina rocks of increased alkalinity with a predominance of potassium, and belong to the transitional geochemical type between A- and S-type granites. Unlike earlier granitoids from the batholithic stage of the Stanovoy volcano-plutonic belt’s formation, they are enriched in rare elements, are significantly more differentiated, and lose the geochemical features of adakite-type magmatism typical of earlier igneous rocks in the eastern segment of this belt. These rocks were probably formed under conditions of lithospheric tension, which is fully consistent with the concept of the Stanovoy volcano-plutonic belt’s formation during the post-collisional stage of geological evolution in the northeastern sector of the Central Asian orogenic belt.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

The Age of the Terminal Stage of Magmatism in the Stanovoy Volcano-Plutonic Belt

  • A. M. Larin,
  • A. B. Kotov,
  • E. B. Salnikova,
  • S. D. Velikoslavinsky,
  • V. P. Kovach,
  • T. M. Skovitina,
  • A. A. Ivanova,
  • Yu. V. Plotkina,
  • N. L. Alekseev

摘要

Abstract

Geochemical and geochronological (U–Pb method on zircon, ID-TIMS) studies of igneous rocks of the Olekma–Stanovoy dike complex in the eastern segment of the Stanovoy volcano-plutonic belt of the Central Asian orogenic belt have been carried out. The age of intrusion of rhyolite dikes of this complex has been established as 110 ± 1 Ma. This age corresponds to the completion of the Stanovoy volcano-plutonic belt’s formation in its eastern segment within the Dzhugdzhuro–Stanovoy superterrain. This terminal magmatic impulse in the Stanovoy belt (110 Ma) is represented exclusively by felsic rocks, including rhyolite dikes of the Olekma–Stanovoy complex, rhyolites of the Ugan volcanic field, and granites of the Irakan complex. All of them are classified as high-silica and high-alumina rocks of increased alkalinity with a predominance of potassium, and belong to the transitional geochemical type between A- and S-type granites. Unlike earlier granitoids from the batholithic stage of the Stanovoy volcano-plutonic belt’s formation, they are enriched in rare elements, are significantly more differentiated, and lose the geochemical features of adakite-type magmatism typical of earlier igneous rocks in the eastern segment of this belt. These rocks were probably formed under conditions of lithospheric tension, which is fully consistent with the concept of the Stanovoy volcano-plutonic belt’s formation during the post-collisional stage of geological evolution in the northeastern sector of the Central Asian orogenic belt.