LITHOSPHERIC MANTLE COMPOSITION AND STRUCTURE VARIATIONS UNDER THE SIBERIAN PLATFORM KIMBERLITE FIELDS OF DIFFERENT AGES

• Published in: Geodynamics & Tectonophysics
• Main Authors: N. P. Pokhilenko, V. P. Afanasiev, A. M. Agashev, L. N. Pokhilenko, N. S. Tychkov, Н. П. Похиленко, В. П. Афанасьев, А. М. Агашев, Л. Н. Похиленко, Н. С. Тычков
• Other Authors: This study was implemented for the basic project of the IGM SB RAS, and was supported by the Russian Foundation for Basic Research (grant 20-05-00662)., Данное исследование выполнялось в рамках базового проекта ИГМ СО РАН, а также было поддержано РФФИ (грант 20-05-00662). Авторы благодарны сотрудникам Аналитического центра многоэлементных и изотопных исследований ИГМ СО РАН (г. Новосибирск, Россия), где проводились аналитические исследования.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Institute of the Earth's crust of the Russian Academy of Sciences, Siberian Branch 2022
• Subjects: мантийный метасоматоз; kimberlites; pyropes; lithospheric mantle; mantle metasomatism; кимберлиты; пиропы; литосферная мантия; Arctic
• Online Access: https://www.gt-crust.ru/jour/article/view/1561; https://doi.org/10.5800/GT-2022-13-4-0666

We discuss herein the differences both in composition and structure of the lithospheric mantle of the Siberian Platform under kimberlite fields of different ages. Having analyzed the pyrope garnets from kimberlites of different ages this study aimed to identify the genesis, extent and probable causes for the evolution of the composition and structure of the lithospheric mantle within various SP blocks. Acquired results revealed noticeable differences in the lithosphere thickness of different blocks for Middle Paleozoic and Mesozoic, as well as within the same time. It was found, that the greatest differences in the thickness of the lithosphere individual blocks are typical for the Middle Paleozoic. The results obtained for pyrope garnets from the Paleozoic sedimentary secondary collectors was used to get direct evidence on the existence of thick lithosphere blocks (230–240 km) under the southern margin of the Olenek uplift, north and south of the Kyutyungde trough, as well as under the western and eastern margins of the Udzhinsky uplift. Significant variations in the intensity and extent of silicate-type metasomatism were identified by investigating of pyropes from peridotites of the lithospheric mantle, sampled by kimberlites of both Middle Paleozoic and Triassic fields. Direct evidence indicates high prospects for discovering new fields of diamondiferous high-grade kimberlites of the Middle Paleozoic age in some areas of the Siberian Platform, primarily in its Arctic region. Обсуждается проблема различий состава и строения литосферной мантии Сибирской платформы под разновозрастными кимберлитовыми полями. Целью работы являлось выяснение характера, масштабов и вероятных причин эволюции состава и строения литосферной мантии различных блоков платформы на основании изучения пироповых гранатов из разновозрастных кимберлитов различных полей. Анализ полученных результатов показал наличие существенных различий в мощности литосферы различных блоков не только на разное время (среднепалеозойское и мезозойское), но и для ...