Abstract <p>The age data on Precambrian dolerites of dyke swarms of the southern flank of the Siberian craton published after 2010, were analyzed. It is shown that post-collisional mafic magmatism with an age of 1880–1840 Ma is developed in all basement salients of the south of the craton and records the final stage of its structural formation. The dolerite dykes with an age of about 1750 Ma were discovered within the Baikal salient of the basement and belong to the Timpton Large Igneous Province. Rifting-related dolerite dykes with an age of 1640–1615 Ma are described in the Biryusa block. In the south of the craton, rare Mesoproterozoic dolerites with ages 1350–1338, 1260, and about 1000 Ma formed in an intraplate extension setting were found. The “Franklinˮ ages (about 720 Ma) were obtained for dolerites from dyke swarms of the Sayan–Baikal dyke belt, marking the early stages of rifting that led to the breakup of the Rodinia supercontinent. A dozen of new ages (from 640 to 615 Ma) has been reported for alkaline–ultramafic and mafic rocks, which were intruded at the final stages of the Late Precambrian extension event within the southern margin of the Siberian craton. The obvious progress in the study of Precambrian mafic magmatism in the south of the Siberian craton has been achieved in recent years. Based on the larger number and the better quality of isotope dates, the main events of the emplacement of Proterozoic mafic dykes were recognized and geodynamic settings of their formation was proposed.</p>

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Main Stages of the Proterozoic Mafic Magmatism in the Southern Siberian Craton: Progress in the Study for the Period of 2010–2025

  • D. P. Gladkochub,
  • T. V. Donskaya

摘要

Abstract

The age data on Precambrian dolerites of dyke swarms of the southern flank of the Siberian craton published after 2010, were analyzed. It is shown that post-collisional mafic magmatism with an age of 1880–1840 Ma is developed in all basement salients of the south of the craton and records the final stage of its structural formation. The dolerite dykes with an age of about 1750 Ma were discovered within the Baikal salient of the basement and belong to the Timpton Large Igneous Province. Rifting-related dolerite dykes with an age of 1640–1615 Ma are described in the Biryusa block. In the south of the craton, rare Mesoproterozoic dolerites with ages 1350–1338, 1260, and about 1000 Ma formed in an intraplate extension setting were found. The “Franklinˮ ages (about 720 Ma) were obtained for dolerites from dyke swarms of the Sayan–Baikal dyke belt, marking the early stages of rifting that led to the breakup of the Rodinia supercontinent. A dozen of new ages (from 640 to 615 Ma) has been reported for alkaline–ultramafic and mafic rocks, which were intruded at the final stages of the Late Precambrian extension event within the southern margin of the Siberian craton. The obvious progress in the study of Precambrian mafic magmatism in the south of the Siberian craton has been achieved in recent years. Based on the larger number and the better quality of isotope dates, the main events of the emplacement of Proterozoic mafic dykes were recognized and geodynamic settings of their formation was proposed.