STRUCTURAL AND COMPOSITIONAL CHARACTERISTICS OF IMPACTITES OF THE COPTOMICT FACIES OF THE KARA ASTROBLEME RIM
N.I. Maksimenko, T.G. Shumilova
Institute of Geology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
Keywords: Suevite, impactite, impact facies, shock metamorphism, impactite genesis, Kara astrobleme
Abstract
The impact facies are subdivided into coptogenic (primarily deposited) and coptomict (redeposited) units. The redeposited impact facies have been poorly studied. In this work, the deposits of the coptomict facies are characterized in detail for the first time by the example of the Kara astrobleme. The structures and textures of impactites are examined at the macrolevel, and the structural and compositional specifics of the components (lithoclasts, vitroclasts, and matrix) of lapilli and agglomerate suevites of the Sayakha River area have been described at the microlevel. The reconstruction of the past events has shown that the clastic impactites of the northwestern rim of the Kara astrobleme formed under conditions of landslide from the crater lip at the stage of the early modification of the astrobleme. The results obtained can be used to construct a model for the formation of the Kara impact structure and to improve the unified model for the formation of clastic impactites of the coptomict facies in a large meteorite crater.
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