Recurrent magmatic activity on a lithosphere-scale structure: Crystallization and deformation in kimberlitic zircons

• Published in: Gondwana research 2017-02, Vol.42, p.126-132
• Main Authors: Tretiakova, Irina G., Belousova, Elena A., Malkovets, Vladimir G., Griffin, William L., Piazolo, Sandra, Pearson, Norman J., O'Reilly, Suzanne Y., Nishido, Hirotsugu
• Format: Article
• Language: English
• Subjects: Hf-isotopes; Lithospheric mantle; Siberian Craton; U-Pb dating; Yakutian kimberlite province
• ISSN: 1342-937X; 1878-0571
• DOI: 10.1016/j.gr.2016.10.006

Kimberlites are not only the most economically important source of diamonds; they also carry unique information encapsulated in rock fragments entrained as the magma traverses the whole thickness of the lithosphere. The Nurbinskaya pipe in the Siberian kimberlite province (Russia) is one of several intruded along the Vilyui Rift, a major terrane boundary. The pipe contains three populations of mantle-derived zircon xenocrysts: Archean (mean age 2709±9Ma), Devonian (mean age 371±2.3Ma), and a subset of grains with evidence of brittle deformation and rehealing, and a range of ages between 370 and 450Ma. The Hf-isotope, O-isotope and trace-element signatures of the last group provide a link between the Archean and Devonian events, indicating at least three episodes of magmatic activity and zircon crystallization in the lithosphere beneath the pipe. The emplacement of the Nurbinskaya pipe ca 370Ma ago was only the youngest activity in a magma plumbing system that has been periodically reactivated over at least 2.7 billion years, controlled by the lithosphere-scale structure of the Vilyui Rift. Mosaic zircons from the Nurbinskaya pipe as the link between Archean and Devonian populations of mantle-derived zircons [Display omitted] •Archean and Devonian zircons are presented in kimberlite of the Nurbinskaya pipe.•Found zircons with mosaic-like internal structure are the evidence of deformation.•Mosaic zircons show difference in age within the grain, dating the deformation.•Older zircon population and mosaic grains are crystallized from the same protolith.•Recurrent activity in mantle formed various in age zircons and caused deformation.