Sheared peridotite xenolith from the V. Grib kimberlite pipe, Arkhangelsk Diamond Province, Russia: Texture, composition, and origin

Geoscience Frontiers

Vladimir Anatolievich Pervov¹  Lyudmila Vyacheslavovna Sazonova²  Anna Andreevna Nosova²  Alexey Vladimirovich Kargin²  Elena Vladimirovna Minevrina²  Zhanna Petrovna Burmii³  Vladimir Anatolievich Khvostikov³ 

[1] Departamento de Geologia, Sociedade Mineira de Catoca, Repblica de Angola, Lunda Sul, Catoca;Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences (IGEM RAS), Moscow, Russia;Institute of Technological Problems of Microelectronics and Ultrapure Materials, Russian Academy of Sciences, Chernogolovka, Russia;

关键词: Sheared peridotite;    Mantle metasomatism;    Kimberlite;    Olivine;    Garnet;    Clinopyroxene;   

DOI  :  10.1016/j.gsf.2016.03.001

来源: DOAJ

【 摘 要 】

The petrography and mineral composition of a mantle-derived garnet peridotite xenolith from the V. Grib kimberlite pipe (Arkhangelsk Diamond Province, Russia) was studied. Based on petrographic characteristics, the peridotite xenolith reflects a sheared peridotite. The sheared peridotite experienced a complex evolution with formation of three main mineral assemblages: (1) a relict harzburgite assemblage consist of olivine and orthopyroxene porphyroclasts and cores of garnet grains (Gar1) with sinusoidal rare earth elements (REE) chondrite C1 normalized patterns; (2) a neoblastic olivine and orthopyroxene assemblage; (3) the last assemblage associated with the formation of clinopyroxene and garnet marginal zones (Gar2). Major and trace element compositions of olivine, orthopyroxene, clinopyroxene and garnet indicate that both the neoblast and clinopyroxene-Gar2 mineral assemblages were in equilibrium with a high Fe-Ti carbonate-silicate metasomatic agent. The nature of the metasomatic agent was estimated based on high field strength elements (HFSE) composition of olivine neoblasts, the garnet-clinopyroxene equilibrium condition and calculated by REE-composition of Gar2 and clinopyroxene. All these evidences indicate that the agent was a high temperature carbonate-silicate melt that is geochemically linked to the formation of the protokimberlite melt.

【 授权许可】

Unknown