Age of zircons from chromites in the residual ophiolitic rocks as a reflection of upper mantle magmatic events
Age of zircons from chromites in the residual ophiolitic rocks as a reflection of upper mantle magmatic events
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残余蛇绿岩中铬铁矿的锆石年龄反映了上地幔岩浆事件
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
N. Berezhnaya
中科院分区：
文献类型：
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作者：
G. Savelieva;P. V. Suslov;A. Larionov;N. Berezhnaya
地幔残留物中新矿物组合（如锆石、橄榄石、铬尖晶石和单斜辉石）的形成很可能与地幔熔体注入有关。本文报道了铬铁矿矿床的锆石U-Pb定年结果，并试图推断Voikar-Syninsky蛇绿岩带残留地幔超镁铁质岩中岩浆事件的时间。乌拉尔蛇绿岩杂岩形成于中生代大洋岩石圈动力学演化的三个阶段：早奥陶世在一个共同的古欧亚盆地南段的扩张;奥陶世在东欧大陆边缘的裂谷作用;早泥盆世在乌拉尔极地段明显表现的俯冲扩张[4，5]。与此同时，对极地乌拉尔地质结构的详细研究、蛇绿岩杂岩岩石的新同位素测年[6]以及岩石地球化学重建都证明了东欧板块边缘沿着存在一个古老的（前古生代）海洋岩石圈[7]。深成岩体和脉岩杂岩的同位素年龄测定
It is highly possible that processes related to the injection of melts through mantle are responsible for the formation of new mineral assemblages in mantle residues (for example, zircon, olivine, Cr-spinel, and clinopyroxene). The present paper reports the results of U‐Pb zircon dating on chromite deposits and attempts to infer the timing of magmatic events in residual mantle ultramafic rocks of the Voikar‐Syninsky ophiolite massif. Ophiolite complexes of the Urals were formed during three stages of the Phanerozoic geodynamic evolution of the oceanic lithosphere: Early Ordovician spreading in the southern segment of a common Paleouralian basin; Ordovician rifting of the East European continental margin; and suprasubduction spreading in Early Devonian time, which was distinctly expressed in the polar segment of the Urals [4, 5]. At the same time, detailed studies of the geological structure of the Polar Urals, new isotope datings on the rocks of ophiolite complexes [6], and palinspastic reconstructions testify to the existence of an ancient (pre-Paleozoic) oceanic lithosphere along the margin of the East European plate [7]. Isotope datings on plutonic and dike complexes of