The results of petrological-geochemical and isotope-geochemical studies of the Late Pleistocene-Holocene lavas of the Kazbek neovolcanic center, one of the largest centers of youngest magmatism in the Greater Caucasus, are presented. It has been established that the volcanic rocks of the Kazbek center form a continuous compositional series basaltic (trachy-)andesites–(trachy-)andesites–dacites with a predominance of calc-alkaline intermediate and moderately-acid lavas. The obtained results indicate that fractional crystallization and mixing of melts had a leading role in the petrogenesis of the rocks. The crustal assimilation was of limited importance; its influence is noticeable only in the rocks of the earliest and late pulses of magmatic activity within the Kazbek center. The common crustal lithologies participating in the assimilation were metamorphosed Jurassic sediments (mainly shales and sandstones) forming the base of the Kazbek center and rarely Mesozoic mafic metamorphosed volcanites. The specific features of AFC processes during the development of the studied magmatic system (including the presence of noticeable amount of water in the melt, the leading role of Amp in the cumulus and the absence of Pl fractionation) led to the appearance of dacitic lavas with geochemical signs of adakites as an evolutional end-member. The volcanic rocks of the Kazbek center are derived from trachybasalt magmas, the source of which was presented by the mantle reservoir of OIB-type. Recent and previously published results of studies of the Neogene-Quaternary magmatism manifested within the Greater Caucasus show that the main petrological and geochemical characteristics of this regional mantle reservoir remained constant from the end of the Miocene to the present time.

中文翻译：

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卡兹别克新火山中心（高加索地区）的熔岩的岩石地球化学特征，岩浆融解的来源和演化

介绍了大高加索地区最大的年轻岩浆活动中心之一的卡兹别克新火山中心晚更新世-全新世熔岩的岩石地球化学和同位素地球化学研究的结果。已经确定，卡兹别克中心的火山岩形成了一个连续的组成系列玄武质（钙长岩）-安山岩-（trachy-）安山岩-钙钛矿，其中以钙碱性中度和中度酸性的熔岩为主。所得结果表明，部分结晶和熔体混合在岩石成岩中起着主导作用。地壳同化的重要性有限；它的影响仅在卡兹别克中心内岩浆活动的最早和晚期脉冲的岩石中才明显。参与同化作用的常见地壳岩性是形成卡兹别克中心基底的侏罗纪变质沉积物（主要是页岩和砂岩），很少有中生代镁铁质变质火山岩。研究的岩浆系统发展过程中AFC过程的特殊特征（包括熔体中存在大量水，积云中的安培和P1分离的缺失导致出现了具有熔岩的地球化学迹象的达卡特熔岩的出现，作为演化的最终成员。卡兹别克中心的火山岩是从玄武岩岩浆中提取的，其来源是由OIB型地幔储层提供的。大高加索地区新近纪-第四纪岩浆作用研究的最新和先前发表的结果表明，该区域地幔储层的主要岩石学和地球化学特征从中新世末期到目前一直保持不变。