Abstract

Alaid Volcano on Atlasov Island is the northernmost and highest volcano of the Kuril island arc. The first time lavas were discharged by the terminal eruption of 2015–2016 was in October 2018. The samples were studied by petromagnetic, petrogeochemical, and microprobe techniques. The chemical composition of the 2015–2016 ejecta is very similar to that of the 1933–1934, 1972, and 1981 eruptions, attesting to a common deep source of magmas. That source can be inferred to lie at a depth greater than 50 km, judging from their potassium–sodium products and from estimates of the P–T conditions that prevailed during the precipitation of rock-forming mineral phases from the melt. It was for the first time that data were obtained concerning the structure and composition of the magnetic fraction in the Alaid igneous rocks, and the depth was determined for the last equilibrium state of magma during the 2015–2016 eruption. A joint analysis of the petromagnetic and petrogeochemical characteristics of the Alaid trachybasalts studied here revealed significant correlative relationships between (a) concentrations of Ti and Cu and petromagnetic concentration characteristics, (b) alkali elements (Li, Rb, Cs) and rare-earth elements and coercive petromagnetic parameters.

中文翻译：

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2015-2016年千岛群岛阿拉德火山释放的火山岩的岩石磁和地球化学描述

摘要

Atlasov岛上的Alad火山是千岛群岛弧线中最北端和最高的火山。熔岩在2015-2016年的首次喷发中于2018年10月首次排出。样品采用了磁磁，岩石化学化学和微探针技术进行了研究。2015-2016年喷出物的化学成分与1933-1934年，1972年和1981年喷发的化学成分非常相似，证明了常见的深部岩浆来源。从其钾钠产品以及从熔体中析出成岩矿物相的过程中普遍存在的PT条件估计，可以推断出该源位于大于50 km的深度。这是首次获得有关阿拉木火成岩中磁性成分的结构和组成的数据，确定了2015-2016年喷发期间岩浆的最后平衡状态的深度。此处研究的阿拉法次玄武岩的岩石磁和岩石化学特征的联合分析显示（a）Ti和Cu的浓度与岩石磁浓度特征之间的显着相关关系，（b）碱性元素（Li，Rb，Cs）和稀土元素和矫顽的岩石磁参数。