Progress of the researches on Kamchatka Arc magmatism

• Published in: Acta Petrologica Sinica
• Main Authors: Liu HaiYang, Xue YingYu, Sun WeiDong
• Format: Report
• Language: English
• Published: SCIENCE PRESS 2020
• Subjects: Subduction zone; Mantle melting; Melt/fluid metasomatism; Geochemistry; Kamchatka Arc; West Pacific; Geology; Kamchatka Peninsula; Pacific; Kamchatka
• Online Access: http://ir.qdio.ac.cn/handle/337002/167469; http://ir.qdio.ac.cn/handle/337002/167470; https://doi.org/10.18654/1000-0569/2020.02.14

The West Pacific contains most of the intraoceanic subduction zones, and is also the most abundant area of the trench- arc-basin system in the world. The Kamchatka Peninsula ( 51 degrees similar to 60 degrees N, 155 degrees similar to 164 degrees E) in Far East, Russia, located in the northwestern Pacific, and is the crucial portion of the Pacific Ring of fire. In order to elucidate the origin of the Kamchatka Arc magmatism, large amounts of researches have been carried out on the characteristics of mantle sources, melting process, magma fractionation and melt/fluid metasomatism of the mantle wedge. The latest researches demonstrated that : (1) variably depleted mantle sources exist below the Eastern Volcanic Front (EVF) and Central Kamchatka Depression (CKD) area of the Kamchatka Arc, while the mantle source below Sredinny Ridge (SR) region is significantly enriched compared to an Normal-Middle Ocean Ridge Basalt (N-MORB) source; (2) the degree of melting changes from 20% for EVF to 9% similar to 12% for CKD and SR, which may result from the fluid properties in the different regions; (3) polygenetic volcanoes (e. g. , Klyuchevskoy) show significant variations in geochemical compositions, which may reflect the difference of melting conditions and the process of magma fractionation; ( 4 ) major and trace elements as well as isotopes (e. g. , delta B-11) of arc lavas show systematic variations from the volcanic arc front to back-arc, which may result from the difference in flux and properties of slab-derived fluids; (5) the Northern Central Kamchatka Depression (NCKD) arc magmatism displays signatures of slab-derived melts, which is caused by superimposing hot mantle wedge and special plate configuration. This paper reviews the progress about the research on Kamchatka Arc magmatism, hoping to promote the understanding of the genesis of island arc magma.