Geochronological and geochemical study of the high-grade orthogneissic rocks from the Northern Fuyun Complex: Implications for crustal architecture and Early-Middle Paleozoic evolution of the Chinese Altai

High-grade metamorphic complexes are critical for the understanding of regional crustal configuration and accretionary history of the Altai orogenic belt. The orthogneissic rocks from the Northern Fuyun Complex, southern Chinese Altai, are investigated in this study. Zircon UPb isotopic analysis yields ages of ca. 411–398 Ma, arguing against previous views that these rocks represent old Precambrian basement. All the samples are calc-alkaline,...