Zircon U-Pb Chronology, Geochemistry and Tectonic Significance of Neoarchean High-Mg Andesites and Magnesian Diorites in Qinglong-Shuangshanzi Area, Eastern Hebei
Chang Qingsong
Wang Huichu
Rong Guilin
Chu Hang
Zhang Jian
Abstract：Eastern Hebei Province is located in the northern margin of the North China Craton, but magmatic genesis and tectonic setting of Neoarchean igneous rocks in the area still remain controversial.Systematic geochronologic and geochemical study of Neoarchean supracrustal and intrusive rocks in Qinglong-Shuangshanzi area, eastern Hebei are presented in this paper.Zircon LA-MC-ICP-MS U-Pb isotopic dating reveals that the meta-andesite erupted at 2 576Ma, and the intrusive rocks (gabbro-diorites, tonalites and quartz diorites) emplaced in a range of 2 484Ma to 2 535Ma.Part of the early-formed meta-andesites shows high-Mg andesite geochemical characteristics, which indicates these rocks were generated from partial melting of mantle wedge peridotite metasomatised by fluids from dehydration of the subducted slab.The magnesian diorites show adakite characteristics, which suggests they have source characteristics of partial melting of mantle wedge peridotite metasomatised by felsic melts of the subducted slab.Both of the high-Mg meta-andesites and adakite like magnesian diorites belong to a suite of island arc assemblages.Combining previous regional studies, it is concluded that Qinglong-Shuangshanzi area was under a tectonic setting of active continental margin during Neoarchean era.
Keywords：eastern Hebeihigh-Mg andesitesadakite like rocksmagnesian dioriteszircon U-Pb chronologygeochemistry
Publication Date：2019-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：14( 23-36 )