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Geochemistry and chronology of a diorite pluton in the Yinshan Block, implications for crustal growth and evolution of North China Craton
Author(s) -
Ma Xudong,
Zhong Yan
Publication year - 2018
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3124
Subject(s) - diorite , pluton , zircon , geology , geochemistry , craton , petrology , partial melting , protolith , geochronology , subduction , adakite , crust , oceanic crust , tectonics , paleontology
The Yinshan Block constitutes the northwestern segment of the North China Craton. We characterized the geochemistry, zircon U–Pb geochronology, and Hf isotopic composition of a diorite pluton in the Yinshan Block. The zircon U–Pb data yield a protolith formation age of 2535 ± 8 Ma (MSWD = 0.46), followed by recrystallization at 2465 ± 14 Ma or 2431 ± 30 Ma; the granite vein which intruded into the diorite pluton gives a formation age of 2453 ± 5 Ma (MSWD = 1.6), according with the recrystallization age of the diorite. These diorites are characterized by moderate Mg# value and MgO, Cr, and Ni content and have relatively low Sr/Y and (La/Yb) N ratios and slightly Eu anomalies and are enriched in LILEs and depletion in high field strength elements. High‐Sr + Ba granites with low K 2 O/Na 2 O characteristics are also shown by these diorites, and the εHf(t) of zircons lie between +1.3 and −7.2, imply these diorites are most likely derived from partial melting of a thickened lower crust with minor involvement of enriched mantle. These geochemical and isotopic characteristics suggest the diorite magmas derived from an accreted arc‐related rocks remelting in a low‐pressure environment along the continent margin. Hereby, we propose a supplement to the model of crustal growth and evolution in the Yinshan Block, involving subduction and collision in the Neoarchean.