Origin of sanukitoid and hornblendite enclaves in the Dajitu pluton from the Yinshan Block, North China Craton: product of Neoarchaean ridge subduction?
Date
2014
Authors
Ma, X.
Fan, H.
Santosh, M.
Liu, X.
Guo, J.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
International Geology Review, 2014; 56(10):1197-1212
Statement of Responsibility
Xudong Ma, Hong-Rui Fan, M. Santosh, Xuan Liu and Jing-Hui Guo
Conference Name
Abstract
A Neoarchaean sanukitoid pluton that was intruded into the base of the Guyang greenstone belt in the Yinshan Block of the North China Craton hosts a number of hornblendite enclaves. Geochemically, the pluton is characterized by high MgO, Mg#, Cr, Ni, large-ion lithophile element (LILE), and heavy rare earth element (HREE) contents and low TiO₂ and high-field strength element (HFSE) contents, and has relatively low Sr/Y ratios and negative Eu anomalies. Whole-rock Sr–Nd isotopic analyses indicate that it has εNd(t) values of +1.4 to +2.0. These geochemical and isotopic characteristic suggest that the sanukitoid was formed under a low-pressure and high-temperature environment by slab melting and assimilation of hornblendite enclaves. The hornblendite enclaves show high MgO, Mg#, Cr, and Ni contents, high and variable K₂O, LREE, and Th contents, enrichment in LILEs and LREEs, and depletion in HFSEs. They have high Y contents and relatively low Sr/Y values, strongly negative Eu anomalies, and whole-rock εNd(t) values of +1.0 to +1.9. The geochemical and isotopic characteristics indicate that these enclaves might have been derived from a mixed source of an enriched mantle, metasomatized by melts expelled from subducted sediments in a high-temperature, low-pressure environment. To explain these characteristics, a ridge subduction model is proposed for the formation of the sanukitoid and hornblendite in the Yinshan Block in the Neoarchaean.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© 2014 Taylor & Francis