Abstract:

We reported the major and trace element data of the granites from the Sulu orogenic belt. The granites are characterized by high SiO₂ contents varying from 71.3% to 74.5％, enrichment in alkali, potassium and LREE, but depletion in HREE, with negative Eu anomalies(δEu=0.51-0.61). In addition to these, the granites have high Ga/Al(×10⁴) ratios (2.85-3.41) , and Zr+Nb+Ce+Y contents (384-714)×10^-6. On primitive mantle-normalized spider diagrams, the granites show positive Rb,Th,K,La,Nd,Hf,Zr and Pb anomalies and negative Ba,Ta,P and Ti anomalies. This indicates that these granites are peraluminous, typical A-type granites. These A-type granites could be derived from partial melting of the enriched lithospheric mantle beneath the North China Craton (NCC). The magma underwent intense mineral fractional crystallization such as plagioclase, K-feldspar, biotite, and apatite, but no crustal contamination. The calculated zircon saturation temperatures (TZr) for A-type granites are between 876℃ and 961℃, representing the crystalline temperature of the magma.

Key words: A-type granites, elemental geochemistry, petrogenesis, lithospheric mantle, Sulu orogen belt