Petrogenesis of the Huili Paleoproterozoic leucogranite in the Jiaobei Terrane of the North China Craton: A highly fractionated albite granite forced by K-feldspar fractionation

All samples have consistent εNd values (t = 1.86 Ga) of − 4.0 to − 6.2 with two-stage Nd model ages (TDM2) of 2.67 to 2.85 Ga. It is concluded that the 1.86 Ga Huili leucogranite is highly fractionated, derived from ancient crustal material extracted from the depleted mantle at 2.7-2.8 Ga, and experienced significant fractionation of K-feldspar in association with biotite and monazite fractionation during the magmatic evolution. Group III leucogranite is albite granite with albite phenocrysts, whereas groups I & II are K-feldspar granites with K-feldspar phenocrysts. It is here argued that the Huili albite granite (group III leucogranite) is derived from a highly differentiated residual melt separated from the K-rich magma represented by groups I and II leucogranite due to Kf fractionation during magma evolution.