REE Geochemistry of Some Metamorphic Rock Types of the Late Archean Fuping Group and Their Anatectic Derivatives in Pingshan,Hebei Province,China─A Preliminary Study

The Late Archean Fuping Group of the Xiaojiao area in Pingshan County, HebeiProvince consists mainly of three metamorphic rock types of supracrustal affinity, i. e., K-feldspar leucoleptite, biotite leptite-gneiss and hornblendic rocks. Their anatectic derivativesformed in the initial stage of anatexis are petrochemically of K-feldspar granitic, trondhjemiticand granodioritic compositions respectively, and in general have inherited the main petrochemi-cal features from their parent rock types. Probably due to the fact that they contain less REE-rich accessory minerals as compared with their parent rocks, the anatectic derivatives are ingeneral lower in ∑REE content. But both the derivatives and their parent rocks have similarREE patterns, which serves as an additional indication of the genetic relationship betweenthem.