CONTRASTING ARCHAEAN GRANULITE FACIES ROCKS FROM EASTERN HEBEI, NORTH CHINA
冀东太古代高级变质地体中两类麻粒岩相深成片麻岩

In the eastern Hebei, North China, the Taipingzbai area is separated from Shuichang area by shear zone. Higher P-T conditions are recorded for Taipingzhai granulites, therefore two areas, representing different crustal levels, were in juxtaposition. The granulite facies orthogneisses from Taipingzhai and the charnockites from Shuichang have strikingly different chemistry. The Taipingzhai granulites are strongly depleted in heat-producing elements and other large ion lithophile elements, whereas, Shuichang charnockites are enriched in these elements. This is postulated to be due to the action of metamorphic fluids in the lower crust. Different models for source of fluids from both areas have been proposed. In Shuichang area, there is an intimite relationship between the production of granites and the charnockates. Differences in mineral and chemical composition between granites and charnockites are considered. It is suggested that such differences could result from partial melting processes occurred in metasedimentary gneisses.