Research on Relationship between Chemical Composition of Garnet and Metamorphicgrade in BIF Iron Ores of Qianan-Luan County Area, East Hebei, China

摘要

Garnet is one of the common metamorphic minerals in sedimento-metamorphic iron ores of East Hebei Area. The rock samples containing garnet were collected from representative iron ores of Qianan-Luan area. According to electron microprobe analysis (EMPA) of garnets, Sima area belongs to amphibolite facies, Xingshan-Huangbaiyu belt belongs to amphibolite-granulite facies and Shuichang-Dashihe belt belongs to granulite facies, which is consistent with previous researcher's conclusion of metamorphic facies through analyzing paragenetic assemblage of primary minerals of Qianan-Luan County Area; meanwhile end member components of garnet in sedimento-metamorphic iron ores of Qianan-Luan County Area regularly changes with the degree of metamorphism: almandite and grossularite in Sima area→almandite in Xingshan-Huangbaiyu belt→almandite and pyrope in Shuichang-Dashihe belt.