The role of organic matter in the formation of siderite from Xuanlong Area, Hebei Province

Based on the analysis of siderite distribution, occurrence, chemical composition, structural characteristics, carbon-oxygen isotopic characteristics and relationship between siderite and hematite, this paper presents a systematic study of siderite in the region studied, suggesting that the siderite in the Xuanlong area genetically resulted from organically reduced primary hematite during the diagenesis. The ferric and ferrous relations directly depend on organic contents. In the presence of organic matter ferrous iron can be converted to ferric iron through or ganic reduction. The above conclusion has also been proved by organic geochemistry data.