- 期刊
Phosphorus Sources and Enrichment Mechanism of the Cambrian Xinji Formation, Baofeng, Western Henan
摘要
Large phosphorus deposition periods in geological history are often accompanied by major events such as global climate change, changes in atmospheric oxygen levels, and biogenic eruptions. The Xinji Formation of the Cambrian at the North China Craton southern margin is an important phosphorus‐bearing formation in the north. In this paper, a typical phosphorus‐bearing section of the Xinji Formation middle part in Baofeng, west Henan, was selected for study. The phosphorus‐bearing section of the Xinji Formation was investigated using field section measurements, optical microscopy. The results show that the phosphorus nodules of the Xinji Formation are black in colour, vary in morphology and size, and their grain size varies from 0.2 cm to 2 cm, and they are distributed in fine sandstones along the facies; the main mineral of phosphorus nodules is colloidal phosphorite and some of them form oolitic colloidal phosphorite in the form of phosphatic shells of quartz grains. Deep‐sea phosphorus‐rich waters and small crustal organisms provide the material basis for phosphorus nodules in the Xinji Formation in the study areawhere colloidal phosphorites were deposited with quartz and other minerals in the early stages of deposition, and oolitic colloidal phosphorites were formed in the pores of the rocks in the early stages of diagenesis. The study of the phosphorus‐bearing stratigraphy of the Xinji Formation can provide richer evidence for the recovery of the early Cambrian paleoenvironment of the North China Craton southern margin.