Geochemical characteristics of in situ elements in spherical fossils from Weng'an biota in Guizhou and their indications for phosphorization
There is a special kind of microfossil group produced in the upper phosphate ore section(b ore layer)of Edicaran Doushantuo Formation in Weng'an-Fuquan phosphate mining area of Guizhou,known as the Weng'an biota,which contains a large variety of abundant spherical fossils.However,previous studies have mostly focused on the spherical fossils themselves,lacking in-depth research on the relationship between spherical fossils and phosphorization.Therefore,this study employs optical microscopy,extended depth of field microscopy,scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),and laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)to investigate the distribution of in situ elements and the geochemical characteristics of major and trace elements.The results show that the spherical fossils of the Weng'an biota have undergone the formation of collophane and their high P2O5 content(30.13%～44.92%,average 43.17%)indicates the occurrence and widespread presence of phosphorization.The average V/Cr ratio,which is less than 2,the significant negative Ce anomaly,and the Ceanom,which is less than-0.1,indicate an oxidizing environment of phosphorization.The PAAS distribution pattern of rare earth elements exhibits a"hat-like"feature,reflecting that organisms were involved in and played an important role in the phosphorization.
Weng'an biotaspherical fossilsgeochemistry of in situ elementsphosphorizationEdiacaran System
万方数据
维普
