Pyrite Formation in Organic-rich Clay, Calcitic and Coal-Forming Environments |
| |
Authors: | Gordana DEVIC Petar PFENDT Branimir JOVANCICEVIC Zoran POPOVIC |
| |
Affiliation: | Gordana DEVI(C),Petar PFENDT,Branimir JOVAN(C)I(C)EVI(C),Zoran POPOVIC |
| |
Abstract: | The early diagenetic characteristics of pyrite formation processes in a Miocene freshwater sequence of mixed sediments (coal fragments in clays, sandstones or shales) alternating with continuous brown coal layers was investigated. Based on abundant minerals, the following main sedimentary environments were distinguished: the illite-montmorillonitic (I-M), calcitic (Ct) and coal-forming environment (CL). For these hydrogeochemically differing environments the effects of limiting factors on the pyrite formation process (availability of sulphate and Fe, amount of organic matter and participation of organic sulphur) were assessed by correlation analysis. Significant differences in the effects of these limiting factors in the particular environments were observed. These differences were explained taking in account the different oxidative activity, Fe-complex and surface complex forming properties of humic substances in dependence of pH of environment and the abundance of sorptionally active clay minerals. In environments having a relatively low pH and containing clay minerals (I-M-and CL-environments) the oxidative activity of humic substances (Hs) on pyrite precursors was greatly prevented however pyrite formation depended on reactive Fe availability as the consequence of complex formation. On the contrary, in environments with a relatively high pH, as it was the calcitic, the oxidative activity of Hs was greatly enhanced, thus oxidizing the sulfur precursors of pyrite. The oxidation degree of organic matter was probably also a consequence of the differing activity of the humic electron-acceptors. |
| |
Keywords: | early diagenesis pyrite formation humic electron-acceptors calcitic environment illitemontmorillonitic environment coal mixed sediments |
本文献已被 CNKI 维普 万方数据 等数据库收录! |
| 点击此处可从《《地质学报》英文版》浏览原始摘要信息 |
|
点击此处可从《《地质学报》英文版》下载全文 |
|