Pyrite formation in organic-rich clay, calcitic and coal-forming environments
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 / illite-montmorillonitic environment / coal / mixed sedimentsSource:
Acta Geologica Sinica. English Edition, 2006, 80, 4, 574-588Publisher:
- Geological Soc China, Beijing
Collections
Institution/Community
Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Dević, Gordana N. AU - Pfendt, Petar A. AU - Jovančićević, Branimir AU - Popović, Zoran PY - 2006 UR - https://cherry.chem.bg.ac.rs/handle/123456789/800 AB - 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. PB - Geological Soc China, Beijing T2 - Acta Geologica Sinica. English Edition T1 - Pyrite formation in organic-rich clay, calcitic and coal-forming environments VL - 80 IS - 4 SP - 574 EP - 588 UR - https://hdl.handle.net/21.15107/rcub_cherry_800 ER -
@article{ author = "Dević, Gordana N. and Pfendt, Petar A. and Jovančićević, Branimir and Popović, Zoran", year = "2006", 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.", publisher = "Geological Soc China, Beijing", journal = "Acta Geologica Sinica. English Edition", title = "Pyrite formation in organic-rich clay, calcitic and coal-forming environments", volume = "80", number = "4", pages = "574-588", url = "https://hdl.handle.net/21.15107/rcub_cherry_800" }
Dević, G. N., Pfendt, P. A., Jovančićević, B.,& Popović, Z.. (2006). Pyrite formation in organic-rich clay, calcitic and coal-forming environments. in Acta Geologica Sinica. English Edition Geological Soc China, Beijing., 80(4), 574-588. https://hdl.handle.net/21.15107/rcub_cherry_800
Dević GN, Pfendt PA, Jovančićević B, Popović Z. Pyrite formation in organic-rich clay, calcitic and coal-forming environments. in Acta Geologica Sinica. English Edition. 2006;80(4):574-588. https://hdl.handle.net/21.15107/rcub_cherry_800 .
Dević, Gordana N., Pfendt, Petar A., Jovančićević, Branimir, Popović, Zoran, "Pyrite formation in organic-rich clay, calcitic and coal-forming environments" in Acta Geologica Sinica. English Edition, 80, no. 4 (2006):574-588, https://hdl.handle.net/21.15107/rcub_cherry_800 .