Identification and origins of iron sulfides in Czech Loess

• Published in: Geophysical research letters Vol. 28; no. 20; pp. 3903 - 3906
• Main Authors: Shi, C. D., Zhu, R. X., Suchy, V., Zeman, A., Guo, B., Pan, Y. X.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 15.10.2001; American Geophysical Union
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Marine and continental quaternary; Mineralogy; Non silicates; Surficial geology; Central Europe; Czech Republic; oxides; fine-grained materials; loess; X-ray diffraction; SEM data; pseudomorphism; pyrite; identification; provenance; Cenozoic; terrigenous materials; particles; loam; sulfides; electron probe data; scanning electron microscopy; iron sulfides; Quaternary; Europe; iron oxides; pyrrhotite; glaciofluvial sedimentation; chemical analysis; framboidal texture; eluvium; upper Pleistocene; magnetic properties; magnetic susceptibility; Phanerozoic; Pleistocene
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2001GL013108

Multiple rock‐magnetic and non‐magnetic techniques were employed to identify iron sulfides in late Pleistocene Czech loess deposits. The results indicate that iron sulfides in the loess at Znojmo section are mainly pyrrhotite and pyrite, with stoichiometry ranging from Fe10S11 to FeS2. Although early pedogenic origin of fine sulfide fraction can not be ruled out, scanning electron microscopy (SEM) of individual grains and microscopic observations of magnetic extracts show that iron sulfide grains are probably of detrital origin. Potential sources of these sulfides may have been eluvium loams above hypothetical ore deposits in the vicinity of the section or glacifluvial sediments from nearby glacial margins. Framboidal pyrite forms, now completely replaced by iron oxides, suggest that some particles of biogenic sulfides may have also been transported into loess from presumably fluvial sediments.