Traces and related chemical changes in a Late Ordovician paleosol,Glossifungitesichnofacies, southern Appalachians, USA
| Autor: | J. Lincoln Foreman, Steven G. Driese |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Ichnos. 1:207-219 |
| ISSN: | 1563-5236 1042-0940 |
| DOI: | 10.1080/10420949109386353 |
| Popis: | Traces interpreted as Skolithos sp. in a Glossifungites ichnofacies occur in the upper part of the Beans Gap Claystone paleosol, in association with a Late Ordovician marine erosional surface. Paleosol color and whole‐rock chemistry are distinctly different in the vicinity of burrows, which are enveloped by olive gray mottles, 1 to 10 cm in diameter, in which total iron (measured as Fe2O3) is 30% lower than in grayish red, “unaltered”; claystone. Post‐pedogenic bioturbation increased permeability locally and permitted the introduction of marine fluids and coarser sediment into the top of the paleosol. Anaerobic microbial decay of organic matter in the burrows and surrounding claystone permitted reduction (and mobilization) of formerly oxidized iron, which then combined with marine‐derived sulfate to form pyrite, both within burrows and along oxidation‐reduction fronts in the claystone proximal to burrows. Pyrite was later converted to hematite as a result of outcrop‐related oxidation by meteoric water. Pa... |
| Databáze: | OpenAIRE |
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