An indicator of water-column anoxia: Resolution of biofacies variations inthe Kimmeridge Clay (Upper Jurassic, UK)

Authors
Raiswell, R Newton, R Wignall, PB
Citation
R. Raiswell et al., An indicator of water-column anoxia: Resolution of biofacies variations inthe Kimmeridge Clay (Upper Jurassic, UK), J SED RES, 71(2), 2001, pp. 286-294
Citations number
58
Categorie Soggetti
Earth Sciences
Journal title
JOURNAL OF SEDIMENTARY RESEARCH
ISSN journal
15271404 → ACNP
Volume
71
Issue
2
Year of publication
2001
Part
B
Pages
286 - 294
Database
ISI
SICI code
1527-1404(200103)71:2<286:AIOWAR>2.0.ZU;2-Y
Abstract
An Indicator of Anoxicity (IA), defined as the ratio (Pyrite Fe + Oxide Fe) /Total Fe, can be used to recognize sediments deposited under an anoxic wat er column. Modern marine sediments deposited under oxygenated bottom waters mainly have IA values < 0.4 whereas sediments deposited under anoxic, iron -rich or sulfidic bottom waters mainly have IA > 0.5. IA values in the cent ral Kimmeridge Clay (Upper Jurassic, UK) for fissile, organic-rich shales i ndicate that deposition occurred principally from anoxic bottom waters with infrequent oxygenation events.