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The Middle-Upper Jurassic oolitic ironstone level in the Iberian range (Spain). Eustatic implications.

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Aurell, Marcos and Fernández López, Sixto Rafael and Meléndez, Guillermo (1994) The Middle-Upper Jurassic oolitic ironstone level in the Iberian range (Spain). Eustatic implications. Geobios, 17 . pp. 549-561. ISSN 0016-6995

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Official URL: http://www.elsevier.com/journals/geobios/0016-6995



Abstract

The oolitic ironstone level occurring at the Callovian-Oxfordian boundary across wide areas in the central Iberian
Range (Eastern Spain) is interpreted here as formed on an extended, very shallow to temporarily emerged, uniform
carbonate platform. Main evidence to support this interpretation comes from both sedimentological analysis
of facies and taphonomic analysis of the ammonites. The sedimentological analysis gives support to the idea of
iron oolites being formed on, or in the surroundings of, emerged areas. On the other hand, the taphonomic analysis
shows that some inner moulds of ammonites from this level display evidence of taphonomic reworking, such as
the presence of ellipsoidal abrasion facets on the final part of the last preserved whorl, or annular abrasion
furrows carved on the external region. These features would have developed by the action of directional currents
under extremely shallow conditions. Bathymetric implications are relevant for the interpretation of the sea level
fluctuations at this stratigraphic interval: A relative lowstand of sea level is proposed for the Upper Callovian-Lower
Oxfordian interval in the studied area.


Item Type:Article
Uncontrolled Keywords:Facies analysis, Taphonomic analysis, Eustatic changes, Callovian-Oxfordian Boundary, Iberian range
Subjects:Sciences > Geology > Stratigraphic geology
ID Code:21472
Deposited On:22 May 2013 07:47
Last Modified:11 Dec 2018 08:43

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