Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4734986 | Proceedings of the Geologists' Association | 2016 | 17 Pages |
Abstract
In this paper the stratigraphy and biostratigraphy of the Bathonian-Callovian rocks of the Murcia Region, based on high-resolution sampling yielding good ammonite dating, is reported. All the ammonites analysed are from four sections located on a pelagic swell (External Subbetic palaeogeographic domain) of the External Zones of the Betic Cordillera, Murcia Region, southern Spain. These represent characteristic Bathonian-Callovian sections of the Subbetic epipelagic swells in the Betic Cordillera. The lithology consists mainly of both nodular limestones and marly limestones. Discontinuities with hiatuses of variable duration, submarine hardgrounds, Fe-Mn macrooncoids, limonite crusts, neptunian dykes, etc., occur in the Middle Bathonian-Callovian interval. Extreme condensation episodes are common, but abundant ammonite faunal records have enabled a consistent and accurate chronostratigraphy. The Parkinsoni Zone, Daubenyi and Dimorphus subzones (uppermost Bajocian), the Zigzag and Aurigerus zones (Lower Bathonian), the Sofanus and Costatus zones (Middle Bathonian), the Orbis Zone (Upper Bathonian), and the Bullatus and Gracilis Zones (Lower Callovian) are recognised and characterised. The ammonite fauna shows a typical Mediterranean character. Phylloceratina and Lytoceratina are the predominant elements within the ammonite fauna, but Lytoceratina is dominant in the Lower Bathonian whereas Phylloceratina predominates in the rest of the Bathonian and in the Callovian. Other ammonites, such as Oppeliidae, Lissoceratidae, Stephanoceratidae, Perisphinctidae, Tulitidae, and Reineckeiidae, are also common throughout the uppermost Bajocian to Lower Callovian interval. Strigoceratidae are present, but scarce.
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Authors
J. Sandoval,