Research-paper
Stable isotope data (delta13C, delta18O) from the Middle and Upper Turonian (Upper Cretaceous) of Liencres (Cantabria, northern Spain) with a comparison to northern Germany (Söhlde & Salzgitter-Salder)
Wiese, Frank
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Abstract (German)
Zusammenfassung. Vom Küstenaufschluß Playa Portio nahe Liencres (Nordkantabrisches Becken, Spanien) werden die stabilen Isotopenkurven (Kohlenstoff, Sauerstoff) für den Zeitraum Mittel-Turon bis Unter-Coniac präsentiert und mit den Kurven von Salzgitter-Salder und Söhlde (Niedersachsen, N-Deutschland) sowie teilweise mit den Daten von Dover (Kent, England) verglichen. Die Brauchbarkeit einiger Bioevents für eine überregionale Korrelation wurde auf Grundlage der delta13C-Kurve geprüft. Es zeigt sich, daß, entgegen früheren Interpretationen, das Inoceramus costellatus/Sternotaxis plana Event (unteres Ober-Turon) und die Didymotis Events des oberen Ober-Turon nicht vorbehaltslos zur beckenübergreifenden Korrelation genutzt werden können. Das Einsetzen des oberturonen Index-Ammoniten Subprionocyclus neptuni fällt in England und Nordspanien etwa in das gleiche stratigraphische Intervall. In Norddeutschland setzt die Art offen- ...
Abstract
Stable isotope curves (carbon, oxygen) of Middle Turonian to Lower Coniacian strata of the Playa Portio section at Liencres (North Cantabrian Basin, Spain) were compared to those of Salzgitter-Salder and Söhlde (Lower Saxony Basin, northern Germany), and, to some extent, to those of Dover (Anglo-Paris Basin, southern England). Based on the delta18C data, the interbasinal correlation potential of several bio-events was investigated. It can be shown that the Inoceramus costellatus/Sternotaxis plana Event (Middle/Late Turonian boundary interval) of northern Germany does not equate with the Romaniceras deverianum Event of northern Spain, contrary to previous interpretations. This is also true for the proposed interbasinal correlation of the Didymotis I & II events between Germany and Spain; these events cannot be used for long-range correlation. The FAD of the early Late Turonian index-ammonite Subprionocyclus neptuni is isochronous in England and northern Spain. In northern Germany, it appears to enter later. The FAD of 'modern' Micraster and Mytiloides scupini is virtually isochronous in Germany and Spain. The Late Turonian acmeoccurrence of distinct echinoid faunas, the Micraster Event of northern Germany and the Sternotaxis plana Event of northern Spain, are more or less isochronous and associated with a maximum flooding interval. The delta18O curve shows two excursion towards more positive values in the Upper Turonian, thus suggesting progressive cooling. This interpretation is confirmed by a southward shift of Boreal faunas into the North Cantabrian Basin.