Cyclostratigraphy and Chronology of the Albian Stage (Piobbico Core, Italy)
Published:January 01, 2004
Allesandro Grippo, Alfred G. Fischer, Linda A. Hinnov, Timothy D. Herbert, Isabella Premoli Silva, 2004. "Cyclostratigraphy and Chronology of the Albian Stage (Piobbico Core, Italy)", Cyclostratigraphy: Approaches and Case Histories, Bruno D’Argenio, Alfred G. Fischer, Isabella Premoli Silva, Helmut Weissert, Vittoria Ferreri
Download citation file:
The mid-Cretaceous (Albian) deep-water sediments (coccolith-globigerinacean marls) of the Umbria-Marche Apennines show complex rhythmic bedding. We integrated earlier work with a time-series study of a digitized and image-processed photographic log of the Piobbico core. A drab facies is viewed as recording normal stratified conditions, and a red facies as the product of downwelling warm saline (halothermal) waters. Both are pervaded by orbital (Milankovitch) rhythms. These reflect fluctuations in the composition and abundance of the calcareous plankton in the upper waters. The drab facies is overprinted by redox oscillations on the bottom, including episodic precessional anaerobic pulses (PAPs). Contrasts between the individual beds representing the alternate phases of the precessional rhythm rose and fell with orbital eccentricity, in the classical pattern of Berger’s climatic precession or precession index curve, varyingly complicated by the obliquity rhythm. We conclude that greenhouse oceans in general, and perhaps this area in particular, were very sensitive to orbital forcing. Our count of 29 406-ky eccentricity cycles yields an Albian duration of 11.8 ± 0.4 My.
Figures & Tables
Cyclostratigraphy: Approaches and Case Histories
This volume is derived from an SEPM international workshop entitled Multidisciplinary Approach to Cyclostratigraphy, organized by the editors in May 2001 and held in Sorrento (Naples, Italy). In the Introduction we offer a brief history of how concepts of orbital cyclicity and its effects on the Earth evolved, an appraisal of the present state of research, and an overview of the papers in this volume. The main body of the volume consists of the contributed studies. These include a paper on conceptual and pragmatic approaches to stratification cycles by one of the pioneers of cyclostratigraphy, Walther Schwarzacher, who, in the 1940s, discovered the hierarchical expression of orbital cycles in rocks. The other contributions are specific studies of cyclic sequences, extending from the Quaternary back to the Triassic, covering the range from continental deposits to the deep sea, and employing a wide variety of techniques for extracting and processing the information.