Antarctic Sediment Drifts and Plio-Pleistocene Orbital Periodicities (ODP Sites 1095, 1096, and 1101)
Published:January 01, 2004
Marina Iorio, Thomas Wolf-Welling, Tobias Moerz, 2004. "Antarctic Sediment Drifts and Plio-Pleistocene Orbital Periodicities (ODP Sites 1095, 1096, and 1101)", Cyclostratigraphy: Approaches and Case Histories, Bruno D’Argenio, Alfred G. Fischer, Isabella Premoli Silva, Helmut Weissert, Vittoria Ferreri
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Petrophysical datasets and related spectral analysis from Plio-Pleistocene sediments cored on the Western Antarctic continental rise during the Ocean Drilling Program, Leg 178, are discussed. It is shown that in different cores, nonharmonic wavelength peaks, when normalized, exhibit a very high correlation factor with predicted Earth’s orbital variations. It is also found that both short (~ 95–125 ky)and long (~ 400 ky) eccentricity periodicities emerge clearly from the signal during the whole Pleistocene, without an evident switch to obliquity at mid-Pleistocene (~ 0.9 Ma), as reported in the literature. This suggests that the lithological parameters, a proxy for glacial cycles, are controlled, directly or indirectly, by astronomically forced processes (Milankovitch cycles). Moreover, the good correlatability among distant coring sites, based on systematic sedimentological variations at intervals of about 140 and 370 ky, allows extension of the results to regional scale.
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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.