Coring-related deformation of Leg 208 sediments from Walvis Ridge: Implications for paleomagnetic data
نویسنده
چکیده
Both shipboard and shore-based magnetic studies of Ocean Drilling Program (ODP) Leg 208 sediments produced poor-quality irectional data. A noisy inclination signal and a pervasive declination bias demonstrate that the sediments had been remagnetized nd/or deformed. In an attempt to characterize any deformation, we carried out anisotropy of magnetic susceptibility (AMS) experments on a suite of samples from Sites 1262 and 1267. Results show that the cores have suffered at least two kinds of deformation, ne producing a tilting of the foliation (by up to 40◦ from horizontal in some intervals), and the other producing a lineated fabric. he former is firmly linked to lithology – higher carbonate content results in a higher degree of tilting – while the latter may be more losely tied to depth, suggesting the two fabrics result from different processes. The remanence directions show no obvious correlaion to either fabric, suggesting that some third mechanism may have remagnetized the sediments, possibly an isothermal remanence cquired during the drilling process. In this study, the severity of the deformation may be linked to the high carbonate content of the ores, but pinpointing precise causes for both the AMS fabric and the directional anomalies remains elusive. It is clear, however, hat the deformation is complex, pervasive and has significant implications for the interpretation paleomagnetic data from Leg 208. 2007 Elsevier B.V. All rights reserved.
منابع مشابه
Leg 208 Preliminary Report
This report was prepared from shipboard files by scientists who participated in the cruise. The report was assembled under time constraints and does not contain all works and findings that will appear in the DISCLAIMER Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Scien...
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