Dating errors in high-resolution stratigraphy: a detailed X-ray radiograph and AMS-14C study of Zoophycos burrows
✍ Scribed by Ludvig Löwemark; Friedrich Werner
- Book ID
- 104156983
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 385 KB
- Volume
- 177
- Category
- Article
- ISSN
- 0025-3227
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✦ Synopsis
Bioturbation in oxic deep-sea settings is often considered (if considered at all) to consist of a 2±10 cm thick homogenized layer and some easily recognizable distinct burrows which could be avoided when sub-sampling the sediment cores. However, there is one trace that is often dif®cult to discern in unlithi®ed sediments, that manifests transport of considerable amounts of sediment over large vertical distances, and that is widely spread in deep-sea sediments in all oceans. This trace, Zoophycos, is therefore predestined to cause errors and even age reversals in high-resolution dating. In order to better estimate the size of these age errors, we have performed AMS-14 C dating of the trace itself and of directly surrounding material in two gravity cores from the Portuguese continental slope. The results show an age falsi®cation of 1110±2525 years at sedimentation rates of 10± 20 cm ka 21 . Since Zoophycos burrows are often poorly or not at all visible in fresh cores, all observations of Zoophycos were made on X-ray radiographs. To avoid dating errors of this kind, an X-ray radiograph study prior to sub-sampling is strongly recommended.