Dating errors in high-resolution stratigraphy: a detailed X-ray radiograph and AMS- 14 C study of Zoophycos burrows
Dating errors in high-resolution stratigraphy: a detailed X-ray radiograph and AMS- 14 C study of Zoophycos burrows
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高分辨率地层学中的年代测定错误：Zoophycos 洞穴的详细 X 射线射线照片和 AMS-14 C 研究
DOI：
10.1016/s0025-3227(01)00167-0
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发表时间：
2001
期刊：
影响因子：
2.9
通讯作者：
F. Werner
中科院分区：
文献类型：
--
作者：
L. Löwemark;F. Werner
深海缺氧环境中的生物扰动通常被认为（如果考虑的话）由2-10cm厚的均质层和一些易于识别的不同洞穴组成，这些洞穴在沉积物岩心的亚采样时可以避免。然而，在未石化的沉积物中有一种通常难以辨别的痕迹，它表明大量沉积物在大的垂直距离上的移动，并且在所有海洋的深海沉积物中广泛存在。因此，这种动物藻的痕迹注定会在高分辨率测年中导致错误甚至年龄逆转。为了更好地估计这些年龄误差的大小，我们对来自葡萄牙大陆斜坡的两个重力岩心的痕迹本身和直接周围物质进行了AMS-14C测年。结果表明，沉积速率为10-20cmka−1，年龄伪造为1110-2525年。由于植生虫的洞穴在新鲜岩心中通常很差或根本不可见，因此所有植生虫的观察都是在x射线照片上进行的。为了避免这类测年错误，强烈建议在进行次抽样之前进行x射线检查。
Bioturbation in oxic deep-sea settings is often considered (if considered at all) to consist of a 2–10cm 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 difficult to discern in unlithified 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-14C dating of the trace itself and of directly surrounding material in two gravity cores from the Portuguese continental slope. The results show an age falsification of 1110–2525 years at sedimentation rates of 10–20cmka−1. 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.