Description and chemical composition of ferromanganese nodules from Station 123, Oneida Lake, New York

226Ra is used to document the growth histories of six manganese nodules from Oneida Lake, New York. Detailed sectioning and analysis reveal that there are discontinuous gradients in 226Ra content in these samples. These gradients result from periods of rapid growth (>1 mm/100 years) separated by periods of no growth of erosion. Although the 226Ra 'age' of the nodules approximates the age of Oneida Lake, the nodules are not sediment-covered because they occur only in areas of the lake where fine-grained sediments are not accumulating.

本研究采用镭-226（²²⁶Ra）示踪纽约州奥奈达湖（Oneida Lake）中6个锰结核（manganese nodules）的生长历史。通过精细切片与分析发现，这些样品中的镭-226含量存在不连续梯度。此类梯度源于锰结核的快速生长阶段（生长速率大于1毫米/百年）与无生长或侵蚀阶段交替出现。尽管锰结核的镭-226“年龄”与奥奈达湖的形成年代近似，但这些锰结核并未被沉积物覆盖，这是因为它们仅分布于湖内细粒沉积物未发生沉积的区域。