The first level is designed to block large contaminants such as debris , fish and sediments .
第一层被设计用于滤除较大的污染物,诸如垃圾残骸,鱼以及沉淀物。
And at this point traces of industrialization can only be found in sediments in europe .
而在这一点上,工业化的痕迹只在欧洲的沉积物中找到。
Having shown that climatic or environmental events were improbable explanations , ms hellawell and her colleagues started analysing the sediments in more detail .
已经表明了气候和环境的事件不可能解释这起事件,赫拉维尔女士和她的同事开始更加细致的分析沉淀物。
The fossils were found in a seam of limestone that was 50 feet thick and was created when ocean sediments solidified millions of years ago .
化石是在50英尺深的石灰岩层里,它形成在大约百万年前由于海水泥沙沉淀物的堆积硬化。
The deepest sediments were laid down in the distant past , while more recent sediments were nearer the surface .
最深处的沉积物来自最遥远的过去,而表层的沉积物来自较近的时代。
They are well preserved , and encased in sediments that allow uncommonly precise dating .
这些化石保存完好,被封存在可进行精确年代测定的沉积物中,这实属罕见。
Dr field 's team set about the task by analysing ancient records of birch pollen preserved in lake sediments from known mammoth breeding grounds like siberia .