Physical and chemical structure of freshwater ferromanganese nodules

研究将集中在淡水锰铁结核上，这种结核可以在加拿大的许多湖泊中找到。这些结核出现在湖泊的沉积物上，由于铁和锰氧化物层的不断积累，它们在数百年到数千年的时间里缓慢生长。放射性年代测定法表明，一些结核可能和它们生长的湖泊一样古老——在某些情况下甚至有1万年的历史。它们似乎以一种大致同心的方式围绕着一个鹅卵石核生长，并且，类似于树干上的年轮，它们可能包含了全新世大部分时间（过去12000年）的水化学和气候条件的时间序列记录。这项研究计划的目的是发展测量化学和同位素组成剖面的方法，以便提供水化学和气候条件的历史记录。

The research will focus on freshwater ferromanganese nodules which can be found in many lakes throughout Canada. These nodules occur on the sediment in the lake and grow slowly over hundreds to thousands of years by the continuous accumulation of iron- and manganese-oxide layers. Radiometric age dating indicates that some nodules may be as old as the lakes in which they grow - in some cases up to 10,000 years old. They appear to grow in a roughly concentric manner around a pebble nucleus, and, similar to growth rings in a tree trunk, they could contain a time series record of aquatic-chemical and climate conditions over much of the Holocene (the past 12,000 years). The objective of this research proposal is to develop methods to measure chemical and isotopic composition profiles in order to provide a historical record of aquatic-chemical and climate conditions.