Physical and chemical structure of freshwater ferromanganese nodules

这项研究将侧重于在加拿大许多湖泊中发现的淡水铁锰结核。 这些结核出现在湖中的沉积物上，通过铁和锰氧化物层的不断积累，在数百至数千年的时间里缓慢生长。 放射性测年法表明，有些结核的年龄可能与它们生长的湖泊一样古老，有些情况下甚至可达10 000年。 它们似乎以大致同心的方式围绕卵石核生长，并且，类似于树干上的年轮，它们可能包含全新世大部分时间（过去12，000年）的水生化学和气候条件的时间序列记录。 这项研究提案的目的是制定测量化学和同位素组成概况的方法，以便提供水生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.