Hydrocarbon induced changes of magnetic properties in soil

点击翻译按钮获取中文摘要

It is widely accepted that magnetic proxy measurements can serve as a fast and efficient tool for screening anthropogenic heavy metal accumulation in soils and sediments. There is also some indication that the input of hydrocarbons into soils lead to a change of soil magnetic properties. Within this proposal we want to study the relationship between magnetic properties of soil and the presence organic compounds at the former oil field Wietze in northern Germany. Oil was penetrating there into soil and people exploited these resources in surficial oil pits already since -400 years. Hydrocarbon concentration is still severe at several places and clearly dominates other effects, therefore providing an ideal test site to identify the role of input of organic compounds on the soil magnetic properties. The present study will include quantification of magnetic properties in respect to oil concentration and chemistry, history of exploitation, soil characteristics and, very important, geomicrobiological processes involving microbially catalyzed redox transformation of iron minerals that lead to changes in the magnetic mineralogy of soil. Results will be relevant for both using magnetic proxies (1) to qualitatively or semiquantitatively delineate organic contamination of soil and (2) to contribute to the development of a supplementary tool for hydrocarbon exploration/exploitation.