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  • Author or Editor: R. McNeely x
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Abstract  

Low-energy -ray spectrometry is used to detect fallout155Eu and207Bi in a210Pb-dated sediment core from McKay Lake, Ottawa, Canada. Unlike207Bi which is detected only in two core sections deposited in the mid 1970's,155Eu is consistently detectable to mid 1960's. A comparison of corresponding137Cs and155Eu inventories in the sediment core indicates that fallout155Eu derives primarily from the thermal neutron fission of235U. The derived flux of unsupported210Pb at the sediment/water interface is in agreement with previously estimated flux of atmospheric210Pb in the Great Lakes region.

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Abstract  

Lead-210 dates are assigned to a sediment core retrieved from McKay Lake, Ottawa, Canada. Sediment mixing is found to have little, but discernible, influence on the age/depth profile. Consideration of mixing yields lower estimates of the derived ages, in agreement with the prediction based on a mathematical model. The inferred dates support the previous assignments based on Ambrosia horizon and the known occurrence of a catastrophic event. The procedures used in the calculation of the age profiles are fully described.

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