Measurement of I in ferromanganese crust with AMS.

In the present study, the analytical method for iodine (I) in ferromanganese crusts is developed and iodine/iodine (I/I) ratio in ferromanganese crusts is measured by the accelerator mass spectrometry (AMS). The developed method is applied to analyze I/I ratio in two ferromanganese crusts MP5D44 and CXD08-1 collected from the Mid-Pacific Ocean. The results show that I/I ratio in MP5D44 and CXD08-1 crusts varies from 7×10 to 1.27×10, with the lowest value falling on the detection limit level of AMS reported by previous literatures. For the depth distribution of I/I, it is found that both MP5D44 and CXD08-1 crusts have two growth generations, and the I/I profiles in two generations all displayed an approximate exponential decay. According to the I/I ratio, the generate age of bottom layer of MP5D44 and CXD08-1 was estimated to be 54.77 and 69.69 Ma, respectively. [ABSTRACT FROM AUTHOR]