Ionium-Thorium Chronology of Deep-Sea Sediments of the Western North Pacific Ocean
Yasuo Miyake 1 and
Yukio Sugimura 1
1 Geochemical Laboratory, Meteorological Research Institute, Suginami, Tokyo, Japan
The rate of deposition of deep-sea deposits collected at the depths of 6215 to 8450 m in the western part of the North Pacific Ocean was estimated by means of the ionium/thorium ratio. The ratio was determined by an alpha-ray spectrometer. Results showed the rate of 0.5 to 0.8 mm/103 yr for the upper 10-cm layer below the sea bottom.