Growth ages of ferromanganese crusts from the western and central Pacific:Comparison between nannofo

• 作 者: M. Hiroyuki
• 机 构: Micro Analysis Laboratory Tandem Accelerator University of Tokyo Tokyo 113-0032 Japan,
• 出 处: Chinese Science Bulletin
• 发表日期: 2006年24期
• 关键词: dating Be dating crust Miocene isotope have geologic specimen younger thick

Based on results of nannofossil analysis and 10Be dating in ferromanganese crusts M1-1 and A1-1 (no nannofossils were found in it),from the western and central Pacific respectively,it is found that the crust growth ages from nannofossil biostrati-graphy agree well with those based on 10Be isotope analysis. Both crusts have three growth layers,and the oldest layer was deposited in Miocene at about 12.80 Ma. The maximum,minimum,and average growth rates of crust A1-1 (from the central Pacific) are 8.11,1.92 and 3.47 mm/Ma,and those of crust M1-1 (from the western Pacific) are 2.93,0.47,and 0.94 mm/Ma.

Based on results of nanofossil analysis and 10Be dating in ferromanganese crusts M1-1 and A1-1 (no nannofossils were found in it), from the western and central Pacific respectively, it is found that the crust growth ages from nannofossil biostrati-graphy agree Both with crusts having three growth layers, and the oldest layer was deposited in Miocene at about 12.80 Ma. The maximum, minimum, and average growth rates of crust A1-1 (from the central Pacific) are 8.11, 1.92 and 3.47 mm / Ma, and those of crust M1-1 (from the western Pacific) are 2.93, 0.47, and 0.94 mm / Ma.