The subdivision of geologic time based on one of several different criteria. Timescales related to the rate of sedimentation (see subsidence), the rate of sea-floor spreading, and radiometric dating are used. See appendix b: time scales.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。