A South African stage of the Upper Archaean, from about 3000–2500 Ma ago, preceded by the Swazian and followed by the Vaalian, that includes the Ventersdorp, Witwatersrand, and Dominion Reef sequences.
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。