- 责任者：Zhang Youlian (Seismological Press ; Beijing 100081 ; China) ; Du Jianguo
- 刊名：Advances in Earth Science
- 出版年：2011
- 卷期：26(4)
- 关键词：地核 ; core
- 页码：p.365-374
- 图表：3 illus., 63 refs.
- 分类号：0400
- issnNo：ISSN1001-8166
- isbnNo：CN62-1091/P
The age, physical properties and chemical compositions of the Earth’s core are reviewed. The formation time of the core and mantle is determined by W-Hf isotope dating to be 30 Ma at the beginning of the earth formation. However, the time of the inner core crystallization from the liquid core remains an open question. The inner core is anisotropic in elastic wave velocity, which is considered as a result of the c axis of hcp-structure iron arranged predominantly along the Earth′s pole axis. The density difference of the core between the PREM model and liquid iron at the core temperature and pressure is about 10%, which indicates that the core contains light elements, such as C, S, P, Si, O, H, Mg, etc. The light elements in the core may play an important role in the formation of D″ layer between the core and mantle, formation and evolution of the plume and activities of volcano and earthquake, which is the new field for us to investigate.