Details

Autor(en) / Beteiligte

• Wood, Bernard J
• Wade, Jonathan
• Walter, Michael J

Titel

Accretion of the Earth and segregation of its core

Ist Teil von

• Nature, 2006-06, Vol.441 (7095), p.825-833

Ort / Verlag

London: Nature Publishing

Erscheinungsjahr

2006

Quelle

EBSCOhost Psychology and Behavioral Sciences Collection

Beschreibungen/Notizen

• The Earth took 30-40 million years to accrete from smaller 'planetesimals'. Many of these planetesimals had metallic iron cores and during growth of the Earth this metal re-equilibrated with the Earth's silicate mantle, extracting siderophile ('iron-loving') elements into the Earth's iron-rich core. The current composition of the mantle indicates that much of the re-equilibration took place in a deep (> 400 km) molten silicate layer, or 'magma ocean', and that conditions became more oxidizing with time as the Earth grew. The high-pressure nature of the core-forming process led to the Earth's core being richer in low-atomic-number elements, notably silicon and possibly oxygen, than the cores of the smaller planetesimal building blocks.