The low mantle to study

2004/05/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia

The metallic core of the Earth is believed to be surrounded by a silicate mantle, but the characteristics of the boundary between the two and the lower mantle are not well known.

Given the impossibility of obtaining samples from there, seismic velocity and density maps have been used to obtain information. However, they cannot explain some of the structures that have been deducted through it. This is the case, for example, of the seismic discontinuity D, located 200 km from the limit between the mantle and the nucleus.

The analysis of magnesium silicate has allowed to obtain new information in this regard. This silicate is one of the main supposed components of the lower mantle. According to tests done in the laboratory, it suffers a phase change in the pressure and temperature of the cutting zone D, which causes the interruption.