What is another word for lower mantle?
Pronunciation: [lˈə͡ʊə mˈantə͡l] (IPA) 
The lower mantle is a crucial layer of the Earth's interior, situated beneath the upper mantle and above the core. It is a region where temperatures can reach up to 4000 degrees Celsius and pressures can be as high as 1.3 million atmospheres. There are a number of synonyms used to describe this layer of the Earth, including the interior mantle, the mesosphere, the mesostasis, and the ultramafic mantle. Other terms used to describe the lower mantle include the transition zone, the D" layer, and the core-mantle boundary. Regardless of the terminology used, the lower mantle plays a critical role in maintaining the structure and function of the Earth.
