first, i apologize for not copying any of these articles but they are copyrighted
however
very very interesting about the core and mantle of this planet
if you are interested at all
here is the first one that caught my eye
Earth's Core Blobs: Chemical Interaction May Shed Light On Composition Of Other Planets
http://www.huffingtonpost.com/2012/12/15/earths-core-blobs-geology-iron_n_2302878.html?utm_hp_ref=science
and here is the link to the reason for the first article
Deep penetration of molten iron into the mantle caused by a morphological instability
http://www.nature.com/nature/journal/v492/n7428/full/nature11663.html
en~joy :)