At https://www.livescience.com/planet-earth/volcanos/mysterious-blobs-in-earths-mantle-are-not-what-we-thought-study-claims …. not everyone was too pleased with the idea of blobs of unknown material residing in Earth’s Mantle, in order to explain problems at the surface. Matthiys Smit, an earth scientist in British Columbia, has said lava erupting from hot spots on the surface seem similar to magma upwelling everywhere else. Structures observed in the deep Mantle, by seismic waves, may not be evidence of different types of rock density but of temperature differences. Smit adds, we are finally liberated from this idea that there are unmixed pockets inside the Mantle that have sat there since the Earth came into being. Such ideas come and go we may note but as nobody can actually peer inside the Mantle the next research paper may disagree.
Smit’s findings may not please other committed earth scientists – who will stick rigidly to the blob theory. Will it make a difference to Plate Tectonics? After all, as a result of subduction, plates are said to slide beneath other plates, creating mountain chains. Those subducting plates end up in the Mantle – but do they form blobs?