The heavier silicates named as ‘Sima’ or silica + magnesium are most abundant in the????????????????

Question

The heavier silicates named as ‘Sima’ or silica + magnesium are most abundant in the????????????????

Continental drift: An idea
before its time
Continental drift hypothesis
• Continents quot;driftedquot; to present positions Evidence used in support of continental drift hypothesis
• Fit of…
Science