21. Among the different kinds of flood basalt, the SiO, content is highest in: AContinental tholeiites B. Oceanic tholeiites C. Alkaline olivine basalts D) Spilites (AMU-2015)
I think it should be A.
Continental tholeiites consist majorly of SiO2, K2O and are more evolved as compared to the one that belong to oceanic tholeiites.
Alkali Olivine Basalt, ...