Continental flood basalts of the world are represented either by picrobasalt/picrite layers (with abundant growth of olivine) or by (almost) olivine-depleted tholeiite basalts. We have taken a case study from the olivine-depleted basaltic rocks from Khandwa (21°49'N: 76°21'E) Eastern Deccan Volcanic Province. Our research shows that recent cooling experiments (available in the literature) involving a dry basalt and construction of some selected binary major element variation diagrams (entailing lever rules) can explain (and quantify) the insignificant level (${\sim}$2–4%) of olivine crystallization (${\sim}$olivine decadence) in tholeiite basalts. Such decadent olivine retains a skeletal crystallographically-oriented geometry. We contemplate that our simplistic model of olivine decadence can be extended to other flood basalt provinces of the world as well.

$\bf{Highlights}$

$\bullet$ First-time cogent model of olivine decadence in Deccan basalts

$\bullet$ Integration of newly obtained experimental data and binary variation diagrams

$\bullet$ Petrographic support validates the model

$\bullet$ Model can be extended to other continental Flood basalts