Recent data have documented the importance of Si, Na, K, O, and H derived from the lower layers of the mantle, along Benioff zones. In the Tethys and circum-Pacific volcanic zones, continental layers have formed from the generation of juvenile granite and eruptions of intermediate and acidic lava. Numerous data contradict the contention that andesitic and rhyolitic magma are differentiates of basaltic magma; the downsliding and assimilation of basaltic oceanic crust do not account for the bulk of the continental granitic and andesitic crust. Lighter materials have ascended from the deep layers of the mantle, and these compose the main masses of continental crust.

First Page Preview

First page PDF preview
You do not currently have access to this article.