ultrabasic

adj, noun — 2 senses

adj

Etymology From ultra- + basic.

Geography, Geology, Natural sciences ultramafic

In the process of basification, the top layer of the crust becomes basic, while the lower becomes ultrabasic acquiring the density of the mantle or an even greater density1980, A. W. Bally, Dynamics of Plate Interiors, →ISBN, page 49:

noun

Etymology From ultra- + basic.

Geography, Geology, Natural sciences ultramafic

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.