[ lə-īt′ ]

  1. Any of a series of igneous rocks that are similar in composition to basalt, but are richer in silica and iron and poorer in aluminum than basalt is. Tholeiites form especially at mid-ocean ridges and in continental rift areas.

Words Nearby tholeiite

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.