ultramafic

American  

[uhl-truh-maf-ik] / ˌʌl trəˈmæf ɪk /

adjective

Geology.

1. ultrabasic.

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ultramafic Scientific  

/ ŭl′trə-măf′ĭk /

1. Containing mainly mafic minerals. Used of igneous rocks and often used interchangeably with ultrabasic. Dunite is an ultramafic rock.

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Etymology

Origin of ultramafic

First recorded in 1940–45; ultra- + mafic

Example Sentences

On the figure above, the top row has both plutonic and volcanic igneous rocks arranged in a continuous spectrum from felsic on the left to intermediate, mafic, and ultramafic toward the right.

From Textbooks • Jan. 1, 2017

This differentiated the Earth from a homogenous planet into a heterogeneous one with layers of felsic crust, mafic crust, ultramafic mantle, and iron and nickel core.

From Textbooks • Jan. 1, 2017

The down-pointing arrow on the far right shows increasing amounts of silica, sodium, aluminum, and potassium as the mineral composition goes from ultramafic to felsic.

From Textbooks • Jan. 1, 2017

In the figure, the righthand column lists the four groups of igneous rock from top to bottom: ultramafic, mafic, intermediate, and felsic.

From Textbooks • Jan. 1, 2017

Magmas range in composition from ultramafic to felsic.

From Textbooks • Jan. 1, 2015