basement complex

American  

noun

Geology.

1. the undifferentiated assemblage of rock basementrock underlying the oldest stratified rocks in any region: usually crystalline, metamorphosed, and mostly, but not necessarily, Precambrian in age.

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Etymology

Origin of basement complex

First recorded in 1895–1900

Example Sentences

“This special resource originates from deep within the earth in the Placerita Schist basement complex of rocks.”

From Los Angeles Times • Feb. 4, 2026

Williams wants to put in a basement complex which will come perilously close to Tower House.

From The Guardian • Jul. 8, 2018

We speak of them as a geologist speaks of his "basement complex."

From Socialism and Democracy in Europe by Orth, Samuel P.

Erosion has laid bare portions of the earth's crust which were once deeply buried, and reveals the character of the "basement complex," as it has been termed, which forms the foundation of the continent.

From North America by Russell, Israel C. (Cook)