Definition of complex

i. A large-scale field association or assemblage of different rocks of any age or origin, having structural relations so intricately involved or otherwise complicated that the rocks cannot be readily differentiated in mapping, e.g., a volcanic complex.

See Also: igneous complex, basement complex

Ref: AGI

ii. A unit that consists of a mixture of rocks of two or more genetic classes, i.e., igneous, sedimentary, or metamorphic, with or without highly complicated structure; example: Franciscan Complex.

Ref: AGI

iii. Said of an ore that carries several metals difficult to extract.

Ref: von Bernewitz

iv. An assemblage of rocks of any age or origin that has been folded together, intricately mixed, involved, or otherwise complicated.

Ref: Stokes