Late Archaean granites of the southeastern Yilgarn Block, Western Australia; age, geochemistry, and origin

New geochemical data for granitic rocks of this area further document the overall compositional heterogeneity of the late Archaean magmatism of this region. However, much of the data comes from rock types representing an insignificant area of outcrop as shown by published studies on the average composition of Yilgarn crust. The dominant rock type of the S Yilgarn appears to be the coarse-grained 2660-2665 m.y. monzogranite characterized by negative Sr and Eu anomalies and a REE pattern with a steep slope. Other important rock types are equigranular and porphyritic granodiorites, tonalites and more fractionated rocks apparently derived from an original tonalitic parent. A mantle plume model developed for the origin of the crust-derived rocks that form an important part of the late Archaean thermal and structural reworking of the Yilgarn craton mass have applications to other areas of areally extensive intraplate magmatism.