oceanic crust composed of primarily more felsic rocks makes up the surface of the earth.
oceanic crust composed of primarily more felsic rocks makes up the surface of the earth.
what type of crust composed of primarily more felsic rocks makes up the surface of the earth?
oceanic
the crust lies on top of the mantle, a configuration that is stable because the upper mantle is made of peridotite and so is significantly denser than the crust. the boundary between the crust and mantle is conventionally placed at the mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. 









































the crust of the earth is of two distinctive types: 









































bullet::::1. oceanic: to thick and composed primarily of denser, more mafic rocks, such as basalt, diabase, and gabbro.









































bullet::::2. continental: to thick and mostly composed of less dense, more felsic rocks, such as granite.
crust (geology)
the hooggenoeg formation felsic rocks can be divided into two groups: an intrusive group of interlocking and shallow intrusive rocks, and a porphyritic group of rocks from the veins. lavas from the upper part of the felsic unit are too altered to be assigned to one of these groups. the intrusive group is related to the tonalite-trondhjemite-granodiorite ttg-suite stolzburg pluton, which intruded along the southern margin of the barberton greenstone belt. melting of an amphibolite quartz eclogite has been suggested as a probable origin for these high-alo felsic magmas. ultramafic rocks of the hooggenoeg formation were most likely not parental for the felsic rocks. subduction processes may have played a role in the generation of the felsic rocks, but a tectonic setting for the ultramafic rocks remains uncertain. the felsic units of the hooggenoeg formation are very similar to those of the panorama formation of the early archaean coppin gap greenstone belt of western australia (see yilgarn craton). similarities in geological setting, petrography, and geochemical (trace element in particular) characteristics suggest a possible genetic relation between the two formations and support the theory that a combined continent vaalbara existed ~3.45 ga.
barberton greenstone belt