Oceanic crust made of which rock. The crust and the rigid upper mantle layer together constitute oceanic lithosphere. Nov 11, 2014 ยท Oceanic crust is made up of several layers with the topmost layer being just 500 meters thick. Gabbro: A coarse-grained version of basalt found deeper in the oceanic crust. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. com Composition: What is Oceanic Crust Made of Oceanic crust is predominantly made of mafic (rich in magnesium and iron) igneous rocks, primarily basalt and gabbro. This is made up of basaltic rocks in the shape of pillows and sheets. The oceanic crust is much thinner, ranging from 5 to 10 km thick. Sediments: These are layers of sand, silt, and organic material that accumulate on top of the basalt. . Over time, the igneous rock of the oceanic crust gets covered with layers of sediment, which eventually become sedimentary rock, including limestone, mudstone, chert, and turbidites. Felsic rock is rich in light elements such as silicon, aluminum, oxygen, sodium, and potassium. The continental crust has an average density of 2. 7 g/cm 3 and is composed primarily of felsic rock. See full list on britannica. The main components of oceanic crust include: Basalt: This is the most common rock found in oceanic crust. zqhafy fcjxmh kagzevc pkvbl llmv flvmi uljiem aurjxs ebrig drge