Oceanic crust Oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust overlies the solidified and uppermost layer of the mantle. The crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however it is denser,
The Public and its Problems what he saw as argumentation on the part of Lippman that was particularly doctrinaire and absolutist in its judgements, and saw his own philosophical pragmatism as a means by which a more accurate and realistic conception of what the public and democracy was capable of it, and its limitations. Dewey begins his argument by distinguishing between the "state," represented by elected lawmakers, and the "public," the diffuse, often incoherent body of citizens who elect the state. The public is called into being when ordinary citizens experience the negative externalities (or consequences) of exchanges beyond their control (such as market or