Noun. 1. heat sink-a metal conductor specially designed to conduct (and radiate) heat. conductor-a device designed to transmit electricity, heat, etc. sink - (technology) a process that acts to absorb or remove energy or a substance from a system; the ocean is a sink for carbon dioxide.
The crust is composed of many different types of rocks that fall within three main categories: igneous, metamorphic and sedimentary. However, most of those rocks originated as either granite or basalt. The mantle beneath is made of peridotite. Bridgmanite, the most common mineral on Earth, is found in the deep mantle. How We Know the Earth Has a Crust
The continental crust is made mostly of rocks with a composition similar to granite (a light-colored rock you would expect to find in the Sierra Nevada), whereas the oceanic crust is made mostly of rocks with a composition of basalt (a dark-colored rock, like the rocks that make up the Hawaiian volcanoes).oth oceanic crust and continental crust are less dense than the mantle, but oceanic crust is denser than continental crust. This is partly why the continents are at a higher elevation than the ocean floor.