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
There are two types of crust: continental and oceanic. Continental crust is the crust under which the continents are built and is 10-70 km thick, while oceanic crust is the crust under the oceans, and is only 5-7 km thick. The deepest mine shaft ever built (Western Deep in South Africa) currently reaches 3.9 km, which is tiny compared to the continental crust.