Medical Definition of amnesia. 1: loss of memory sometimes including the memory of personal identity due to brain injury, shock, fatigue, repression, or illness or sometimes induced by anesthesia a period of amnesia after the wreck.
Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call mud. This composition places shale in a category of sedimentary rocks known as mudstones.
Underground, they are formed when magma deep within the Earth becomes trapped in small pockets. As these pockets of magma cool slowly they become igneous rocks. Igneous rocks are also formed when volcanoes erupt. Igneous rocks are formed as the lava cools above ground.The upper 16 km of the Earthâs crust is composed of 95% igneous rock. Intrusive igneous rocks are formed from magma that cools and solidifies underground.These rocks are coarse grained.xtrusive igneous rocks are formed at the crustâs surface as a result of the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks and are fine grained.