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.
The answer to how are igneous rocks formed is pretty straight forward: Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when magma deep within the Earth becomes trapped in small pockets.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.