NMDA reÂ·cepÂ·tor. a type of glutamate receptor that participates in excitatory neurotransmission and also binds N-methyl-d -aspartate; may be particularly involved in the cell damage observed in individuals with Huntington disease.
â Ultramafic magma is extremely low in silica, with less than 45 percent of the same, but rich in heavier elements like iron and magnesium. It can have a temperature of about 2732 Â°F. It has very low viscosity and thus, its eruptive behavior is gentle.
Making the crust. Mantle material, usually made of a dark heavy rock called peridotite, is odd stuff. Whenever Iâve seen it on the surface it always looks out of place somehow, too homogeneous, too brown, too massive. Yet it forms over 80% of the earthâs volume â excepting the metallic core it is what earth is made of.